/*------------------------------------------------------------------------- * * tablecmds.c * Commands for creating and altering table structures and settings * * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.222 2007/05/12 00:54:59 tgl Exp $ * *------------------------------------------------------------------------- */ #include "postgres.h" #include "access/genam.h" #include "access/heapam.h" #include "access/reloptions.h" #include "access/xact.h" #include "catalog/catalog.h" #include "catalog/dependency.h" #include "catalog/heap.h" #include "catalog/index.h" #include "catalog/indexing.h" #include "catalog/namespace.h" #include "catalog/pg_constraint.h" #include "catalog/pg_depend.h" #include "catalog/pg_inherits.h" #include "catalog/pg_namespace.h" #include "catalog/pg_opclass.h" #include "catalog/pg_trigger.h" #include "catalog/pg_type.h" #include "catalog/toasting.h" #include "commands/cluster.h" #include "commands/defrem.h" #include "commands/tablecmds.h" #include "commands/tablespace.h" #include "commands/trigger.h" #include "commands/typecmds.h" #include "executor/executor.h" #include "miscadmin.h" #include "nodes/makefuncs.h" #include "optimizer/clauses.h" #include "optimizer/plancat.h" #include "optimizer/prep.h" #include "parser/analyze.h" #include "parser/gramparse.h" #include "parser/parse_clause.h" #include "parser/parse_coerce.h" #include "parser/parse_expr.h" #include "parser/parse_oper.h" #include "parser/parse_relation.h" #include "parser/parse_type.h" #include "parser/parser.h" #include "rewrite/rewriteDefine.h" #include "rewrite/rewriteHandler.h" #include "storage/smgr.h" #include "utils/acl.h" #include "utils/builtins.h" #include "utils/fmgroids.h" #include "utils/inval.h" #include "utils/lsyscache.h" #include "utils/memutils.h" #include "utils/relcache.h" #include "utils/syscache.h" /* * ON COMMIT action list */ typedef struct OnCommitItem { Oid relid; /* relid of relation */ OnCommitAction oncommit; /* what to do at end of xact */ /* * If this entry was created during the current transaction, * creating_subid is the ID of the creating subxact; if created in a prior * transaction, creating_subid is zero. If deleted during the current * transaction, deleting_subid is the ID of the deleting subxact; if no * deletion request is pending, deleting_subid is zero. */ SubTransactionId creating_subid; SubTransactionId deleting_subid; } OnCommitItem; static List *on_commits = NIL; /* * State information for ALTER TABLE * * The pending-work queue for an ALTER TABLE is a List of AlteredTableInfo * structs, one for each table modified by the operation (the named table * plus any child tables that are affected). We save lists of subcommands * to apply to this table (possibly modified by parse transformation steps); * these lists will be executed in Phase 2. If a Phase 3 step is needed, * necessary information is stored in the constraints and newvals lists. * * Phase 2 is divided into multiple passes; subcommands are executed in * a pass determined by subcommand type. */ #define AT_PASS_DROP 0 /* DROP (all flavors) */ #define AT_PASS_ALTER_TYPE 1 /* ALTER COLUMN TYPE */ #define AT_PASS_OLD_INDEX 2 /* re-add existing indexes */ #define AT_PASS_OLD_CONSTR 3 /* re-add existing constraints */ #define AT_PASS_COL_ATTRS 4 /* set other column attributes */ /* We could support a RENAME COLUMN pass here, but not currently used */ #define AT_PASS_ADD_COL 5 /* ADD COLUMN */ #define AT_PASS_ADD_INDEX 6 /* ADD indexes */ #define AT_PASS_ADD_CONSTR 7 /* ADD constraints, defaults */ #define AT_PASS_MISC 8 /* other stuff */ #define AT_NUM_PASSES 9 typedef struct AlteredTableInfo { /* Information saved before any work commences: */ Oid relid; /* Relation to work on */ char relkind; /* Its relkind */ TupleDesc oldDesc; /* Pre-modification tuple descriptor */ /* Information saved by Phase 1 for Phase 2: */ List *subcmds[AT_NUM_PASSES]; /* Lists of AlterTableCmd */ /* Information saved by Phases 1/2 for Phase 3: */ List *constraints; /* List of NewConstraint */ List *newvals; /* List of NewColumnValue */ bool new_notnull; /* T if we added new NOT NULL constraints */ Oid newTableSpace; /* new tablespace; 0 means no change */ /* Objects to rebuild after completing ALTER TYPE operations */ List *changedConstraintOids; /* OIDs of constraints to rebuild */ List *changedConstraintDefs; /* string definitions of same */ List *changedIndexOids; /* OIDs of indexes to rebuild */ List *changedIndexDefs; /* string definitions of same */ } AlteredTableInfo; /* Struct describing one new constraint to check in Phase 3 scan */ /* Note: new NOT NULL constraints are handled elsewhere */ typedef struct NewConstraint { char *name; /* Constraint name, or NULL if none */ ConstrType contype; /* CHECK or FOREIGN */ Oid refrelid; /* PK rel, if FOREIGN */ Oid conid; /* OID of pg_constraint entry, if FOREIGN */ Node *qual; /* Check expr or FkConstraint struct */ List *qualstate; /* Execution state for CHECK */ } NewConstraint; /* * Struct describing one new column value that needs to be computed during * Phase 3 copy (this could be either a new column with a non-null default, or * a column that we're changing the type of). Columns without such an entry * are just copied from the old table during ATRewriteTable. Note that the * expr is an expression over *old* table values. */ typedef struct NewColumnValue { AttrNumber attnum; /* which column */ Expr *expr; /* expression to compute */ ExprState *exprstate; /* execution state */ } NewColumnValue; static void truncate_check_rel(Relation rel); static List *MergeAttributes(List *schema, List *supers, bool istemp, List **supOids, List **supconstr, int *supOidCount); static void MergeConstraintsIntoExisting(Relation child_rel, Relation parent_rel); static void MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel); static void add_nonduplicate_constraint(Constraint *cdef, ConstrCheck *check, int *ncheck); static bool change_varattnos_walker(Node *node, const AttrNumber *newattno); static void StoreCatalogInheritance(Oid relationId, List *supers); static void StoreCatalogInheritance1(Oid relationId, Oid parentOid, int16 seqNumber, Relation inhRelation); static int findAttrByName(const char *attributeName, List *schema); static void setRelhassubclassInRelation(Oid relationId, bool relhassubclass); static void AlterIndexNamespaces(Relation classRel, Relation rel, Oid oldNspOid, Oid newNspOid); static void AlterSeqNamespaces(Relation classRel, Relation rel, Oid oldNspOid, Oid newNspOid, const char *newNspName); static int transformColumnNameList(Oid relId, List *colList, int16 *attnums, Oid *atttypids); static int transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid, List **attnamelist, int16 *attnums, Oid *atttypids, Oid *opclasses); static Oid transformFkeyCheckAttrs(Relation pkrel, int numattrs, int16 *attnums, Oid *opclasses); static void validateForeignKeyConstraint(FkConstraint *fkconstraint, Relation rel, Relation pkrel, Oid constraintOid); static void createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint, Oid constraintOid); static void ATController(Relation rel, List *cmds, bool recurse); static void ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd, bool recurse, bool recursing); static void ATRewriteCatalogs(List **wqueue); static void ATExecCmd(AlteredTableInfo *tab, Relation rel, AlterTableCmd *cmd); static void ATRewriteTables(List **wqueue); static void ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap); static AlteredTableInfo *ATGetQueueEntry(List **wqueue, Relation rel); static void ATSimplePermissions(Relation rel, bool allowView); static void ATSimplePermissionsRelationOrIndex(Relation rel); static void ATSimpleRecursion(List **wqueue, Relation rel, AlterTableCmd *cmd, bool recurse); static void ATOneLevelRecursion(List **wqueue, Relation rel, AlterTableCmd *cmd); static void ATPrepAddColumn(List **wqueue, Relation rel, bool recurse, AlterTableCmd *cmd); static void ATExecAddColumn(AlteredTableInfo *tab, Relation rel, ColumnDef *colDef); static void add_column_datatype_dependency(Oid relid, int32 attnum, Oid typid); static void ATExecDropNotNull(Relation rel, const char *colName); static void ATExecSetNotNull(AlteredTableInfo *tab, Relation rel, const char *colName); static void ATExecColumnDefault(Relation rel, const char *colName, Node *newDefault); static void ATPrepSetStatistics(Relation rel, const char *colName, Node *flagValue); static void ATExecSetStatistics(Relation rel, const char *colName, Node *newValue); static void ATExecSetStorage(Relation rel, const char *colName, Node *newValue); static void ATExecDropColumn(Relation rel, const char *colName, DropBehavior behavior, bool recurse, bool recursing); static void ATExecAddIndex(AlteredTableInfo *tab, Relation rel, IndexStmt *stmt, bool is_rebuild); static void ATExecAddConstraint(AlteredTableInfo *tab, Relation rel, Node *newConstraint); static void ATAddForeignKeyConstraint(AlteredTableInfo *tab, Relation rel, FkConstraint *fkconstraint); static void ATPrepDropConstraint(List **wqueue, Relation rel, bool recurse, AlterTableCmd *cmd); static void ATExecDropConstraint(Relation rel, const char *constrName, DropBehavior behavior, bool quiet); static void ATPrepAlterColumnType(List **wqueue, AlteredTableInfo *tab, Relation rel, bool recurse, bool recursing, AlterTableCmd *cmd); static void ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel, const char *colName, TypeName *typename); static void ATPostAlterTypeCleanup(List **wqueue, AlteredTableInfo *tab); static void ATPostAlterTypeParse(char *cmd, List **wqueue); static void change_owner_recurse_to_sequences(Oid relationOid, Oid newOwnerId); static void ATExecClusterOn(Relation rel, const char *indexName); static void ATExecDropCluster(Relation rel); static void ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel, char *tablespacename); static void ATExecSetTableSpace(Oid tableOid, Oid newTableSpace); static void ATExecSetRelOptions(Relation rel, List *defList, bool isReset); static void ATExecEnableDisableTrigger(Relation rel, char *trigname, char fires_when, bool skip_system); static void ATExecEnableDisableRule(Relation rel, char *rulename, char fires_when); static void ATExecAddInherit(Relation rel, RangeVar *parent); static void ATExecDropInherit(Relation rel, RangeVar *parent); static void copy_relation_data(Relation rel, SMgrRelation dst); /* ---------------------------------------------------------------- * DefineRelation * Creates a new relation. * * If successful, returns the OID of the new relation. * ---------------------------------------------------------------- */ Oid DefineRelation(CreateStmt *stmt, char relkind) { char relname[NAMEDATALEN]; Oid namespaceId; List *schema = stmt->tableElts; Oid relationId; Oid tablespaceId; Relation rel; TupleDesc descriptor; List *inheritOids; List *old_constraints; bool localHasOids; int parentOidCount; List *rawDefaults; Datum reloptions; ListCell *listptr; AttrNumber attnum; /* * Truncate relname to appropriate length (probably a waste of time, as * parser should have done this already). */ StrNCpy(relname, stmt->relation->relname, NAMEDATALEN); /* * Check consistency of arguments */ if (stmt->oncommit != ONCOMMIT_NOOP && !stmt->relation->istemp) ereport(ERROR, (errcode(ERRCODE_INVALID_TABLE_DEFINITION), errmsg("ON COMMIT can only be used on temporary tables"))); /* * Look up the namespace in which we are supposed to create the relation. * Check we have permission to create there. Skip check if bootstrapping, * since permissions machinery may not be working yet. */ namespaceId = RangeVarGetCreationNamespace(stmt->relation); if (!IsBootstrapProcessingMode()) { AclResult aclresult; aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(), ACL_CREATE); if (aclresult != ACLCHECK_OK) aclcheck_error(aclresult, ACL_KIND_NAMESPACE, get_namespace_name(namespaceId)); } /* * Select tablespace to use. If not specified, use default_tablespace * (which may in turn default to database's default). */ if (stmt->tablespacename) { tablespaceId = get_tablespace_oid(stmt->tablespacename); if (!OidIsValid(tablespaceId)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("tablespace \"%s\" does not exist", stmt->tablespacename))); } else { tablespaceId = GetDefaultTablespace(); /* note InvalidOid is OK in this case */ } /* * Parse and validate reloptions, if any. */ reloptions = transformRelOptions((Datum) 0, stmt->options, true, false); (void) heap_reloptions(relkind, reloptions, true); /* Check permissions except when using database's default */ if (OidIsValid(tablespaceId)) { AclResult aclresult; aclresult = pg_tablespace_aclcheck(tablespaceId, GetUserId(), ACL_CREATE); if (aclresult != ACLCHECK_OK) aclcheck_error(aclresult, ACL_KIND_TABLESPACE, get_tablespace_name(tablespaceId)); } /* * Look up inheritance ancestors and generate relation schema, including * inherited attributes. */ schema = MergeAttributes(schema, stmt->inhRelations, stmt->relation->istemp, &inheritOids, &old_constraints, &parentOidCount); /* * Create a relation descriptor from the relation schema and create the * relation. Note that in this stage only inherited (pre-cooked) defaults * and constraints will be included into the new relation. * (BuildDescForRelation takes care of the inherited defaults, but we have * to copy inherited constraints here.) */ descriptor = BuildDescForRelation(schema); localHasOids = interpretOidsOption(stmt->options); descriptor->tdhasoid = (localHasOids || parentOidCount > 0); if (old_constraints || stmt->constraints) { ConstrCheck *check; int ncheck = 0; /* make array that's certainly big enough */ check = (ConstrCheck *) palloc((list_length(old_constraints) + list_length(stmt->constraints)) * sizeof(ConstrCheck)); /* deal with constraints from MergeAttributes */ foreach(listptr, old_constraints) { Constraint *cdef = (Constraint *) lfirst(listptr); if (cdef->contype == CONSTR_CHECK) add_nonduplicate_constraint(cdef, check, &ncheck); } /* * analyze.c might have passed some precooked constraints too, * due to LIKE tab INCLUDING CONSTRAINTS */ foreach(listptr, stmt->constraints) { Constraint *cdef = (Constraint *) lfirst(listptr); if (cdef->contype == CONSTR_CHECK && cdef->cooked_expr != NULL) add_nonduplicate_constraint(cdef, check, &ncheck); } /* if we found any, insert 'em into the descriptor */ if (ncheck > 0) { if (descriptor->constr == NULL) { descriptor->constr = (TupleConstr *) palloc(sizeof(TupleConstr)); descriptor->constr->defval = NULL; descriptor->constr->num_defval = 0; descriptor->constr->has_not_null = false; } descriptor->constr->num_check = ncheck; descriptor->constr->check = check; } } relationId = heap_create_with_catalog(relname, namespaceId, tablespaceId, InvalidOid, GetUserId(), descriptor, relkind, false, localHasOids, parentOidCount, stmt->oncommit, reloptions, allowSystemTableMods); StoreCatalogInheritance(relationId, inheritOids); /* * We must bump the command counter to make the newly-created relation * tuple visible for opening. */ CommandCounterIncrement(); /* * Open the new relation and acquire exclusive lock on it. This isn't * really necessary for locking out other backends (since they can't see * the new rel anyway until we commit), but it keeps the lock manager from * complaining about deadlock risks. */ rel = relation_open(relationId, AccessExclusiveLock); /* * Now add any newly specified column default values and CHECK constraints * to the new relation. These are passed to us in the form of raw * parsetrees; we need to transform them to executable expression trees * before they can be added. The most convenient way to do that is to * apply the parser's transformExpr routine, but transformExpr doesn't * work unless we have a pre-existing relation. So, the transformation has * to be postponed to this final step of CREATE TABLE. * * First, scan schema to find new column defaults. */ rawDefaults = NIL; attnum = 0; foreach(listptr, schema) { ColumnDef *colDef = lfirst(listptr); attnum++; if (colDef->raw_default != NULL) { RawColumnDefault *rawEnt; Assert(colDef->cooked_default == NULL); rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault)); rawEnt->attnum = attnum; rawEnt->raw_default = colDef->raw_default; rawDefaults = lappend(rawDefaults, rawEnt); } } /* * Parse and add the defaults/constraints, if any. */ if (rawDefaults || stmt->constraints) AddRelationRawConstraints(rel, rawDefaults, stmt->constraints); /* * Clean up. We keep lock on new relation (although it shouldn't be * visible to anyone else anyway, until commit). */ relation_close(rel, NoLock); return relationId; } /* * RemoveRelation * Deletes a relation. */ void RemoveRelation(const RangeVar *relation, DropBehavior behavior) { Oid relOid; ObjectAddress object; relOid = RangeVarGetRelid(relation, false); object.classId = RelationRelationId; object.objectId = relOid; object.objectSubId = 0; performDeletion(&object, behavior); } /* * ExecuteTruncate * Executes a TRUNCATE command. * * This is a multi-relation truncate. We first open and grab exclusive * lock on all relations involved, checking permissions and otherwise * verifying that the relation is OK for truncation. In CASCADE mode, * relations having FK references to the targeted relations are automatically * added to the group; in RESTRICT mode, we check that all FK references are * internal to the group that's being truncated. Finally all the relations * are truncated and reindexed. */ void ExecuteTruncate(TruncateStmt *stmt) { List *rels = NIL; List *relids = NIL; ListCell *cell; /* * Open, exclusive-lock, and check all the explicitly-specified relations */ foreach(cell, stmt->relations) { RangeVar *rv = lfirst(cell); Relation rel; rel = heap_openrv(rv, AccessExclusiveLock); truncate_check_rel(rel); rels = lappend(rels, rel); relids = lappend_oid(relids, RelationGetRelid(rel)); } /* * In CASCADE mode, suck in all referencing relations as well. This * requires multiple iterations to find indirectly-dependent relations. At * each phase, we need to exclusive-lock new rels before looking for their * dependencies, else we might miss something. Also, we check each rel as * soon as we open it, to avoid a faux pas such as holding lock for a long * time on a rel we have no permissions for. */ if (stmt->behavior == DROP_CASCADE) { for (;;) { List *newrelids; newrelids = heap_truncate_find_FKs(relids); if (newrelids == NIL) break; /* nothing else to add */ foreach(cell, newrelids) { Oid relid = lfirst_oid(cell); Relation rel; rel = heap_open(relid, AccessExclusiveLock); ereport(NOTICE, (errmsg("truncate cascades to table \"%s\"", RelationGetRelationName(rel)))); truncate_check_rel(rel); rels = lappend(rels, rel); relids = lappend_oid(relids, relid); } } } /* * Check foreign key references. In CASCADE mode, this should be * unnecessary since we just pulled in all the references; but as a * cross-check, do it anyway if in an Assert-enabled build. */ #ifdef USE_ASSERT_CHECKING heap_truncate_check_FKs(rels, false); #else if (stmt->behavior == DROP_RESTRICT) heap_truncate_check_FKs(rels, false); #endif /* * Also check for pending AFTER trigger events on the target relations. We * can't just leave those be, since they will try to fetch tuples that the * TRUNCATE removes. */ AfterTriggerCheckTruncate(relids); /* * OK, truncate each table. */ foreach(cell, rels) { Relation rel = (Relation) lfirst(cell); Oid heap_relid; Oid toast_relid; /* * Create a new empty storage file for the relation, and assign it as * the relfilenode value. The old storage file is scheduled for * deletion at commit. */ setNewRelfilenode(rel); heap_relid = RelationGetRelid(rel); toast_relid = rel->rd_rel->reltoastrelid; heap_close(rel, NoLock); /* * The same for the toast table, if any. */ if (OidIsValid(toast_relid)) { rel = relation_open(toast_relid, AccessExclusiveLock); setNewRelfilenode(rel); heap_close(rel, NoLock); } /* * Reconstruct the indexes to match, and we're done. */ reindex_relation(heap_relid, true); } } /* * Check that a given rel is safe to truncate. Subroutine for ExecuteTruncate */ static void truncate_check_rel(Relation rel) { /* Only allow truncate on regular tables */ if (rel->rd_rel->relkind != RELKIND_RELATION) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("\"%s\" is not a table", RelationGetRelationName(rel)))); /* Permissions checks */ if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS, RelationGetRelationName(rel)); if (!allowSystemTableMods && IsSystemRelation(rel)) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("permission denied: \"%s\" is a system catalog", RelationGetRelationName(rel)))); /* * We can never allow truncation of shared or nailed-in-cache relations, * because we can't support changing their relfilenode values. */ if (rel->rd_rel->relisshared || rel->rd_isnailed) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot truncate system relation \"%s\"", RelationGetRelationName(rel)))); /* * Don't allow truncate on temp tables of other backends ... their local * buffer manager is not going to cope. */ if (isOtherTempNamespace(RelationGetNamespace(rel))) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot truncate temporary tables of other sessions"))); } /*---------- * MergeAttributes * Returns new schema given initial schema and superclasses. * * Input arguments: * 'schema' is the column/attribute definition for the table. (It's a list * of ColumnDef's.) It is destructively changed. * 'supers' is a list of names (as RangeVar nodes) of parent relations. * 'istemp' is TRUE if we are creating a temp relation. * * Output arguments: * 'supOids' receives a list of the OIDs of the parent relations. * 'supconstr' receives a list of constraints belonging to the parents, * updated as necessary to be valid for the child. * 'supOidCount' is set to the number of parents that have OID columns. * * Return value: * Completed schema list. * * Notes: * The order in which the attributes are inherited is very important. * Intuitively, the inherited attributes should come first. If a table * inherits from multiple parents, the order of those attributes are * according to the order of the parents specified in CREATE TABLE. * * Here's an example: * * create table person (name text, age int4, location point); * create table emp (salary int4, manager text) inherits(person); * create table student (gpa float8) inherits (person); * create table stud_emp (percent int4) inherits (emp, student); * * The order of the attributes of stud_emp is: * * person {1:name, 2:age, 3:location} * / \ * {6:gpa} student emp {4:salary, 5:manager} * \ / * stud_emp {7:percent} * * If the same attribute name appears multiple times, then it appears * in the result table in the proper location for its first appearance. * * Constraints (including NOT NULL constraints) for the child table * are the union of all relevant constraints, from both the child schema * and parent tables. * * The default value for a child column is defined as: * (1) If the child schema specifies a default, that value is used. * (2) If neither the child nor any parent specifies a default, then * the column will not have a default. * (3) If conflicting defaults are inherited from different parents * (and not overridden by the child), an error is raised. * (4) Otherwise the inherited default is used. * Rule (3) is new in Postgres 7.1; in earlier releases you got a * rather arbitrary choice of which parent default to use. *---------- */ static List * MergeAttributes(List *schema, List *supers, bool istemp, List **supOids, List **supconstr, int *supOidCount) { ListCell *entry; List *inhSchema = NIL; List *parentOids = NIL; List *constraints = NIL; int parentsWithOids = 0; bool have_bogus_defaults = false; char *bogus_marker = "Bogus!"; /* marks conflicting defaults */ int child_attno; /* * Check for and reject tables with too many columns. We perform this * check relatively early for two reasons: (a) we don't run the risk of * overflowing an AttrNumber in subsequent code (b) an O(n^2) algorithm is * okay if we're processing <= 1600 columns, but could take minutes to * execute if the user attempts to create a table with hundreds of * thousands of columns. * * Note that we also need to check that any we do not exceed this figure * after including columns from inherited relations. */ if (list_length(schema) > MaxHeapAttributeNumber) ereport(ERROR, (errcode(ERRCODE_TOO_MANY_COLUMNS), errmsg("tables can have at most %d columns", MaxHeapAttributeNumber))); /* * Check for duplicate names in the explicit list of attributes. * * Although we might consider merging such entries in the same way that we * handle name conflicts for inherited attributes, it seems to make more * sense to assume such conflicts are errors. */ foreach(entry, schema) { ColumnDef *coldef = lfirst(entry); ListCell *rest; for_each_cell(rest, lnext(entry)) { ColumnDef *restdef = lfirst(rest); if (strcmp(coldef->colname, restdef->colname) == 0) ereport(ERROR, (errcode(ERRCODE_DUPLICATE_COLUMN), errmsg("column \"%s\" duplicated", coldef->colname))); } } /* * Scan the parents left-to-right, and merge their attributes to form a * list of inherited attributes (inhSchema). Also check to see if we need * to inherit an OID column. */ child_attno = 0; foreach(entry, supers) { RangeVar *parent = (RangeVar *) lfirst(entry); Relation relation; TupleDesc tupleDesc; TupleConstr *constr; AttrNumber *newattno; AttrNumber parent_attno; relation = heap_openrv(parent, AccessShareLock); if (relation->rd_rel->relkind != RELKIND_RELATION) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("inherited relation \"%s\" is not a table", parent->relname))); /* Permanent rels cannot inherit from temporary ones */ if (!istemp && isTempNamespace(RelationGetNamespace(relation))) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("cannot inherit from temporary relation \"%s\"", parent->relname))); /* * We should have an UNDER permission flag for this, but for now, * demand that creator of a child table own the parent. */ if (!pg_class_ownercheck(RelationGetRelid(relation), GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS, RelationGetRelationName(relation)); /* * Reject duplications in the list of parents. */ if (list_member_oid(parentOids, RelationGetRelid(relation))) ereport(ERROR, (errcode(ERRCODE_DUPLICATE_TABLE), errmsg("inherited relation \"%s\" duplicated", parent->relname))); parentOids = lappend_oid(parentOids, RelationGetRelid(relation)); if (relation->rd_rel->relhasoids) parentsWithOids++; tupleDesc = RelationGetDescr(relation); constr = tupleDesc->constr; /* * newattno[] will contain the child-table attribute numbers for the * attributes of this parent table. (They are not the same for * parents after the first one, nor if we have dropped columns.) */ newattno = (AttrNumber *) palloc(tupleDesc->natts * sizeof(AttrNumber)); for (parent_attno = 1; parent_attno <= tupleDesc->natts; parent_attno++) { Form_pg_attribute attribute = tupleDesc->attrs[parent_attno - 1]; char *attributeName = NameStr(attribute->attname); int exist_attno; ColumnDef *def; /* * Ignore dropped columns in the parent. */ if (attribute->attisdropped) { /* * change_varattnos_of_a_node asserts that this is greater * than zero, so if anything tries to use it, we should find * out. */ newattno[parent_attno - 1] = 0; continue; } /* * Does it conflict with some previously inherited column? */ exist_attno = findAttrByName(attributeName, inhSchema); if (exist_attno > 0) { Oid defTypeId; int32 deftypmod; /* * Yes, try to merge the two column definitions. They must * have the same type and typmod. */ ereport(NOTICE, (errmsg("merging multiple inherited definitions of column \"%s\"", attributeName))); def = (ColumnDef *) list_nth(inhSchema, exist_attno - 1); defTypeId = typenameTypeId(NULL, def->typename); deftypmod = typenameTypeMod(NULL, def->typename, defTypeId); if (defTypeId != attribute->atttypid || deftypmod != attribute->atttypmod) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("inherited column \"%s\" has a type conflict", attributeName), errdetail("%s versus %s", TypeNameToString(def->typename), format_type_be(attribute->atttypid)))); def->inhcount++; /* Merge of NOT NULL constraints = OR 'em together */ def->is_not_null |= attribute->attnotnull; /* Default and other constraints are handled below */ newattno[parent_attno - 1] = exist_attno; } else { /* * No, create a new inherited column */ def = makeNode(ColumnDef); def->colname = pstrdup(attributeName); def->typename = makeTypeNameFromOid(attribute->atttypid, attribute->atttypmod); def->inhcount = 1; def->is_local = false; def->is_not_null = attribute->attnotnull; def->raw_default = NULL; def->cooked_default = NULL; def->constraints = NIL; inhSchema = lappend(inhSchema, def); newattno[parent_attno - 1] = ++child_attno; } /* * Copy default if any */ if (attribute->atthasdef) { char *this_default = NULL; AttrDefault *attrdef; int i; /* Find default in constraint structure */ Assert(constr != NULL); attrdef = constr->defval; for (i = 0; i < constr->num_defval; i++) { if (attrdef[i].adnum == parent_attno) { this_default = attrdef[i].adbin; break; } } Assert(this_default != NULL); /* * If default expr could contain any vars, we'd need to fix * 'em, but it can't; so default is ready to apply to child. * * If we already had a default from some prior parent, check * to see if they are the same. If so, no problem; if not, * mark the column as having a bogus default. Below, we will * complain if the bogus default isn't overridden by the child * schema. */ Assert(def->raw_default == NULL); if (def->cooked_default == NULL) def->cooked_default = pstrdup(this_default); else if (strcmp(def->cooked_default, this_default) != 0) { def->cooked_default = bogus_marker; have_bogus_defaults = true; } } } /* * Now copy the constraints of this parent, adjusting attnos using the * completed newattno[] map */ if (constr && constr->num_check > 0) { ConstrCheck *check = constr->check; int i; for (i = 0; i < constr->num_check; i++) { Constraint *cdef = makeNode(Constraint); Node *expr; cdef->contype = CONSTR_CHECK; cdef->name = pstrdup(check[i].ccname); cdef->raw_expr = NULL; /* adjust varattnos of ccbin here */ expr = stringToNode(check[i].ccbin); change_varattnos_of_a_node(expr, newattno); cdef->cooked_expr = nodeToString(expr); constraints = lappend(constraints, cdef); } } pfree(newattno); /* * Close the parent rel, but keep our AccessShareLock on it until xact * commit. That will prevent someone else from deleting or ALTERing * the parent before the child is committed. */ heap_close(relation, NoLock); } /* * If we had no inherited attributes, the result schema is just the * explicitly declared columns. Otherwise, we need to merge the declared * columns into the inherited schema list. */ if (inhSchema != NIL) { foreach(entry, schema) { ColumnDef *newdef = lfirst(entry); char *attributeName = newdef->colname; int exist_attno; /* * Does it conflict with some previously inherited column? */ exist_attno = findAttrByName(attributeName, inhSchema); if (exist_attno > 0) { ColumnDef *def; Oid defTypeId, newTypeId; int32 deftypmod, newtypmod; /* * Yes, try to merge the two column definitions. They must * have the same type and typmod. */ ereport(NOTICE, (errmsg("merging column \"%s\" with inherited definition", attributeName))); def = (ColumnDef *) list_nth(inhSchema, exist_attno - 1); defTypeId = typenameTypeId(NULL, def->typename); deftypmod = typenameTypeMod(NULL, def->typename, defTypeId); newTypeId = typenameTypeId(NULL, newdef->typename); newtypmod = typenameTypeMod(NULL, newdef->typename, newTypeId); if (defTypeId != newTypeId || deftypmod != newtypmod) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("column \"%s\" has a type conflict", attributeName), errdetail("%s versus %s", TypeNameToString(def->typename), TypeNameToString(newdef->typename)))); /* Mark the column as locally defined */ def->is_local = true; /* Merge of NOT NULL constraints = OR 'em together */ def->is_not_null |= newdef->is_not_null; /* If new def has a default, override previous default */ if (newdef->raw_default != NULL) { def->raw_default = newdef->raw_default; def->cooked_default = newdef->cooked_default; } } else { /* * No, attach new column to result schema */ inhSchema = lappend(inhSchema, newdef); } } schema = inhSchema; /* * Check that we haven't exceeded the legal # of columns after merging * in inherited columns. */ if (list_length(schema) > MaxHeapAttributeNumber) ereport(ERROR, (errcode(ERRCODE_TOO_MANY_COLUMNS), errmsg("tables can have at most %d columns", MaxHeapAttributeNumber))); } /* * If we found any conflicting parent default values, check to make sure * they were overridden by the child. */ if (have_bogus_defaults) { foreach(entry, schema) { ColumnDef *def = lfirst(entry); if (def->cooked_default == bogus_marker) ereport(ERROR, (errcode(ERRCODE_INVALID_COLUMN_DEFINITION), errmsg("column \"%s\" inherits conflicting default values", def->colname), errhint("To resolve the conflict, specify a default explicitly."))); } } *supOids = parentOids; *supconstr = constraints; *supOidCount = parentsWithOids; return schema; } /* * In multiple-inheritance situations, it's possible to inherit * the same grandparent constraint through multiple parents. * Hence, we want to discard inherited constraints that match as to * both name and expression. Otherwise, gripe if there are conflicting * names. Nonconflicting constraints are added to the array check[] * of length *ncheck ... caller must ensure there is room! */ static void add_nonduplicate_constraint(Constraint *cdef, ConstrCheck *check, int *ncheck) { int i; /* Should only see precooked constraints here */ Assert(cdef->contype == CONSTR_CHECK); Assert(cdef->name != NULL); Assert(cdef->raw_expr == NULL && cdef->cooked_expr != NULL); for (i = 0; i < *ncheck; i++) { if (strcmp(check[i].ccname, cdef->name) != 0) continue; if (strcmp(check[i].ccbin, cdef->cooked_expr) == 0) return; /* duplicate constraint, so ignore it */ ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("duplicate check constraint name \"%s\"", cdef->name))); } /* No match on name, so add it to array */ check[*ncheck].ccname = cdef->name; check[*ncheck].ccbin = pstrdup(cdef->cooked_expr); (*ncheck)++; } /* * Replace varattno values in an expression tree according to the given * map array, that is, varattno N is replaced by newattno[N-1]. It is * caller's responsibility to ensure that the array is long enough to * define values for all user varattnos present in the tree. System column * attnos remain unchanged. * * Note that the passed node tree is modified in-place! */ void change_varattnos_of_a_node(Node *node, const AttrNumber *newattno) { /* no setup needed, so away we go */ (void) change_varattnos_walker(node, newattno); } static bool change_varattnos_walker(Node *node, const AttrNumber *newattno) { if (node == NULL) return false; if (IsA(node, Var)) { Var *var = (Var *) node; if (var->varlevelsup == 0 && var->varno == 1 && var->varattno > 0) { /* * ??? the following may be a problem when the node is multiply * referenced though stringToNode() doesn't create such a node * currently. */ Assert(newattno[var->varattno - 1] > 0); var->varattno = newattno[var->varattno - 1]; } return false; } return expression_tree_walker(node, change_varattnos_walker, (void *) newattno); } /* * Generate a map for change_varattnos_of_a_node from old and new TupleDesc's, * matching according to column name. */ AttrNumber * varattnos_map(TupleDesc old, TupleDesc new) { AttrNumber *attmap; int i, j; attmap = (AttrNumber *) palloc0(sizeof(AttrNumber) * old->natts); for (i = 1; i <= old->natts; i++) { if (old->attrs[i - 1]->attisdropped) continue; /* leave the entry as zero */ for (j = 1; j <= new->natts; j++) { if (strcmp(NameStr(old->attrs[i - 1]->attname), NameStr(new->attrs[j - 1]->attname)) == 0) { attmap[i - 1] = j; break; } } } return attmap; } /* * Generate a map for change_varattnos_of_a_node from a TupleDesc and a list * of ColumnDefs */ AttrNumber * varattnos_map_schema(TupleDesc old, List *schema) { AttrNumber *attmap; int i; attmap = (AttrNumber *) palloc0(sizeof(AttrNumber) * old->natts); for (i = 1; i <= old->natts; i++) { if (old->attrs[i - 1]->attisdropped) continue; /* leave the entry as zero */ attmap[i - 1] = findAttrByName(NameStr(old->attrs[i - 1]->attname), schema); } return attmap; } /* * StoreCatalogInheritance * Updates the system catalogs with proper inheritance information. * * supers is a list of the OIDs of the new relation's direct ancestors. */ static void StoreCatalogInheritance(Oid relationId, List *supers) { Relation relation; int16 seqNumber; ListCell *entry; /* * sanity checks */ AssertArg(OidIsValid(relationId)); if (supers == NIL) return; /* * Store INHERITS information in pg_inherits using direct ancestors only. * Also enter dependencies on the direct ancestors, and make sure they are * marked with relhassubclass = true. * * (Once upon a time, both direct and indirect ancestors were found here * and then entered into pg_ipl. Since that catalog doesn't exist * anymore, there's no need to look for indirect ancestors.) */ relation = heap_open(InheritsRelationId, RowExclusiveLock); seqNumber = 1; foreach(entry, supers) { Oid parentOid = lfirst_oid(entry); StoreCatalogInheritance1(relationId, parentOid, seqNumber, relation); seqNumber++; } heap_close(relation, RowExclusiveLock); } /* * Make catalog entries showing relationId as being an inheritance child * of parentOid. inhRelation is the already-opened pg_inherits catalog. */ static void StoreCatalogInheritance1(Oid relationId, Oid parentOid, int16 seqNumber, Relation inhRelation) { TupleDesc desc = RelationGetDescr(inhRelation); Datum datum[Natts_pg_inherits]; char nullarr[Natts_pg_inherits]; ObjectAddress childobject, parentobject; HeapTuple tuple; /* * Make the pg_inherits entry */ datum[0] = ObjectIdGetDatum(relationId); /* inhrelid */ datum[1] = ObjectIdGetDatum(parentOid); /* inhparent */ datum[2] = Int16GetDatum(seqNumber); /* inhseqno */ nullarr[0] = ' '; nullarr[1] = ' '; nullarr[2] = ' '; tuple = heap_formtuple(desc, datum, nullarr); simple_heap_insert(inhRelation, tuple); CatalogUpdateIndexes(inhRelation, tuple); heap_freetuple(tuple); /* * Store a dependency too */ parentobject.classId = RelationRelationId; parentobject.objectId = parentOid; parentobject.objectSubId = 0; childobject.classId = RelationRelationId; childobject.objectId = relationId; childobject.objectSubId = 0; recordDependencyOn(&childobject, &parentobject, DEPENDENCY_NORMAL); /* * Mark the parent as having subclasses. */ setRelhassubclassInRelation(parentOid, true); } /* * Look for an existing schema entry with the given name. * * Returns the index (starting with 1) if attribute already exists in schema, * 0 if it doesn't. */ static int findAttrByName(const char *attributeName, List *schema) { ListCell *s; int i = 1; foreach(s, schema) { ColumnDef *def = lfirst(s); if (strcmp(attributeName, def->colname) == 0) return i; i++; } return 0; } /* * Update a relation's pg_class.relhassubclass entry to the given value */ static void setRelhassubclassInRelation(Oid relationId, bool relhassubclass) { Relation relationRelation; HeapTuple tuple; Form_pg_class classtuple; /* * Fetch a modifiable copy of the tuple, modify it, update pg_class. * * If the tuple already has the right relhassubclass setting, we don't * need to update it, but we still need to issue an SI inval message. */ relationRelation = heap_open(RelationRelationId, RowExclusiveLock); tuple = SearchSysCacheCopy(RELOID, ObjectIdGetDatum(relationId), 0, 0, 0); if (!HeapTupleIsValid(tuple)) elog(ERROR, "cache lookup failed for relation %u", relationId); classtuple = (Form_pg_class) GETSTRUCT(tuple); if (classtuple->relhassubclass != relhassubclass) { classtuple->relhassubclass = relhassubclass; simple_heap_update(relationRelation, &tuple->t_self, tuple); /* keep the catalog indexes up to date */ CatalogUpdateIndexes(relationRelation, tuple); } else { /* no need to change tuple, but force relcache rebuild anyway */ CacheInvalidateRelcacheByTuple(tuple); } heap_freetuple(tuple); heap_close(relationRelation, RowExclusiveLock); } /* * renameatt - changes the name of a attribute in a relation * * Attname attribute is changed in attribute catalog. * No record of the previous attname is kept (correct?). * * get proper relrelation from relation catalog (if not arg) * scan attribute catalog * for name conflict (within rel) * for original attribute (if not arg) * modify attname in attribute tuple * insert modified attribute in attribute catalog * delete original attribute from attribute catalog */ void renameatt(Oid myrelid, const char *oldattname, const char *newattname, bool recurse, bool recursing) { Relation targetrelation; Relation attrelation; HeapTuple atttup; Form_pg_attribute attform; int attnum; List *indexoidlist; ListCell *indexoidscan; /* * Grab an exclusive lock on the target table, which we will NOT release * until end of transaction. */ targetrelation = relation_open(myrelid, AccessExclusiveLock); /* * permissions checking. this would normally be done in utility.c, but * this particular routine is recursive. * * normally, only the owner of a class can change its schema. */ if (!pg_class_ownercheck(myrelid, GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS, RelationGetRelationName(targetrelation)); if (!allowSystemTableMods && IsSystemRelation(targetrelation)) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("permission denied: \"%s\" is a system catalog", RelationGetRelationName(targetrelation)))); /* * if the 'recurse' flag is set then we are supposed to rename this * attribute in all classes that inherit from 'relname' (as well as in * 'relname'). * * any permissions or problems with duplicate attributes will cause the * whole transaction to abort, which is what we want -- all or nothing. */ if (recurse) { ListCell *child; List *children; /* this routine is actually in the planner */ children = find_all_inheritors(myrelid); /* * find_all_inheritors does the recursive search of the inheritance * hierarchy, so all we have to do is process all of the relids in the * list that it returns. */ foreach(child, children) { Oid childrelid = lfirst_oid(child); if (childrelid == myrelid) continue; /* note we need not recurse again */ renameatt(childrelid, oldattname, newattname, false, true); } } else { /* * If we are told not to recurse, there had better not be any child * tables; else the rename would put them out of step. */ if (!recursing && find_inheritance_children(myrelid) != NIL) ereport(ERROR, (errcode(ERRCODE_INVALID_TABLE_DEFINITION), errmsg("inherited column \"%s\" must be renamed in child tables too", oldattname))); } attrelation = heap_open(AttributeRelationId, RowExclusiveLock); atttup = SearchSysCacheCopyAttName(myrelid, oldattname); if (!HeapTupleIsValid(atttup)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_COLUMN), errmsg("column \"%s\" does not exist", oldattname))); attform = (Form_pg_attribute) GETSTRUCT(atttup); attnum = attform->attnum; if (attnum <= 0) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot rename system column \"%s\"", oldattname))); /* * if the attribute is inherited, forbid the renaming, unless we are * already inside a recursive rename. */ if (attform->attinhcount > 0 && !recursing) ereport(ERROR, (errcode(ERRCODE_INVALID_TABLE_DEFINITION), errmsg("cannot rename inherited column \"%s\"", oldattname))); /* should not already exist */ /* this test is deliberately not attisdropped-aware */ if (SearchSysCacheExists(ATTNAME, ObjectIdGetDatum(myrelid), PointerGetDatum(newattname), 0, 0)) ereport(ERROR, (errcode(ERRCODE_DUPLICATE_COLUMN), errmsg("column \"%s\" of relation \"%s\" already exists", newattname, RelationGetRelationName(targetrelation)))); namestrcpy(&(attform->attname), newattname); simple_heap_update(attrelation, &atttup->t_self, atttup); /* keep system catalog indexes current */ CatalogUpdateIndexes(attrelation, atttup); heap_freetuple(atttup); /* * Update column names of indexes that refer to the column being renamed. */ indexoidlist = RelationGetIndexList(targetrelation); foreach(indexoidscan, indexoidlist) { Oid indexoid = lfirst_oid(indexoidscan); HeapTuple indextup; Form_pg_index indexform; int i; /* * Scan through index columns to see if there's any simple index * entries for this attribute. We ignore expressional entries. */ indextup = SearchSysCache(INDEXRELID, ObjectIdGetDatum(indexoid), 0, 0, 0); if (!HeapTupleIsValid(indextup)) elog(ERROR, "cache lookup failed for index %u", indexoid); indexform = (Form_pg_index) GETSTRUCT(indextup); for (i = 0; i < indexform->indnatts; i++) { if (attnum != indexform->indkey.values[i]) continue; /* * Found one, rename it. */ atttup = SearchSysCacheCopy(ATTNUM, ObjectIdGetDatum(indexoid), Int16GetDatum(i + 1), 0, 0); if (!HeapTupleIsValid(atttup)) continue; /* should we raise an error? */ /* * Update the (copied) attribute tuple. */ namestrcpy(&(((Form_pg_attribute) GETSTRUCT(atttup))->attname), newattname); simple_heap_update(attrelation, &atttup->t_self, atttup); /* keep system catalog indexes current */ CatalogUpdateIndexes(attrelation, atttup); heap_freetuple(atttup); } ReleaseSysCache(indextup); } list_free(indexoidlist); heap_close(attrelation, RowExclusiveLock); relation_close(targetrelation, NoLock); /* close rel but keep lock */ } /* * renamerel - change the name of a relation * * XXX - When renaming sequences, we don't bother to modify the * sequence name that is stored within the sequence itself * (this would cause problems with MVCC). In the future, * the sequence name should probably be removed from the * sequence, AFAIK there's no need for it to be there. */ void renamerel(Oid myrelid, const char *newrelname) { Relation targetrelation; Relation relrelation; /* for RELATION relation */ HeapTuple reltup; Form_pg_class relform; Oid namespaceId; char *oldrelname; char relkind; bool relhastriggers; /* * Grab an exclusive lock on the target table or index, which we will NOT * release until end of transaction. */ targetrelation = relation_open(myrelid, AccessExclusiveLock); oldrelname = pstrdup(RelationGetRelationName(targetrelation)); namespaceId = RelationGetNamespace(targetrelation); if (!allowSystemTableMods && IsSystemRelation(targetrelation)) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("permission denied: \"%s\" is a system catalog", RelationGetRelationName(targetrelation)))); relkind = targetrelation->rd_rel->relkind; relhastriggers = (targetrelation->rd_rel->reltriggers > 0); /* * Find relation's pg_class tuple, and make sure newrelname isn't in use. */ relrelation = heap_open(RelationRelationId, RowExclusiveLock); reltup = SearchSysCacheCopy(RELOID, ObjectIdGetDatum(myrelid), 0, 0, 0); if (!HeapTupleIsValid(reltup)) /* shouldn't happen */ elog(ERROR, "cache lookup failed for relation %u", myrelid); relform = (Form_pg_class) GETSTRUCT(reltup); if (get_relname_relid(newrelname, namespaceId) != InvalidOid) ereport(ERROR, (errcode(ERRCODE_DUPLICATE_TABLE), errmsg("relation \"%s\" already exists", newrelname))); /* * Update pg_class tuple with new relname. (Scribbling on reltup is OK * because it's a copy...) */ namestrcpy(&(relform->relname), newrelname); simple_heap_update(relrelation, &reltup->t_self, reltup); /* keep the system catalog indexes current */ CatalogUpdateIndexes(relrelation, reltup); heap_freetuple(reltup); heap_close(relrelation, RowExclusiveLock); /* * Also rename the associated type, if any. */ if (OidIsValid(targetrelation->rd_rel->reltype)) TypeRename(targetrelation->rd_rel->reltype, newrelname, namespaceId); /* * Close rel, but keep exclusive lock! */ relation_close(targetrelation, NoLock); } /* * AlterTable * Execute ALTER TABLE, which can be a list of subcommands * * ALTER TABLE is performed in three phases: * 1. Examine subcommands and perform pre-transformation checking. * 2. Update system catalogs. * 3. Scan table(s) to check new constraints, and optionally recopy * the data into new table(s). * Phase 3 is not performed unless one or more of the subcommands requires * it. The intention of this design is to allow multiple independent * updates of the table schema to be performed with only one pass over the * data. * * ATPrepCmd performs phase 1. A "work queue" entry is created for * each table to be affected (there may be multiple affected tables if the * commands traverse a table inheritance hierarchy). Also we do preliminary * validation of the subcommands, including parse transformation of those * expressions that need to be evaluated with respect to the old table * schema. * * ATRewriteCatalogs performs phase 2 for each affected table (note that * phases 2 and 3 do no explicit recursion, since phase 1 already did it). * Certain subcommands need to be performed before others to avoid * unnecessary conflicts; for example, DROP COLUMN should come before * ADD COLUMN. Therefore phase 1 divides the subcommands into multiple * lists, one for each logical "pass" of phase 2. * * ATRewriteTables performs phase 3 for those tables that need it. * * Thanks to the magic of MVCC, an error anywhere along the way rolls back * the whole operation; we don't have to do anything special to clean up. */ void AlterTable(AlterTableStmt *stmt) { Relation rel = relation_openrv(stmt->relation, AccessExclusiveLock); int expected_refcnt; /* * Disallow ALTER TABLE when the current backend has any open reference * to it besides the one we just got (such as an open cursor or active * plan); our AccessExclusiveLock doesn't protect us against stomping on * our own foot, only other people's feet! * * Note: the only case known to cause serious trouble is ALTER COLUMN TYPE, * and some changes are obviously pretty benign, so this could possibly * be relaxed to only error out for certain types of alterations. But * the use-case for allowing any of these things is not obvious, so we * won't work hard at it for now. */ expected_refcnt = rel->rd_isnailed ? 2 : 1; if (rel->rd_refcnt != expected_refcnt) ereport(ERROR, (errcode(ERRCODE_OBJECT_IN_USE), errmsg("relation \"%s\" is being used by active queries in this session", RelationGetRelationName(rel)))); ATController(rel, stmt->cmds, interpretInhOption(stmt->relation->inhOpt)); } /* * AlterTableInternal * * ALTER TABLE with target specified by OID * * We do not reject if the relation is already open, because it's quite * likely that one or more layers of caller have it open. That means it * is unsafe to use this entry point for alterations that could break * existing query plans. */ void AlterTableInternal(Oid relid, List *cmds, bool recurse) { Relation rel = relation_open(relid, AccessExclusiveLock); ATController(rel, cmds, recurse); } static void ATController(Relation rel, List *cmds, bool recurse) { List *wqueue = NIL; ListCell *lcmd; /* Phase 1: preliminary examination of commands, create work queue */ foreach(lcmd, cmds) { AlterTableCmd *cmd = (AlterTableCmd *) lfirst(lcmd); ATPrepCmd(&wqueue, rel, cmd, recurse, false); } /* Close the relation, but keep lock until commit */ relation_close(rel, NoLock); /* Phase 2: update system catalogs */ ATRewriteCatalogs(&wqueue); /* Phase 3: scan/rewrite tables as needed */ ATRewriteTables(&wqueue); } /* * ATPrepCmd * * Traffic cop for ALTER TABLE Phase 1 operations, including simple * recursion and permission checks. * * Caller must have acquired AccessExclusiveLock on relation already. * This lock should be held until commit. */ static void ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd, bool recurse, bool recursing) { AlteredTableInfo *tab; int pass; /* Find or create work queue entry for this table */ tab = ATGetQueueEntry(wqueue, rel); /* * Copy the original subcommand for each table. This avoids conflicts * when different child tables need to make different parse * transformations (for example, the same column may have different column * numbers in different children). */ cmd = copyObject(cmd); /* * Do permissions checking, recursion to child tables if needed, and any * additional phase-1 processing needed. */ switch (cmd->subtype) { case AT_AddColumn: /* ADD COLUMN */ ATSimplePermissions(rel, false); /* Performs own recursion */ ATPrepAddColumn(wqueue, rel, recurse, cmd); pass = AT_PASS_ADD_COL; break; case AT_ColumnDefault: /* ALTER COLUMN DEFAULT */ /* * We allow defaults on views so that INSERT into a view can have * default-ish behavior. This works because the rewriter * substitutes default values into INSERTs before it expands * rules. */ ATSimplePermissions(rel, true); ATSimpleRecursion(wqueue, rel, cmd, recurse); /* No command-specific prep needed */ pass = cmd->def ? AT_PASS_ADD_CONSTR : AT_PASS_DROP; break; case AT_DropNotNull: /* ALTER COLUMN DROP NOT NULL */ ATSimplePermissions(rel, false); ATSimpleRecursion(wqueue, rel, cmd, recurse); /* No command-specific prep needed */ pass = AT_PASS_DROP; break; case AT_SetNotNull: /* ALTER COLUMN SET NOT NULL */ ATSimplePermissions(rel, false); ATSimpleRecursion(wqueue, rel, cmd, recurse); /* No command-specific prep needed */ pass = AT_PASS_ADD_CONSTR; break; case AT_SetStatistics: /* ALTER COLUMN STATISTICS */ ATSimpleRecursion(wqueue, rel, cmd, recurse); /* Performs own permission checks */ ATPrepSetStatistics(rel, cmd->name, cmd->def); pass = AT_PASS_COL_ATTRS; break; case AT_SetStorage: /* ALTER COLUMN STORAGE */ ATSimplePermissions(rel, false); ATSimpleRecursion(wqueue, rel, cmd, recurse); /* No command-specific prep needed */ pass = AT_PASS_COL_ATTRS; break; case AT_DropColumn: /* DROP COLUMN */ ATSimplePermissions(rel, false); /* Recursion occurs during execution phase */ /* No command-specific prep needed except saving recurse flag */ if (recurse) cmd->subtype = AT_DropColumnRecurse; pass = AT_PASS_DROP; break; case AT_AddIndex: /* ADD INDEX */ ATSimplePermissions(rel, false); /* This command never recurses */ /* No command-specific prep needed */ pass = AT_PASS_ADD_INDEX; break; case AT_AddConstraint: /* ADD CONSTRAINT */ ATSimplePermissions(rel, false); /* * Currently we recurse only for CHECK constraints, never for * foreign-key constraints. UNIQUE/PKEY constraints won't be seen * here. */ if (IsA(cmd->def, Constraint)) ATSimpleRecursion(wqueue, rel, cmd, recurse); /* No command-specific prep needed */ pass = AT_PASS_ADD_CONSTR; break; case AT_DropConstraint: /* DROP CONSTRAINT */ ATSimplePermissions(rel, false); /* Performs own recursion */ ATPrepDropConstraint(wqueue, rel, recurse, cmd); pass = AT_PASS_DROP; break; case AT_DropConstraintQuietly: /* DROP CONSTRAINT for child */ ATSimplePermissions(rel, false); ATSimpleRecursion(wqueue, rel, cmd, recurse); /* No command-specific prep needed */ pass = AT_PASS_DROP; break; case AT_AlterColumnType: /* ALTER COLUMN TYPE */ ATSimplePermissions(rel, false); /* Performs own recursion */ ATPrepAlterColumnType(wqueue, tab, rel, recurse, recursing, cmd); pass = AT_PASS_ALTER_TYPE; break; case AT_ChangeOwner: /* ALTER OWNER */ /* This command never recurses */ /* No command-specific prep needed */ pass = AT_PASS_MISC; break; case AT_ClusterOn: /* CLUSTER ON */ case AT_DropCluster: /* SET WITHOUT CLUSTER */ ATSimplePermissions(rel, false); /* These commands never recurse */ /* No command-specific prep needed */ pass = AT_PASS_MISC; break; case AT_DropOids: /* SET WITHOUT OIDS */ ATSimplePermissions(rel, false); /* Performs own recursion */ if (rel->rd_rel->relhasoids) { AlterTableCmd *dropCmd = makeNode(AlterTableCmd); dropCmd->subtype = AT_DropColumn; dropCmd->name = pstrdup("oid"); dropCmd->behavior = cmd->behavior; ATPrepCmd(wqueue, rel, dropCmd, recurse, false); } pass = AT_PASS_DROP; break; case AT_SetTableSpace: /* SET TABLESPACE */ ATSimplePermissionsRelationOrIndex(rel); /* This command never recurses */ ATPrepSetTableSpace(tab, rel, cmd->name); pass = AT_PASS_MISC; /* doesn't actually matter */ break; case AT_SetRelOptions: /* SET (...) */ case AT_ResetRelOptions: /* RESET (...) */ ATSimplePermissionsRelationOrIndex(rel); /* This command never recurses */ /* No command-specific prep needed */ pass = AT_PASS_MISC; break; case AT_EnableTrig: /* ENABLE TRIGGER variants */ case AT_EnableAlwaysTrig: case AT_EnableReplicaTrig: case AT_EnableTrigAll: case AT_EnableTrigUser: case AT_DisableTrig: /* DISABLE TRIGGER variants */ case AT_DisableTrigAll: case AT_DisableTrigUser: case AT_EnableRule: /* ENABLE/DISABLE RULE variants */ case AT_EnableAlwaysRule: case AT_EnableReplicaRule: case AT_DisableRule: case AT_AddInherit: /* INHERIT / NO INHERIT */ case AT_DropInherit: ATSimplePermissions(rel, false); /* These commands never recurse */ /* No command-specific prep needed */ pass = AT_PASS_MISC; break; default: /* oops */ elog(ERROR, "unrecognized alter table type: %d", (int) cmd->subtype); pass = 0; /* keep compiler quiet */ break; } /* Add the subcommand to the appropriate list for phase 2 */ tab->subcmds[pass] = lappend(tab->subcmds[pass], cmd); } /* * ATRewriteCatalogs * * Traffic cop for ALTER TABLE Phase 2 operations. Subcommands are * dispatched in a "safe" execution order (designed to avoid unnecessary * conflicts). */ static void ATRewriteCatalogs(List **wqueue) { int pass; ListCell *ltab; /* * We process all the tables "in parallel", one pass at a time. This is * needed because we may have to propagate work from one table to another * (specifically, ALTER TYPE on a foreign key's PK has to dispatch the * re-adding of the foreign key constraint to the other table). Work can * only be propagated into later passes, however. */ for (pass = 0; pass < AT_NUM_PASSES; pass++) { /* Go through each table that needs to be processed */ foreach(ltab, *wqueue) { AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab); List *subcmds = tab->subcmds[pass]; Relation rel; ListCell *lcmd; if (subcmds == NIL) continue; /* * Exclusive lock was obtained by phase 1, needn't get it again */ rel = relation_open(tab->relid, NoLock); foreach(lcmd, subcmds) ATExecCmd(tab, rel, (AlterTableCmd *) lfirst(lcmd)); /* * After the ALTER TYPE pass, do cleanup work (this is not done in * ATExecAlterColumnType since it should be done only once if * multiple columns of a table are altered). */ if (pass == AT_PASS_ALTER_TYPE) ATPostAlterTypeCleanup(wqueue, tab); relation_close(rel, NoLock); } } /* * Check to see if a toast table must be added, if we executed any * subcommands that might have added a column or changed column storage. */ foreach(ltab, *wqueue) { AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab); if (tab->relkind == RELKIND_RELATION && (tab->subcmds[AT_PASS_ADD_COL] || tab->subcmds[AT_PASS_ALTER_TYPE] || tab->subcmds[AT_PASS_COL_ATTRS])) AlterTableCreateToastTable(tab->relid); } } /* * ATExecCmd: dispatch a subcommand to appropriate execution routine */ static void ATExecCmd(AlteredTableInfo *tab, Relation rel, AlterTableCmd *cmd) { switch (cmd->subtype) { case AT_AddColumn: /* ADD COLUMN */ ATExecAddColumn(tab, rel, (ColumnDef *) cmd->def); break; case AT_ColumnDefault: /* ALTER COLUMN DEFAULT */ ATExecColumnDefault(rel, cmd->name, cmd->def); break; case AT_DropNotNull: /* ALTER COLUMN DROP NOT NULL */ ATExecDropNotNull(rel, cmd->name); break; case AT_SetNotNull: /* ALTER COLUMN SET NOT NULL */ ATExecSetNotNull(tab, rel, cmd->name); break; case AT_SetStatistics: /* ALTER COLUMN STATISTICS */ ATExecSetStatistics(rel, cmd->name, cmd->def); break; case AT_SetStorage: /* ALTER COLUMN STORAGE */ ATExecSetStorage(rel, cmd->name, cmd->def); break; case AT_DropColumn: /* DROP COLUMN */ ATExecDropColumn(rel, cmd->name, cmd->behavior, false, false); break; case AT_DropColumnRecurse: /* DROP COLUMN with recursion */ ATExecDropColumn(rel, cmd->name, cmd->behavior, true, false); break; case AT_AddIndex: /* ADD INDEX */ ATExecAddIndex(tab, rel, (IndexStmt *) cmd->def, false); break; case AT_ReAddIndex: /* ADD INDEX */ ATExecAddIndex(tab, rel, (IndexStmt *) cmd->def, true); break; case AT_AddConstraint: /* ADD CONSTRAINT */ ATExecAddConstraint(tab, rel, cmd->def); break; case AT_DropConstraint: /* DROP CONSTRAINT */ ATExecDropConstraint(rel, cmd->name, cmd->behavior, false); break; case AT_DropConstraintQuietly: /* DROP CONSTRAINT for child */ ATExecDropConstraint(rel, cmd->name, cmd->behavior, true); break; case AT_AlterColumnType: /* ALTER COLUMN TYPE */ ATExecAlterColumnType(tab, rel, cmd->name, (TypeName *) cmd->def); break; case AT_ChangeOwner: /* ALTER OWNER */ ATExecChangeOwner(RelationGetRelid(rel), get_roleid_checked(cmd->name), false); break; case AT_ClusterOn: /* CLUSTER ON */ ATExecClusterOn(rel, cmd->name); break; case AT_DropCluster: /* SET WITHOUT CLUSTER */ ATExecDropCluster(rel); break; case AT_DropOids: /* SET WITHOUT OIDS */ /* * Nothing to do here; we'll have generated a DropColumn * subcommand to do the real work */ break; case AT_SetTableSpace: /* SET TABLESPACE */ /* * Nothing to do here; Phase 3 does the work */ break; case AT_SetRelOptions: /* SET (...) */ ATExecSetRelOptions(rel, (List *) cmd->def, false); break; case AT_ResetRelOptions: /* RESET (...) */ ATExecSetRelOptions(rel, (List *) cmd->def, true); break; case AT_EnableTrig: /* ENABLE TRIGGER name */ ATExecEnableDisableTrigger(rel, cmd->name, TRIGGER_FIRES_ON_ORIGIN, false); break; case AT_EnableAlwaysTrig: /* ENABLE ALWAYS TRIGGER name */ ATExecEnableDisableTrigger(rel, cmd->name, TRIGGER_FIRES_ALWAYS, false); break; case AT_EnableReplicaTrig: /* ENABLE REPLICA TRIGGER name */ ATExecEnableDisableTrigger(rel, cmd->name, TRIGGER_FIRES_ON_REPLICA, false); break; case AT_DisableTrig: /* DISABLE TRIGGER name */ ATExecEnableDisableTrigger(rel, cmd->name, TRIGGER_DISABLED, false); break; case AT_EnableTrigAll: /* ENABLE TRIGGER ALL */ ATExecEnableDisableTrigger(rel, NULL, TRIGGER_FIRES_ON_ORIGIN, false); break; case AT_DisableTrigAll: /* DISABLE TRIGGER ALL */ ATExecEnableDisableTrigger(rel, NULL, TRIGGER_DISABLED, false); break; case AT_EnableTrigUser: /* ENABLE TRIGGER USER */ ATExecEnableDisableTrigger(rel, NULL, TRIGGER_FIRES_ON_ORIGIN, true); break; case AT_DisableTrigUser: /* DISABLE TRIGGER USER */ ATExecEnableDisableTrigger(rel, NULL, TRIGGER_DISABLED, true); break; case AT_EnableRule: /* ENABLE RULE name */ ATExecEnableDisableRule(rel, cmd->name, RULE_FIRES_ON_ORIGIN); break; case AT_EnableAlwaysRule: /* ENABLE ALWAYS RULE name */ ATExecEnableDisableRule(rel, cmd->name, RULE_FIRES_ALWAYS); break; case AT_EnableReplicaRule: /* ENABLE REPLICA RULE name */ ATExecEnableDisableRule(rel, cmd->name, RULE_FIRES_ON_REPLICA); break; case AT_DisableRule: /* DISABLE RULE name */ ATExecEnableDisableRule(rel, cmd->name, RULE_DISABLED); break; case AT_AddInherit: ATExecAddInherit(rel, (RangeVar *) cmd->def); break; case AT_DropInherit: ATExecDropInherit(rel, (RangeVar *) cmd->def); break; default: /* oops */ elog(ERROR, "unrecognized alter table type: %d", (int) cmd->subtype); break; } /* * Bump the command counter to ensure the next subcommand in the sequence * can see the changes so far */ CommandCounterIncrement(); } /* * ATRewriteTables: ALTER TABLE phase 3 */ static void ATRewriteTables(List **wqueue) { ListCell *ltab; /* Go through each table that needs to be checked or rewritten */ foreach(ltab, *wqueue) { AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab); /* * We only need to rewrite the table if at least one column needs to * be recomputed. */ if (tab->newvals != NIL) { /* Build a temporary relation and copy data */ Oid OIDNewHeap; char NewHeapName[NAMEDATALEN]; Oid NewTableSpace; Relation OldHeap; ObjectAddress object; OldHeap = heap_open(tab->relid, NoLock); /* * We can never allow rewriting of shared or nailed-in-cache * relations, because we can't support changing their relfilenode * values. */ if (OldHeap->rd_rel->relisshared || OldHeap->rd_isnailed) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot rewrite system relation \"%s\"", RelationGetRelationName(OldHeap)))); /* * Don't allow rewrite on temp tables of other backends ... their * local buffer manager is not going to cope. */ if (isOtherTempNamespace(RelationGetNamespace(OldHeap))) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot rewrite temporary tables of other sessions"))); /* * Select destination tablespace (same as original unless user * requested a change) */ if (tab->newTableSpace) NewTableSpace = tab->newTableSpace; else NewTableSpace = OldHeap->rd_rel->reltablespace; heap_close(OldHeap, NoLock); /* * Create the new heap, using a temporary name in the same * namespace as the existing table. NOTE: there is some risk of * collision with user relnames. Working around this seems more * trouble than it's worth; in particular, we can't create the new * heap in a different namespace from the old, or we will have * problems with the TEMP status of temp tables. */ snprintf(NewHeapName, sizeof(NewHeapName), "pg_temp_%u", tab->relid); OIDNewHeap = make_new_heap(tab->relid, NewHeapName, NewTableSpace); /* * Copy the heap data into the new table with the desired * modifications, and test the current data within the table * against new constraints generated by ALTER TABLE commands. */ ATRewriteTable(tab, OIDNewHeap); /* Swap the physical files of the old and new heaps. */ swap_relation_files(tab->relid, OIDNewHeap); CommandCounterIncrement(); /* Destroy new heap with old filenode */ object.classId = RelationRelationId; object.objectId = OIDNewHeap; object.objectSubId = 0; /* * The new relation is local to our transaction and we know * nothing depends on it, so DROP_RESTRICT should be OK. */ performDeletion(&object, DROP_RESTRICT); /* performDeletion does CommandCounterIncrement at end */ /* * Rebuild each index on the relation (but not the toast table, * which is all-new anyway). We do not need * CommandCounterIncrement() because reindex_relation does it. */ reindex_relation(tab->relid, false); } else { /* * Test the current data within the table against new constraints * generated by ALTER TABLE commands, but don't rebuild data. */ if (tab->constraints != NIL || tab->new_notnull) ATRewriteTable(tab, InvalidOid); /* * If we had SET TABLESPACE but no reason to reconstruct tuples, * just do a block-by-block copy. */ if (tab->newTableSpace) ATExecSetTableSpace(tab->relid, tab->newTableSpace); } } /* * Foreign key constraints are checked in a final pass, since (a) it's * generally best to examine each one separately, and (b) it's at least * theoretically possible that we have changed both relations of the * foreign key, and we'd better have finished both rewrites before we try * to read the tables. */ foreach(ltab, *wqueue) { AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab); Relation rel = NULL; ListCell *lcon; foreach(lcon, tab->constraints) { NewConstraint *con = lfirst(lcon); if (con->contype == CONSTR_FOREIGN) { FkConstraint *fkconstraint = (FkConstraint *) con->qual; Relation refrel; if (rel == NULL) { /* Long since locked, no need for another */ rel = heap_open(tab->relid, NoLock); } refrel = heap_open(con->refrelid, RowShareLock); validateForeignKeyConstraint(fkconstraint, rel, refrel, con->conid); heap_close(refrel, NoLock); } } if (rel) heap_close(rel, NoLock); } } /* * ATRewriteTable: scan or rewrite one table * * OIDNewHeap is InvalidOid if we don't need to rewrite */ static void ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap) { Relation oldrel; Relation newrel; TupleDesc oldTupDesc; TupleDesc newTupDesc; bool needscan = false; List *notnull_attrs; int i; ListCell *l; EState *estate; /* * Open the relation(s). We have surely already locked the existing * table. */ oldrel = heap_open(tab->relid, NoLock); oldTupDesc = tab->oldDesc; newTupDesc = RelationGetDescr(oldrel); /* includes all mods */ if (OidIsValid(OIDNewHeap)) newrel = heap_open(OIDNewHeap, AccessExclusiveLock); else newrel = NULL; /* * If we need to rewrite the table, the operation has to be propagated to * tables that use this table's rowtype as a column type. * * (Eventually this will probably become true for scans as well, but at * the moment a composite type does not enforce any constraints, so it's * not necessary/appropriate to enforce them just during ALTER.) */ if (newrel) find_composite_type_dependencies(oldrel->rd_rel->reltype, RelationGetRelationName(oldrel), NULL); /* * Generate the constraint and default execution states */ estate = CreateExecutorState(); /* Build the needed expression execution states */ foreach(l, tab->constraints) { NewConstraint *con = lfirst(l); switch (con->contype) { case CONSTR_CHECK: needscan = true; con->qualstate = (List *) ExecPrepareExpr((Expr *) con->qual, estate); break; case CONSTR_FOREIGN: /* Nothing to do here */ break; default: elog(ERROR, "unrecognized constraint type: %d", (int) con->contype); } } foreach(l, tab->newvals) { NewColumnValue *ex = lfirst(l); needscan = true; ex->exprstate = ExecPrepareExpr((Expr *) ex->expr, estate); } notnull_attrs = NIL; if (newrel || tab->new_notnull) { /* * If we are rebuilding the tuples OR if we added any new NOT NULL * constraints, check all not-null constraints. This is a bit of * overkill but it minimizes risk of bugs, and heap_attisnull is a * pretty cheap test anyway. */ for (i = 0; i < newTupDesc->natts; i++) { if (newTupDesc->attrs[i]->attnotnull && !newTupDesc->attrs[i]->attisdropped) notnull_attrs = lappend_int(notnull_attrs, i); } if (notnull_attrs) needscan = true; } if (needscan) { ExprContext *econtext; Datum *values; bool *isnull; TupleTableSlot *oldslot; TupleTableSlot *newslot; HeapScanDesc scan; HeapTuple tuple; MemoryContext oldCxt; List *dropped_attrs = NIL; ListCell *lc; econtext = GetPerTupleExprContext(estate); /* * Make tuple slots for old and new tuples. Note that even when the * tuples are the same, the tupDescs might not be (consider ADD COLUMN * without a default). */ oldslot = MakeSingleTupleTableSlot(oldTupDesc); newslot = MakeSingleTupleTableSlot(newTupDesc); /* Preallocate values/isnull arrays */ i = Max(newTupDesc->natts, oldTupDesc->natts); values = (Datum *) palloc(i * sizeof(Datum)); isnull = (bool *) palloc(i * sizeof(bool)); memset(values, 0, i * sizeof(Datum)); memset(isnull, true, i * sizeof(bool)); /* * Any attributes that are dropped according to the new tuple * descriptor can be set to NULL. We precompute the list of dropped * attributes to avoid needing to do so in the per-tuple loop. */ for (i = 0; i < newTupDesc->natts; i++) { if (newTupDesc->attrs[i]->attisdropped) dropped_attrs = lappend_int(dropped_attrs, i); } /* * Scan through the rows, generating a new row if needed and then * checking all the constraints. */ scan = heap_beginscan(oldrel, SnapshotNow, 0, NULL); /* * Switch to per-tuple memory context and reset it for each tuple * produced, so we don't leak memory. */ oldCxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(estate)); while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL) { if (newrel) { Oid tupOid = InvalidOid; /* Extract data from old tuple */ heap_deform_tuple(tuple, oldTupDesc, values, isnull); if (oldTupDesc->tdhasoid) tupOid = HeapTupleGetOid(tuple); /* Set dropped attributes to null in new tuple */ foreach(lc, dropped_attrs) isnull[lfirst_int(lc)] = true; /* * Process supplied expressions to replace selected columns. * Expression inputs come from the old tuple. */ ExecStoreTuple(tuple, oldslot, InvalidBuffer, false); econtext->ecxt_scantuple = oldslot; foreach(l, tab->newvals) { NewColumnValue *ex = lfirst(l); values[ex->attnum - 1] = ExecEvalExpr(ex->exprstate, econtext, &isnull[ex->attnum - 1], NULL); } /* * Form the new tuple. Note that we don't explicitly pfree it, * since the per-tuple memory context will be reset shortly. */ tuple = heap_form_tuple(newTupDesc, values, isnull); /* Preserve OID, if any */ if (newTupDesc->tdhasoid) HeapTupleSetOid(tuple, tupOid); } /* Now check any constraints on the possibly-changed tuple */ ExecStoreTuple(tuple, newslot, InvalidBuffer, false); econtext->ecxt_scantuple = newslot; foreach(l, notnull_attrs) { int attn = lfirst_int(l); if (heap_attisnull(tuple, attn + 1)) ereport(ERROR, (errcode(ERRCODE_NOT_NULL_VIOLATION), errmsg("column \"%s\" contains null values", NameStr(newTupDesc->attrs[attn]->attname)))); } foreach(l, tab->constraints) { NewConstraint *con = lfirst(l); switch (con->contype) { case CONSTR_CHECK: if (!ExecQual(con->qualstate, econtext, true)) ereport(ERROR, (errcode(ERRCODE_CHECK_VIOLATION), errmsg("check constraint \"%s\" is violated by some row", con->name))); break; case CONSTR_FOREIGN: /* Nothing to do here */ break; default: elog(ERROR, "unrecognized constraint type: %d", (int) con->contype); } } /* Write the tuple out to the new relation */ if (newrel) simple_heap_insert(newrel, tuple); ResetExprContext(econtext); CHECK_FOR_INTERRUPTS(); } MemoryContextSwitchTo(oldCxt); heap_endscan(scan); ExecDropSingleTupleTableSlot(oldslot); ExecDropSingleTupleTableSlot(newslot); } FreeExecutorState(estate); heap_close(oldrel, NoLock); if (newrel) heap_close(newrel, NoLock); } /* * ATGetQueueEntry: find or create an entry in the ALTER TABLE work queue */ static AlteredTableInfo * ATGetQueueEntry(List **wqueue, Relation rel) { Oid relid = RelationGetRelid(rel); AlteredTableInfo *tab; ListCell *ltab; foreach(ltab, *wqueue) { tab = (AlteredTableInfo *) lfirst(ltab); if (tab->relid == relid) return tab; } /* * Not there, so add it. Note that we make a copy of the relation's * existing descriptor before anything interesting can happen to it. */ tab = (AlteredTableInfo *) palloc0(sizeof(AlteredTableInfo)); tab->relid = relid; tab->relkind = rel->rd_rel->relkind; tab->oldDesc = CreateTupleDescCopy(RelationGetDescr(rel)); *wqueue = lappend(*wqueue, tab); return tab; } /* * ATSimplePermissions * * - Ensure that it is a relation (or possibly a view) * - Ensure this user is the owner * - Ensure that it is not a system table */ static void ATSimplePermissions(Relation rel, bool allowView) { if (rel->rd_rel->relkind != RELKIND_RELATION) { if (allowView) { if (rel->rd_rel->relkind != RELKIND_VIEW) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("\"%s\" is not a table or view", RelationGetRelationName(rel)))); } else ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("\"%s\" is not a table", RelationGetRelationName(rel)))); } /* Permissions checks */ if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS, RelationGetRelationName(rel)); if (!allowSystemTableMods && IsSystemRelation(rel)) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("permission denied: \"%s\" is a system catalog", RelationGetRelationName(rel)))); } /* * ATSimplePermissionsRelationOrIndex * * - Ensure that it is a relation or an index * - Ensure this user is the owner * - Ensure that it is not a system table */ static void ATSimplePermissionsRelationOrIndex(Relation rel) { if (rel->rd_rel->relkind != RELKIND_RELATION && rel->rd_rel->relkind != RELKIND_INDEX) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("\"%s\" is not a table or index", RelationGetRelationName(rel)))); /* Permissions checks */ if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS, RelationGetRelationName(rel)); if (!allowSystemTableMods && IsSystemRelation(rel)) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("permission denied: \"%s\" is a system catalog", RelationGetRelationName(rel)))); } /* * ATSimpleRecursion * * Simple table recursion sufficient for most ALTER TABLE operations. * All direct and indirect children are processed in an unspecified order. * Note that if a child inherits from the original table via multiple * inheritance paths, it will be visited just once. */ static void ATSimpleRecursion(List **wqueue, Relation rel, AlterTableCmd *cmd, bool recurse) { /* * Propagate to children if desired. Non-table relations never have * children, so no need to search in that case. */ if (recurse && rel->rd_rel->relkind == RELKIND_RELATION) { Oid relid = RelationGetRelid(rel); ListCell *child; List *children; /* this routine is actually in the planner */ children = find_all_inheritors(relid); /* * find_all_inheritors does the recursive search of the inheritance * hierarchy, so all we have to do is process all of the relids in the * list that it returns. */ foreach(child, children) { Oid childrelid = lfirst_oid(child); Relation childrel; if (childrelid == relid) continue; childrel = relation_open(childrelid, AccessExclusiveLock); /* check for child relation in use in this session */ if (childrel->rd_refcnt != 1) ereport(ERROR, (errcode(ERRCODE_OBJECT_IN_USE), errmsg("relation \"%s\" is being used by active queries in this session", RelationGetRelationName(childrel)))); ATPrepCmd(wqueue, childrel, cmd, false, true); relation_close(childrel, NoLock); } } } /* * ATOneLevelRecursion * * Here, we visit only direct inheritance children. It is expected that * the command's prep routine will recurse again to find indirect children. * When using this technique, a multiply-inheriting child will be visited * multiple times. */ static void ATOneLevelRecursion(List **wqueue, Relation rel, AlterTableCmd *cmd) { Oid relid = RelationGetRelid(rel); ListCell *child; List *children; /* this routine is actually in the planner */ children = find_inheritance_children(relid); foreach(child, children) { Oid childrelid = lfirst_oid(child); Relation childrel; childrel = relation_open(childrelid, AccessExclusiveLock); /* check for child relation in use in this session */ if (childrel->rd_refcnt != 1) ereport(ERROR, (errcode(ERRCODE_OBJECT_IN_USE), errmsg("relation \"%s\" is being used by active queries in this session", RelationGetRelationName(childrel)))); ATPrepCmd(wqueue, childrel, cmd, true, true); relation_close(childrel, NoLock); } } /* * find_composite_type_dependencies * * Check to see if a composite type is being used as a column in some * other table (possibly nested several levels deep in composite types!). * Eventually, we'd like to propagate the check or rewrite operation * into other such tables, but for now, just error out if we find any. * * Caller should provide either a table name or a type name (not both) to * report in the error message, if any. * * We assume that functions and views depending on the type are not reasons * to reject the ALTER. (How safe is this really?) */ void find_composite_type_dependencies(Oid typeOid, const char *origTblName, const char *origTypeName) { Relation depRel; ScanKeyData key[2]; SysScanDesc depScan; HeapTuple depTup; Oid arrayOid; /* * We scan pg_depend to find those things that depend on the rowtype. (We * assume we can ignore refobjsubid for a rowtype.) */ depRel = heap_open(DependRelationId, AccessShareLock); ScanKeyInit(&key[0], Anum_pg_depend_refclassid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(TypeRelationId)); ScanKeyInit(&key[1], Anum_pg_depend_refobjid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(typeOid)); depScan = systable_beginscan(depRel, DependReferenceIndexId, true, SnapshotNow, 2, key); while (HeapTupleIsValid(depTup = systable_getnext(depScan))) { Form_pg_depend pg_depend = (Form_pg_depend) GETSTRUCT(depTup); Relation rel; Form_pg_attribute att; /* Ignore dependees that aren't user columns of relations */ /* (we assume system columns are never of rowtypes) */ if (pg_depend->classid != RelationRelationId || pg_depend->objsubid <= 0) continue; rel = relation_open(pg_depend->objid, AccessShareLock); att = rel->rd_att->attrs[pg_depend->objsubid - 1]; if (rel->rd_rel->relkind == RELKIND_RELATION) { if (origTblName) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot alter table \"%s\" because column \"%s\".\"%s\" uses its rowtype", origTblName, RelationGetRelationName(rel), NameStr(att->attname)))); else ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot alter type \"%s\" because column \"%s\".\"%s\" uses it", origTypeName, RelationGetRelationName(rel), NameStr(att->attname)))); } else if (OidIsValid(rel->rd_rel->reltype)) { /* * A view or composite type itself isn't a problem, but we must * recursively check for indirect dependencies via its rowtype. */ find_composite_type_dependencies(rel->rd_rel->reltype, origTblName, origTypeName); } relation_close(rel, AccessShareLock); } systable_endscan(depScan); relation_close(depRel, AccessShareLock); /* * If there's an array type for the rowtype, must check for uses of it, * too. */ arrayOid = get_array_type(typeOid); if (OidIsValid(arrayOid)) find_composite_type_dependencies(arrayOid, origTblName, origTypeName); } /* * ALTER TABLE ADD COLUMN * * Adds an additional attribute to a relation making the assumption that * CHECK, NOT NULL, and FOREIGN KEY constraints will be removed from the * AT_AddColumn AlterTableCmd by analyze.c and added as independent * AlterTableCmd's. */ static void ATPrepAddColumn(List **wqueue, Relation rel, bool recurse, AlterTableCmd *cmd) { /* * Recurse to add the column to child classes, if requested. * * We must recurse one level at a time, so that multiply-inheriting * children are visited the right number of times and end up with the * right attinhcount. */ if (recurse) { AlterTableCmd *childCmd = copyObject(cmd); ColumnDef *colDefChild = (ColumnDef *) childCmd->def; /* Child should see column as singly inherited */ colDefChild->inhcount = 1; colDefChild->is_local = false; ATOneLevelRecursion(wqueue, rel, childCmd); } else { /* * If we are told not to recurse, there had better not be any child * tables; else the addition would put them out of step. */ if (find_inheritance_children(RelationGetRelid(rel)) != NIL) ereport(ERROR, (errcode(ERRCODE_INVALID_TABLE_DEFINITION), errmsg("column must be added to child tables too"))); } } static void ATExecAddColumn(AlteredTableInfo *tab, Relation rel, ColumnDef *colDef) { Oid myrelid = RelationGetRelid(rel); Relation pgclass, attrdesc; HeapTuple reltup; HeapTuple attributeTuple; Form_pg_attribute attribute; FormData_pg_attribute attributeD; int i; int minattnum, maxatts; HeapTuple typeTuple; Oid typeOid; int32 typmod; Form_pg_type tform; Expr *defval; attrdesc = heap_open(AttributeRelationId, RowExclusiveLock); /* * Are we adding the column to a recursion child? If so, check whether to * merge with an existing definition for the column. */ if (colDef->inhcount > 0) { HeapTuple tuple; /* Does child already have a column by this name? */ tuple = SearchSysCacheCopyAttName(myrelid, colDef->colname); if (HeapTupleIsValid(tuple)) { Form_pg_attribute childatt = (Form_pg_attribute) GETSTRUCT(tuple); Oid ctypeId; int32 ctypmod; /* Okay if child matches by type */ ctypeId = typenameTypeId(NULL, colDef->typename); ctypmod = typenameTypeMod(NULL, colDef->typename, ctypeId); if (ctypeId != childatt->atttypid || ctypmod != childatt->atttypmod) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("child table \"%s\" has different type for column \"%s\"", RelationGetRelationName(rel), colDef->colname))); /* Bump the existing child att's inhcount */ childatt->attinhcount++; simple_heap_update(attrdesc, &tuple->t_self, tuple); CatalogUpdateIndexes(attrdesc, tuple); heap_freetuple(tuple); /* Inform the user about the merge */ ereport(NOTICE, (errmsg("merging definition of column \"%s\" for child \"%s\"", colDef->colname, RelationGetRelationName(rel)))); heap_close(attrdesc, RowExclusiveLock); return; } } pgclass = heap_open(RelationRelationId, RowExclusiveLock); reltup = SearchSysCacheCopy(RELOID, ObjectIdGetDatum(myrelid), 0, 0, 0); if (!HeapTupleIsValid(reltup)) elog(ERROR, "cache lookup failed for relation %u", myrelid); /* * this test is deliberately not attisdropped-aware, since if one tries to * add a column matching a dropped column name, it's gonna fail anyway. */ if (SearchSysCacheExists(ATTNAME, ObjectIdGetDatum(myrelid), PointerGetDatum(colDef->colname), 0, 0)) ereport(ERROR, (errcode(ERRCODE_DUPLICATE_COLUMN), errmsg("column \"%s\" of relation \"%s\" already exists", colDef->colname, RelationGetRelationName(rel)))); minattnum = ((Form_pg_class) GETSTRUCT(reltup))->relnatts; maxatts = minattnum + 1; if (maxatts > MaxHeapAttributeNumber) ereport(ERROR, (errcode(ERRCODE_TOO_MANY_COLUMNS), errmsg("tables can have at most %d columns", MaxHeapAttributeNumber))); i = minattnum + 1; typeTuple = typenameType(NULL, colDef->typename); tform = (Form_pg_type) GETSTRUCT(typeTuple); typeOid = HeapTupleGetOid(typeTuple); typmod = typenameTypeMod(NULL, colDef->typename, typeOid); /* make sure datatype is legal for a column */ CheckAttributeType(colDef->colname, typeOid); attributeTuple = heap_addheader(Natts_pg_attribute, false, ATTRIBUTE_TUPLE_SIZE, (void *) &attributeD); attribute = (Form_pg_attribute) GETSTRUCT(attributeTuple); attribute->attrelid = myrelid; namestrcpy(&(attribute->attname), colDef->colname); attribute->atttypid = typeOid; attribute->attstattarget = -1; attribute->attlen = tform->typlen; attribute->attcacheoff = -1; attribute->atttypmod = typmod; attribute->attnum = i; attribute->attbyval = tform->typbyval; attribute->attndims = list_length(colDef->typename->arrayBounds); attribute->attstorage = tform->typstorage; attribute->attalign = tform->typalign; attribute->attnotnull = colDef->is_not_null; attribute->atthasdef = false; attribute->attisdropped = false; attribute->attislocal = colDef->is_local; attribute->attinhcount = colDef->inhcount; ReleaseSysCache(typeTuple); simple_heap_insert(attrdesc, attributeTuple); /* Update indexes on pg_attribute */ CatalogUpdateIndexes(attrdesc, attributeTuple); heap_close(attrdesc, RowExclusiveLock); /* * Update number of attributes in pg_class tuple */ ((Form_pg_class) GETSTRUCT(reltup))->relnatts = maxatts; simple_heap_update(pgclass, &reltup->t_self, reltup); /* keep catalog indexes current */ CatalogUpdateIndexes(pgclass, reltup); heap_freetuple(reltup); heap_close(pgclass, RowExclusiveLock); /* Make the attribute's catalog entry visible */ CommandCounterIncrement(); /* * Store the DEFAULT, if any, in the catalogs */ if (colDef->raw_default) { RawColumnDefault *rawEnt; rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault)); rawEnt->attnum = attribute->attnum; rawEnt->raw_default = copyObject(colDef->raw_default); /* * This function is intended for CREATE TABLE, so it processes a * _list_ of defaults, but we just do one. */ AddRelationRawConstraints(rel, list_make1(rawEnt), NIL); /* Make the additional catalog changes visible */ CommandCounterIncrement(); } /* * Tell Phase 3 to fill in the default expression, if there is one. * * If there is no default, Phase 3 doesn't have to do anything, because * that effectively means that the default is NULL. The heap tuple access * routines always check for attnum > # of attributes in tuple, and return * NULL if so, so without any modification of the tuple data we will get * the effect of NULL values in the new column. * * An exception occurs when the new column is of a domain type: the domain * might have a NOT NULL constraint, or a check constraint that indirectly * rejects nulls. If there are any domain constraints then we construct * an explicit NULL default value that will be passed through * CoerceToDomain processing. (This is a tad inefficient, since it causes * rewriting the table which we really don't have to do, but the present * design of domain processing doesn't offer any simple way of checking * the constraints more directly.) * * Note: we use build_column_default, and not just the cooked default * returned by AddRelationRawConstraints, so that the right thing happens * when a datatype's default applies. */ defval = (Expr *) build_column_default(rel, attribute->attnum); if (!defval && GetDomainConstraints(typeOid) != NIL) { Oid basetype = getBaseType(typeOid); defval = (Expr *) makeNullConst(basetype); defval = (Expr *) coerce_to_target_type(NULL, (Node *) defval, basetype, typeOid, typmod, COERCION_ASSIGNMENT, COERCE_IMPLICIT_CAST); if (defval == NULL) /* should not happen */ elog(ERROR, "failed to coerce base type to domain"); } if (defval) { NewColumnValue *newval; newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue)); newval->attnum = attribute->attnum; newval->expr = defval; tab->newvals = lappend(tab->newvals, newval); } /* * Add needed dependency entries for the new column. */ add_column_datatype_dependency(myrelid, i, attribute->atttypid); } /* * Install a column's dependency on its datatype. */ static void add_column_datatype_dependency(Oid relid, int32 attnum, Oid typid) { ObjectAddress myself, referenced; myself.classId = RelationRelationId; myself.objectId = relid; myself.objectSubId = attnum; referenced.classId = TypeRelationId; referenced.objectId = typid; referenced.objectSubId = 0; recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL); } /* * ALTER TABLE ALTER COLUMN DROP NOT NULL */ static void ATExecDropNotNull(Relation rel, const char *colName) { HeapTuple tuple; AttrNumber attnum; Relation attr_rel; List *indexoidlist; ListCell *indexoidscan; /* * lookup the attribute */ attr_rel = heap_open(AttributeRelationId, RowExclusiveLock); tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName); if (!HeapTupleIsValid(tuple)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_COLUMN), errmsg("column \"%s\" of relation \"%s\" does not exist", colName, RelationGetRelationName(rel)))); attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum; /* Prevent them from altering a system attribute */ if (attnum <= 0) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot alter system column \"%s\"", colName))); /* * Check that the attribute is not in a primary key */ /* Loop over all indexes on the relation */ indexoidlist = RelationGetIndexList(rel); foreach(indexoidscan, indexoidlist) { Oid indexoid = lfirst_oid(indexoidscan); HeapTuple indexTuple; Form_pg_index indexStruct; int i; indexTuple = SearchSysCache(INDEXRELID, ObjectIdGetDatum(indexoid), 0, 0, 0); if (!HeapTupleIsValid(indexTuple)) elog(ERROR, "cache lookup failed for index %u", indexoid); indexStruct = (Form_pg_index) GETSTRUCT(indexTuple); /* If the index is not a primary key, skip the check */ if (indexStruct->indisprimary) { /* * Loop over each attribute in the primary key and see if it * matches the to-be-altered attribute */ for (i = 0; i < indexStruct->indnatts; i++) { if (indexStruct->indkey.values[i] == attnum) ereport(ERROR, (errcode(ERRCODE_INVALID_TABLE_DEFINITION), errmsg("column \"%s\" is in a primary key", colName))); } } ReleaseSysCache(indexTuple); } list_free(indexoidlist); /* * Okay, actually perform the catalog change ... if needed */ if (((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull) { ((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = FALSE; simple_heap_update(attr_rel, &tuple->t_self, tuple); /* keep the system catalog indexes current */ CatalogUpdateIndexes(attr_rel, tuple); } heap_close(attr_rel, RowExclusiveLock); } /* * ALTER TABLE ALTER COLUMN SET NOT NULL */ static void ATExecSetNotNull(AlteredTableInfo *tab, Relation rel, const char *colName) { HeapTuple tuple; AttrNumber attnum; Relation attr_rel; /* * lookup the attribute */ attr_rel = heap_open(AttributeRelationId, RowExclusiveLock); tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName); if (!HeapTupleIsValid(tuple)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_COLUMN), errmsg("column \"%s\" of relation \"%s\" does not exist", colName, RelationGetRelationName(rel)))); attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum; /* Prevent them from altering a system attribute */ if (attnum <= 0) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot alter system column \"%s\"", colName))); /* * Okay, actually perform the catalog change ... if needed */ if (!((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull) { ((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = TRUE; simple_heap_update(attr_rel, &tuple->t_self, tuple); /* keep the system catalog indexes current */ CatalogUpdateIndexes(attr_rel, tuple); /* Tell Phase 3 it needs to test the constraint */ tab->new_notnull = true; } heap_close(attr_rel, RowExclusiveLock); } /* * ALTER TABLE ALTER COLUMN SET/DROP DEFAULT */ static void ATExecColumnDefault(Relation rel, const char *colName, Node *newDefault) { AttrNumber attnum; /* * get the number of the attribute */ attnum = get_attnum(RelationGetRelid(rel), colName); if (attnum == InvalidAttrNumber) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_COLUMN), errmsg("column \"%s\" of relation \"%s\" does not exist", colName, RelationGetRelationName(rel)))); /* Prevent them from altering a system attribute */ if (attnum <= 0) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot alter system column \"%s\"", colName))); /* * Remove any old default for the column. We use RESTRICT here for * safety, but at present we do not expect anything to depend on the * default. */ RemoveAttrDefault(RelationGetRelid(rel), attnum, DROP_RESTRICT, false); if (newDefault) { /* SET DEFAULT */ RawColumnDefault *rawEnt; rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault)); rawEnt->attnum = attnum; rawEnt->raw_default = newDefault; /* * This function is intended for CREATE TABLE, so it processes a * _list_ of defaults, but we just do one. */ AddRelationRawConstraints(rel, list_make1(rawEnt), NIL); } } /* * ALTER TABLE ALTER COLUMN SET STATISTICS */ static void ATPrepSetStatistics(Relation rel, const char *colName, Node *flagValue) { /* * We do our own permission checking because (a) we want to allow SET * STATISTICS on indexes (for expressional index columns), and (b) we want * to allow SET STATISTICS on system catalogs without requiring * allowSystemTableMods to be turned on. */ if (rel->rd_rel->relkind != RELKIND_RELATION && rel->rd_rel->relkind != RELKIND_INDEX) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("\"%s\" is not a table or index", RelationGetRelationName(rel)))); /* Permissions checks */ if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS, RelationGetRelationName(rel)); } static void ATExecSetStatistics(Relation rel, const char *colName, Node *newValue) { int newtarget; Relation attrelation; HeapTuple tuple; Form_pg_attribute attrtuple; Assert(IsA(newValue, Integer)); newtarget = intVal(newValue); /* * Limit target to a sane range */ if (newtarget < -1) { ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("statistics target %d is too low", newtarget))); } else if (newtarget > 1000) { newtarget = 1000; ereport(WARNING, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("lowering statistics target to %d", newtarget))); } attrelation = heap_open(AttributeRelationId, RowExclusiveLock); tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName); if (!HeapTupleIsValid(tuple)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_COLUMN), errmsg("column \"%s\" of relation \"%s\" does not exist", colName, RelationGetRelationName(rel)))); attrtuple = (Form_pg_attribute) GETSTRUCT(tuple); if (attrtuple->attnum <= 0) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot alter system column \"%s\"", colName))); attrtuple->attstattarget = newtarget; simple_heap_update(attrelation, &tuple->t_self, tuple); /* keep system catalog indexes current */ CatalogUpdateIndexes(attrelation, tuple); heap_freetuple(tuple); heap_close(attrelation, RowExclusiveLock); } /* * ALTER TABLE ALTER COLUMN SET STORAGE */ static void ATExecSetStorage(Relation rel, const char *colName, Node *newValue) { char *storagemode; char newstorage; Relation attrelation; HeapTuple tuple; Form_pg_attribute attrtuple; Assert(IsA(newValue, String)); storagemode = strVal(newValue); if (pg_strcasecmp(storagemode, "plain") == 0) newstorage = 'p'; else if (pg_strcasecmp(storagemode, "external") == 0) newstorage = 'e'; else if (pg_strcasecmp(storagemode, "extended") == 0) newstorage = 'x'; else if (pg_strcasecmp(storagemode, "main") == 0) newstorage = 'm'; else { ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("invalid storage type \"%s\"", storagemode))); newstorage = 0; /* keep compiler quiet */ } attrelation = heap_open(AttributeRelationId, RowExclusiveLock); tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName); if (!HeapTupleIsValid(tuple)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_COLUMN), errmsg("column \"%s\" of relation \"%s\" does not exist", colName, RelationGetRelationName(rel)))); attrtuple = (Form_pg_attribute) GETSTRUCT(tuple); if (attrtuple->attnum <= 0) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot alter system column \"%s\"", colName))); /* * safety check: do not allow toasted storage modes unless column datatype * is TOAST-aware. */ if (newstorage == 'p' || TypeIsToastable(attrtuple->atttypid)) attrtuple->attstorage = newstorage; else ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("column data type %s can only have storage PLAIN", format_type_be(attrtuple->atttypid)))); simple_heap_update(attrelation, &tuple->t_self, tuple); /* keep system catalog indexes current */ CatalogUpdateIndexes(attrelation, tuple); heap_freetuple(tuple); heap_close(attrelation, RowExclusiveLock); } /* * ALTER TABLE DROP COLUMN * * DROP COLUMN cannot use the normal ALTER TABLE recursion mechanism, * because we have to decide at runtime whether to recurse or not depending * on whether attinhcount goes to zero or not. (We can't check this in a * static pre-pass because it won't handle multiple inheritance situations * correctly.) Since DROP COLUMN doesn't need to create any work queue * entries for Phase 3, it's okay to recurse internally in this routine * without considering the work queue. */ static void ATExecDropColumn(Relation rel, const char *colName, DropBehavior behavior, bool recurse, bool recursing) { HeapTuple tuple; Form_pg_attribute targetatt; AttrNumber attnum; List *children; ObjectAddress object; /* At top level, permission check was done in ATPrepCmd, else do it */ if (recursing) ATSimplePermissions(rel, false); /* * get the number of the attribute */ tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName); if (!HeapTupleIsValid(tuple)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_COLUMN), errmsg("column \"%s\" of relation \"%s\" does not exist", colName, RelationGetRelationName(rel)))); targetatt = (Form_pg_attribute) GETSTRUCT(tuple); attnum = targetatt->attnum; /* Can't drop a system attribute, except OID */ if (attnum <= 0 && attnum != ObjectIdAttributeNumber) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot drop system column \"%s\"", colName))); /* Don't drop inherited columns */ if (targetatt->attinhcount > 0 && !recursing) ereport(ERROR, (errcode(ERRCODE_INVALID_TABLE_DEFINITION), errmsg("cannot drop inherited column \"%s\"", colName))); ReleaseSysCache(tuple); /* * Propagate to children as appropriate. Unlike most other ALTER * routines, we have to do this one level of recursion at a time; we can't * use find_all_inheritors to do it in one pass. */ children = find_inheritance_children(RelationGetRelid(rel)); if (children) { Relation attr_rel; ListCell *child; attr_rel = heap_open(AttributeRelationId, RowExclusiveLock); foreach(child, children) { Oid childrelid = lfirst_oid(child); Relation childrel; Form_pg_attribute childatt; childrel = heap_open(childrelid, AccessExclusiveLock); /* check for child relation in use in this session */ if (childrel->rd_refcnt != 1) ereport(ERROR, (errcode(ERRCODE_OBJECT_IN_USE), errmsg("relation \"%s\" is being used by active queries in this session", RelationGetRelationName(childrel)))); tuple = SearchSysCacheCopyAttName(childrelid, colName); if (!HeapTupleIsValid(tuple)) /* shouldn't happen */ elog(ERROR, "cache lookup failed for attribute \"%s\" of relation %u", colName, childrelid); childatt = (Form_pg_attribute) GETSTRUCT(tuple); if (childatt->attinhcount <= 0) /* shouldn't happen */ elog(ERROR, "relation %u has non-inherited attribute \"%s\"", childrelid, colName); if (recurse) { /* * If the child column has other definition sources, just * decrement its inheritance count; if not, recurse to delete * it. */ if (childatt->attinhcount == 1 && !childatt->attislocal) { /* Time to delete this child column, too */ ATExecDropColumn(childrel, colName, behavior, true, true); } else { /* Child column must survive my deletion */ childatt->attinhcount--; simple_heap_update(attr_rel, &tuple->t_self, tuple); /* keep the system catalog indexes current */ CatalogUpdateIndexes(attr_rel, tuple); /* Make update visible */ CommandCounterIncrement(); } } else { /* * If we were told to drop ONLY in this table (no recursion), * we need to mark the inheritors' attribute as locally * defined rather than inherited. */ childatt->attinhcount--; childatt->attislocal = true; simple_heap_update(attr_rel, &tuple->t_self, tuple); /* keep the system catalog indexes current */ CatalogUpdateIndexes(attr_rel, tuple); /* Make update visible */ CommandCounterIncrement(); } heap_freetuple(tuple); heap_close(childrel, NoLock); } heap_close(attr_rel, RowExclusiveLock); } /* * Perform the actual column deletion */ object.classId = RelationRelationId; object.objectId = RelationGetRelid(rel); object.objectSubId = attnum; performDeletion(&object, behavior); /* * If we dropped the OID column, must adjust pg_class.relhasoids */ if (attnum == ObjectIdAttributeNumber) { Relation class_rel; Form_pg_class tuple_class; class_rel = heap_open(RelationRelationId, RowExclusiveLock); tuple = SearchSysCacheCopy(RELOID, ObjectIdGetDatum(RelationGetRelid(rel)), 0, 0, 0); if (!HeapTupleIsValid(tuple)) elog(ERROR, "cache lookup failed for relation %u", RelationGetRelid(rel)); tuple_class = (Form_pg_class) GETSTRUCT(tuple); tuple_class->relhasoids = false; simple_heap_update(class_rel, &tuple->t_self, tuple); /* Keep the catalog indexes up to date */ CatalogUpdateIndexes(class_rel, tuple); heap_close(class_rel, RowExclusiveLock); } } /* * ALTER TABLE ADD INDEX * * There is no such command in the grammar, but the parser converts UNIQUE * and PRIMARY KEY constraints into AT_AddIndex subcommands. This lets us * schedule creation of the index at the appropriate time during ALTER. */ static void ATExecAddIndex(AlteredTableInfo *tab, Relation rel, IndexStmt *stmt, bool is_rebuild) { bool check_rights; bool skip_build; bool quiet; Assert(IsA(stmt, IndexStmt)); /* suppress schema rights check when rebuilding existing index */ check_rights = !is_rebuild; /* skip index build if phase 3 will have to rewrite table anyway */ skip_build = (tab->newvals != NIL); /* suppress notices when rebuilding existing index */ quiet = is_rebuild; /* * Run parse analysis. We don't have convenient access to the query text * here, but it's probably not worth worrying about. */ stmt = analyzeIndexStmt(stmt, NULL); /* ... and do it */ DefineIndex(stmt->relation, /* relation */ stmt->idxname, /* index name */ InvalidOid, /* no predefined OID */ stmt->accessMethod, /* am name */ stmt->tableSpace, stmt->indexParams, /* parameters */ (Expr *) stmt->whereClause, stmt->options, stmt->unique, stmt->primary, stmt->isconstraint, true, /* is_alter_table */ check_rights, skip_build, quiet, false); } /* * ALTER TABLE ADD CONSTRAINT */ static void ATExecAddConstraint(AlteredTableInfo *tab, Relation rel, Node *newConstraint) { switch (nodeTag(newConstraint)) { case T_Constraint: { Constraint *constr = (Constraint *) newConstraint; /* * Currently, we only expect to see CONSTR_CHECK nodes * arriving here (see the preprocessing done in * parser/analyze.c). Use a switch anyway to make it easier * to add more code later. */ switch (constr->contype) { case CONSTR_CHECK: { List *newcons; ListCell *lcon; /* * Call AddRelationRawConstraints to do the work. * It returns a list of cooked constraints. */ newcons = AddRelationRawConstraints(rel, NIL, list_make1(constr)); /* Add each constraint to Phase 3's queue */ foreach(lcon, newcons) { CookedConstraint *ccon = (CookedConstraint *) lfirst(lcon); NewConstraint *newcon; newcon = (NewConstraint *) palloc0(sizeof(NewConstraint)); newcon->name = ccon->name; newcon->contype = ccon->contype; /* ExecQual wants implicit-AND format */ newcon->qual = (Node *) make_ands_implicit((Expr *) ccon->expr); tab->constraints = lappend(tab->constraints, newcon); } break; } default: elog(ERROR, "unrecognized constraint type: %d", (int) constr->contype); } break; } case T_FkConstraint: { FkConstraint *fkconstraint = (FkConstraint *) newConstraint; /* * Assign or validate constraint name */ if (fkconstraint->constr_name) { if (ConstraintNameIsUsed(CONSTRAINT_RELATION, RelationGetRelid(rel), RelationGetNamespace(rel), fkconstraint->constr_name)) ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("constraint \"%s\" for relation \"%s\" already exists", fkconstraint->constr_name, RelationGetRelationName(rel)))); } else fkconstraint->constr_name = ChooseConstraintName(RelationGetRelationName(rel), strVal(linitial(fkconstraint->fk_attrs)), "fkey", RelationGetNamespace(rel), NIL); ATAddForeignKeyConstraint(tab, rel, fkconstraint); break; } default: elog(ERROR, "unrecognized node type: %d", (int) nodeTag(newConstraint)); } } /* * Add a foreign-key constraint to a single table * * Subroutine for ATExecAddConstraint. Must already hold exclusive * lock on the rel, and have done appropriate validity/permissions checks * for it. */ static void ATAddForeignKeyConstraint(AlteredTableInfo *tab, Relation rel, FkConstraint *fkconstraint) { Relation pkrel; AclResult aclresult; int16 pkattnum[INDEX_MAX_KEYS]; int16 fkattnum[INDEX_MAX_KEYS]; Oid pktypoid[INDEX_MAX_KEYS]; Oid fktypoid[INDEX_MAX_KEYS]; Oid opclasses[INDEX_MAX_KEYS]; Oid pfeqoperators[INDEX_MAX_KEYS]; Oid ppeqoperators[INDEX_MAX_KEYS]; Oid ffeqoperators[INDEX_MAX_KEYS]; int i; int numfks, numpks; Oid indexOid; Oid constrOid; /* * Grab an exclusive lock on the pk table, so that someone doesn't delete * rows out from under us. (Although a lesser lock would do for that * purpose, we'll need exclusive lock anyway to add triggers to the pk * table; trying to start with a lesser lock will just create a risk of * deadlock.) */ pkrel = heap_openrv(fkconstraint->pktable, AccessExclusiveLock); /* * Validity and permissions checks * * Note: REFERENCES permissions checks are redundant with CREATE TRIGGER, * but we may as well error out sooner instead of later. */ if (pkrel->rd_rel->relkind != RELKIND_RELATION) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("referenced relation \"%s\" is not a table", RelationGetRelationName(pkrel)))); aclresult = pg_class_aclcheck(RelationGetRelid(pkrel), GetUserId(), ACL_REFERENCES); if (aclresult != ACLCHECK_OK) aclcheck_error(aclresult, ACL_KIND_CLASS, RelationGetRelationName(pkrel)); if (!allowSystemTableMods && IsSystemRelation(pkrel)) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("permission denied: \"%s\" is a system catalog", RelationGetRelationName(pkrel)))); aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(), ACL_REFERENCES); if (aclresult != ACLCHECK_OK) aclcheck_error(aclresult, ACL_KIND_CLASS, RelationGetRelationName(rel)); /* * Disallow reference from permanent table to temp table or vice versa. * (The ban on perm->temp is for fairly obvious reasons. The ban on * temp->perm is because other backends might need to run the RI triggers * on the perm table, but they can't reliably see tuples the owning * backend has created in the temp table, because non-shared buffers are * used for temp tables.) */ if (isTempNamespace(RelationGetNamespace(pkrel))) { if (!isTempNamespace(RelationGetNamespace(rel))) ereport(ERROR, (errcode(ERRCODE_INVALID_TABLE_DEFINITION), errmsg("cannot reference temporary table from permanent table constraint"))); } else { if (isTempNamespace(RelationGetNamespace(rel))) ereport(ERROR, (errcode(ERRCODE_INVALID_TABLE_DEFINITION), errmsg("cannot reference permanent table from temporary table constraint"))); } /* * Look up the referencing attributes to make sure they exist, and record * their attnums and type OIDs. */ MemSet(pkattnum, 0, sizeof(pkattnum)); MemSet(fkattnum, 0, sizeof(fkattnum)); MemSet(pktypoid, 0, sizeof(pktypoid)); MemSet(fktypoid, 0, sizeof(fktypoid)); MemSet(opclasses, 0, sizeof(opclasses)); MemSet(pfeqoperators, 0, sizeof(pfeqoperators)); MemSet(ppeqoperators, 0, sizeof(ppeqoperators)); MemSet(ffeqoperators, 0, sizeof(ffeqoperators)); numfks = transformColumnNameList(RelationGetRelid(rel), fkconstraint->fk_attrs, fkattnum, fktypoid); /* * If the attribute list for the referenced table was omitted, lookup the * definition of the primary key and use it. Otherwise, validate the * supplied attribute list. In either case, discover the index OID and * index opclasses, and the attnums and type OIDs of the attributes. */ if (fkconstraint->pk_attrs == NIL) { numpks = transformFkeyGetPrimaryKey(pkrel, &indexOid, &fkconstraint->pk_attrs, pkattnum, pktypoid, opclasses); } else { numpks = transformColumnNameList(RelationGetRelid(pkrel), fkconstraint->pk_attrs, pkattnum, pktypoid); /* Look for an index matching the column list */ indexOid = transformFkeyCheckAttrs(pkrel, numpks, pkattnum, opclasses); } /* * Look up the equality operators to use in the constraint. * * Note that we have to be careful about the difference between the actual * PK column type and the opclass' declared input type, which might be * only binary-compatible with it. The declared opcintype is the right * thing to probe pg_amop with. */ if (numfks != numpks) ereport(ERROR, (errcode(ERRCODE_INVALID_FOREIGN_KEY), errmsg("number of referencing and referenced columns for foreign key disagree"))); for (i = 0; i < numpks; i++) { Oid pktype = pktypoid[i]; Oid fktype = fktypoid[i]; Oid fktyped; HeapTuple cla_ht; Form_pg_opclass cla_tup; Oid amid; Oid opfamily; Oid opcintype; Oid pfeqop; Oid ppeqop; Oid ffeqop; int16 eqstrategy; /* We need several fields out of the pg_opclass entry */ cla_ht = SearchSysCache(CLAOID, ObjectIdGetDatum(opclasses[i]), 0, 0, 0); if (!HeapTupleIsValid(cla_ht)) elog(ERROR, "cache lookup failed for opclass %u", opclasses[i]); cla_tup = (Form_pg_opclass) GETSTRUCT(cla_ht); amid = cla_tup->opcmethod; opfamily = cla_tup->opcfamily; opcintype = cla_tup->opcintype; ReleaseSysCache(cla_ht); /* * Check it's a btree; currently this can never fail since no other * index AMs support unique indexes. If we ever did have other * types of unique indexes, we'd need a way to determine which * operator strategy number is equality. (Is it reasonable to * insist that every such index AM use btree's number for equality?) */ if (amid != BTREE_AM_OID) elog(ERROR, "only b-tree indexes are supported for foreign keys"); eqstrategy = BTEqualStrategyNumber; /* * There had better be a primary equality operator for the index. * We'll use it for PK = PK comparisons. */ ppeqop = get_opfamily_member(opfamily, opcintype, opcintype, eqstrategy); if (!OidIsValid(ppeqop)) elog(ERROR, "missing operator %d(%u,%u) in opfamily %u", eqstrategy, opcintype, opcintype, opfamily); /* * Are there equality operators that take exactly the FK type? * Assume we should look through any domain here. */ fktyped = getBaseType(fktype); pfeqop = get_opfamily_member(opfamily, opcintype, fktyped, eqstrategy); if (OidIsValid(pfeqop)) ffeqop = get_opfamily_member(opfamily, fktyped, fktyped, eqstrategy); else ffeqop = InvalidOid; /* keep compiler quiet */ if (!(OidIsValid(pfeqop) && OidIsValid(ffeqop))) { /* * Otherwise, look for an implicit cast from the FK type to * the opcintype, and if found, use the primary equality operator. * This is a bit tricky because opcintype might be a generic type * such as ANYARRAY, and so what we have to test is whether the * two actual column types can be concurrently cast to that type. * (Otherwise, we'd fail to reject combinations such as int[] and * point[].) */ Oid input_typeids[2]; Oid target_typeids[2]; input_typeids[0] = pktype; input_typeids[1] = fktype; target_typeids[0] = opcintype; target_typeids[1] = opcintype; if (can_coerce_type(2, input_typeids, target_typeids, COERCION_IMPLICIT)) pfeqop = ffeqop = ppeqop; } if (!(OidIsValid(pfeqop) && OidIsValid(ffeqop))) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("foreign key constraint \"%s\" " "cannot be implemented", fkconstraint->constr_name), errdetail("Key columns \"%s\" and \"%s\" " "are of incompatible types: %s and %s.", strVal(list_nth(fkconstraint->fk_attrs, i)), strVal(list_nth(fkconstraint->pk_attrs, i)), format_type_be(fktype), format_type_be(pktype)))); pfeqoperators[i] = pfeqop; ppeqoperators[i] = ppeqop; ffeqoperators[i] = ffeqop; } /* * Record the FK constraint in pg_constraint. */ constrOid = CreateConstraintEntry(fkconstraint->constr_name, RelationGetNamespace(rel), CONSTRAINT_FOREIGN, fkconstraint->deferrable, fkconstraint->initdeferred, RelationGetRelid(rel), fkattnum, numfks, InvalidOid, /* not a domain * constraint */ RelationGetRelid(pkrel), pkattnum, pfeqoperators, ppeqoperators, ffeqoperators, numpks, fkconstraint->fk_upd_action, fkconstraint->fk_del_action, fkconstraint->fk_matchtype, indexOid, NULL, /* no check constraint */ NULL, NULL); /* * Create the triggers that will enforce the constraint. */ createForeignKeyTriggers(rel, fkconstraint, constrOid); /* * Tell Phase 3 to check that the constraint is satisfied by existing rows * (we can skip this during table creation). */ if (!fkconstraint->skip_validation) { NewConstraint *newcon; newcon = (NewConstraint *) palloc0(sizeof(NewConstraint)); newcon->name = fkconstraint->constr_name; newcon->contype = CONSTR_FOREIGN; newcon->refrelid = RelationGetRelid(pkrel); newcon->conid = constrOid; newcon->qual = (Node *) fkconstraint; tab->constraints = lappend(tab->constraints, newcon); } /* * Close pk table, but keep lock until we've committed. */ heap_close(pkrel, NoLock); } /* * transformColumnNameList - transform list of column names * * Lookup each name and return its attnum and type OID */ static int transformColumnNameList(Oid relId, List *colList, int16 *attnums, Oid *atttypids) { ListCell *l; int attnum; attnum = 0; foreach(l, colList) { char *attname = strVal(lfirst(l)); HeapTuple atttuple; atttuple = SearchSysCacheAttName(relId, attname); if (!HeapTupleIsValid(atttuple)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_COLUMN), errmsg("column \"%s\" referenced in foreign key constraint does not exist", attname))); if (attnum >= INDEX_MAX_KEYS) ereport(ERROR, (errcode(ERRCODE_TOO_MANY_COLUMNS), errmsg("cannot have more than %d keys in a foreign key", INDEX_MAX_KEYS))); attnums[attnum] = ((Form_pg_attribute) GETSTRUCT(atttuple))->attnum; atttypids[attnum] = ((Form_pg_attribute) GETSTRUCT(atttuple))->atttypid; ReleaseSysCache(atttuple); attnum++; } return attnum; } /* * transformFkeyGetPrimaryKey - * * Look up the names, attnums, and types of the primary key attributes * for the pkrel. Also return the index OID and index opclasses of the * index supporting the primary key. * * All parameters except pkrel are output parameters. Also, the function * return value is the number of attributes in the primary key. * * Used when the column list in the REFERENCES specification is omitted. */ static int transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid, List **attnamelist, int16 *attnums, Oid *atttypids, Oid *opclasses) { List *indexoidlist; ListCell *indexoidscan; HeapTuple indexTuple = NULL; Form_pg_index indexStruct = NULL; Datum indclassDatum; bool isnull; oidvector *indclass; int i; /* * Get the list of index OIDs for the table from the relcache, and look up * each one in the pg_index syscache until we find one marked primary key * (hopefully there isn't more than one such). */ *indexOid = InvalidOid; indexoidlist = RelationGetIndexList(pkrel); foreach(indexoidscan, indexoidlist) { Oid indexoid = lfirst_oid(indexoidscan); indexTuple = SearchSysCache(INDEXRELID, ObjectIdGetDatum(indexoid), 0, 0, 0); if (!HeapTupleIsValid(indexTuple)) elog(ERROR, "cache lookup failed for index %u", indexoid); indexStruct = (Form_pg_index) GETSTRUCT(indexTuple); if (indexStruct->indisprimary) { *indexOid = indexoid; break; } ReleaseSysCache(indexTuple); } list_free(indexoidlist); /* * Check that we found it */ if (!OidIsValid(*indexOid)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("there is no primary key for referenced table \"%s\"", RelationGetRelationName(pkrel)))); /* Must get indclass the hard way */ indclassDatum = SysCacheGetAttr(INDEXRELID, indexTuple, Anum_pg_index_indclass, &isnull); Assert(!isnull); indclass = (oidvector *) DatumGetPointer(indclassDatum); /* * Now build the list of PK attributes from the indkey definition (we * assume a primary key cannot have expressional elements) */ *attnamelist = NIL; for (i = 0; i < indexStruct->indnatts; i++) { int pkattno = indexStruct->indkey.values[i]; attnums[i] = pkattno; atttypids[i] = attnumTypeId(pkrel, pkattno); opclasses[i] = indclass->values[i]; *attnamelist = lappend(*attnamelist, makeString(pstrdup(NameStr(*attnumAttName(pkrel, pkattno))))); } ReleaseSysCache(indexTuple); return i; } /* * transformFkeyCheckAttrs - * * Make sure that the attributes of a referenced table belong to a unique * (or primary key) constraint. Return the OID of the index supporting * the constraint, as well as the opclasses associated with the index * columns. */ static Oid transformFkeyCheckAttrs(Relation pkrel, int numattrs, int16 *attnums, Oid *opclasses) /* output parameter */ { Oid indexoid = InvalidOid; bool found = false; List *indexoidlist; ListCell *indexoidscan; /* * Get the list of index OIDs for the table from the relcache, and look up * each one in the pg_index syscache, and match unique indexes to the list * of attnums we are given. */ indexoidlist = RelationGetIndexList(pkrel); foreach(indexoidscan, indexoidlist) { HeapTuple indexTuple; Form_pg_index indexStruct; int i, j; indexoid = lfirst_oid(indexoidscan); indexTuple = SearchSysCache(INDEXRELID, ObjectIdGetDatum(indexoid), 0, 0, 0); if (!HeapTupleIsValid(indexTuple)) elog(ERROR, "cache lookup failed for index %u", indexoid); indexStruct = (Form_pg_index) GETSTRUCT(indexTuple); /* * Must have the right number of columns; must be unique and not a * partial index; forget it if there are any expressions, too */ if (indexStruct->indnatts == numattrs && indexStruct->indisunique && heap_attisnull(indexTuple, Anum_pg_index_indpred) && heap_attisnull(indexTuple, Anum_pg_index_indexprs)) { /* Must get indclass the hard way */ Datum indclassDatum; bool isnull; oidvector *indclass; indclassDatum = SysCacheGetAttr(INDEXRELID, indexTuple, Anum_pg_index_indclass, &isnull); Assert(!isnull); indclass = (oidvector *) DatumGetPointer(indclassDatum); /* * The given attnum list may match the index columns in any order. * Check that each list is a subset of the other. */ for (i = 0; i < numattrs; i++) { found = false; for (j = 0; j < numattrs; j++) { if (attnums[i] == indexStruct->indkey.values[j]) { found = true; break; } } if (!found) break; } if (found) { for (i = 0; i < numattrs; i++) { found = false; for (j = 0; j < numattrs; j++) { if (attnums[j] == indexStruct->indkey.values[i]) { opclasses[j] = indclass->values[i]; found = true; break; } } if (!found) break; } } } ReleaseSysCache(indexTuple); if (found) break; } if (!found) ereport(ERROR, (errcode(ERRCODE_INVALID_FOREIGN_KEY), errmsg("there is no unique constraint matching given keys for referenced table \"%s\"", RelationGetRelationName(pkrel)))); list_free(indexoidlist); return indexoid; } /* * Scan the existing rows in a table to verify they meet a proposed FK * constraint. * * Caller must have opened and locked both relations. */ static void validateForeignKeyConstraint(FkConstraint *fkconstraint, Relation rel, Relation pkrel, Oid constraintOid) { HeapScanDesc scan; HeapTuple tuple; Trigger trig; /* * Build a trigger call structure; we'll need it either way. */ MemSet(&trig, 0, sizeof(trig)); trig.tgoid = InvalidOid; trig.tgname = fkconstraint->constr_name; trig.tgenabled = TRIGGER_FIRES_ON_ORIGIN; trig.tgisconstraint = TRUE; trig.tgconstrrelid = RelationGetRelid(pkrel); trig.tgconstraint = constraintOid; trig.tgdeferrable = FALSE; trig.tginitdeferred = FALSE; /* we needn't fill in tgargs */ /* * See if we can do it with a single LEFT JOIN query. A FALSE result * indicates we must proceed with the fire-the-trigger method. */ if (RI_Initial_Check(&trig, rel, pkrel)) return; /* * Scan through each tuple, calling RI_FKey_check_ins (insert trigger) as * if that tuple had just been inserted. If any of those fail, it should * ereport(ERROR) and that's that. */ scan = heap_beginscan(rel, SnapshotNow, 0, NULL); while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL) { FunctionCallInfoData fcinfo; TriggerData trigdata; /* * Make a call to the trigger function * * No parameters are passed, but we do set a context */ MemSet(&fcinfo, 0, sizeof(fcinfo)); /* * We assume RI_FKey_check_ins won't look at flinfo... */ trigdata.type = T_TriggerData; trigdata.tg_event = TRIGGER_EVENT_INSERT | TRIGGER_EVENT_ROW; trigdata.tg_relation = rel; trigdata.tg_trigtuple = tuple; trigdata.tg_newtuple = NULL; trigdata.tg_trigger = &trig; trigdata.tg_trigtuplebuf = scan->rs_cbuf; trigdata.tg_newtuplebuf = InvalidBuffer; fcinfo.context = (Node *) &trigdata; RI_FKey_check_ins(&fcinfo); } heap_endscan(scan); } static void CreateFKCheckTrigger(RangeVar *myRel, FkConstraint *fkconstraint, Oid constraintOid, bool on_insert) { CreateTrigStmt *fk_trigger; fk_trigger = makeNode(CreateTrigStmt); fk_trigger->trigname = fkconstraint->constr_name; fk_trigger->relation = myRel; fk_trigger->before = false; fk_trigger->row = true; /* Either ON INSERT or ON UPDATE */ if (on_insert) { fk_trigger->funcname = SystemFuncName("RI_FKey_check_ins"); fk_trigger->actions[0] = 'i'; } else { fk_trigger->funcname = SystemFuncName("RI_FKey_check_upd"); fk_trigger->actions[0] = 'u'; } fk_trigger->actions[1] = '\0'; fk_trigger->isconstraint = true; fk_trigger->deferrable = fkconstraint->deferrable; fk_trigger->initdeferred = fkconstraint->initdeferred; fk_trigger->constrrel = fkconstraint->pktable; fk_trigger->args = NIL; (void) CreateTrigger(fk_trigger, constraintOid); /* Make changes-so-far visible */ CommandCounterIncrement(); } /* * Create the triggers that implement an FK constraint. */ static void createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint, Oid constraintOid) { RangeVar *myRel; CreateTrigStmt *fk_trigger; /* * Reconstruct a RangeVar for my relation (not passed in, unfortunately). */ myRel = makeRangeVar(get_namespace_name(RelationGetNamespace(rel)), pstrdup(RelationGetRelationName(rel))); /* Make changes-so-far visible */ CommandCounterIncrement(); /* * Build and execute a CREATE CONSTRAINT TRIGGER statement for the CHECK * action for both INSERTs and UPDATEs on the referencing table. */ CreateFKCheckTrigger(myRel, fkconstraint, constraintOid, true); CreateFKCheckTrigger(myRel, fkconstraint, constraintOid, false); /* * Build and execute a CREATE CONSTRAINT TRIGGER statement for the ON * DELETE action on the referenced table. */ fk_trigger = makeNode(CreateTrigStmt); fk_trigger->trigname = fkconstraint->constr_name; fk_trigger->relation = fkconstraint->pktable; fk_trigger->before = false; fk_trigger->row = true; fk_trigger->actions[0] = 'd'; fk_trigger->actions[1] = '\0'; fk_trigger->isconstraint = true; fk_trigger->constrrel = myRel; switch (fkconstraint->fk_del_action) { case FKCONSTR_ACTION_NOACTION: fk_trigger->deferrable = fkconstraint->deferrable; fk_trigger->initdeferred = fkconstraint->initdeferred; fk_trigger->funcname = SystemFuncName("RI_FKey_noaction_del"); break; case FKCONSTR_ACTION_RESTRICT: fk_trigger->deferrable = false; fk_trigger->initdeferred = false; fk_trigger->funcname = SystemFuncName("RI_FKey_restrict_del"); break; case FKCONSTR_ACTION_CASCADE: fk_trigger->deferrable = false; fk_trigger->initdeferred = false; fk_trigger->funcname = SystemFuncName("RI_FKey_cascade_del"); break; case FKCONSTR_ACTION_SETNULL: fk_trigger->deferrable = false; fk_trigger->initdeferred = false; fk_trigger->funcname = SystemFuncName("RI_FKey_setnull_del"); break; case FKCONSTR_ACTION_SETDEFAULT: fk_trigger->deferrable = false; fk_trigger->initdeferred = false; fk_trigger->funcname = SystemFuncName("RI_FKey_setdefault_del"); break; default: elog(ERROR, "unrecognized FK action type: %d", (int) fkconstraint->fk_del_action); break; } fk_trigger->args = NIL; (void) CreateTrigger(fk_trigger, constraintOid); /* Make changes-so-far visible */ CommandCounterIncrement(); /* * Build and execute a CREATE CONSTRAINT TRIGGER statement for the ON * UPDATE action on the referenced table. */ fk_trigger = makeNode(CreateTrigStmt); fk_trigger->trigname = fkconstraint->constr_name; fk_trigger->relation = fkconstraint->pktable; fk_trigger->before = false; fk_trigger->row = true; fk_trigger->actions[0] = 'u'; fk_trigger->actions[1] = '\0'; fk_trigger->isconstraint = true; fk_trigger->constrrel = myRel; switch (fkconstraint->fk_upd_action) { case FKCONSTR_ACTION_NOACTION: fk_trigger->deferrable = fkconstraint->deferrable; fk_trigger->initdeferred = fkconstraint->initdeferred; fk_trigger->funcname = SystemFuncName("RI_FKey_noaction_upd"); break; case FKCONSTR_ACTION_RESTRICT: fk_trigger->deferrable = false; fk_trigger->initdeferred = false; fk_trigger->funcname = SystemFuncName("RI_FKey_restrict_upd"); break; case FKCONSTR_ACTION_CASCADE: fk_trigger->deferrable = false; fk_trigger->initdeferred = false; fk_trigger->funcname = SystemFuncName("RI_FKey_cascade_upd"); break; case FKCONSTR_ACTION_SETNULL: fk_trigger->deferrable = false; fk_trigger->initdeferred = false; fk_trigger->funcname = SystemFuncName("RI_FKey_setnull_upd"); break; case FKCONSTR_ACTION_SETDEFAULT: fk_trigger->deferrable = false; fk_trigger->initdeferred = false; fk_trigger->funcname = SystemFuncName("RI_FKey_setdefault_upd"); break; default: elog(ERROR, "unrecognized FK action type: %d", (int) fkconstraint->fk_upd_action); break; } fk_trigger->args = NIL; (void) CreateTrigger(fk_trigger, constraintOid); } /* * ALTER TABLE DROP CONSTRAINT */ static void ATPrepDropConstraint(List **wqueue, Relation rel, bool recurse, AlterTableCmd *cmd) { /* * We don't want errors or noise from child tables, so we have to pass * down a modified command. */ if (recurse) { AlterTableCmd *childCmd = copyObject(cmd); childCmd->subtype = AT_DropConstraintQuietly; ATSimpleRecursion(wqueue, rel, childCmd, recurse); } } static void ATExecDropConstraint(Relation rel, const char *constrName, DropBehavior behavior, bool quiet) { int deleted; deleted = RemoveRelConstraints(rel, constrName, behavior); if (!quiet) { /* If zero constraints deleted, complain */ if (deleted == 0) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("constraint \"%s\" does not exist", constrName))); /* Otherwise if more than one constraint deleted, notify */ else if (deleted > 1) ereport(NOTICE, (errmsg("multiple constraints named \"%s\" were dropped", constrName))); } } /* * ALTER COLUMN TYPE */ static void ATPrepAlterColumnType(List **wqueue, AlteredTableInfo *tab, Relation rel, bool recurse, bool recursing, AlterTableCmd *cmd) { char *colName = cmd->name; TypeName *typename = (TypeName *) cmd->def; HeapTuple tuple; Form_pg_attribute attTup; AttrNumber attnum; Oid targettype; int32 targettypmod; Node *transform; NewColumnValue *newval; ParseState *pstate = make_parsestate(NULL); /* lookup the attribute so we can check inheritance status */ tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName); if (!HeapTupleIsValid(tuple)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_COLUMN), errmsg("column \"%s\" of relation \"%s\" does not exist", colName, RelationGetRelationName(rel)))); attTup = (Form_pg_attribute) GETSTRUCT(tuple); attnum = attTup->attnum; /* Can't alter a system attribute */ if (attnum <= 0) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot alter system column \"%s\"", colName))); /* Don't alter inherited columns */ if (attTup->attinhcount > 0 && !recursing) ereport(ERROR, (errcode(ERRCODE_INVALID_TABLE_DEFINITION), errmsg("cannot alter inherited column \"%s\"", colName))); /* Look up the target type */ targettype = typenameTypeId(NULL, typename); targettypmod = typenameTypeMod(NULL, typename, targettype); /* make sure datatype is legal for a column */ CheckAttributeType(colName, targettype); /* * Set up an expression to transform the old data value to the new type. * If a USING option was given, transform and use that expression, else * just take the old value and try to coerce it. We do this first so that * type incompatibility can be detected before we waste effort, and * because we need the expression to be parsed against the original table * rowtype. */ if (cmd->transform) { RangeTblEntry *rte; /* Expression must be able to access vars of old table */ rte = addRangeTableEntryForRelation(pstate, rel, NULL, false, true); addRTEtoQuery(pstate, rte, false, true, true); transform = transformExpr(pstate, cmd->transform); /* It can't return a set */ if (expression_returns_set(transform)) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("transform expression must not return a set"))); /* No subplans or aggregates, either... */ if (pstate->p_hasSubLinks) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot use subquery in transform expression"))); if (pstate->p_hasAggs) ereport(ERROR, (errcode(ERRCODE_GROUPING_ERROR), errmsg("cannot use aggregate function in transform expression"))); } else { transform = (Node *) makeVar(1, attnum, attTup->atttypid, attTup->atttypmod, 0); } transform = coerce_to_target_type(pstate, transform, exprType(transform), targettype, targettypmod, COERCION_ASSIGNMENT, COERCE_IMPLICIT_CAST); if (transform == NULL) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("column \"%s\" cannot be cast to type \"%s\"", colName, TypeNameToString(typename)))); /* * Add a work queue item to make ATRewriteTable update the column * contents. */ newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue)); newval->attnum = attnum; newval->expr = (Expr *) transform; tab->newvals = lappend(tab->newvals, newval); ReleaseSysCache(tuple); /* * The recursion case is handled by ATSimpleRecursion. However, if we are * told not to recurse, there had better not be any child tables; else the * alter would put them out of step. */ if (recurse) ATSimpleRecursion(wqueue, rel, cmd, recurse); else if (!recursing && find_inheritance_children(RelationGetRelid(rel)) != NIL) ereport(ERROR, (errcode(ERRCODE_INVALID_TABLE_DEFINITION), errmsg("type of inherited column \"%s\" must be changed in child tables too", colName))); } static void ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel, const char *colName, TypeName *typename) { HeapTuple heapTup; Form_pg_attribute attTup; AttrNumber attnum; HeapTuple typeTuple; Form_pg_type tform; Oid targettype; int32 targettypmod; Node *defaultexpr; Relation attrelation; Relation depRel; ScanKeyData key[3]; SysScanDesc scan; HeapTuple depTup; attrelation = heap_open(AttributeRelationId, RowExclusiveLock); /* Look up the target column */ heapTup = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName); if (!HeapTupleIsValid(heapTup)) /* shouldn't happen */ ereport(ERROR, (errcode(ERRCODE_UNDEFINED_COLUMN), errmsg("column \"%s\" of relation \"%s\" does not exist", colName, RelationGetRelationName(rel)))); attTup = (Form_pg_attribute) GETSTRUCT(heapTup); attnum = attTup->attnum; /* Check for multiple ALTER TYPE on same column --- can't cope */ if (attTup->atttypid != tab->oldDesc->attrs[attnum - 1]->atttypid || attTup->atttypmod != tab->oldDesc->attrs[attnum - 1]->atttypmod) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot alter type of column \"%s\" twice", colName))); /* Look up the target type (should not fail, since prep found it) */ typeTuple = typenameType(NULL, typename); tform = (Form_pg_type) GETSTRUCT(typeTuple); targettype = HeapTupleGetOid(typeTuple); targettypmod = typenameTypeMod(NULL, typename, targettype); /* * If there is a default expression for the column, get it and ensure we * can coerce it to the new datatype. (We must do this before changing * the column type, because build_column_default itself will try to * coerce, and will not issue the error message we want if it fails.) * * We remove any implicit coercion steps at the top level of the old * default expression; this has been agreed to satisfy the principle of * least surprise. (The conversion to the new column type should act like * it started from what the user sees as the stored expression, and the * implicit coercions aren't going to be shown.) */ if (attTup->atthasdef) { defaultexpr = build_column_default(rel, attnum); Assert(defaultexpr); defaultexpr = strip_implicit_coercions(defaultexpr); defaultexpr = coerce_to_target_type(NULL, /* no UNKNOWN params */ defaultexpr, exprType(defaultexpr), targettype, targettypmod, COERCION_ASSIGNMENT, COERCE_IMPLICIT_CAST); if (defaultexpr == NULL) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("default for column \"%s\" cannot be cast to type \"%s\"", colName, TypeNameToString(typename)))); } else defaultexpr = NULL; /* * Find everything that depends on the column (constraints, indexes, etc), * and record enough information to let us recreate the objects. * * The actual recreation does not happen here, but only after we have * performed all the individual ALTER TYPE operations. We have to save * the info before executing ALTER TYPE, though, else the deparser will * get confused. * * There could be multiple entries for the same object, so we must check * to ensure we process each one only once. Note: we assume that an index * that implements a constraint will not show a direct dependency on the * column. */ depRel = heap_open(DependRelationId, RowExclusiveLock); ScanKeyInit(&key[0], Anum_pg_depend_refclassid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(RelationRelationId)); ScanKeyInit(&key[1], Anum_pg_depend_refobjid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(RelationGetRelid(rel))); ScanKeyInit(&key[2], Anum_pg_depend_refobjsubid, BTEqualStrategyNumber, F_INT4EQ, Int32GetDatum((int32) attnum)); scan = systable_beginscan(depRel, DependReferenceIndexId, true, SnapshotNow, 3, key); while (HeapTupleIsValid(depTup = systable_getnext(scan))) { Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(depTup); ObjectAddress foundObject; /* We don't expect any PIN dependencies on columns */ if (foundDep->deptype == DEPENDENCY_PIN) elog(ERROR, "cannot alter type of a pinned column"); foundObject.classId = foundDep->classid; foundObject.objectId = foundDep->objid; foundObject.objectSubId = foundDep->objsubid; switch (getObjectClass(&foundObject)) { case OCLASS_CLASS: { char relKind = get_rel_relkind(foundObject.objectId); if (relKind == RELKIND_INDEX) { Assert(foundObject.objectSubId == 0); if (!list_member_oid(tab->changedIndexOids, foundObject.objectId)) { tab->changedIndexOids = lappend_oid(tab->changedIndexOids, foundObject.objectId); tab->changedIndexDefs = lappend(tab->changedIndexDefs, pg_get_indexdef_string(foundObject.objectId)); } } else if (relKind == RELKIND_SEQUENCE) { /* * This must be a SERIAL column's sequence. We need * not do anything to it. */ Assert(foundObject.objectSubId == 0); } else { /* Not expecting any other direct dependencies... */ elog(ERROR, "unexpected object depending on column: %s", getObjectDescription(&foundObject)); } break; } case OCLASS_CONSTRAINT: Assert(foundObject.objectSubId == 0); if (!list_member_oid(tab->changedConstraintOids, foundObject.objectId)) { char *defstring = pg_get_constraintdef_string(foundObject.objectId); /* * Put NORMAL dependencies at the front of the list and * AUTO dependencies at the back. This makes sure that * foreign-key constraints depending on this column will * be dropped before unique or primary-key constraints of * the column; which we must have because the FK * constraints depend on the indexes belonging to the * unique constraints. */ if (foundDep->deptype == DEPENDENCY_NORMAL) { tab->changedConstraintOids = lcons_oid(foundObject.objectId, tab->changedConstraintOids); tab->changedConstraintDefs = lcons(defstring, tab->changedConstraintDefs); } else { tab->changedConstraintOids = lappend_oid(tab->changedConstraintOids, foundObject.objectId); tab->changedConstraintDefs = lappend(tab->changedConstraintDefs, defstring); } } break; case OCLASS_REWRITE: /* XXX someday see if we can cope with revising views */ ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot alter type of a column used by a view or rule"), errdetail("%s depends on column \"%s\"", getObjectDescription(&foundObject), colName))); break; case OCLASS_DEFAULT: /* * Ignore the column's default expression, since we will fix * it below. */ Assert(defaultexpr); break; case OCLASS_PROC: case OCLASS_TYPE: case OCLASS_CAST: case OCLASS_CONVERSION: case OCLASS_LANGUAGE: case OCLASS_OPERATOR: case OCLASS_OPCLASS: case OCLASS_TRIGGER: case OCLASS_SCHEMA: /* * We don't expect any of these sorts of objects to depend on * a column. */ elog(ERROR, "unexpected object depending on column: %s", getObjectDescription(&foundObject)); break; default: elog(ERROR, "unrecognized object class: %u", foundObject.classId); } } systable_endscan(scan); /* * Now scan for dependencies of this column on other things. The only * thing we should find is the dependency on the column datatype, which we * want to remove. */ ScanKeyInit(&key[0], Anum_pg_depend_classid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(RelationRelationId)); ScanKeyInit(&key[1], Anum_pg_depend_objid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(RelationGetRelid(rel))); ScanKeyInit(&key[2], Anum_pg_depend_objsubid, BTEqualStrategyNumber, F_INT4EQ, Int32GetDatum((int32) attnum)); scan = systable_beginscan(depRel, DependDependerIndexId, true, SnapshotNow, 3, key); while (HeapTupleIsValid(depTup = systable_getnext(scan))) { Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(depTup); if (foundDep->deptype != DEPENDENCY_NORMAL) elog(ERROR, "found unexpected dependency type '%c'", foundDep->deptype); if (foundDep->refclassid != TypeRelationId || foundDep->refobjid != attTup->atttypid) elog(ERROR, "found unexpected dependency for column"); simple_heap_delete(depRel, &depTup->t_self); } systable_endscan(scan); heap_close(depRel, RowExclusiveLock); /* * Here we go --- change the recorded column type. (Note heapTup is a * copy of the syscache entry, so okay to scribble on.) */ attTup->atttypid = targettype; attTup->atttypmod = targettypmod; attTup->attndims = list_length(typename->arrayBounds); attTup->attlen = tform->typlen; attTup->attbyval = tform->typbyval; attTup->attalign = tform->typalign; attTup->attstorage = tform->typstorage; ReleaseSysCache(typeTuple); simple_heap_update(attrelation, &heapTup->t_self, heapTup); /* keep system catalog indexes current */ CatalogUpdateIndexes(attrelation, heapTup); heap_close(attrelation, RowExclusiveLock); /* Install dependency on new datatype */ add_column_datatype_dependency(RelationGetRelid(rel), attnum, targettype); /* * Drop any pg_statistic entry for the column, since it's now wrong type */ RemoveStatistics(RelationGetRelid(rel), attnum); /* * Update the default, if present, by brute force --- remove and re-add * the default. Probably unsafe to take shortcuts, since the new version * may well have additional dependencies. (It's okay to do this now, * rather than after other ALTER TYPE commands, since the default won't * depend on other column types.) */ if (defaultexpr) { /* Must make new row visible since it will be updated again */ CommandCounterIncrement(); /* * We use RESTRICT here for safety, but at present we do not expect * anything to depend on the default. */ RemoveAttrDefault(RelationGetRelid(rel), attnum, DROP_RESTRICT, true); StoreAttrDefault(rel, attnum, nodeToString(defaultexpr)); } /* Cleanup */ heap_freetuple(heapTup); } /* * Cleanup after we've finished all the ALTER TYPE operations for a * particular relation. We have to drop and recreate all the indexes * and constraints that depend on the altered columns. */ static void ATPostAlterTypeCleanup(List **wqueue, AlteredTableInfo *tab) { ObjectAddress obj; ListCell *l; /* * Re-parse the index and constraint definitions, and attach them to the * appropriate work queue entries. We do this before dropping because in * the case of a FOREIGN KEY constraint, we might not yet have exclusive * lock on the table the constraint is attached to, and we need to get * that before dropping. It's safe because the parser won't actually look * at the catalogs to detect the existing entry. */ foreach(l, tab->changedIndexDefs) ATPostAlterTypeParse((char *) lfirst(l), wqueue); foreach(l, tab->changedConstraintDefs) ATPostAlterTypeParse((char *) lfirst(l), wqueue); /* * Now we can drop the existing constraints and indexes --- constraints * first, since some of them might depend on the indexes. In fact, we * have to delete FOREIGN KEY constraints before UNIQUE constraints, but * we already ordered the constraint list to ensure that would happen. It * should be okay to use DROP_RESTRICT here, since nothing else should be * depending on these objects. */ foreach(l, tab->changedConstraintOids) { obj.classId = ConstraintRelationId; obj.objectId = lfirst_oid(l); obj.objectSubId = 0; performDeletion(&obj, DROP_RESTRICT); } foreach(l, tab->changedIndexOids) { obj.classId = RelationRelationId; obj.objectId = lfirst_oid(l); obj.objectSubId = 0; performDeletion(&obj, DROP_RESTRICT); } /* * The objects will get recreated during subsequent passes over the work * queue. */ } static void ATPostAlterTypeParse(char *cmd, List **wqueue) { List *raw_parsetree_list; List *querytree_list; ListCell *list_item; /* * We expect that we only have to do raw parsing and parse analysis, not * any rule rewriting, since these will all be utility statements. */ raw_parsetree_list = raw_parser(cmd); querytree_list = NIL; foreach(list_item, raw_parsetree_list) { Node *parsetree = (Node *) lfirst(list_item); querytree_list = list_concat(querytree_list, parse_analyze(parsetree, cmd, NULL, 0)); } /* * Attach each generated command to the proper place in the work queue. * Note this could result in creation of entirely new work-queue entries. */ foreach(list_item, querytree_list) { Query *query = (Query *) lfirst(list_item); Relation rel; AlteredTableInfo *tab; Assert(IsA(query, Query)); Assert(query->commandType == CMD_UTILITY); switch (nodeTag(query->utilityStmt)) { case T_IndexStmt: { IndexStmt *stmt = (IndexStmt *) query->utilityStmt; AlterTableCmd *newcmd; rel = relation_openrv(stmt->relation, AccessExclusiveLock); tab = ATGetQueueEntry(wqueue, rel); newcmd = makeNode(AlterTableCmd); newcmd->subtype = AT_ReAddIndex; newcmd->def = (Node *) stmt; tab->subcmds[AT_PASS_OLD_INDEX] = lappend(tab->subcmds[AT_PASS_OLD_INDEX], newcmd); relation_close(rel, NoLock); break; } case T_AlterTableStmt: { AlterTableStmt *stmt = (AlterTableStmt *) query->utilityStmt; ListCell *lcmd; rel = relation_openrv(stmt->relation, AccessExclusiveLock); tab = ATGetQueueEntry(wqueue, rel); foreach(lcmd, stmt->cmds) { AlterTableCmd *cmd = (AlterTableCmd *) lfirst(lcmd); switch (cmd->subtype) { case AT_AddIndex: cmd->subtype = AT_ReAddIndex; tab->subcmds[AT_PASS_OLD_INDEX] = lappend(tab->subcmds[AT_PASS_OLD_INDEX], cmd); break; case AT_AddConstraint: tab->subcmds[AT_PASS_OLD_CONSTR] = lappend(tab->subcmds[AT_PASS_OLD_CONSTR], cmd); break; default: elog(ERROR, "unexpected statement type: %d", (int) cmd->subtype); } } relation_close(rel, NoLock); break; } default: elog(ERROR, "unexpected statement type: %d", (int) nodeTag(query->utilityStmt)); } } } /* * ALTER TABLE OWNER * * recursing is true if we are recursing from a table to its indexes, * sequences, or toast table. We don't allow the ownership of those things to * be changed separately from the parent table. Also, we can skip permission * checks (this is necessary not just an optimization, else we'd fail to * handle toast tables properly). * * recursing is also true if ALTER TYPE OWNER is calling us to fix up a * free-standing composite type. */ void ATExecChangeOwner(Oid relationOid, Oid newOwnerId, bool recursing) { Relation target_rel; Relation class_rel; HeapTuple tuple; Form_pg_class tuple_class; /* * Get exclusive lock till end of transaction on the target table. Use * relation_open so that we can work on indexes and sequences. */ target_rel = relation_open(relationOid, AccessExclusiveLock); /* Get its pg_class tuple, too */ class_rel = heap_open(RelationRelationId, RowExclusiveLock); tuple = SearchSysCache(RELOID, ObjectIdGetDatum(relationOid), 0, 0, 0); if (!HeapTupleIsValid(tuple)) elog(ERROR, "cache lookup failed for relation %u", relationOid); tuple_class = (Form_pg_class) GETSTRUCT(tuple); /* Can we change the ownership of this tuple? */ switch (tuple_class->relkind) { case RELKIND_RELATION: case RELKIND_VIEW: /* ok to change owner */ break; case RELKIND_INDEX: if (!recursing) { /* * Because ALTER INDEX OWNER used to be allowed, and in fact * is generated by old versions of pg_dump, we give a warning * and do nothing rather than erroring out. Also, to avoid * unnecessary chatter while restoring those old dumps, say * nothing at all if the command would be a no-op anyway. */ if (tuple_class->relowner != newOwnerId) ereport(WARNING, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("cannot change owner of index \"%s\"", NameStr(tuple_class->relname)), errhint("Change the ownership of the index's table, instead."))); /* quick hack to exit via the no-op path */ newOwnerId = tuple_class->relowner; } break; case RELKIND_SEQUENCE: if (!recursing && tuple_class->relowner != newOwnerId) { /* if it's an owned sequence, disallow changing it by itself */ Oid tableId; int32 colId; if (sequenceIsOwned(relationOid, &tableId, &colId)) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot change owner of sequence \"%s\"", NameStr(tuple_class->relname)), errdetail("Sequence \"%s\" is linked to table \"%s\".", NameStr(tuple_class->relname), get_rel_name(tableId)))); } break; case RELKIND_TOASTVALUE: case RELKIND_COMPOSITE_TYPE: if (recursing) break; /* FALL THRU */ default: ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("\"%s\" is not a table, view, or sequence", NameStr(tuple_class->relname)))); } /* * If the new owner is the same as the existing owner, consider the * command to have succeeded. This is for dump restoration purposes. */ if (tuple_class->relowner != newOwnerId) { Datum repl_val[Natts_pg_class]; char repl_null[Natts_pg_class]; char repl_repl[Natts_pg_class]; Acl *newAcl; Datum aclDatum; bool isNull; HeapTuple newtuple; /* skip permission checks when recursing to index or toast table */ if (!recursing) { /* Superusers can always do it */ if (!superuser()) { Oid namespaceOid = tuple_class->relnamespace; AclResult aclresult; /* Otherwise, must be owner of the existing object */ if (!pg_class_ownercheck(relationOid, GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS, RelationGetRelationName(target_rel)); /* Must be able to become new owner */ check_is_member_of_role(GetUserId(), newOwnerId); /* New owner must have CREATE privilege on namespace */ aclresult = pg_namespace_aclcheck(namespaceOid, newOwnerId, ACL_CREATE); if (aclresult != ACLCHECK_OK) aclcheck_error(aclresult, ACL_KIND_NAMESPACE, get_namespace_name(namespaceOid)); } } memset(repl_null, ' ', sizeof(repl_null)); memset(repl_repl, ' ', sizeof(repl_repl)); repl_repl[Anum_pg_class_relowner - 1] = 'r'; repl_val[Anum_pg_class_relowner - 1] = ObjectIdGetDatum(newOwnerId); /* * Determine the modified ACL for the new owner. This is only * necessary when the ACL is non-null. */ aclDatum = SysCacheGetAttr(RELOID, tuple, Anum_pg_class_relacl, &isNull); if (!isNull) { newAcl = aclnewowner(DatumGetAclP(aclDatum), tuple_class->relowner, newOwnerId); repl_repl[Anum_pg_class_relacl - 1] = 'r'; repl_val[Anum_pg_class_relacl - 1] = PointerGetDatum(newAcl); } newtuple = heap_modifytuple(tuple, RelationGetDescr(class_rel), repl_val, repl_null, repl_repl); simple_heap_update(class_rel, &newtuple->t_self, newtuple); CatalogUpdateIndexes(class_rel, newtuple); heap_freetuple(newtuple); /* * Update owner dependency reference, if any. A composite type has * none, because it's tracked for the pg_type entry instead of here; * indexes don't have their own entries either. */ if (tuple_class->relkind != RELKIND_COMPOSITE_TYPE && tuple_class->relkind != RELKIND_INDEX) changeDependencyOnOwner(RelationRelationId, relationOid, newOwnerId); /* * Also change the ownership of the table's rowtype, if it has one */ if (tuple_class->relkind != RELKIND_INDEX) AlterTypeOwnerInternal(tuple_class->reltype, newOwnerId, tuple_class->relkind == RELKIND_COMPOSITE_TYPE); /* * If we are operating on a table, also change the ownership of any * indexes and sequences that belong to the table, as well as the * table's toast table (if it has one) */ if (tuple_class->relkind == RELKIND_RELATION || tuple_class->relkind == RELKIND_TOASTVALUE) { List *index_oid_list; ListCell *i; /* Find all the indexes belonging to this relation */ index_oid_list = RelationGetIndexList(target_rel); /* For each index, recursively change its ownership */ foreach(i, index_oid_list) ATExecChangeOwner(lfirst_oid(i), newOwnerId, true); list_free(index_oid_list); } if (tuple_class->relkind == RELKIND_RELATION) { /* If it has a toast table, recurse to change its ownership */ if (tuple_class->reltoastrelid != InvalidOid) ATExecChangeOwner(tuple_class->reltoastrelid, newOwnerId, true); /* If it has dependent sequences, recurse to change them too */ change_owner_recurse_to_sequences(relationOid, newOwnerId); } } ReleaseSysCache(tuple); heap_close(class_rel, RowExclusiveLock); relation_close(target_rel, NoLock); } /* * change_owner_recurse_to_sequences * * Helper function for ATExecChangeOwner. Examines pg_depend searching * for sequences that are dependent on serial columns, and changes their * ownership. */ static void change_owner_recurse_to_sequences(Oid relationOid, Oid newOwnerId) { Relation depRel; SysScanDesc scan; ScanKeyData key[2]; HeapTuple tup; /* * SERIAL sequences are those having an auto dependency on one of the * table's columns (we don't care *which* column, exactly). */ depRel = heap_open(DependRelationId, AccessShareLock); ScanKeyInit(&key[0], Anum_pg_depend_refclassid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(RelationRelationId)); ScanKeyInit(&key[1], Anum_pg_depend_refobjid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(relationOid)); /* we leave refobjsubid unspecified */ scan = systable_beginscan(depRel, DependReferenceIndexId, true, SnapshotNow, 2, key); while (HeapTupleIsValid(tup = systable_getnext(scan))) { Form_pg_depend depForm = (Form_pg_depend) GETSTRUCT(tup); Relation seqRel; /* skip dependencies other than auto dependencies on columns */ if (depForm->refobjsubid == 0 || depForm->classid != RelationRelationId || depForm->objsubid != 0 || depForm->deptype != DEPENDENCY_AUTO) continue; /* Use relation_open just in case it's an index */ seqRel = relation_open(depForm->objid, AccessExclusiveLock); /* skip non-sequence relations */ if (RelationGetForm(seqRel)->relkind != RELKIND_SEQUENCE) { /* No need to keep the lock */ relation_close(seqRel, AccessExclusiveLock); continue; } /* We don't need to close the sequence while we alter it. */ ATExecChangeOwner(depForm->objid, newOwnerId, true); /* Now we can close it. Keep the lock till end of transaction. */ relation_close(seqRel, NoLock); } systable_endscan(scan); relation_close(depRel, AccessShareLock); } /* * ALTER TABLE CLUSTER ON * * The only thing we have to do is to change the indisclustered bits. */ static void ATExecClusterOn(Relation rel, const char *indexName) { Oid indexOid; indexOid = get_relname_relid(indexName, rel->rd_rel->relnamespace); if (!OidIsValid(indexOid)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("index \"%s\" for table \"%s\" does not exist", indexName, RelationGetRelationName(rel)))); /* Check index is valid to cluster on */ check_index_is_clusterable(rel, indexOid, false); /* And do the work */ mark_index_clustered(rel, indexOid); } /* * ALTER TABLE SET WITHOUT CLUSTER * * We have to find any indexes on the table that have indisclustered bit * set and turn it off. */ static void ATExecDropCluster(Relation rel) { mark_index_clustered(rel, InvalidOid); } /* * ALTER TABLE SET TABLESPACE */ static void ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel, char *tablespacename) { Oid tablespaceId; AclResult aclresult; /* Check that the tablespace exists */ tablespaceId = get_tablespace_oid(tablespacename); if (!OidIsValid(tablespaceId)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("tablespace \"%s\" does not exist", tablespacename))); /* Check its permissions */ aclresult = pg_tablespace_aclcheck(tablespaceId, GetUserId(), ACL_CREATE); if (aclresult != ACLCHECK_OK) aclcheck_error(aclresult, ACL_KIND_TABLESPACE, tablespacename); /* Save info for Phase 3 to do the real work */ if (OidIsValid(tab->newTableSpace)) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("cannot have multiple SET TABLESPACE subcommands"))); tab->newTableSpace = tablespaceId; } /* * ALTER TABLE/INDEX SET (...) or RESET (...) */ static void ATExecSetRelOptions(Relation rel, List *defList, bool isReset) { Oid relid; Relation pgclass; HeapTuple tuple; HeapTuple newtuple; Datum datum; bool isnull; Datum newOptions; Datum repl_val[Natts_pg_class]; char repl_null[Natts_pg_class]; char repl_repl[Natts_pg_class]; if (defList == NIL) return; /* nothing to do */ pgclass = heap_open(RelationRelationId, RowExclusiveLock); /* Get the old reloptions */ relid = RelationGetRelid(rel); tuple = SearchSysCache(RELOID, ObjectIdGetDatum(relid), 0, 0, 0); if (!HeapTupleIsValid(tuple)) elog(ERROR, "cache lookup failed for relation %u", relid); datum = SysCacheGetAttr(RELOID, tuple, Anum_pg_class_reloptions, &isnull); /* Generate new proposed reloptions (text array) */ newOptions = transformRelOptions(isnull ? (Datum) 0 : datum, defList, false, isReset); /* Validate */ switch (rel->rd_rel->relkind) { case RELKIND_RELATION: case RELKIND_TOASTVALUE: (void) heap_reloptions(rel->rd_rel->relkind, newOptions, true); break; case RELKIND_INDEX: (void) index_reloptions(rel->rd_am->amoptions, newOptions, true); break; default: ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("\"%s\" is not a table, index, or TOAST table", RelationGetRelationName(rel)))); break; } /* * All we need do here is update the pg_class row; the new options will be * propagated into relcaches during post-commit cache inval. */ memset(repl_val, 0, sizeof(repl_val)); memset(repl_null, ' ', sizeof(repl_null)); memset(repl_repl, ' ', sizeof(repl_repl)); if (newOptions != (Datum) 0) repl_val[Anum_pg_class_reloptions - 1] = newOptions; else repl_null[Anum_pg_class_reloptions - 1] = 'n'; repl_repl[Anum_pg_class_reloptions - 1] = 'r'; newtuple = heap_modifytuple(tuple, RelationGetDescr(pgclass), repl_val, repl_null, repl_repl); simple_heap_update(pgclass, &newtuple->t_self, newtuple); CatalogUpdateIndexes(pgclass, newtuple); heap_freetuple(newtuple); ReleaseSysCache(tuple); heap_close(pgclass, RowExclusiveLock); } /* * Execute ALTER TABLE SET TABLESPACE for cases where there is no tuple * rewriting to be done, so we just want to copy the data as fast as possible. */ static void ATExecSetTableSpace(Oid tableOid, Oid newTableSpace) { Relation rel; Oid oldTableSpace; Oid reltoastrelid; Oid reltoastidxid; RelFileNode newrnode; SMgrRelation dstrel; Relation pg_class; HeapTuple tuple; Form_pg_class rd_rel; /* * Need lock here in case we are recursing to toast table or index */ rel = relation_open(tableOid, AccessExclusiveLock); /* * We can never allow moving of shared or nailed-in-cache relations, * because we can't support changing their reltablespace values. */ if (rel->rd_rel->relisshared || rel->rd_isnailed) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot move system relation \"%s\"", RelationGetRelationName(rel)))); /* * Don't allow moving temp tables of other backends ... their local buffer * manager is not going to cope. */ if (isOtherTempNamespace(RelationGetNamespace(rel))) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot move temporary tables of other sessions"))); /* * No work if no change in tablespace. */ oldTableSpace = rel->rd_rel->reltablespace; if (newTableSpace == oldTableSpace || (newTableSpace == MyDatabaseTableSpace && oldTableSpace == 0)) { relation_close(rel, NoLock); return; } reltoastrelid = rel->rd_rel->reltoastrelid; reltoastidxid = rel->rd_rel->reltoastidxid; /* Get a modifiable copy of the relation's pg_class row */ pg_class = heap_open(RelationRelationId, RowExclusiveLock); tuple = SearchSysCacheCopy(RELOID, ObjectIdGetDatum(tableOid), 0, 0, 0); if (!HeapTupleIsValid(tuple)) elog(ERROR, "cache lookup failed for relation %u", tableOid); rd_rel = (Form_pg_class) GETSTRUCT(tuple); /* create another storage file. Is it a little ugly ? */ /* NOTE: any conflict in relfilenode value will be caught here */ newrnode = rel->rd_node; newrnode.spcNode = newTableSpace; dstrel = smgropen(newrnode); smgrcreate(dstrel, rel->rd_istemp, false); /* copy relation data to the new physical file */ copy_relation_data(rel, dstrel); /* schedule unlinking old physical file */ RelationOpenSmgr(rel); smgrscheduleunlink(rel->rd_smgr, rel->rd_istemp); /* * Now drop smgr references. The source was already dropped by * smgrscheduleunlink. */ smgrclose(dstrel); /* update the pg_class row */ rd_rel->reltablespace = (newTableSpace == MyDatabaseTableSpace) ? InvalidOid : newTableSpace; simple_heap_update(pg_class, &tuple->t_self, tuple); CatalogUpdateIndexes(pg_class, tuple); heap_freetuple(tuple); heap_close(pg_class, RowExclusiveLock); relation_close(rel, NoLock); /* Make sure the reltablespace change is visible */ CommandCounterIncrement(); /* Move associated toast relation and/or index, too */ if (OidIsValid(reltoastrelid)) ATExecSetTableSpace(reltoastrelid, newTableSpace); if (OidIsValid(reltoastidxid)) ATExecSetTableSpace(reltoastidxid, newTableSpace); } /* * Copy data, block by block */ static void copy_relation_data(Relation rel, SMgrRelation dst) { SMgrRelation src; bool use_wal; BlockNumber nblocks; BlockNumber blkno; char buf[BLCKSZ]; Page page = (Page) buf; /* * Since we copy the file directly without looking at the shared buffers, * we'd better first flush out any pages of the source relation that are * in shared buffers. We assume no new changes will be made while we are * holding exclusive lock on the rel. */ FlushRelationBuffers(rel); /* * We need to log the copied data in WAL iff WAL archiving is enabled AND * it's not a temp rel. */ use_wal = XLogArchivingActive() && !rel->rd_istemp; nblocks = RelationGetNumberOfBlocks(rel); /* RelationGetNumberOfBlocks will certainly have opened rd_smgr */ src = rel->rd_smgr; for (blkno = 0; blkno < nblocks; blkno++) { smgrread(src, blkno, buf); /* XLOG stuff */ if (use_wal) log_newpage(&dst->smgr_rnode, blkno, page); /* * Now write the page. We say isTemp = true even if it's not a temp * rel, because there's no need for smgr to schedule an fsync for this * write; we'll do it ourselves below. */ smgrextend(dst, blkno, buf, true); } /* * If the rel isn't temp, we must fsync it down to disk before it's safe * to commit the transaction. (For a temp rel we don't care since the rel * will be uninteresting after a crash anyway.) * * It's obvious that we must do this when not WAL-logging the copy. It's * less obvious that we have to do it even if we did WAL-log the copied * pages. The reason is that since we're copying outside shared buffers, a * CHECKPOINT occurring during the copy has no way to flush the previously * written data to disk (indeed it won't know the new rel even exists). A * crash later on would replay WAL from the checkpoint, therefore it * wouldn't replay our earlier WAL entries. If we do not fsync those pages * here, they might still not be on disk when the crash occurs. */ if (!rel->rd_istemp) smgrimmedsync(dst); } /* * ALTER TABLE ENABLE/DISABLE TRIGGER * * We just pass this off to trigger.c. */ static void ATExecEnableDisableTrigger(Relation rel, char *trigname, char fires_when, bool skip_system) { EnableDisableTrigger(rel, trigname, fires_when, skip_system); } /* * ALTER TABLE ENABLE/DISABLE RULE * * We just pass this off to rewriteDefine.c. */ static void ATExecEnableDisableRule(Relation rel, char *trigname, char fires_when) { EnableDisableRule(rel, trigname, fires_when); } /* * ALTER TABLE INHERIT * * Add a parent to the child's parents. This verifies that all the columns and * check constraints of the parent appear in the child and that they have the * same data types and expressions. */ static void ATExecAddInherit(Relation child_rel, RangeVar *parent) { Relation parent_rel, catalogRelation; SysScanDesc scan; ScanKeyData key; HeapTuple inheritsTuple; int32 inhseqno; List *children; /* * AccessShareLock on the parent is what's obtained during normal CREATE * TABLE ... INHERITS ..., so should be enough here. */ parent_rel = heap_openrv(parent, AccessShareLock); /* * Must be owner of both parent and child -- child was checked by * ATSimplePermissions call in ATPrepCmd */ ATSimplePermissions(parent_rel, false); /* Permanent rels cannot inherit from temporary ones */ if (!isTempNamespace(RelationGetNamespace(child_rel)) && isTempNamespace(RelationGetNamespace(parent_rel))) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("cannot inherit from temporary relation \"%s\"", RelationGetRelationName(parent_rel)))); /* * Check for duplicates in the list of parents, and determine the highest * inhseqno already present; we'll use the next one for the new parent. * (Note: get RowExclusiveLock because we will write pg_inherits below.) * * Note: we do not reject the case where the child already inherits from * the parent indirectly; CREATE TABLE doesn't reject comparable cases. */ catalogRelation = heap_open(InheritsRelationId, RowExclusiveLock); ScanKeyInit(&key, Anum_pg_inherits_inhrelid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(RelationGetRelid(child_rel))); scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndexId, true, SnapshotNow, 1, &key); /* inhseqno sequences start at 1 */ inhseqno = 0; while (HeapTupleIsValid(inheritsTuple = systable_getnext(scan))) { Form_pg_inherits inh = (Form_pg_inherits) GETSTRUCT(inheritsTuple); if (inh->inhparent == RelationGetRelid(parent_rel)) ereport(ERROR, (errcode(ERRCODE_DUPLICATE_TABLE), errmsg("inherited relation \"%s\" duplicated", RelationGetRelationName(parent_rel)))); if (inh->inhseqno > inhseqno) inhseqno = inh->inhseqno; } systable_endscan(scan); /* * Prevent circularity by seeing if proposed parent inherits from child. * (In particular, this disallows making a rel inherit from itself.) * * This is not completely bulletproof because of race conditions: in * multi-level inheritance trees, someone else could concurrently * be making another inheritance link that closes the loop but does * not join either of the rels we have locked. Preventing that seems * to require exclusive locks on the entire inheritance tree, which is * a cure worse than the disease. find_all_inheritors() will cope with * circularity anyway, so don't sweat it too much. */ children = find_all_inheritors(RelationGetRelid(child_rel)); if (list_member_oid(children, RelationGetRelid(parent_rel))) ereport(ERROR, (errcode(ERRCODE_DUPLICATE_TABLE), errmsg("circular inheritance not allowed"), errdetail("\"%s\" is already a child of \"%s\".", parent->relname, RelationGetRelationName(child_rel)))); /* If parent has OIDs then child must have OIDs */ if (parent_rel->rd_rel->relhasoids && !child_rel->rd_rel->relhasoids) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("table \"%s\" without OIDs cannot inherit from table \"%s\" with OIDs", RelationGetRelationName(child_rel), RelationGetRelationName(parent_rel)))); /* Match up the columns and bump attinhcount and attislocal */ MergeAttributesIntoExisting(child_rel, parent_rel); /* Match up the constraints and make sure they're present in child */ MergeConstraintsIntoExisting(child_rel, parent_rel); /* * OK, it looks valid. Make the catalog entries that show inheritance. */ StoreCatalogInheritance1(RelationGetRelid(child_rel), RelationGetRelid(parent_rel), inhseqno + 1, catalogRelation); /* Now we're done with pg_inherits */ heap_close(catalogRelation, RowExclusiveLock); /* keep our lock on the parent relation until commit */ heap_close(parent_rel, NoLock); } /* * Obtain the source-text form of the constraint expression for a check * constraint, given its pg_constraint tuple */ static char * decompile_conbin(HeapTuple contup, TupleDesc tupdesc) { Form_pg_constraint con; bool isnull; Datum attr; Datum expr; con = (Form_pg_constraint) GETSTRUCT(contup); attr = heap_getattr(contup, Anum_pg_constraint_conbin, tupdesc, &isnull); if (isnull) elog(ERROR, "null conbin for constraint %u", HeapTupleGetOid(contup)); expr = DirectFunctionCall2(pg_get_expr, attr, ObjectIdGetDatum(con->conrelid)); return DatumGetCString(DirectFunctionCall1(textout, expr)); } /* * Check columns in child table match up with columns in parent, and increment * their attinhcount. * * Called by ATExecAddInherit * * Currently all parent columns must be found in child. Missing columns are an * error. One day we might consider creating new columns like CREATE TABLE * does. However, that is widely unpopular --- in the common use case of * partitioned tables it's a foot-gun. * * The data type must match exactly. If the parent column is NOT NULL then * the child must be as well. Defaults are not compared, however. */ static void MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel) { Relation attrrel; AttrNumber parent_attno; int parent_natts; TupleDesc tupleDesc; TupleConstr *constr; HeapTuple tuple; attrrel = heap_open(AttributeRelationId, RowExclusiveLock); tupleDesc = RelationGetDescr(parent_rel); parent_natts = tupleDesc->natts; constr = tupleDesc->constr; for (parent_attno = 1; parent_attno <= parent_natts; parent_attno++) { Form_pg_attribute attribute = tupleDesc->attrs[parent_attno - 1]; char *attributeName = NameStr(attribute->attname); /* Ignore dropped columns in the parent. */ if (attribute->attisdropped) continue; /* Find same column in child (matching on column name). */ tuple = SearchSysCacheCopyAttName(RelationGetRelid(child_rel), attributeName); if (HeapTupleIsValid(tuple)) { /* Check they are same type and typmod */ Form_pg_attribute childatt = (Form_pg_attribute) GETSTRUCT(tuple); if (attribute->atttypid != childatt->atttypid || attribute->atttypmod != childatt->atttypmod) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("child table \"%s\" has different type for column \"%s\"", RelationGetRelationName(child_rel), attributeName))); if (attribute->attnotnull && !childatt->attnotnull) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("column \"%s\" in child table must be marked NOT NULL", attributeName))); /* * OK, bump the child column's inheritance count. (If we fail * later on, this change will just roll back.) */ childatt->attinhcount++; simple_heap_update(attrrel, &tuple->t_self, tuple); CatalogUpdateIndexes(attrrel, tuple); heap_freetuple(tuple); } else { ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("child table is missing column \"%s\"", attributeName))); } } heap_close(attrrel, RowExclusiveLock); } /* * Check constraints in child table match up with constraints in parent * * Called by ATExecAddInherit * * Currently all constraints in parent must be present in the child. One day we * may consider adding new constraints like CREATE TABLE does. We may also want * to allow an optional flag on parent table constraints indicating they are * intended to ONLY apply to the master table, not to the children. That would * make it possible to ensure no records are mistakenly inserted into the * master in partitioned tables rather than the appropriate child. * * XXX This is O(N^2) which may be an issue with tables with hundreds of * constraints. As long as tables have more like 10 constraints it shouldn't be * a problem though. Even 100 constraints ought not be the end of the world. */ static void MergeConstraintsIntoExisting(Relation child_rel, Relation parent_rel) { Relation catalogRelation; TupleDesc tupleDesc; SysScanDesc scan; ScanKeyData key; HeapTuple constraintTuple; ListCell *elem; List *constraints; /* First gather up the child's constraint definitions */ catalogRelation = heap_open(ConstraintRelationId, AccessShareLock); tupleDesc = RelationGetDescr(catalogRelation); ScanKeyInit(&key, Anum_pg_constraint_conrelid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(RelationGetRelid(child_rel))); scan = systable_beginscan(catalogRelation, ConstraintRelidIndexId, true, SnapshotNow, 1, &key); constraints = NIL; while (HeapTupleIsValid(constraintTuple = systable_getnext(scan))) { Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(constraintTuple); if (con->contype != CONSTRAINT_CHECK) continue; constraints = lappend(constraints, heap_copytuple(constraintTuple)); } systable_endscan(scan); /* Then scan through the parent's constraints looking for matches */ ScanKeyInit(&key, Anum_pg_constraint_conrelid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(RelationGetRelid(parent_rel))); scan = systable_beginscan(catalogRelation, ConstraintRelidIndexId, true, SnapshotNow, 1, &key); while (HeapTupleIsValid(constraintTuple = systable_getnext(scan))) { Form_pg_constraint parent_con = (Form_pg_constraint) GETSTRUCT(constraintTuple); bool found = false; Form_pg_constraint child_con = NULL; HeapTuple child_contuple = NULL; if (parent_con->contype != CONSTRAINT_CHECK) continue; foreach(elem, constraints) { child_contuple = (HeapTuple) lfirst(elem); child_con = (Form_pg_constraint) GETSTRUCT(child_contuple); if (strcmp(NameStr(parent_con->conname), NameStr(child_con->conname)) == 0) { found = true; break; } } if (!found) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("child table is missing constraint \"%s\"", NameStr(parent_con->conname)))); if (parent_con->condeferrable != child_con->condeferrable || parent_con->condeferred != child_con->condeferred || strcmp(decompile_conbin(constraintTuple, tupleDesc), decompile_conbin(child_contuple, tupleDesc)) != 0) ereport(ERROR, (errcode(ERRCODE_DATATYPE_MISMATCH), errmsg("constraint definition for check constraint \"%s\" does not match", NameStr(parent_con->conname)))); /* * TODO: add conislocal,coninhcount to constraints. This is where we * would have to bump them just like attributes */ } systable_endscan(scan); heap_close(catalogRelation, AccessShareLock); } /* * ALTER TABLE NO INHERIT * * Drop a parent from the child's parents. This just adjusts the attinhcount * and attislocal of the columns and removes the pg_inherit and pg_depend * entries. * * If attinhcount goes to 0 then attislocal gets set to true. If it goes back * up attislocal stays true, which means if a child is ever removed from a * parent then its columns will never be automatically dropped which may * surprise. But at least we'll never surprise by dropping columns someone * isn't expecting to be dropped which would actually mean data loss. */ static void ATExecDropInherit(Relation rel, RangeVar *parent) { Relation parent_rel; Relation catalogRelation; SysScanDesc scan; ScanKeyData key[3]; HeapTuple inheritsTuple, attributeTuple, depTuple; bool found = false; /* * AccessShareLock on the parent is probably enough, seeing that DROP TABLE * doesn't lock parent tables at all. We need some lock since we'll be * inspecting the parent's schema. */ parent_rel = heap_openrv(parent, AccessShareLock); /* * We don't bother to check ownership of the parent table --- ownership * of the child is presumed enough rights. */ /* * Find and destroy the pg_inherits entry linking the two, or error out * if there is none. */ catalogRelation = heap_open(InheritsRelationId, RowExclusiveLock); ScanKeyInit(&key[0], Anum_pg_inherits_inhrelid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(RelationGetRelid(rel))); scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndexId, true, SnapshotNow, 1, key); while (HeapTupleIsValid(inheritsTuple = systable_getnext(scan))) { Oid inhparent; inhparent = ((Form_pg_inherits) GETSTRUCT(inheritsTuple))->inhparent; if (inhparent == RelationGetRelid(parent_rel)) { simple_heap_delete(catalogRelation, &inheritsTuple->t_self); found = true; break; } } systable_endscan(scan); heap_close(catalogRelation, RowExclusiveLock); if (!found) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_TABLE), errmsg("relation \"%s\" is not a parent of relation \"%s\"", RelationGetRelationName(parent_rel), RelationGetRelationName(rel)))); /* * Search through child columns looking for ones matching parent rel */ catalogRelation = heap_open(AttributeRelationId, RowExclusiveLock); ScanKeyInit(&key[0], Anum_pg_attribute_attrelid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(RelationGetRelid(rel))); scan = systable_beginscan(catalogRelation, AttributeRelidNumIndexId, true, SnapshotNow, 1, key); while (HeapTupleIsValid(attributeTuple = systable_getnext(scan))) { Form_pg_attribute att = (Form_pg_attribute) GETSTRUCT(attributeTuple); /* Ignore if dropped or not inherited */ if (att->attisdropped) continue; if (att->attinhcount <= 0) continue; if (SearchSysCacheExistsAttName(RelationGetRelid(parent_rel), NameStr(att->attname))) { /* Decrement inhcount and possibly set islocal to true */ HeapTuple copyTuple = heap_copytuple(attributeTuple); Form_pg_attribute copy_att = (Form_pg_attribute) GETSTRUCT(copyTuple); copy_att->attinhcount--; if (copy_att->attinhcount == 0) copy_att->attislocal = true; simple_heap_update(catalogRelation, ©Tuple->t_self, copyTuple); CatalogUpdateIndexes(catalogRelation, copyTuple); heap_freetuple(copyTuple); } } systable_endscan(scan); heap_close(catalogRelation, RowExclusiveLock); /* * Drop the dependency * * There's no convenient way to do this, so go trawling through pg_depend */ catalogRelation = heap_open(DependRelationId, RowExclusiveLock); ScanKeyInit(&key[0], Anum_pg_depend_classid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(RelationRelationId)); ScanKeyInit(&key[1], Anum_pg_depend_objid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(RelationGetRelid(rel))); ScanKeyInit(&key[2], Anum_pg_depend_objsubid, BTEqualStrategyNumber, F_INT4EQ, Int32GetDatum(0)); scan = systable_beginscan(catalogRelation, DependDependerIndexId, true, SnapshotNow, 3, key); while (HeapTupleIsValid(depTuple = systable_getnext(scan))) { Form_pg_depend dep = (Form_pg_depend) GETSTRUCT(depTuple); if (dep->refclassid == RelationRelationId && dep->refobjid == RelationGetRelid(parent_rel) && dep->refobjsubid == 0 && dep->deptype == DEPENDENCY_NORMAL) simple_heap_delete(catalogRelation, &depTuple->t_self); } systable_endscan(scan); heap_close(catalogRelation, RowExclusiveLock); /* keep our lock on the parent relation until commit */ heap_close(parent_rel, NoLock); } /* * Execute ALTER TABLE SET SCHEMA * * Note: caller must have checked ownership of the relation already */ void AlterTableNamespace(RangeVar *relation, const char *newschema) { Relation rel; Oid relid; Oid oldNspOid; Oid nspOid; Relation classRel; rel = heap_openrv(relation, AccessExclusiveLock); relid = RelationGetRelid(rel); oldNspOid = RelationGetNamespace(rel); /* heap_openrv allows TOAST, but we don't want to */ if (rel->rd_rel->relkind == RELKIND_TOASTVALUE) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("\"%s\" is a TOAST relation", RelationGetRelationName(rel)))); /* if it's an owned sequence, disallow moving it by itself */ if (rel->rd_rel->relkind == RELKIND_SEQUENCE) { Oid tableId; int32 colId; if (sequenceIsOwned(relid, &tableId, &colId)) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot move an owned sequence into another schema"), errdetail("Sequence \"%s\" is linked to table \"%s\".", RelationGetRelationName(rel), get_rel_name(tableId)))); } /* get schema OID and check its permissions */ nspOid = LookupCreationNamespace(newschema); if (oldNspOid == nspOid) ereport(ERROR, (errcode(ERRCODE_DUPLICATE_TABLE), errmsg("relation \"%s\" is already in schema \"%s\"", RelationGetRelationName(rel), newschema))); /* disallow renaming into or out of temp schemas */ if (isAnyTempNamespace(nspOid) || isAnyTempNamespace(oldNspOid)) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot move objects into or out of temporary schemas"))); /* same for TOAST schema */ if (nspOid == PG_TOAST_NAMESPACE || oldNspOid == PG_TOAST_NAMESPACE) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot move objects into or out of TOAST schema"))); /* OK, modify the pg_class row and pg_depend entry */ classRel = heap_open(RelationRelationId, RowExclusiveLock); AlterRelationNamespaceInternal(classRel, relid, oldNspOid, nspOid, true); /* Fix the table's rowtype too */ AlterTypeNamespaceInternal(rel->rd_rel->reltype, nspOid, false, false); /* Fix other dependent stuff */ if (rel->rd_rel->relkind == RELKIND_RELATION) { AlterIndexNamespaces(classRel, rel, oldNspOid, nspOid); AlterSeqNamespaces(classRel, rel, oldNspOid, nspOid, newschema); AlterConstraintNamespaces(relid, oldNspOid, nspOid, false); } heap_close(classRel, RowExclusiveLock); /* close rel, but keep lock until commit */ relation_close(rel, NoLock); } /* * The guts of relocating a relation to another namespace: fix the pg_class * entry, and the pg_depend entry if any. Caller must already have * opened and write-locked pg_class. */ void AlterRelationNamespaceInternal(Relation classRel, Oid relOid, Oid oldNspOid, Oid newNspOid, bool hasDependEntry) { HeapTuple classTup; Form_pg_class classForm; classTup = SearchSysCacheCopy(RELOID, ObjectIdGetDatum(relOid), 0, 0, 0); if (!HeapTupleIsValid(classTup)) elog(ERROR, "cache lookup failed for relation %u", relOid); classForm = (Form_pg_class) GETSTRUCT(classTup); Assert(classForm->relnamespace == oldNspOid); /* check for duplicate name (more friendly than unique-index failure) */ if (get_relname_relid(NameStr(classForm->relname), newNspOid) != InvalidOid) ereport(ERROR, (errcode(ERRCODE_DUPLICATE_TABLE), errmsg("relation \"%s\" already exists in schema \"%s\"", NameStr(classForm->relname), get_namespace_name(newNspOid)))); /* classTup is a copy, so OK to scribble on */ classForm->relnamespace = newNspOid; simple_heap_update(classRel, &classTup->t_self, classTup); CatalogUpdateIndexes(classRel, classTup); /* Update dependency on schema if caller said so */ if (hasDependEntry && changeDependencyFor(RelationRelationId, relOid, NamespaceRelationId, oldNspOid, newNspOid) != 1) elog(ERROR, "failed to change schema dependency for relation \"%s\"", NameStr(classForm->relname)); heap_freetuple(classTup); } /* * Move all indexes for the specified relation to another namespace. * * Note: we assume adequate permission checking was done by the caller, * and that the caller has a suitable lock on the owning relation. */ static void AlterIndexNamespaces(Relation classRel, Relation rel, Oid oldNspOid, Oid newNspOid) { List *indexList; ListCell *l; indexList = RelationGetIndexList(rel); foreach(l, indexList) { Oid indexOid = lfirst_oid(l); /* * Note: currently, the index will not have its own dependency on the * namespace, so we don't need to do changeDependencyFor(). There's no * rowtype in pg_type, either. */ AlterRelationNamespaceInternal(classRel, indexOid, oldNspOid, newNspOid, false); } list_free(indexList); } /* * Move all SERIAL-column sequences of the specified relation to another * namespace. * * Note: we assume adequate permission checking was done by the caller, * and that the caller has a suitable lock on the owning relation. */ static void AlterSeqNamespaces(Relation classRel, Relation rel, Oid oldNspOid, Oid newNspOid, const char *newNspName) { Relation depRel; SysScanDesc scan; ScanKeyData key[2]; HeapTuple tup; /* * SERIAL sequences are those having an auto dependency on one of the * table's columns (we don't care *which* column, exactly). */ depRel = heap_open(DependRelationId, AccessShareLock); ScanKeyInit(&key[0], Anum_pg_depend_refclassid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(RelationRelationId)); ScanKeyInit(&key[1], Anum_pg_depend_refobjid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(RelationGetRelid(rel))); /* we leave refobjsubid unspecified */ scan = systable_beginscan(depRel, DependReferenceIndexId, true, SnapshotNow, 2, key); while (HeapTupleIsValid(tup = systable_getnext(scan))) { Form_pg_depend depForm = (Form_pg_depend) GETSTRUCT(tup); Relation seqRel; /* skip dependencies other than auto dependencies on columns */ if (depForm->refobjsubid == 0 || depForm->classid != RelationRelationId || depForm->objsubid != 0 || depForm->deptype != DEPENDENCY_AUTO) continue; /* Use relation_open just in case it's an index */ seqRel = relation_open(depForm->objid, AccessExclusiveLock); /* skip non-sequence relations */ if (RelationGetForm(seqRel)->relkind != RELKIND_SEQUENCE) { /* No need to keep the lock */ relation_close(seqRel, AccessExclusiveLock); continue; } /* Fix the pg_class and pg_depend entries */ AlterRelationNamespaceInternal(classRel, depForm->objid, oldNspOid, newNspOid, true); /* * Sequences have entries in pg_type. We need to be careful to move * them to the new namespace, too. */ AlterTypeNamespaceInternal(RelationGetForm(seqRel)->reltype, newNspOid, false, false); /* Now we can close it. Keep the lock till end of transaction. */ relation_close(seqRel, NoLock); } systable_endscan(scan); relation_close(depRel, AccessShareLock); } /* * This code supports * CREATE TEMP TABLE ... ON COMMIT { DROP | PRESERVE ROWS | DELETE ROWS } * * Because we only support this for TEMP tables, it's sufficient to remember * the state in a backend-local data structure. */ /* * Register a newly-created relation's ON COMMIT action. */ void register_on_commit_action(Oid relid, OnCommitAction action) { OnCommitItem *oc; MemoryContext oldcxt; /* * We needn't bother registering the relation unless there is an ON COMMIT * action we need to take. */ if (action == ONCOMMIT_NOOP || action == ONCOMMIT_PRESERVE_ROWS) return; oldcxt = MemoryContextSwitchTo(CacheMemoryContext); oc = (OnCommitItem *) palloc(sizeof(OnCommitItem)); oc->relid = relid; oc->oncommit = action; oc->creating_subid = GetCurrentSubTransactionId(); oc->deleting_subid = InvalidSubTransactionId; on_commits = lcons(oc, on_commits); MemoryContextSwitchTo(oldcxt); } /* * Unregister any ON COMMIT action when a relation is deleted. * * Actually, we only mark the OnCommitItem entry as to be deleted after commit. */ void remove_on_commit_action(Oid relid) { ListCell *l; foreach(l, on_commits) { OnCommitItem *oc = (OnCommitItem *) lfirst(l); if (oc->relid == relid) { oc->deleting_subid = GetCurrentSubTransactionId(); break; } } } /* * Perform ON COMMIT actions. * * This is invoked just before actually committing, since it's possible * to encounter errors. */ void PreCommit_on_commit_actions(void) { ListCell *l; List *oids_to_truncate = NIL; foreach(l, on_commits) { OnCommitItem *oc = (OnCommitItem *) lfirst(l); /* Ignore entry if already dropped in this xact */ if (oc->deleting_subid != InvalidSubTransactionId) continue; switch (oc->oncommit) { case ONCOMMIT_NOOP: case ONCOMMIT_PRESERVE_ROWS: /* Do nothing (there shouldn't be such entries, actually) */ break; case ONCOMMIT_DELETE_ROWS: oids_to_truncate = lappend_oid(oids_to_truncate, oc->relid); break; case ONCOMMIT_DROP: { ObjectAddress object; object.classId = RelationRelationId; object.objectId = oc->relid; object.objectSubId = 0; performDeletion(&object, DROP_CASCADE); /* * Note that table deletion will call * remove_on_commit_action, so the entry should get marked * as deleted. */ Assert(oc->deleting_subid != InvalidSubTransactionId); break; } } } if (oids_to_truncate != NIL) { heap_truncate(oids_to_truncate); CommandCounterIncrement(); /* XXX needed? */ } } /* * Post-commit or post-abort cleanup for ON COMMIT management. * * All we do here is remove no-longer-needed OnCommitItem entries. * * During commit, remove entries that were deleted during this transaction; * during abort, remove those created during this transaction. */ void AtEOXact_on_commit_actions(bool isCommit) { ListCell *cur_item; ListCell *prev_item; prev_item = NULL; cur_item = list_head(on_commits); while (cur_item != NULL) { OnCommitItem *oc = (OnCommitItem *) lfirst(cur_item); if (isCommit ? oc->deleting_subid != InvalidSubTransactionId : oc->creating_subid != InvalidSubTransactionId) { /* cur_item must be removed */ on_commits = list_delete_cell(on_commits, cur_item, prev_item); pfree(oc); if (prev_item) cur_item = lnext(prev_item); else cur_item = list_head(on_commits); } else { /* cur_item must be preserved */ oc->creating_subid = InvalidSubTransactionId; oc->deleting_subid = InvalidSubTransactionId; prev_item = cur_item; cur_item = lnext(prev_item); } } } /* * Post-subcommit or post-subabort cleanup for ON COMMIT management. * * During subabort, we can immediately remove entries created during this * subtransaction. During subcommit, just relabel entries marked during * this subtransaction as being the parent's responsibility. */ void AtEOSubXact_on_commit_actions(bool isCommit, SubTransactionId mySubid, SubTransactionId parentSubid) { ListCell *cur_item; ListCell *prev_item; prev_item = NULL; cur_item = list_head(on_commits); while (cur_item != NULL) { OnCommitItem *oc = (OnCommitItem *) lfirst(cur_item); if (!isCommit && oc->creating_subid == mySubid) { /* cur_item must be removed */ on_commits = list_delete_cell(on_commits, cur_item, prev_item); pfree(oc); if (prev_item) cur_item = lnext(prev_item); else cur_item = list_head(on_commits); } else { /* cur_item must be preserved */ if (oc->creating_subid == mySubid) oc->creating_subid = parentSubid; if (oc->deleting_subid == mySubid) oc->deleting_subid = isCommit ? parentSubid : InvalidSubTransactionId; prev_item = cur_item; cur_item = lnext(prev_item); } } }