/*------------------------------------------------------------------------- * * heap.c * code to create and destroy POSTGRES heap relations * * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.167 2001/06/12 05:55:49 tgl Exp $ * * * INTERFACE ROUTINES * heap_create() - Create an uncataloged heap relation * heap_create_with_catalog() - Create a cataloged relation * heap_drop_with_catalog() - Removes named relation from catalogs * * NOTES * this code taken from access/heap/create.c, which contains * the old heap_create_with_catalog, amcreate, and amdestroy. * those routines will soon call these routines using the function * manager, * just like the poorly named "NewXXX" routines do. The * "New" routines are all going to die soon, once and for all! * -cim 1/13/91 * *------------------------------------------------------------------------- */ #include "postgres.h" #include "access/heapam.h" #include "access/genam.h" #include "catalog/catalog.h" #include "catalog/catname.h" #include "catalog/heap.h" #include "catalog/index.h" #include "catalog/indexing.h" #include "catalog/pg_attrdef.h" #include "catalog/pg_inherits.h" #include "catalog/pg_index.h" #include "catalog/pg_proc.h" #include "catalog/pg_relcheck.h" #include "catalog/pg_statistic.h" #include "catalog/pg_type.h" #include "commands/comment.h" #include "commands/trigger.h" #include "miscadmin.h" #include "optimizer/clauses.h" #include "optimizer/planmain.h" #include "optimizer/prep.h" #include "optimizer/var.h" #include "nodes/makefuncs.h" #include "parser/parse_clause.h" #include "parser/parse_expr.h" #include "parser/parse_relation.h" #include "parser/parse_target.h" #include "parser/parse_type.h" #include "rewrite/rewriteRemove.h" #include "storage/smgr.h" #include "utils/builtins.h" #include "utils/catcache.h" #include "utils/fmgroids.h" #include "utils/lsyscache.h" #include "utils/relcache.h" #include "utils/syscache.h" #include "utils/temprel.h" static void AddNewRelationTuple(Relation pg_class_desc, Relation new_rel_desc, Oid new_rel_oid, Oid new_type_oid, int natts, char relkind, char *temp_relname); static void DeleteAttributeTuples(Relation rel); static void DeleteRelationTuple(Relation rel); static void DeleteTypeTuple(Relation rel); static void RelationRemoveIndexes(Relation relation); static void RelationRemoveInheritance(Relation relation); static void AddNewRelationType(char *typeName, Oid new_rel_oid, Oid new_type_oid); static void StoreAttrDefault(Relation rel, AttrNumber attnum, char *adbin, bool updatePgAttribute); static void StoreRelCheck(Relation rel, char *ccname, char *ccbin); static void StoreConstraints(Relation rel); static void RemoveConstraints(Relation rel); static void RemoveStatistics(Relation rel); /* ---------------------------------------------------------------- * XXX UGLY HARD CODED BADNESS FOLLOWS XXX * * these should all be moved to someplace in the lib/catalog * module, if not obliterated first. * ---------------------------------------------------------------- */ /* * Note: * Should the system special case these attributes in the future? * Advantage: consume much less space in the ATTRIBUTE relation. * Disadvantage: special cases will be all over the place. */ static FormData_pg_attribute a1 = { 0, {"ctid"}, TIDOID, 0, sizeof(ItemPointerData), SelfItemPointerAttributeNumber, 0, -1, -1, false, 'p', false, 'i', false, false }; static FormData_pg_attribute a2 = { 0, {"oid"}, OIDOID, 0, sizeof(Oid), ObjectIdAttributeNumber, 0, -1, -1, true, 'p', false, 'i', false, false }; static FormData_pg_attribute a3 = { 0, {"xmin"}, XIDOID, 0, sizeof(TransactionId), MinTransactionIdAttributeNumber, 0, -1, -1, true, 'p', false, 'i', false, false }; static FormData_pg_attribute a4 = { 0, {"cmin"}, CIDOID, 0, sizeof(CommandId), MinCommandIdAttributeNumber, 0, -1, -1, true, 'p', false, 'i', false, false }; static FormData_pg_attribute a5 = { 0, {"xmax"}, XIDOID, 0, sizeof(TransactionId), MaxTransactionIdAttributeNumber, 0, -1, -1, true, 'p', false, 'i', false, false }; static FormData_pg_attribute a6 = { 0, {"cmax"}, CIDOID, 0, sizeof(CommandId), MaxCommandIdAttributeNumber, 0, -1, -1, true, 'p', false, 'i', false, false }; /* * We decided to call this attribute "tableoid" rather than say * "classoid" on the basis that in the future there may be more than one * table of a particular class/type. In any case table is still the word * used in SQL. */ static FormData_pg_attribute a7 = { 0, {"tableoid"}, OIDOID, 0, sizeof(Oid), TableOidAttributeNumber, 0, -1, -1, true, 'p', false, 'i', false, false }; static Form_pg_attribute SysAtt[] = {&a1, &a2, &a3, &a4, &a5, &a6, &a7}; /* * This function returns a Form_pg_attribute pointer for a system attribute. */ Form_pg_attribute SystemAttributeDefinition(AttrNumber attno) { if (attno >= 0 || attno < - (int) lengthof(SysAtt)) elog(ERROR, "SystemAttributeDefinition: invalid attribute number %d", attno); return SysAtt[-attno - 1]; } /* ---------------------------------------------------------------- * XXX END OF UGLY HARD CODED BADNESS XXX * ---------------------------------------------------------------- */ /* ---------------------------------------------------------------- * heap_create - Create an uncataloged heap relation * * Fields relpages, reltuples, reltuples, relkeys, relhistory, * relisindexed, and relkind of rel->rd_rel are initialized * to all zeros, as are rd_last and rd_hook. Rd_refcnt is set to 1. * * Remove the system relation specific code to elsewhere eventually. * * Eventually, must place information about this temporary relation * into the transaction context block. * * NOTE: if istemp is TRUE then heap_create will overwrite relname with * the unique "real" name chosen for the temp relation. * * If storage_create is TRUE then heap_storage_create is called here, * else caller must call heap_storage_create later. * ---------------------------------------------------------------- */ Relation heap_create(char *relname, TupleDesc tupDesc, bool istemp, bool storage_create, bool allow_system_table_mods) { static unsigned int uniqueId = 0; Oid relid; Relation rel; bool nailme = false; int natts = tupDesc->natts; int i; MemoryContext oldcxt; Oid tblNode = MyDatabaseId; /* * sanity checks */ AssertArg(natts > 0); if (relname && !allow_system_table_mods && IsSystemRelationName(relname) && IsNormalProcessingMode()) { elog(ERROR, "Illegal class name '%s'" "\n\tThe 'pg_' name prefix is reserved for system catalogs", relname); } /* * Real ugly stuff to assign the proper relid in the relation * descriptor follows. Note that only "bootstrapped" relations * whose OIDs are hard-coded in pg_class.h need be listed here. */ if (relname && IsSystemRelationName(relname)) { if (strcmp(TypeRelationName, relname) == 0) { nailme = true; relid = RelOid_pg_type; } else if (strcmp(AttributeRelationName, relname) == 0) { nailme = true; relid = RelOid_pg_attribute; } else if (strcmp(ProcedureRelationName, relname) == 0) { nailme = true; relid = RelOid_pg_proc; } else if (strcmp(RelationRelationName, relname) == 0) { nailme = true; relid = RelOid_pg_class; } else if (strcmp(ShadowRelationName, relname) == 0) { tblNode = InvalidOid; relid = RelOid_pg_shadow; } else if (strcmp(GroupRelationName, relname) == 0) { tblNode = InvalidOid; relid = RelOid_pg_group; } else if (strcmp(DatabaseRelationName, relname) == 0) { tblNode = InvalidOid; relid = RelOid_pg_database; } else if (strcmp(LogRelationName, relname) == 0) { tblNode = InvalidOid; relid = RelOid_pg_log; } else { relid = newoid(); if (IsSharedSystemRelationName(relname)) tblNode = InvalidOid; } } else relid = newoid(); if (istemp) { /* * replace relname of caller with a unique name for a temp * relation */ snprintf(relname, NAMEDATALEN, "pg_temp.%d.%u", (int) MyProcPid, uniqueId++); } /* * switch to the cache context to create the relcache entry. */ if (!CacheMemoryContext) CreateCacheMemoryContext(); oldcxt = MemoryContextSwitchTo(CacheMemoryContext); /* * allocate a new relation descriptor. */ rel = (Relation) palloc(sizeof(RelationData)); MemSet((char *) rel, 0, sizeof(RelationData)); rel->rd_fd = -1; /* physical file is not open */ RelationSetReferenceCount(rel, 1); /* * create a new tuple descriptor from the one passed in */ rel->rd_att = CreateTupleDescCopyConstr(tupDesc); /* * nail the reldesc if this is a bootstrap create reln and we may need * it in the cache later on in the bootstrap process so we don't ever * want it kicked out. e.g. pg_attribute!!! */ if (nailme) rel->rd_isnailed = true; /* * initialize the fields of our new relation descriptor */ rel->rd_rel = (Form_pg_class) palloc(sizeof *rel->rd_rel); MemSet((char *) rel->rd_rel, 0, sizeof *rel->rd_rel); strcpy(RelationGetPhysicalRelationName(rel), relname); rel->rd_rel->relkind = RELKIND_UNCATALOGED; rel->rd_rel->relnatts = natts; rel->rd_rel->reltype = InvalidOid; if (tupDesc->constr) rel->rd_rel->relchecks = tupDesc->constr->num_check; for (i = 0; i < natts; i++) rel->rd_att->attrs[i]->attrelid = relid; RelationGetRelid(rel) = relid; rel->rd_node.tblNode = tblNode; rel->rd_node.relNode = relid; rel->rd_rel->relfilenode = relid; /* * done building relcache entry. */ MemoryContextSwitchTo(oldcxt); /* * have the storage manager create the relation. */ if (storage_create) heap_storage_create(rel); RelationRegisterRelation(rel); return rel; } void heap_storage_create(Relation rel) { Assert(rel->rd_fd < 0); rel->rd_fd = smgrcreate(DEFAULT_SMGR, rel); Assert(rel->rd_fd >= 0); } /* ---------------------------------------------------------------- * heap_create_with_catalog - Create a cataloged relation * * this is done in 6 steps: * * 1) CheckAttributeNames() is used to make certain the tuple * descriptor contains a valid set of attribute names * * 2) pg_class is opened and RelationFindRelid() * performs a scan to ensure that no relation with the * same name already exists. * * 3) heap_create() is called to create the new relation on disk. * * 4) AddNewRelationTuple() is called to register the * relation in pg_class. * * 5) TypeCreate() is called to define a new type corresponding * to the new relation. * * 6) AddNewAttributeTuples() is called to register the * new relation's schema in pg_attribute. * * 7) StoreConstraints is called () - vadim 08/22/97 * * 8) the relations are closed and the new relation's oid * is returned. * * ---------------------------------------------------------------- */ /* -------------------------------- * CheckAttributeNames * * this is used to make certain the tuple descriptor contains a * valid set of attribute names. a problem simply generates * elog(ERROR) which aborts the current transaction. * -------------------------------- */ static void CheckAttributeNames(TupleDesc tupdesc) { int i; int j; int natts = tupdesc->natts; /* * first check for collision with system attribute names * * also, warn user if attribute to be created has an unknown typid * (usually as a result of a 'retrieve into' - jolly */ for (i = 0; i < natts; i++) { for (j = 0; j < (int) lengthof(SysAtt); j++) { if (strcmp(NameStr(SysAtt[j]->attname), NameStr(tupdesc->attrs[i]->attname)) == 0) { elog(ERROR, "Attribute '%s' has a name conflict" "\n\tName matches an existing system attribute", NameStr(SysAtt[j]->attname)); } } if (tupdesc->attrs[i]->atttypid == UNKNOWNOID) { elog(NOTICE, "Attribute '%s' has an unknown type" "\n\tRelation created; continue", NameStr(tupdesc->attrs[i]->attname)); } } /* * next check for repeated attribute names */ for (i = 1; i < natts; i++) { for (j = 0; j < i; j++) { if (strcmp(NameStr(tupdesc->attrs[j]->attname), NameStr(tupdesc->attrs[i]->attname)) == 0) { elog(ERROR, "Attribute '%s' is repeated", NameStr(tupdesc->attrs[j]->attname)); } } } } /* -------------------------------- * RelnameFindRelid * * Find any existing relation of the given name. * -------------------------------- */ Oid RelnameFindRelid(const char *relname) { Oid relid; /* * If this is not bootstrap (initdb) time, use the catalog index on * pg_class. */ if (!IsBootstrapProcessingMode()) { relid = GetSysCacheOid(RELNAME, PointerGetDatum(relname), 0, 0, 0); } else { Relation pg_class_desc; ScanKeyData key; HeapScanDesc pg_class_scan; HeapTuple tuple; pg_class_desc = heap_openr(RelationRelationName, AccessShareLock); /* * At bootstrap time, we have to do this the hard way. Form the * scan key. */ ScanKeyEntryInitialize(&key, 0, (AttrNumber) Anum_pg_class_relname, (RegProcedure) F_NAMEEQ, (Datum) relname); /* * begin the scan */ pg_class_scan = heap_beginscan(pg_class_desc, 0, SnapshotNow, 1, &key); /* * get a tuple. if the tuple is NULL then it means we didn't find * an existing relation. */ tuple = heap_getnext(pg_class_scan, 0); if (HeapTupleIsValid(tuple)) relid = tuple->t_data->t_oid; else relid = InvalidOid; heap_endscan(pg_class_scan); heap_close(pg_class_desc, AccessShareLock); } return relid; } /* -------------------------------- * AddNewAttributeTuples * * this registers the new relation's schema by adding * tuples to pg_attribute. * -------------------------------- */ static void AddNewAttributeTuples(Oid new_rel_oid, TupleDesc tupdesc) { Form_pg_attribute *dpp; int i; HeapTuple tup; Relation rel; bool hasindex; Relation idescs[Num_pg_attr_indices]; int natts = tupdesc->natts; /* * open pg_attribute */ rel = heap_openr(AttributeRelationName, RowExclusiveLock); /* * Check if we have any indices defined on pg_attribute. */ hasindex = RelationGetForm(rel)->relhasindex; if (hasindex) CatalogOpenIndices(Num_pg_attr_indices, Name_pg_attr_indices, idescs); /* * first we add the user attributes.. */ dpp = tupdesc->attrs; for (i = 0; i < natts; i++) { /* Fill in the correct relation OID */ (*dpp)->attrelid = new_rel_oid; /* Make sure these are OK, too */ (*dpp)->attstattarget = DEFAULT_ATTSTATTARGET; (*dpp)->attcacheoff = -1; tup = heap_addheader(Natts_pg_attribute, ATTRIBUTE_TUPLE_SIZE, (void *) *dpp); heap_insert(rel, tup); if (hasindex) CatalogIndexInsert(idescs, Num_pg_attr_indices, rel, tup); heap_freetuple(tup); dpp++; } /* * next we add the system attributes.. */ dpp = SysAtt; for (i = 0; i < -1 - FirstLowInvalidHeapAttributeNumber; i++) { Form_pg_attribute attStruct; tup = heap_addheader(Natts_pg_attribute, ATTRIBUTE_TUPLE_SIZE, (void *) *dpp); /* Fill in the correct relation OID in the copied tuple */ attStruct = (Form_pg_attribute) GETSTRUCT(tup); attStruct->attrelid = new_rel_oid; /* Unneeded since they should be OK in the constant data anyway */ /* attStruct->attstattarget = 0; */ /* attStruct->attcacheoff = -1; */ heap_insert(rel, tup); if (hasindex) CatalogIndexInsert(idescs, Num_pg_attr_indices, rel, tup); heap_freetuple(tup); dpp++; } /* * close pg_attribute indices */ if (hasindex) CatalogCloseIndices(Num_pg_attr_indices, idescs); heap_close(rel, RowExclusiveLock); } /* -------------------------------- * AddNewRelationTuple * * this registers the new relation in the catalogs by * adding a tuple to pg_class. * -------------------------------- */ static void AddNewRelationTuple(Relation pg_class_desc, Relation new_rel_desc, Oid new_rel_oid, Oid new_type_oid, int natts, char relkind, char *temp_relname) { Form_pg_class new_rel_reltup; HeapTuple tup; Relation idescs[Num_pg_class_indices]; /* * first we update some of the information in our uncataloged * relation's relation descriptor. */ new_rel_reltup = new_rel_desc->rd_rel; /* * Here we insert bogus estimates of the size of the new relation. In * reality, of course, the new relation has 0 tuples and pages, and if * we were tracking these statistics accurately then we'd set the * fields that way. But at present the stats will be updated only by * VACUUM or CREATE INDEX, and the user might insert a lot of tuples * before he gets around to doing either of those. So, instead of * saying the relation is empty, we insert guesstimates. The point is * to keep the optimizer from making really stupid choices on * never-yet-vacuumed tables; so the estimates need only be large * enough to discourage the optimizer from using nested-loop plans. * With this hack, nested-loop plans will be preferred only after the * table has been proven to be small by VACUUM or CREATE INDEX. * Maintaining the stats on-the-fly would solve the problem more * cleanly, but the overhead of that would likely cost more than it'd * save. (NOTE: CREATE INDEX inserts the same bogus estimates if it * finds the relation has 0 rows and pages. See index.c.) */ switch (relkind) { case RELKIND_RELATION: case RELKIND_INDEX: case RELKIND_TOASTVALUE: new_rel_reltup->relpages = 10; /* bogus estimates */ new_rel_reltup->reltuples = 1000; break; case RELKIND_SEQUENCE: new_rel_reltup->relpages = 1; new_rel_reltup->reltuples = 1; break; default: /* views, etc */ new_rel_reltup->relpages = 0; new_rel_reltup->reltuples = 0; break; } new_rel_reltup->relowner = GetUserId(); new_rel_reltup->reltype = new_type_oid; new_rel_reltup->relkind = relkind; new_rel_reltup->relnatts = natts; /* ---------------- * now form a tuple to add to pg_class * XXX Natts_pg_class_fixed is a hack - see pg_class.h * ---------------- */ tup = heap_addheader(Natts_pg_class_fixed, CLASS_TUPLE_SIZE, (void *) new_rel_reltup); /* force tuple to have the desired OID */ tup->t_data->t_oid = new_rel_oid; /* * finally insert the new tuple and free it. */ heap_insert(pg_class_desc, tup); if (temp_relname) create_temp_relation(temp_relname, tup); if (!IsIgnoringSystemIndexes()) { /* * First, open the catalog indices and insert index tuples for the * new relation. */ CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, idescs); CatalogIndexInsert(idescs, Num_pg_class_indices, pg_class_desc, tup); CatalogCloseIndices(Num_pg_class_indices, idescs); } heap_freetuple(tup); } /* -------------------------------- * AddNewRelationType - * * define a complex type corresponding to the new relation * -------------------------------- */ static void AddNewRelationType(char *typeName, Oid new_rel_oid, Oid new_type_oid) { /* * The sizes are set to oid size because it makes implementing sets * MUCH easier, and no one (we hope) uses these fields to figure out * how much space to allocate for the type. An oid is the type used * for a set definition. When a user requests a set, what they * actually get is the oid of a tuple in the pg_proc catalog, so the * size of the "set" is the size of an oid. Similarly, byval being * true makes sets much easier, and it isn't used by anything else. * * XXX Note the assumption that OIDs are the same size as int4s. */ TypeCreate(typeName, /* type name */ new_type_oid, /* preassigned oid for type */ new_rel_oid, /* relation oid */ sizeof(Oid), /* internal size */ sizeof(Oid), /* external size */ 'c', /* type-type (catalog) */ ',', /* default array delimiter */ "int4in", /* input procedure */ "int4out", /* output procedure */ "int4in", /* receive procedure */ "int4out", /* send procedure */ NULL, /* array element type - irrelevant */ "-", /* default type value */ true, /* passed by value */ 'i', /* default alignment */ 'p'); /* Not TOASTable */ } /* -------------------------------- * heap_create_with_catalog * * creates a new cataloged relation. see comments above. * -------------------------------- */ Oid heap_create_with_catalog(char *relname, TupleDesc tupdesc, char relkind, bool istemp, bool allow_system_table_mods) { Relation pg_class_desc; Relation new_rel_desc; Oid new_rel_oid; Oid new_type_oid; int natts = tupdesc->natts; char *temp_relname = NULL; /* * sanity checks */ Assert(IsNormalProcessingMode() || IsBootstrapProcessingMode()); if (natts <= 0 || natts > MaxHeapAttributeNumber) elog(ERROR, "Number of attributes is out of range" "\n\tFrom 1 to %d attributes may be specified", MaxHeapAttributeNumber); CheckAttributeNames(tupdesc); /* temp tables can mask non-temp tables */ if ((!istemp && RelnameFindRelid(relname)) || (istemp && is_temp_rel_name(relname))) elog(ERROR, "Relation '%s' already exists", relname); if (istemp) { /* save user relation name because heap_create changes it */ temp_relname = pstrdup(relname); /* save original value */ relname = palloc(NAMEDATALEN); strcpy(relname, temp_relname); /* heap_create will change this */ } /* * Tell heap_create not to create a physical file; we'll do that below * after all our catalog updates are done. (This isn't really * necessary anymore, but we may as well avoid the cycles of creating * and deleting the file in case we fail.) * * Note: The call to heap_create() changes relname for temp tables; it * becomes the true physical relname. The call to * heap_storage_create() does all the "real" work of creating the disk * file for the relation. */ new_rel_desc = heap_create(relname, tupdesc, istemp, false, allow_system_table_mods); /* Fetch the relation OID assigned by heap_create */ new_rel_oid = new_rel_desc->rd_att->attrs[0]->attrelid; /* Assign an OID for the relation's tuple type */ new_type_oid = newoid(); /* * now create an entry in pg_class for the relation. * * NOTE: we could get a unique-index failure here, in case someone else * is creating the same relation name in parallel but hadn't committed * yet when we checked for a duplicate name above. */ pg_class_desc = heap_openr(RelationRelationName, RowExclusiveLock); AddNewRelationTuple(pg_class_desc, new_rel_desc, new_rel_oid, new_type_oid, natts, relkind, temp_relname); /* * since defining a relation also defines a complex type, we add a new * system type corresponding to the new relation. * * NOTE: we could get a unique-index failure here, in case the same name * has already been used for a type. */ AddNewRelationType(relname, new_rel_oid, new_type_oid); /* * now add tuples to pg_attribute for the attributes in our new * relation. */ AddNewAttributeTuples(new_rel_oid, tupdesc); StoreConstraints(new_rel_desc); if (istemp) { pfree(relname); pfree(temp_relname); } /* * We create the disk file for this relation here */ if (relkind != RELKIND_VIEW) heap_storage_create(new_rel_desc); /* * ok, the relation has been cataloged, so close our relations and * return the oid of the newly created relation. * * SOMEDAY: fill the STATISTIC relation properly. */ heap_close(new_rel_desc, NoLock); /* do not unlock till end of xact */ heap_close(pg_class_desc, RowExclusiveLock); return new_rel_oid; } /* ---------------------------------------------------------------- * heap_drop_with_catalog - removes all record of named relation from catalogs * * 1) open relation, check for existence, etc. * 2) remove inheritance information * 3) remove indexes * 4) remove pg_class tuple * 5) remove pg_attribute tuples and related descriptions * 6) remove pg_description tuples * 7) remove pg_type tuples * 8) RemoveConstraints () * 9) unlink relation * * old comments * Except for vital relations, removes relation from * relation catalog, and related attributes from * attribute catalog (needed?). (Anything else?) * * get proper relation from relation catalog (if not arg) * scan attribute catalog deleting attributes of reldesc * (necessary?) * delete relation from relation catalog * (How are the tuples of the relation discarded?) * * XXX Must fix to work with indexes. * There may be a better order for doing things. * Problems with destroying a deleted database--cannot create * a struct reldesc without having an open file descriptor. * ---------------------------------------------------------------- */ /* -------------------------------- * RelationRemoveInheritance * * Note: for now, we cause an exception if relation is a * superclass. Someday, we may want to allow this and merge * the type info into subclass procedures.... this seems like * lots of work. * -------------------------------- */ static void RelationRemoveInheritance(Relation relation) { Relation catalogRelation; HeapTuple tuple; HeapScanDesc scan; ScanKeyData entry; bool found = false; /* * open pg_inherits */ catalogRelation = heap_openr(InheritsRelationName, RowExclusiveLock); /* * form a scan key for the subclasses of this class and begin scanning */ ScanKeyEntryInitialize(&entry, 0x0, Anum_pg_inherits_inhparent, F_OIDEQ, ObjectIdGetDatum(RelationGetRelid(relation))); scan = heap_beginscan(catalogRelation, false, SnapshotNow, 1, &entry); /* * if any subclasses exist, then we disallow the deletion. */ tuple = heap_getnext(scan, 0); if (HeapTupleIsValid(tuple)) { Oid subclass = ((Form_pg_inherits) GETSTRUCT(tuple))->inhrelid; char *subclassname; subclassname = get_rel_name(subclass); /* Just in case get_rel_name fails... */ if (subclassname) elog(ERROR, "Relation \"%s\" inherits from \"%s\"", subclassname, RelationGetRelationName(relation)); else elog(ERROR, "Relation %u inherits from \"%s\"", subclass, RelationGetRelationName(relation)); } heap_endscan(scan); /* * If we get here, it means the relation has no subclasses so we can * trash it. First we remove dead INHERITS tuples. */ entry.sk_attno = Anum_pg_inherits_inhrelid; scan = heap_beginscan(catalogRelation, false, SnapshotNow, 1, &entry); while (HeapTupleIsValid(tuple = heap_getnext(scan, 0))) { simple_heap_delete(catalogRelation, &tuple->t_self); found = true; } heap_endscan(scan); heap_close(catalogRelation, RowExclusiveLock); } /* -------------------------------- * RelationRemoveIndexes * * -------------------------------- */ static void RelationRemoveIndexes(Relation relation) { Relation indexRelation; HeapTuple tuple; HeapScanDesc scan; ScanKeyData entry; indexRelation = heap_openr(IndexRelationName, RowExclusiveLock); ScanKeyEntryInitialize(&entry, 0x0, Anum_pg_index_indrelid, F_OIDEQ, ObjectIdGetDatum(RelationGetRelid(relation))); scan = heap_beginscan(indexRelation, false, SnapshotNow, 1, &entry); while (HeapTupleIsValid(tuple = heap_getnext(scan, 0))) { index_drop(((Form_pg_index) GETSTRUCT(tuple))->indexrelid); /* advance cmd counter to make catalog changes visible */ CommandCounterIncrement(); } heap_endscan(scan); heap_close(indexRelation, RowExclusiveLock); } /* -------------------------------- * DeleteRelationTuple * * -------------------------------- */ static void DeleteRelationTuple(Relation rel) { Relation pg_class_desc; HeapTuple tup; /* * open pg_class */ pg_class_desc = heap_openr(RelationRelationName, RowExclusiveLock); tup = SearchSysCacheCopy(RELOID, ObjectIdGetDatum(rel->rd_id), 0, 0, 0); if (!HeapTupleIsValid(tup)) elog(ERROR, "Relation \"%s\" does not exist", RelationGetRelationName(rel)); /* * delete the relation tuple from pg_class, and finish up. */ simple_heap_delete(pg_class_desc, &tup->t_self); heap_freetuple(tup); heap_close(pg_class_desc, RowExclusiveLock); } /* -------------------------------- * RelationTruncateIndexes - This routine is used to truncate all * indices associated with the heap relation to zero tuples. * The routine will truncate and then reconstruct the indices on * the relation specified by the heapId parameter. * -------------------------------- */ static void RelationTruncateIndexes(Oid heapId) { Relation indexRelation; ScanKeyData entry; HeapScanDesc scan; HeapTuple indexTuple; /* Scan pg_index to find indexes on specified heap */ indexRelation = heap_openr(IndexRelationName, AccessShareLock); ScanKeyEntryInitialize(&entry, 0, Anum_pg_index_indrelid, F_OIDEQ, ObjectIdGetDatum(heapId)); scan = heap_beginscan(indexRelation, false, SnapshotNow, 1, &entry); while (HeapTupleIsValid(indexTuple = heap_getnext(scan, 0))) { Oid indexId, accessMethodId; IndexInfo *indexInfo; HeapTuple classTuple; Relation heapRelation, currentIndex; /* * For each index, fetch info needed for index_build */ indexId = ((Form_pg_index) GETSTRUCT(indexTuple))->indexrelid; indexInfo = BuildIndexInfo(indexTuple); /* Fetch access method from pg_class tuple for this index */ classTuple = SearchSysCache(RELOID, ObjectIdGetDatum(indexId), 0, 0, 0); if (!HeapTupleIsValid(classTuple)) elog(ERROR, "RelationTruncateIndexes: index %u not found in pg_class", indexId); accessMethodId = ((Form_pg_class) GETSTRUCT(classTuple))->relam; ReleaseSysCache(classTuple); /* * We have to re-open the heap rel each time through this loop * because index_build will close it again. We need grab no lock, * however, because we assume heap_truncate is holding an * exclusive lock on the heap rel. */ heapRelation = heap_open(heapId, NoLock); /* Open the index relation */ currentIndex = index_open(indexId); /* Obtain exclusive lock on it, just to be sure */ LockRelation(currentIndex, AccessExclusiveLock); /* * Drop any buffers associated with this index. If they're dirty, * they're just dropped without bothering to flush to disk. */ DropRelationBuffers(currentIndex); /* Now truncate the actual data and set blocks to zero */ smgrtruncate(DEFAULT_SMGR, currentIndex, 0); currentIndex->rd_nblocks = 0; /* Initialize the index and rebuild */ InitIndexStrategy(indexInfo->ii_NumIndexAttrs, currentIndex, accessMethodId); index_build(heapRelation, currentIndex, indexInfo, NULL); /* * index_build will close both the heap and index relations (but * not give up the locks we hold on them). */ } /* Complete the scan and close pg_index */ heap_endscan(scan); heap_close(indexRelation, AccessShareLock); } /* ---------------------------- * heap_truncate * * This routine is used to truncate the data from the * storage manager of any data within the relation handed * to this routine. * ---------------------------- */ void heap_truncate(char *relname) { Relation rel; Oid rid; /* Open relation for processing, and grab exclusive access on it. */ rel = heap_openr(relname, AccessExclusiveLock); rid = RelationGetRelid(rel); /* * TRUNCATE TABLE within a transaction block is dangerous, because if * the transaction is later rolled back we have no way to undo * truncation of the relation's physical file. Disallow it except for * a rel created in the current xact (which would be deleted on abort, * anyway). */ if (IsTransactionBlock() && !rel->rd_myxactonly) elog(ERROR, "TRUNCATE TABLE cannot run inside a BEGIN/END block"); /* * Release any buffers associated with this relation. If they're * dirty, they're just dropped without bothering to flush to disk. */ DropRelationBuffers(rel); /* Now truncate the actual data and set blocks to zero */ smgrtruncate(DEFAULT_SMGR, rel, 0); rel->rd_nblocks = 0; /* If this relation has indexes, truncate the indexes too */ RelationTruncateIndexes(rid); /* * Close the relation, but keep exclusive lock on it until commit. */ heap_close(rel, NoLock); } /* -------------------------------- * DeleteAttributeTuples * * -------------------------------- */ static void DeleteAttributeTuples(Relation rel) { Relation pg_attribute_desc; HeapTuple tup; int2 attnum; /* * open pg_attribute */ pg_attribute_desc = heap_openr(AttributeRelationName, RowExclusiveLock); for (attnum = FirstLowInvalidHeapAttributeNumber + 1; attnum <= rel->rd_att->natts; attnum++) { tup = SearchSysCacheCopy(ATTNUM, ObjectIdGetDatum(RelationGetRelid(rel)), Int16GetDatum(attnum), 0, 0); if (HeapTupleIsValid(tup)) { /*** Delete any comments associated with this attribute ***/ DeleteComments(tup->t_data->t_oid); simple_heap_delete(pg_attribute_desc, &tup->t_self); heap_freetuple(tup); } } heap_close(pg_attribute_desc, RowExclusiveLock); } /* -------------------------------- * DeleteTypeTuple * * If the user attempts to destroy a relation and there * exists attributes in other relations of type * "relation we are deleting", then we have to do something * special. presently we disallow the destroy. * -------------------------------- */ static void DeleteTypeTuple(Relation rel) { Relation pg_type_desc; HeapScanDesc pg_type_scan; Relation pg_attribute_desc; HeapScanDesc pg_attribute_scan; ScanKeyData key; ScanKeyData attkey; HeapTuple tup; HeapTuple atttup; Oid typoid; /* * open pg_type */ pg_type_desc = heap_openr(TypeRelationName, RowExclusiveLock); /* * create a scan key to locate the type tuple corresponding to this * relation. */ ScanKeyEntryInitialize(&key, 0, Anum_pg_type_typrelid, F_OIDEQ, ObjectIdGetDatum(RelationGetRelid(rel))); pg_type_scan = heap_beginscan(pg_type_desc, 0, SnapshotNow, 1, &key); /* * use heap_getnext() to fetch the pg_type tuple. If this tuple is * not valid then something's wrong. */ tup = heap_getnext(pg_type_scan, 0); if (!HeapTupleIsValid(tup)) { heap_endscan(pg_type_scan); heap_close(pg_type_desc, RowExclusiveLock); elog(ERROR, "DeleteTypeTuple: type \"%s\" does not exist", RelationGetRelationName(rel)); } /* * now scan pg_attribute. if any other relations have attributes of * the type of the relation we are deleteing then we have to disallow * the deletion. should talk to stonebraker about this. -cim 6/19/90 */ typoid = tup->t_data->t_oid; pg_attribute_desc = heap_openr(AttributeRelationName, RowExclusiveLock); ScanKeyEntryInitialize(&attkey, 0, Anum_pg_attribute_atttypid, F_OIDEQ, typoid); pg_attribute_scan = heap_beginscan(pg_attribute_desc, 0, SnapshotNow, 1, &attkey); /* * try and get a pg_attribute tuple. if we succeed it means we can't * delete the relation because something depends on the schema. */ atttup = heap_getnext(pg_attribute_scan, 0); if (HeapTupleIsValid(atttup)) { Oid relid = ((Form_pg_attribute) GETSTRUCT(atttup))->attrelid; heap_endscan(pg_attribute_scan); heap_close(pg_attribute_desc, RowExclusiveLock); heap_endscan(pg_type_scan); heap_close(pg_type_desc, RowExclusiveLock); elog(ERROR, "DeleteTypeTuple: att of type %s exists in relation %u", RelationGetRelationName(rel), relid); } heap_endscan(pg_attribute_scan); heap_close(pg_attribute_desc, RowExclusiveLock); /* * Ok, it's safe so we delete the relation tuple from pg_type and * finish up. */ simple_heap_delete(pg_type_desc, &tup->t_self); heap_endscan(pg_type_scan); heap_close(pg_type_desc, RowExclusiveLock); } /* -------------------------------- * heap_drop_with_catalog * * -------------------------------- */ void heap_drop_with_catalog(const char *relname, bool allow_system_table_mods) { Relation rel; Oid rid; bool has_toasttable; bool istemp = is_temp_rel_name(relname); int i; /* * Open and lock the relation. */ rel = heap_openr(relname, AccessExclusiveLock); rid = RelationGetRelid(rel); has_toasttable = rel->rd_rel->reltoastrelid != InvalidOid; /* * prevent deletion of system relations */ /* allow temp of pg_class? Guess so. */ if (!istemp && !allow_system_table_mods && IsSystemRelationName(RelationGetRelationName(rel))) elog(ERROR, "System relation \"%s\" may not be dropped", RelationGetRelationName(rel)); /* * Release all buffers that belong to this relation, after writing any * that are dirty */ i = FlushRelationBuffers(rel, (BlockNumber) 0); if (i < 0) elog(ERROR, "heap_drop_with_catalog: FlushRelationBuffers returned %d", i); /* * remove rules if necessary */ if (rel->rd_rules != NULL) RelationRemoveRules(rid); /* triggers */ RelationRemoveTriggers(rel); /* * remove inheritance information */ RelationRemoveInheritance(rel); /* * remove indexes if necessary */ RelationRemoveIndexes(rel); /* * delete attribute tuples */ DeleteAttributeTuples(rel); /* * delete comments, statistics, and constraints */ DeleteComments(RelationGetRelid(rel)); RemoveStatistics(rel); RemoveConstraints(rel); /* * delete type tuple */ DeleteTypeTuple(rel); /* * delete relation tuple */ DeleteRelationTuple(rel); /* * unlink the relation's physical file and finish up. */ if (rel->rd_rel->relkind != RELKIND_VIEW) smgrunlink(DEFAULT_SMGR, rel); /* * Close relcache entry, but *keep* AccessExclusiveLock on the * relation until transaction commit. This ensures no one else will * try to do something with the doomed relation. */ heap_close(rel, NoLock); /* * flush the relation from the relcache */ RelationForgetRelation(rid); /* and from the temp-table map */ if (istemp) remove_temp_rel_by_relid(rid); if (has_toasttable) { char toast_relname[NAMEDATALEN]; sprintf(toast_relname, "pg_toast_%u", rid); heap_drop_with_catalog(toast_relname, true); } } /* * Store a default expression for column attnum of relation rel. * The expression must be presented as a nodeToString() string. * If updatePgAttribute is true, update the pg_attribute entry * for the column to show that a default exists. */ static void StoreAttrDefault(Relation rel, AttrNumber attnum, char *adbin, bool updatePgAttribute) { Node *expr; char *adsrc; Relation adrel; Relation idescs[Num_pg_attrdef_indices]; HeapTuple tuple; Datum values[4]; static char nulls[4] = {' ', ' ', ' ', ' '}; Relation attrrel; Relation attridescs[Num_pg_attr_indices]; HeapTuple atttup; Form_pg_attribute attStruct; /* * Need to construct source equivalent of given node-string. */ expr = stringToNode(adbin); /* * deparse it */ adsrc = deparse_expression(expr, deparse_context_for(RelationGetRelationName(rel), RelationGetRelid(rel)), false); values[Anum_pg_attrdef_adrelid - 1] = RelationGetRelid(rel); values[Anum_pg_attrdef_adnum - 1] = attnum; values[Anum_pg_attrdef_adbin - 1] = DirectFunctionCall1(textin, CStringGetDatum(adbin)); values[Anum_pg_attrdef_adsrc - 1] = DirectFunctionCall1(textin, CStringGetDatum(adsrc)); adrel = heap_openr(AttrDefaultRelationName, RowExclusiveLock); tuple = heap_formtuple(adrel->rd_att, values, nulls); heap_insert(adrel, tuple); CatalogOpenIndices(Num_pg_attrdef_indices, Name_pg_attrdef_indices, idescs); CatalogIndexInsert(idescs, Num_pg_attrdef_indices, adrel, tuple); CatalogCloseIndices(Num_pg_attrdef_indices, idescs); heap_close(adrel, RowExclusiveLock); pfree(DatumGetPointer(values[Anum_pg_attrdef_adbin - 1])); pfree(DatumGetPointer(values[Anum_pg_attrdef_adsrc - 1])); heap_freetuple(tuple); pfree(adsrc); if (!updatePgAttribute) return; /* done if pg_attribute is OK */ attrrel = heap_openr(AttributeRelationName, RowExclusiveLock); atttup = SearchSysCacheCopy(ATTNUM, ObjectIdGetDatum(RelationGetRelid(rel)), Int16GetDatum(attnum), 0, 0); if (!HeapTupleIsValid(atttup)) elog(ERROR, "cache lookup of attribute %d in relation %u failed", attnum, RelationGetRelid(rel)); attStruct = (Form_pg_attribute) GETSTRUCT(atttup); if (!attStruct->atthasdef) { attStruct->atthasdef = true; simple_heap_update(attrrel, &atttup->t_self, atttup); /* keep catalog indices current */ CatalogOpenIndices(Num_pg_attr_indices, Name_pg_attr_indices, attridescs); CatalogIndexInsert(attridescs, Num_pg_attr_indices, attrrel, atttup); CatalogCloseIndices(Num_pg_attr_indices, attridescs); } heap_close(attrrel, RowExclusiveLock); heap_freetuple(atttup); } /* * Store a constraint expression for the given relation. * The expression must be presented as a nodeToString() string. * * Caller is responsible for updating the count of constraints * in the pg_class entry for the relation. */ static void StoreRelCheck(Relation rel, char *ccname, char *ccbin) { Node *expr; char *ccsrc; Relation rcrel; Relation idescs[Num_pg_relcheck_indices]; HeapTuple tuple; Datum values[4]; static char nulls[4] = {' ', ' ', ' ', ' '}; /* * Convert condition to a normal boolean expression tree. */ expr = stringToNode(ccbin); expr = (Node *) make_ands_explicit((List *) expr); /* * deparse it */ ccsrc = deparse_expression(expr, deparse_context_for(RelationGetRelationName(rel), RelationGetRelid(rel)), false); values[Anum_pg_relcheck_rcrelid - 1] = RelationGetRelid(rel); values[Anum_pg_relcheck_rcname - 1] = DirectFunctionCall1(namein, CStringGetDatum(ccname)); values[Anum_pg_relcheck_rcbin - 1] = DirectFunctionCall1(textin, CStringGetDatum(ccbin)); values[Anum_pg_relcheck_rcsrc - 1] = DirectFunctionCall1(textin, CStringGetDatum(ccsrc)); rcrel = heap_openr(RelCheckRelationName, RowExclusiveLock); tuple = heap_formtuple(rcrel->rd_att, values, nulls); heap_insert(rcrel, tuple); CatalogOpenIndices(Num_pg_relcheck_indices, Name_pg_relcheck_indices, idescs); CatalogIndexInsert(idescs, Num_pg_relcheck_indices, rcrel, tuple); CatalogCloseIndices(Num_pg_relcheck_indices, idescs); heap_close(rcrel, RowExclusiveLock); pfree(DatumGetPointer(values[Anum_pg_relcheck_rcname - 1])); pfree(DatumGetPointer(values[Anum_pg_relcheck_rcbin - 1])); pfree(DatumGetPointer(values[Anum_pg_relcheck_rcsrc - 1])); heap_freetuple(tuple); pfree(ccsrc); } /* * Store defaults and constraints passed in via the tuple constraint struct. * * NOTE: only pre-cooked expressions will be passed this way, which is to * say expressions inherited from an existing relation. Newly parsed * expressions can be added later, by direct calls to StoreAttrDefault * and StoreRelCheck (see AddRelationRawConstraints()). We assume that * pg_attribute and pg_class entries for the relation were already set * to reflect the existence of these defaults/constraints. */ static void StoreConstraints(Relation rel) { TupleConstr *constr = rel->rd_att->constr; int i; if (!constr) return; /* * deparsing of constraint expressions will fail unless the * just-created pg_attribute tuples for this relation are made * visible. So, bump the command counter. */ CommandCounterIncrement(); for (i = 0; i < constr->num_defval; i++) StoreAttrDefault(rel, constr->defval[i].adnum, constr->defval[i].adbin, false); for (i = 0; i < constr->num_check; i++) StoreRelCheck(rel, constr->check[i].ccname, constr->check[i].ccbin); } /* * AddRelationRawConstraints * * Add raw (not-yet-transformed) column default expressions and/or constraint * check expressions to an existing relation. This is defined to do both * for efficiency in DefineRelation, but of course you can do just one or * the other by passing empty lists. * * rel: relation to be modified * rawColDefaults: list of RawColumnDefault structures * rawConstraints: list of Constraint nodes * * All entries in rawColDefaults will be processed. Entries in rawConstraints * will be processed only if they are CONSTR_CHECK type and contain a "raw" * expression. * * NB: caller should have opened rel with AccessExclusiveLock, and should * hold that lock till end of transaction. Also, we assume the caller has * done a CommandCounterIncrement if necessary to make the relation's catalog * tuples visible. */ void AddRelationRawConstraints(Relation rel, List *rawColDefaults, List *rawConstraints) { char *relname = RelationGetRelationName(rel); TupleDesc tupleDesc; TupleConstr *oldconstr; int numoldchecks; ConstrCheck *oldchecks; ParseState *pstate; RangeTblEntry *rte; int numchecks; List *listptr; Relation relrel; Relation relidescs[Num_pg_class_indices]; HeapTuple reltup; Form_pg_class relStruct; /* * Get info about existing constraints. */ tupleDesc = RelationGetDescr(rel); oldconstr = tupleDesc->constr; if (oldconstr) { numoldchecks = oldconstr->num_check; oldchecks = oldconstr->check; } else { numoldchecks = 0; oldchecks = NULL; } /* * Create a dummy ParseState and insert the target relation as its * sole rangetable entry. We need a ParseState for transformExpr. */ pstate = make_parsestate(NULL); rte = addRangeTableEntry(pstate, relname, NULL, false, true); addRTEtoQuery(pstate, rte, true, true); /* * Process column default expressions. */ foreach(listptr, rawColDefaults) { RawColumnDefault *colDef = (RawColumnDefault *) lfirst(listptr); Node *expr; Oid type_id; Assert(colDef->raw_default != NULL); /* * Transform raw parsetree to executable expression. */ expr = transformExpr(pstate, colDef->raw_default, EXPR_COLUMN_FIRST); /* * Make sure default expr does not refer to any vars. */ if (contain_var_clause(expr)) elog(ERROR, "Cannot use attribute(s) in DEFAULT clause"); /* * No subplans or aggregates, either... */ if (contain_subplans(expr)) elog(ERROR, "Cannot use subselect in DEFAULT clause"); if (contain_agg_clause(expr)) elog(ERROR, "Cannot use aggregate in DEFAULT clause"); /* * Check that it will be possible to coerce the expression to the * column's type. We store the expression without coercion, * however, to avoid premature coercion in cases like * * CREATE TABLE tbl (fld datetime DEFAULT 'now'); * * NB: this should match the code in updateTargetListEntry() that * will actually do the coercion, to ensure we don't accept an * unusable default expression. */ type_id = exprType(expr); if (type_id != InvalidOid) { Form_pg_attribute atp = rel->rd_att->attrs[colDef->attnum - 1]; if (type_id != atp->atttypid) { if (CoerceTargetExpr(NULL, expr, type_id, atp->atttypid, atp->atttypmod) == NULL) elog(ERROR, "Attribute '%s' is of type '%s'" " but default expression is of type '%s'" "\n\tYou will need to rewrite or cast the expression", NameStr(atp->attname), typeidTypeName(atp->atttypid), typeidTypeName(type_id)); } } /* * Might as well try to reduce any constant expressions. */ expr = eval_const_expressions(expr); /* * Must fix opids, in case any operators remain... */ fix_opids(expr); /* * OK, store it. */ StoreAttrDefault(rel, colDef->attnum, nodeToString(expr), true); } /* * Process constraint expressions. */ numchecks = numoldchecks; foreach(listptr, rawConstraints) { Constraint *cdef = (Constraint *) lfirst(listptr); char *ccname; Node *expr; if (cdef->contype != CONSTR_CHECK || cdef->raw_expr == NULL) continue; Assert(cdef->cooked_expr == NULL); /* Check name uniqueness, or generate a new name */ if (cdef->name != NULL) { int i; List *listptr2; ccname = cdef->name; /* Check against old constraints */ for (i = 0; i < numoldchecks; i++) { if (strcmp(oldchecks[i].ccname, ccname) == 0) elog(ERROR, "Duplicate CHECK constraint name: '%s'", ccname); } /* Check against other new constraints */ foreach(listptr2, rawConstraints) { Constraint *cdef2 = (Constraint *) lfirst(listptr2); if (cdef2 == cdef || cdef2->contype != CONSTR_CHECK || cdef2->raw_expr == NULL || cdef2->name == NULL) continue; if (strcmp(cdef2->name, ccname) == 0) elog(ERROR, "Duplicate CHECK constraint name: '%s'", ccname); } } else { int i; int j; bool success; List *listptr2; ccname = (char *) palloc(NAMEDATALEN); /* Loop until we find a non-conflicting constraint name */ /* What happens if this loops forever? */ j = numchecks + 1; do { success = true; snprintf(ccname, NAMEDATALEN, "$%d", j); /* Check against old constraints */ for (i = 0; i < numoldchecks; i++) { if (strcmp(oldchecks[i].ccname, ccname) == 0) { success = false; break; } } /* Check against other new constraints, if the check hasn't already failed */ if (success) { foreach(listptr2, rawConstraints) { Constraint *cdef2 = (Constraint *) lfirst(listptr2); if (cdef2 == cdef || cdef2->contype != CONSTR_CHECK || cdef2->raw_expr == NULL || cdef2->name == NULL) continue; if (strcmp(cdef2->name, ccname) == 0) { success = false; break; } } } ++j; } while (!success); } /* * Transform raw parsetree to executable expression. */ expr = transformExpr(pstate, cdef->raw_expr, EXPR_COLUMN_FIRST); /* * Make sure it yields a boolean result. */ if (exprType(expr) != BOOLOID) elog(ERROR, "CHECK '%s' does not yield boolean result", ccname); /* * Make sure no outside relations are referred to. */ if (length(pstate->p_rtable) != 1) elog(ERROR, "Only relation \"%s\" can be referenced in CHECK", relname); /* * No subplans or aggregates, either... */ if (contain_subplans(expr)) elog(ERROR, "Cannot use subselect in CHECK clause"); if (contain_agg_clause(expr)) elog(ERROR, "Cannot use aggregate in CHECK clause"); /* * Might as well try to reduce any constant expressions. */ expr = eval_const_expressions(expr); /* * Constraints are evaluated with execQual, which expects an * implicit-AND list, so convert expression to implicit-AND form. * (We could go so far as to convert to CNF, but that's probably * overkill...) */ expr = (Node *) make_ands_implicit((Expr *) expr); /* * Must fix opids in operator clauses. */ fix_opids(expr); /* * OK, store it. */ StoreRelCheck(rel, ccname, nodeToString(expr)); numchecks++; } /* * Update the count of constraints in the relation's pg_class tuple. * We do this even if there was no change, in order to ensure that an * SI update message is sent out for the pg_class tuple, which will * force other backends to rebuild their relcache entries for the rel. * (Of course, for a newly created rel there is no need for an SI * message, but for ALTER TABLE ADD ATTRIBUTE this'd be important.) */ relrel = heap_openr(RelationRelationName, RowExclusiveLock); reltup = SearchSysCacheCopy(RELOID, ObjectIdGetDatum(RelationGetRelid(rel)), 0, 0, 0); if (!HeapTupleIsValid(reltup)) elog(ERROR, "cache lookup of relation %u failed", RelationGetRelid(rel)); relStruct = (Form_pg_class) GETSTRUCT(reltup); relStruct->relchecks = numchecks; simple_heap_update(relrel, &reltup->t_self, reltup); /* keep catalog indices current */ CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, relidescs); CatalogIndexInsert(relidescs, Num_pg_class_indices, relrel, reltup); CatalogCloseIndices(Num_pg_class_indices, relidescs); heap_freetuple(reltup); heap_close(relrel, RowExclusiveLock); } static void RemoveAttrDefault(Relation rel) { Relation adrel; HeapScanDesc adscan; ScanKeyData key; HeapTuple tup; adrel = heap_openr(AttrDefaultRelationName, RowExclusiveLock); ScanKeyEntryInitialize(&key, 0, Anum_pg_attrdef_adrelid, F_OIDEQ, RelationGetRelid(rel)); adscan = heap_beginscan(adrel, 0, SnapshotNow, 1, &key); while (HeapTupleIsValid(tup = heap_getnext(adscan, 0))) simple_heap_delete(adrel, &tup->t_self); heap_endscan(adscan); heap_close(adrel, RowExclusiveLock); } static void RemoveRelCheck(Relation rel) { Relation rcrel; HeapScanDesc rcscan; ScanKeyData key; HeapTuple tup; rcrel = heap_openr(RelCheckRelationName, RowExclusiveLock); ScanKeyEntryInitialize(&key, 0, Anum_pg_relcheck_rcrelid, F_OIDEQ, RelationGetRelid(rel)); rcscan = heap_beginscan(rcrel, 0, SnapshotNow, 1, &key); while (HeapTupleIsValid(tup = heap_getnext(rcscan, 0))) simple_heap_delete(rcrel, &tup->t_self); heap_endscan(rcscan); heap_close(rcrel, RowExclusiveLock); } /* * Removes all CHECK constraints on a relation that match the given name. * It is the responsibility of the calling function to acquire a lock on * the relation. * Returns: The number of CHECK constraints removed. */ int RemoveCheckConstraint(Relation rel, const char *constrName, bool inh) { Oid relid; Relation rcrel; Relation relrel; Relation inhrel; Relation relidescs[Num_pg_class_indices]; TupleDesc tupleDesc; TupleConstr *oldconstr; int numoldchecks; int numchecks; HeapScanDesc rcscan; ScanKeyData key[2]; HeapTuple rctup; HeapTuple reltup; Form_pg_class relStruct; int rel_deleted = 0; int all_deleted = 0; /* Find id of the relation */ relid = RelationGetRelid(rel); /* Process child tables and remove constraints of the same name. */ if (inh) { List *child, *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 = lfirsti(child); if (childrelid == relid) continue; inhrel = heap_open(childrelid, AccessExclusiveLock); all_deleted += RemoveCheckConstraint(inhrel, constrName, false); heap_close(inhrel, NoLock); } } /* Grab an exclusive lock on the pg_relcheck relation */ rcrel = heap_openr(RelCheckRelationName, RowExclusiveLock); /* * Create two scan keys. We need to match on the oid of the table * the CHECK is in and also we need to match the name of the CHECK * constraint. */ ScanKeyEntryInitialize(&key[0], 0, Anum_pg_relcheck_rcrelid, F_OIDEQ, RelationGetRelid(rel)); ScanKeyEntryInitialize(&key[1], 0, Anum_pg_relcheck_rcname, F_NAMEEQ, PointerGetDatum(constrName)); /* Begin scanning the heap */ rcscan = heap_beginscan(rcrel, 0, SnapshotNow, 2, key); /* * Scan over the result set, removing any matching entries. Note * that this has the side-effect of removing ALL CHECK constraints * that share the specified constraint name. */ while (HeapTupleIsValid(rctup = heap_getnext(rcscan, 0))) { simple_heap_delete(rcrel, &rctup->t_self); ++rel_deleted; ++all_deleted; } /* Clean up after the scan */ heap_endscan(rcscan); /* * Update the count of constraints in the relation's pg_class tuple. * We do this even if there was no change, in order to ensure that an * SI update message is sent out for the pg_class tuple, which will * force other backends to rebuild their relcache entries for the rel. * (Of course, for a newly created rel there is no need for an SI * message, but for ALTER TABLE ADD ATTRIBUTE this'd be important.) */ /* * Get number of existing constraints. */ tupleDesc = RelationGetDescr(rel); oldconstr = tupleDesc->constr; if (oldconstr) numoldchecks = oldconstr->num_check; else numoldchecks = 0; /* Calculate the new number of checks in the table, fail if negative */ numchecks = numoldchecks - rel_deleted; if (numchecks < 0) elog(ERROR, "check count became negative"); relrel = heap_openr(RelationRelationName, RowExclusiveLock); reltup = SearchSysCacheCopy(RELOID, ObjectIdGetDatum(RelationGetRelid(rel)), 0, 0, 0); if (!HeapTupleIsValid(reltup)) elog(ERROR, "cache lookup of relation %u failed", RelationGetRelid(rel)); relStruct = (Form_pg_class) GETSTRUCT(reltup); relStruct->relchecks = numchecks; simple_heap_update(relrel, &reltup->t_self, reltup); /* Keep catalog indices current */ CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, relidescs); CatalogIndexInsert(relidescs, Num_pg_class_indices, relrel, reltup); CatalogCloseIndices(Num_pg_class_indices, relidescs); /* Clean up after the scan */ heap_freetuple(reltup); heap_close(relrel, RowExclusiveLock); /* Close the heap relation */ heap_close(rcrel, RowExclusiveLock); /* Return the number of tuples deleted */ return all_deleted; } static void RemoveConstraints(Relation rel) { TupleConstr *constr = rel->rd_att->constr; if (!constr) return; if (constr->num_defval > 0) RemoveAttrDefault(rel); if (constr->num_check > 0) RemoveRelCheck(rel); } static void RemoveStatistics(Relation rel) { Relation pgstatistic; HeapScanDesc scan; ScanKeyData key; HeapTuple tuple; pgstatistic = heap_openr(StatisticRelationName, RowExclusiveLock); ScanKeyEntryInitialize(&key, 0x0, Anum_pg_statistic_starelid, F_OIDEQ, ObjectIdGetDatum(RelationGetRelid(rel))); scan = heap_beginscan(pgstatistic, false, SnapshotNow, 1, &key); while (HeapTupleIsValid(tuple = heap_getnext(scan, 0))) simple_heap_delete(pgstatistic, &tuple->t_self); heap_endscan(scan); heap_close(pgstatistic, RowExclusiveLock); }