/*------------------------------------------------------------------------- * * tablecmds.c * Commands for creating and altering table structures and settings * * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.165 2005/08/01 04:03:55 tgl Exp $ * *------------------------------------------------------------------------- */ #include "postgres.h" #include "access/genam.h" #include "access/tuptoaster.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 "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 "lib/stringinfo.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/parser.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 "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 */ 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 */ typedef struct NewConstraint { char *name; /* Constraint name, or NULL if none */ ConstrType contype; /* CHECK, NOT_NULL, or FOREIGN */ AttrNumber attnum; /* only relevant for NOT_NULL */ Oid refrelid; /* PK rel, 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 List *MergeAttributes(List *schema, List *supers, bool istemp, List **supOids, List **supconstr, int *supOidCount); static bool change_varattnos_of_a_node(Node *node, const AttrNumber *newattno); static void StoreCatalogInheritance(Oid relationId, List *supers); static int findAttrByName(const char *attributeName, List *schema); static void setRelhassubclassInRelation(Oid relationId, bool relhassubclass); static bool needs_toast_table(Relation rel); 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 void RebuildSerialDefaultExpr(Relation rel, AttrNumber attnum, const char *seqname, const char *nspname); 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); static void createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint, Oid constrOid); static char *fkMatchTypeToString(char match_type); 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 ATSimpleRecursion(List **wqueue, Relation rel, AlterTableCmd *cmd, bool recurse); static void ATOneLevelRecursion(List **wqueue, Relation rel, AlterTableCmd *cmd); static void find_composite_type_dependencies(Oid typeOid, const char *origTblName); 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 add_column_support_dependency(Oid relid, int32 attnum, RangeVar *support); 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 ATExecChangeOwner(Oid relationOid, Oid newOwnerId); 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 copy_relation_data(Relation rel, SMgrRelation dst); static void update_ri_trigger_args(Oid relid, const char *oldname, const char *newname, bool fk_scan, bool update_relname); /* ---------------------------------------------------------------- * 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; ListCell *listptr; int i; 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 */ } /* 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->hasoids); descriptor->tdhasoid = (localHasOids || parentOidCount > 0); if (old_constraints != NIL) { ConstrCheck *check = (ConstrCheck *) palloc0(list_length(old_constraints) * sizeof(ConstrCheck)); int ncheck = 0; foreach(listptr, old_constraints) { Constraint *cdef = (Constraint *) lfirst(listptr); bool dup = false; if (cdef->contype != CONSTR_CHECK) continue; Assert(cdef->name != NULL); Assert(cdef->raw_expr == NULL && cdef->cooked_expr != NULL); /* * In multiple-inheritance situations, it's possible to * inherit the same grandparent constraint through multiple * parents. Hence, discard inherited constraints that match as * to both name and expression. Otherwise, gripe if the names * conflict. */ for (i = 0; i < ncheck; i++) { if (strcmp(check[i].ccname, cdef->name) != 0) continue; if (strcmp(check[i].ccbin, cdef->cooked_expr) == 0) { dup = true; break; } ereport(ERROR, (errcode(ERRCODE_DUPLICATE_OBJECT), errmsg("duplicate check constraint name \"%s\"", cdef->name))); } if (!dup) { check[ncheck].ccname = cdef->name; check[ncheck].ccbin = pstrdup(cdef->cooked_expr); ncheck++; } } 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, descriptor, relkind, false, localHasOids, parentOidCount, stmt->oncommit, 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. * * Another task that's conveniently done at this step is to add * dependency links between columns and supporting relations (such as * SERIAL sequences). * * 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); } /* Create dependency for supporting relation for this column */ if (colDef->support != NULL) add_column_support_dependency(relationId, attnum, colDef->support); } /* * 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. It first opens and grabs exclusive * locks on all relations involved, checking permissions and otherwise * verifying that the relation is OK for truncation. When they are all * open, it checks foreign key references on them, namely that FK references * are all internal to the group that's being truncated. Finally all * relations are truncated and reindexed. */ void ExecuteTruncate(List *relations) { List *rels = NIL; ListCell *cell; foreach(cell, relations) { RangeVar *rv = lfirst(cell); Relation rel; /* Grab exclusive lock in preparation for truncate */ rel = heap_openrv(rv, AccessExclusiveLock); /* 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"))); /* Save it into the list of rels to truncate */ rels = lappend(rels, rel); } /* * Check foreign key references. */ heap_truncate_check_FKs(rels, false); /* * OK, truncate each table. */ foreach(cell, rels) { Relation rel = 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); } } /*---------- * 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; TypeName *typename; /* * 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) { /* * 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); if (typenameTypeId(def->typename) != attribute->atttypid || def->typename->typmod != 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); typename = makeNode(TypeName); typename->typeid = attribute->atttypid; typename->typmod = attribute->atttypmod; def->typename = typename; def->inhcount = 1; def->is_local = false; def->is_not_null = attribute->attnotnull; def->raw_default = NULL; def->cooked_default = NULL; def->constraints = NIL; def->support = NULL; 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; /* * 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); if (typenameTypeId(def->typename) != typenameTypeId(newdef->typename) || def->typename->typmod != newdef->typename->typmod) 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; } /* * complementary static functions for MergeAttributes(). * * Varattnos of pg_constraint.conbin must be rewritten when subclasses inherit * constraints from parent classes, since the inherited attributes could * be given different column numbers in multiple-inheritance cases. * * Note that the passed node tree is modified in place! */ 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); } static bool change_varattnos_of_a_node(Node *node, const AttrNumber *newattno) { return change_varattnos_walker(node, newattno); } /* * 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; TupleDesc desc; int16 seqNumber; ListCell *entry; HeapTuple tuple; /* * 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); desc = RelationGetDescr(relation); seqNumber = 1; foreach(entry, supers) { Oid parentOid = lfirst_oid(entry); Datum datum[Natts_pg_inherits]; char nullarr[Natts_pg_inherits]; ObjectAddress childobject, parentobject; datum[0] = ObjectIdGetDatum(relationId); /* inhrel */ 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(relation, tuple); CatalogUpdateIndexes(relation, 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); seqNumber += 1; } heap_close(relation, RowExclusiveLock); } /* * 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); /* * Update att name in any RI triggers associated with the relation. */ if (targetrelation->rd_rel->reltriggers > 0) { /* update tgargs column reference where att is primary key */ update_ri_trigger_args(RelationGetRelid(targetrelation), oldattname, newattname, false, false); /* update tgargs column reference where att is foreign key */ update_ri_trigger_args(RelationGetRelid(targetrelation), oldattname, newattname, true, false); } 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; 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, PointerGetDatum(myrelid), 0, 0, 0); if (!HeapTupleIsValid(reltup)) /* shouldn't happen */ elog(ERROR, "cache lookup failed for relation %u", myrelid); 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(&(((Form_pg_class) GETSTRUCT(reltup))->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 (relkind != RELKIND_INDEX) TypeRename(oldrelname, namespaceId, newrelname); /* * Update rel name in any RI triggers associated with the relation. */ if (relhastriggers) { /* update tgargs where relname is primary key */ update_ri_trigger_args(myrelid, oldrelname, newrelname, false, true); /* update tgargs where relname is foreign key */ update_ri_trigger_args(myrelid, oldrelname, newrelname, true, true); } /* * Close rel, but keep exclusive lock! */ relation_close(targetrelation, NoLock); } /* * Scan pg_trigger for RI triggers that are on the specified relation * (if fk_scan is false) or have it as the tgconstrrel (if fk_scan * is true). Update RI trigger args fields matching oldname to contain * newname instead. If update_relname is true, examine the relname * fields; otherwise examine the attname fields. */ static void update_ri_trigger_args(Oid relid, const char *oldname, const char *newname, bool fk_scan, bool update_relname) { Relation tgrel; ScanKeyData skey[1]; SysScanDesc trigscan; HeapTuple tuple; Datum values[Natts_pg_trigger]; char nulls[Natts_pg_trigger]; char replaces[Natts_pg_trigger]; tgrel = heap_open(TriggerRelationId, RowExclusiveLock); if (fk_scan) { ScanKeyInit(&skey[0], Anum_pg_trigger_tgconstrrelid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(relid)); trigscan = systable_beginscan(tgrel, TriggerConstrRelidIndexId, true, SnapshotNow, 1, skey); } else { ScanKeyInit(&skey[0], Anum_pg_trigger_tgrelid, BTEqualStrategyNumber, F_OIDEQ, ObjectIdGetDatum(relid)); trigscan = systable_beginscan(tgrel, TriggerRelidNameIndexId, true, SnapshotNow, 1, skey); } while ((tuple = systable_getnext(trigscan)) != NULL) { Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple); bytea *val; bytea *newtgargs; bool isnull; int tg_type; bool examine_pk; bool changed; int tgnargs; int i; int newlen; const char *arga[RI_MAX_ARGUMENTS]; const char *argp; tg_type = RI_FKey_trigger_type(pg_trigger->tgfoid); if (tg_type == RI_TRIGGER_NONE) { /* Not an RI trigger, forget it */ continue; } /* * It is an RI trigger, so parse the tgargs bytea. * * NB: we assume the field will never be compressed or moved out of * line; so does trigger.c ... */ tgnargs = pg_trigger->tgnargs; val = (bytea *) DatumGetPointer(fastgetattr(tuple, Anum_pg_trigger_tgargs, tgrel->rd_att, &isnull)); if (isnull || tgnargs < RI_FIRST_ATTNAME_ARGNO || tgnargs > RI_MAX_ARGUMENTS) { /* This probably shouldn't happen, but ignore busted triggers */ continue; } argp = (const char *) VARDATA(val); for (i = 0; i < tgnargs; i++) { arga[i] = argp; argp += strlen(argp) + 1; } /* * Figure out which item(s) to look at. If the trigger is * primary-key type and attached to my rel, I should look at the * PK fields; if it is foreign-key type and attached to my rel, I * should look at the FK fields. But the opposite rule holds when * examining triggers found by tgconstrrel search. */ examine_pk = (tg_type == RI_TRIGGER_PK) == (!fk_scan); changed = false; if (update_relname) { /* Change the relname if needed */ i = examine_pk ? RI_PK_RELNAME_ARGNO : RI_FK_RELNAME_ARGNO; if (strcmp(arga[i], oldname) == 0) { arga[i] = newname; changed = true; } } else { /* Change attname(s) if needed */ i = examine_pk ? RI_FIRST_ATTNAME_ARGNO + RI_KEYPAIR_PK_IDX : RI_FIRST_ATTNAME_ARGNO + RI_KEYPAIR_FK_IDX; for (; i < tgnargs; i += 2) { if (strcmp(arga[i], oldname) == 0) { arga[i] = newname; changed = true; } } } if (!changed) { /* Don't need to update this tuple */ continue; } /* * Construct modified tgargs bytea. */ newlen = VARHDRSZ; for (i = 0; i < tgnargs; i++) newlen += strlen(arga[i]) + 1; newtgargs = (bytea *) palloc(newlen); VARATT_SIZEP(newtgargs) = newlen; newlen = VARHDRSZ; for (i = 0; i < tgnargs; i++) { strcpy(((char *) newtgargs) + newlen, arga[i]); newlen += strlen(arga[i]) + 1; } /* * Build modified tuple. */ for (i = 0; i < Natts_pg_trigger; i++) { values[i] = (Datum) 0; replaces[i] = ' '; nulls[i] = ' '; } values[Anum_pg_trigger_tgargs - 1] = PointerGetDatum(newtgargs); replaces[Anum_pg_trigger_tgargs - 1] = 'r'; tuple = heap_modifytuple(tuple, RelationGetDescr(tgrel), values, nulls, replaces); /* * Update pg_trigger and its indexes */ simple_heap_update(tgrel, &tuple->t_self, tuple); CatalogUpdateIndexes(tgrel, tuple); /* * Invalidate trigger's relation's relcache entry so that other * backends (and this one too!) are sent SI message to make them * rebuild relcache entries. (Ideally this should happen * automatically...) * * We can skip this for triggers on relid itself, since that relcache * flush will happen anyway due to the table or column rename. We * just need to catch the far ends of RI relationships. */ pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple); if (pg_trigger->tgrelid != relid) CacheInvalidateRelcacheByRelid(pg_trigger->tgrelid); /* free up our scratch memory */ pfree(newtgargs); heap_freetuple(tuple); } systable_endscan(trigscan); heap_close(tgrel, RowExclusiveLock); /* * Increment cmd counter to make updates visible; this is needed in * case the same tuple has to be updated again by next pass (can * happen in case of a self-referential FK relationship). */ CommandCounterIncrement(); } /* * 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) { ATController(relation_openrv(stmt->relation, AccessExclusiveLock), stmt->cmds, interpretInhOption(stmt->relation->inhOpt)); } /* * AlterTableInternal * * ALTER TABLE with target specified by OID */ void AlterTableInternal(Oid relid, List *cmds, bool recurse) { ATController(relation_open(relid, AccessExclusiveLock), 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 = AT_PASS_ADD_CONSTR; 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_ToastTable: /* CREATE TOAST TABLE */ ATSimplePermissions(rel, false); /* This command never recurses */ /* No command-specific prep needed */ pass = AT_PASS_MISC; 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 */ /* This command never recurses */ ATPrepSetTableSpace(tab, rel, cmd->name); pass = AT_PASS_MISC; /* doesn't actually matter */ 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); } } /* * Do an implicit CREATE TOAST TABLE 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, true); } } /* * 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_ToastTable: /* CREATE TOAST TABLE */ AlterTableCreateToastTable(RelationGetRelid(rel), false); break; case AT_ChangeOwner: /* ALTER OWNER */ ATExecChangeOwner(RelationGetRelid(rel), get_roleid_checked(cmd->name)); 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; 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) 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); 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; 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)); /* * 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; case CONSTR_NOTNULL: needscan = true; 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); } 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) { /* Extract data from old tuple */ heap_deform_tuple(tuple, oldTupDesc, values, isnull); /* 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); } /* Now check any constraints on the possibly-changed tuple */ ExecStoreTuple(tuple, newslot, InvalidBuffer, false); econtext->ecxt_scantuple = newslot; 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_NOTNULL: { Datum d; bool isnull; d = heap_getattr(tuple, con->attnum, newTupDesc, &isnull); if (isnull) ereport(ERROR, (errcode(ERRCODE_NOT_NULL_VIOLATION), errmsg("column \"%s\" contains null values", get_attname(tab->relid, con->attnum)))); } 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); } 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)))); } /* * 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); 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); ATPrepCmd(wqueue, childrel, cmd, true, true); relation_close(childrel, NoLock); } } /* * find_composite_type_dependencies * * Check to see if a table's rowtype 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. * * We assume that functions and views depending on the type are not reasons * to reject the ALTER. (How safe is this really?) */ static void find_composite_type_dependencies(Oid typeOid, const char *origTblName) { Relation depRel; ScanKeyData key[2]; SysScanDesc depScan; HeapTuple depTup; /* * 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) { 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 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); } relation_close(rel, AccessShareLock); } systable_endscan(depScan); relation_close(depRel, AccessShareLock); } /* * 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; /* and don't make a support dependency on the child */ colDefChild->support = NULL; 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; 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); /* Okay if child matches by type */ if (typenameTypeId(colDef->typename) != childatt->atttypid || colDef->typename->typmod != 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(colDef->typename); tform = (Form_pg_type) GETSTRUCT(typeTuple); typeOid = HeapTupleGetOid(typeTuple); /* 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 = colDef->typename->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, colDef->typename->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); if (colDef->support != NULL) add_column_support_dependency(myrelid, i, colDef->support); } /* * 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); } /* * Install a dependency for a column's supporting relation (serial sequence). */ static void add_column_support_dependency(Oid relid, int32 attnum, RangeVar *support) { ObjectAddress colobject, suppobject; colobject.classId = RelationRelationId; colobject.objectId = relid; colobject.objectSubId = attnum; suppobject.classId = RelationRelationId; suppobject.objectId = RangeVarGetRelid(support, false); suppobject.objectSubId = 0; recordDependencyOn(&suppobject, &colobject, DEPENDENCY_INTERNAL); } /* * 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; NewConstraint *newcon; /* * 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 to test the constraint */ newcon = (NewConstraint *) palloc0(sizeof(NewConstraint)); newcon->contype = CONSTR_NOTNULL; newcon->attnum = attnum; newcon->name = "NOT NULL"; tab->constraints = lappend(tab->constraints, newcon); } 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); 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; 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->rangetable, stmt->unique, stmt->primary, stmt->isconstraint, true, /* is_alter_table */ check_rights, skip_build, quiet); } /* * 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; newcon->attnum = ccon->attnum; /* 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]; 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)); 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); } /* Be sure referencing and referenced column types are comparable */ 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++) { /* * pktypoid[i] is the primary key table's i'th key's type * fktypoid[i] is the foreign key table's i'th key's type * * Note that we look for an operator with the PK type on the left; * when the types are different this is critical because the PK * index will need operators with the indexkey on the left. * (Ordinarily both commutator operators will exist if either * does, but we won't get the right answer from the test below on * opclass membership unless we select the proper operator.) */ Operator o = oper(list_make1(makeString("=")), pktypoid[i], fktypoid[i], true); if (o == NULL) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_FUNCTION), 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(fktypoid[i]), format_type_be(pktypoid[i])))); /* * Check that the found operator is compatible with the PK index, * and generate a warning if not, since otherwise costly seqscans * will be incurred to check FK validity. */ if (!op_in_opclass(oprid(o), opclasses[i])) ereport(WARNING, (errmsg("foreign key constraint \"%s\" " "will require costly sequential scans", fkconstraint->constr_name), errdetail("Key columns \"%s\" and \"%s\" " "are of different types: %s and %s.", strVal(list_nth(fkconstraint->fk_attrs, i)), strVal(list_nth(fkconstraint->pk_attrs, i)), format_type_be(fktypoid[i]), format_type_be(pktypoid[i])))); ReleaseSysCache(o); } /* * 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->qual = (Node *) fkconstraint; tab->constraints = lappend(tab->constraints, newcon); } /* * 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, 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); /* * 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). */ 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); indexStruct = NULL; } list_free(indexoidlist); /* * Check that we found it */ if (indexStruct == NULL) 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) { HeapScanDesc scan; HeapTuple tuple; Trigger trig; ListCell *list; int count; /* * 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(fkconstraint, 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. */ MemSet(&trig, 0, sizeof(trig)); trig.tgoid = InvalidOid; trig.tgname = fkconstraint->constr_name; trig.tgenabled = TRUE; trig.tgisconstraint = TRUE; trig.tgconstrrelid = RelationGetRelid(pkrel); trig.tgdeferrable = FALSE; trig.tginitdeferred = FALSE; trig.tgargs = (char **) palloc(sizeof(char *) * (4 + list_length(fkconstraint->fk_attrs) + list_length(fkconstraint->pk_attrs))); trig.tgargs[0] = trig.tgname; trig.tgargs[1] = RelationGetRelationName(rel); trig.tgargs[2] = RelationGetRelationName(pkrel); trig.tgargs[3] = fkMatchTypeToString(fkconstraint->fk_matchtype); count = 4; foreach(list, fkconstraint->fk_attrs) { char *fk_at = strVal(lfirst(list)); trig.tgargs[count] = fk_at; count += 2; } count = 5; foreach(list, fkconstraint->pk_attrs) { char *pk_at = strVal(lfirst(list)); trig.tgargs[count] = pk_at; count += 2; } trig.tgnargs = count - 1; 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); pfree(trig.tgargs); } static void CreateFKCheckTrigger(RangeVar *myRel, FkConstraint *fkconstraint, ObjectAddress *constrobj, ObjectAddress *trigobj, bool on_insert) { CreateTrigStmt *fk_trigger; ListCell *fk_attr; ListCell *pk_attr; 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; fk_trigger->args = lappend(fk_trigger->args, makeString(fkconstraint->constr_name)); fk_trigger->args = lappend(fk_trigger->args, makeString(myRel->relname)); fk_trigger->args = lappend(fk_trigger->args, makeString(fkconstraint->pktable->relname)); fk_trigger->args = lappend(fk_trigger->args, makeString(fkMatchTypeToString(fkconstraint->fk_matchtype))); if (list_length(fkconstraint->fk_attrs) != list_length(fkconstraint->pk_attrs)) ereport(ERROR, (errcode(ERRCODE_INVALID_FOREIGN_KEY), errmsg("number of referencing and referenced columns for foreign key disagree"))); forboth(fk_attr, fkconstraint->fk_attrs, pk_attr, fkconstraint->pk_attrs) { fk_trigger->args = lappend(fk_trigger->args, lfirst(fk_attr)); fk_trigger->args = lappend(fk_trigger->args, lfirst(pk_attr)); } trigobj->objectId = CreateTrigger(fk_trigger, true); /* Register dependency from trigger to constraint */ recordDependencyOn(trigobj, constrobj, DEPENDENCY_INTERNAL); /* Make changes-so-far visible */ CommandCounterIncrement(); } /* * Create the triggers that implement an FK constraint. */ static void createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint, Oid constrOid) { RangeVar *myRel; CreateTrigStmt *fk_trigger; ListCell *fk_attr; ListCell *pk_attr; ObjectAddress trigobj, constrobj; /* * Reconstruct a RangeVar for my relation (not passed in, * unfortunately). */ myRel = makeRangeVar(get_namespace_name(RelationGetNamespace(rel)), pstrdup(RelationGetRelationName(rel))); /* * Preset objectAddress fields */ constrobj.classId = ConstraintRelationId; constrobj.objectId = constrOid; constrobj.objectSubId = 0; trigobj.classId = TriggerRelationId; trigobj.objectSubId = 0; /* 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, &constrobj, &trigobj, true); CreateFKCheckTrigger(myRel, fkconstraint, &constrobj, &trigobj, 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; fk_trigger->args = lappend(fk_trigger->args, makeString(fkconstraint->constr_name)); fk_trigger->args = lappend(fk_trigger->args, makeString(myRel->relname)); fk_trigger->args = lappend(fk_trigger->args, makeString(fkconstraint->pktable->relname)); fk_trigger->args = lappend(fk_trigger->args, makeString(fkMatchTypeToString(fkconstraint->fk_matchtype))); forboth(fk_attr, fkconstraint->fk_attrs, pk_attr, fkconstraint->pk_attrs) { fk_trigger->args = lappend(fk_trigger->args, lfirst(fk_attr)); fk_trigger->args = lappend(fk_trigger->args, lfirst(pk_attr)); } trigobj.objectId = CreateTrigger(fk_trigger, true); /* Register dependency from trigger to constraint */ recordDependencyOn(&trigobj, &constrobj, DEPENDENCY_INTERNAL); /* 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; fk_trigger->args = lappend(fk_trigger->args, makeString(fkconstraint->constr_name)); fk_trigger->args = lappend(fk_trigger->args, makeString(myRel->relname)); fk_trigger->args = lappend(fk_trigger->args, makeString(fkconstraint->pktable->relname)); fk_trigger->args = lappend(fk_trigger->args, makeString(fkMatchTypeToString(fkconstraint->fk_matchtype))); forboth(fk_attr, fkconstraint->fk_attrs, pk_attr, fkconstraint->pk_attrs) { fk_trigger->args = lappend(fk_trigger->args, lfirst(fk_attr)); fk_trigger->args = lappend(fk_trigger->args, lfirst(pk_attr)); } trigobj.objectId = CreateTrigger(fk_trigger, true); /* Register dependency from trigger to constraint */ recordDependencyOn(&trigobj, &constrobj, DEPENDENCY_INTERNAL); } /* * fkMatchTypeToString - * convert FKCONSTR_MATCH_xxx code to string to use in trigger args */ static char * fkMatchTypeToString(char match_type) { switch (match_type) { case FKCONSTR_MATCH_FULL: return pstrdup("FULL"); case FKCONSTR_MATCH_PARTIAL: return pstrdup("PARTIAL"); case FKCONSTR_MATCH_UNSPECIFIED: return pstrdup("UNSPECIFIED"); default: elog(ERROR, "unrecognized match type: %d", (int) match_type); } return NULL; /* can't get here */ } /* * 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; 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 = LookupTypeName(typename); if (!OidIsValid(targettype)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("type \"%s\" does not exist", TypeNameToString(typename)))); /* 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, typename->typmod, 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; 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(typename); tform = (Form_pg_type) GETSTRUCT(typeTuple); targettype = HeapTupleGetOid(typeTuple); /* * 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, typename->typmod, 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)) { tab->changedConstraintOids = lappend_oid(tab->changedConstraintOids, foundObject.objectId); tab->changedConstraintDefs = lappend(tab->changedConstraintDefs, pg_get_constraintdef_string(foundObject.objectId)); } 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 = typename->typmod; 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. * 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, 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 */ static void ATExecChangeOwner(Oid relationOid, Oid newOwnerId) { 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_INDEX: case RELKIND_VIEW: case RELKIND_SEQUENCE: case RELKIND_TOASTVALUE: /* ok to change owner */ break; default: ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("\"%s\" is not a table, TOAST table, index, 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; 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 */ changeDependencyOnOwner(RelationRelationId, relationOid, newOwnerId); /* * 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); 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); /* 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 internal 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 internal dependencies on columns */ if (depForm->refobjsubid == 0 || depForm->classid != RelationRelationId || depForm->objsubid != 0 || depForm->deptype != DEPENDENCY_INTERNAL) 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); /* 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; /* * We do our own permission checking because we want to allow this on * indexes. */ 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)))); /* 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; } /* * 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; rel = relation_open(tableOid, NoLock); /* * 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) { xl_heap_newpage xlrec; XLogRecPtr recptr; XLogRecData rdata[2]; /* NO ELOG(ERROR) from here till newpage op is logged */ START_CRIT_SECTION(); xlrec.node = dst->smgr_rnode; xlrec.blkno = blkno; rdata[0].data = (char *) &xlrec; rdata[0].len = SizeOfHeapNewpage; rdata[0].buffer = InvalidBuffer; rdata[0].next = &(rdata[1]); rdata[1].data = (char *) page; rdata[1].len = BLCKSZ; rdata[1].buffer = InvalidBuffer; rdata[1].next = NULL; recptr = XLogInsert(RM_HEAP_ID, XLOG_HEAP_NEWPAGE, rdata); PageSetLSN(page, recptr); PageSetTLI(page, ThisTimeLineID); END_CRIT_SECTION(); } /* * 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. */ smgrwrite(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 CREATE TOAST TABLE * * Note: this is also invoked from outside this module; in such cases we * expect the caller to have verified that the relation is a table and we * have all the right permissions. Callers expect this function * to end with CommandCounterIncrement if it makes any changes. */ void AlterTableCreateToastTable(Oid relOid, bool silent) { Relation rel; HeapTuple reltup; TupleDesc tupdesc; bool shared_relation; Relation class_rel; Oid toast_relid; Oid toast_idxid; char toast_relname[NAMEDATALEN]; char toast_idxname[NAMEDATALEN]; IndexInfo *indexInfo; Oid classObjectId[2]; ObjectAddress baseobject, toastobject; /* * Grab an exclusive lock on the target table, which we will NOT * release until end of transaction. (This is probably redundant in * all present uses...) */ rel = heap_open(relOid, AccessExclusiveLock); /* * Toast table is shared if and only if its parent is. * * We cannot allow toasting a shared relation after initdb (because * there's no way to mark it toasted in other databases' pg_class). * Unfortunately we can't distinguish initdb from a manually started * standalone backend (toasting happens after the bootstrap phase, so * checking IsBootstrapProcessingMode() won't work). However, we can * at least prevent this mistake under normal multi-user operation. */ shared_relation = rel->rd_rel->relisshared; if (shared_relation && IsUnderPostmaster) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("shared tables cannot be toasted after initdb"))); /* * Is it already toasted? */ if (rel->rd_rel->reltoastrelid != InvalidOid) { if (silent) { heap_close(rel, NoLock); return; } ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("table \"%s\" already has a TOAST table", RelationGetRelationName(rel)))); } /* * Check to see whether the table actually needs a TOAST table. */ if (!needs_toast_table(rel)) { if (silent) { heap_close(rel, NoLock); return; } ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("table \"%s\" does not need a TOAST table", RelationGetRelationName(rel)))); } /* * Create the toast table and its index */ snprintf(toast_relname, sizeof(toast_relname), "pg_toast_%u", relOid); snprintf(toast_idxname, sizeof(toast_idxname), "pg_toast_%u_index", relOid); /* this is pretty painful... need a tuple descriptor */ tupdesc = CreateTemplateTupleDesc(3, false); TupleDescInitEntry(tupdesc, (AttrNumber) 1, "chunk_id", OIDOID, -1, 0); TupleDescInitEntry(tupdesc, (AttrNumber) 2, "chunk_seq", INT4OID, -1, 0); TupleDescInitEntry(tupdesc, (AttrNumber) 3, "chunk_data", BYTEAOID, -1, 0); /* * Ensure that the toast table doesn't itself get toasted, or we'll be * toast :-(. This is essential for chunk_data because type bytea is * toastable; hit the other two just to be sure. */ tupdesc->attrs[0]->attstorage = 'p'; tupdesc->attrs[1]->attstorage = 'p'; tupdesc->attrs[2]->attstorage = 'p'; /* * Note: the toast relation is placed in the regular pg_toast * namespace even if its master relation is a temp table. There * cannot be any naming collision, and the toast rel will be destroyed * when its master is, so there's no need to handle the toast rel as * temp. */ toast_relid = heap_create_with_catalog(toast_relname, PG_TOAST_NAMESPACE, rel->rd_rel->reltablespace, InvalidOid, tupdesc, RELKIND_TOASTVALUE, shared_relation, true, 0, ONCOMMIT_NOOP, true); /* make the toast relation visible, else index creation will fail */ CommandCounterIncrement(); /* * Create unique index on chunk_id, chunk_seq. * * NOTE: the normal TOAST access routines could actually function with a * single-column index on chunk_id only. However, the slice access * routines use both columns for faster access to an individual chunk. * In addition, we want it to be unique as a check against the * possibility of duplicate TOAST chunk OIDs. The index might also be * a little more efficient this way, since btree isn't all that happy * with large numbers of equal keys. */ indexInfo = makeNode(IndexInfo); indexInfo->ii_NumIndexAttrs = 2; indexInfo->ii_KeyAttrNumbers[0] = 1; indexInfo->ii_KeyAttrNumbers[1] = 2; indexInfo->ii_Expressions = NIL; indexInfo->ii_ExpressionsState = NIL; indexInfo->ii_Predicate = NIL; indexInfo->ii_PredicateState = NIL; indexInfo->ii_Unique = true; classObjectId[0] = OID_BTREE_OPS_OID; classObjectId[1] = INT4_BTREE_OPS_OID; toast_idxid = index_create(toast_relid, toast_idxname, InvalidOid, indexInfo, BTREE_AM_OID, rel->rd_rel->reltablespace, classObjectId, true, false, true, false); /* * Update toast rel's pg_class entry to show that it has an index. The * index OID is stored into the reltoastidxid field for easy access by * the tuple toaster. */ setRelhasindex(toast_relid, true, true, toast_idxid); /* * Store the toast table's OID in the parent relation's pg_class row */ class_rel = heap_open(RelationRelationId, RowExclusiveLock); reltup = SearchSysCacheCopy(RELOID, ObjectIdGetDatum(relOid), 0, 0, 0); if (!HeapTupleIsValid(reltup)) elog(ERROR, "cache lookup failed for relation %u", relOid); ((Form_pg_class) GETSTRUCT(reltup))->reltoastrelid = toast_relid; simple_heap_update(class_rel, &reltup->t_self, reltup); /* Keep catalog indexes current */ CatalogUpdateIndexes(class_rel, reltup); heap_freetuple(reltup); heap_close(class_rel, RowExclusiveLock); /* * Register dependency from the toast table to the master, so that the * toast table will be deleted if the master is. */ baseobject.classId = RelationRelationId; baseobject.objectId = relOid; baseobject.objectSubId = 0; toastobject.classId = RelationRelationId; toastobject.objectId = toast_relid; toastobject.objectSubId = 0; recordDependencyOn(&toastobject, &baseobject, DEPENDENCY_INTERNAL); /* * Clean up and make changes visible */ heap_close(rel, NoLock); CommandCounterIncrement(); } /* * Check to see whether the table needs a TOAST table. It does only if * (1) there are any toastable attributes, and (2) the maximum length * of a tuple could exceed TOAST_TUPLE_THRESHOLD. (We don't want to * create a toast table for something like "f1 varchar(20)".) */ static bool needs_toast_table(Relation rel) { int32 data_length = 0; bool maxlength_unknown = false; bool has_toastable_attrs = false; TupleDesc tupdesc; Form_pg_attribute *att; int32 tuple_length; int i; tupdesc = rel->rd_att; att = tupdesc->attrs; for (i = 0; i < tupdesc->natts; i++) { if (att[i]->attisdropped) continue; data_length = att_align(data_length, att[i]->attalign); if (att[i]->attlen > 0) { /* Fixed-length types are never toastable */ data_length += att[i]->attlen; } else { int32 maxlen = type_maximum_size(att[i]->atttypid, att[i]->atttypmod); if (maxlen < 0) maxlength_unknown = true; else data_length += maxlen; if (att[i]->attstorage != 'p') has_toastable_attrs = true; } } if (!has_toastable_attrs) return false; /* nothing to toast? */ if (maxlength_unknown) return true; /* any unlimited-length attrs? */ tuple_length = MAXALIGN(offsetof(HeapTupleHeaderData, t_bits) + BITMAPLEN(tupdesc->natts)) + MAXALIGN(data_length); return (tuple_length > TOAST_TUPLE_THRESHOLD); } /* * 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); /* 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)))); relid = RelationGetRelid(rel); oldNspOid = RelationGetNamespace(rel); /* 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); /* 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 internal 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 internal dependencies on columns */ if (depForm->refobjsubid == 0 || depForm->classid != RelationRelationId || depForm->objsubid != 0 || depForm->deptype != DEPENDENCY_INTERNAL) 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); /* * And we need to rebuild the column default expression that * relies on this sequence. */ if (depForm->refobjsubid > 0) RebuildSerialDefaultExpr(rel, depForm->refobjsubid, RelationGetRelationName(seqRel), newNspName); /* Now we can close it. Keep the lock till end of transaction. */ relation_close(seqRel, NoLock); } systable_endscan(scan); relation_close(depRel, AccessShareLock); } /* * Rebuild the default expression for a SERIAL column identified by rel * and attnum. This is annoying, but we have to do it because the * stored expression has the schema name as a text constant. * * The caller must be sure the specified column is really a SERIAL column, * because no further checks are done here. */ static void RebuildSerialDefaultExpr(Relation rel, AttrNumber attnum, const char *seqname, const char *nspname) { char *qstring; A_Const *snamenode; FuncCall *funccallnode; RawColumnDefault *rawEnt; /* * Create raw parse tree for the updated column default expression. * This should match transformColumnDefinition() in parser/analyze.c. */ qstring = quote_qualified_identifier(nspname, seqname); snamenode = makeNode(A_Const); snamenode->val.type = T_String; snamenode->val.val.str = qstring; funccallnode = makeNode(FuncCall); funccallnode->funcname = SystemFuncName("nextval"); funccallnode->args = list_make1(snamenode); funccallnode->agg_star = false; funccallnode->agg_distinct = false; /* * 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); /* Do the equivalent of ALTER TABLE ... SET DEFAULT */ rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault)); rawEnt->attnum = attnum; rawEnt->raw_default = (Node *) funccallnode; /* * 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); } /* * 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); } } }