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375369acd1
results with tuples as ordinary varlena Datums. This commit does not in itself do much for us, except eliminate the horrid memory leak associated with evaluation of whole-row variables. However, it lays the groundwork for allowing composite types as table columns, and perhaps some other useful features as well. Per my proposal of a few days ago.
2088 lines
57 KiB
C
2088 lines
57 KiB
C
/*-------------------------------------------------------------------------
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*
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* heap.c
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* code to create and destroy POSTGRES heap relations
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*
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* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/catalog/heap.c,v 1.262 2004/04/01 21:28:43 tgl Exp $
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*
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*
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* INTERFACE ROUTINES
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* heap_create() - Create an uncataloged heap relation
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* heap_create_with_catalog() - Create a cataloged relation
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* heap_drop_with_catalog() - Removes named relation from catalogs
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*
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* NOTES
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* this code taken from access/heap/create.c, which contains
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* the old heap_create_with_catalog, amcreate, and amdestroy.
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* those routines will soon call these routines using the function
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* manager,
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* just like the poorly named "NewXXX" routines do. The
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* "New" routines are all going to die soon, once and for all!
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* -cim 1/13/91
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "access/heapam.h"
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#include "access/genam.h"
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#include "catalog/catalog.h"
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#include "catalog/catname.h"
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#include "catalog/dependency.h"
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#include "catalog/heap.h"
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#include "catalog/index.h"
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#include "catalog/indexing.h"
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#include "catalog/pg_attrdef.h"
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#include "catalog/pg_constraint.h"
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#include "catalog/pg_inherits.h"
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#include "catalog/pg_statistic.h"
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#include "catalog/pg_type.h"
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#include "commands/tablecmds.h"
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#include "commands/trigger.h"
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#include "miscadmin.h"
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#include "nodes/makefuncs.h"
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#include "optimizer/clauses.h"
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#include "optimizer/planmain.h"
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#include "optimizer/var.h"
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#include "parser/parse_coerce.h"
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#include "parser/parse_expr.h"
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#include "parser/parse_relation.h"
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#include "rewrite/rewriteRemove.h"
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#include "storage/smgr.h"
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#include "utils/builtins.h"
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#include "utils/fmgroids.h"
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#include "utils/inval.h"
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#include "utils/lsyscache.h"
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#include "utils/relcache.h"
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#include "utils/syscache.h"
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static void AddNewRelationTuple(Relation pg_class_desc,
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Relation new_rel_desc,
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Oid new_rel_oid, Oid new_type_oid,
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char relkind);
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static void AddNewRelationType(const char *typeName,
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Oid typeNamespace,
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Oid new_rel_oid,
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char new_rel_kind,
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Oid new_type_oid);
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static void RelationRemoveInheritance(Relation relation);
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static void StoreAttrDefault(Relation rel, AttrNumber attnum, char *adbin);
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static void StoreRelCheck(Relation rel, char *ccname, char *ccbin);
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static void StoreConstraints(Relation rel, TupleDesc tupdesc);
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static void SetRelationNumChecks(Relation rel, int numchecks);
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/* ----------------------------------------------------------------
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* XXX UGLY HARD CODED BADNESS FOLLOWS XXX
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*
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* these should all be moved to someplace in the lib/catalog
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* module, if not obliterated first.
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* ----------------------------------------------------------------
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*/
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/*
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* Note:
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* Should the system special case these attributes in the future?
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* Advantage: consume much less space in the ATTRIBUTE relation.
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* Disadvantage: special cases will be all over the place.
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*/
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static FormData_pg_attribute a1 = {
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0, {"ctid"}, TIDOID, 0, sizeof(ItemPointerData),
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SelfItemPointerAttributeNumber, 0, -1, -1,
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false, 'p', 's', true, false, false, true, 0
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};
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static FormData_pg_attribute a2 = {
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0, {"oid"}, OIDOID, 0, sizeof(Oid),
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ObjectIdAttributeNumber, 0, -1, -1,
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true, 'p', 'i', true, false, false, true, 0
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};
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static FormData_pg_attribute a3 = {
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0, {"xmin"}, XIDOID, 0, sizeof(TransactionId),
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MinTransactionIdAttributeNumber, 0, -1, -1,
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true, 'p', 'i', true, false, false, true, 0
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};
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static FormData_pg_attribute a4 = {
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0, {"cmin"}, CIDOID, 0, sizeof(CommandId),
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MinCommandIdAttributeNumber, 0, -1, -1,
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true, 'p', 'i', true, false, false, true, 0
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};
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static FormData_pg_attribute a5 = {
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0, {"xmax"}, XIDOID, 0, sizeof(TransactionId),
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MaxTransactionIdAttributeNumber, 0, -1, -1,
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true, 'p', 'i', true, false, false, true, 0
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};
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static FormData_pg_attribute a6 = {
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0, {"cmax"}, CIDOID, 0, sizeof(CommandId),
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MaxCommandIdAttributeNumber, 0, -1, -1,
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true, 'p', 'i', true, false, false, true, 0
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};
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/*
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* We decided to call this attribute "tableoid" rather than say
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* "classoid" on the basis that in the future there may be more than one
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* table of a particular class/type. In any case table is still the word
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* used in SQL.
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*/
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static FormData_pg_attribute a7 = {
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0, {"tableoid"}, OIDOID, 0, sizeof(Oid),
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TableOidAttributeNumber, 0, -1, -1,
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true, 'p', 'i', true, false, false, true, 0
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};
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static Form_pg_attribute SysAtt[] = {&a1, &a2, &a3, &a4, &a5, &a6, &a7};
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/*
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* This function returns a Form_pg_attribute pointer for a system attribute.
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* Note that we elog if the presented attno is invalid, which would only
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* happen if there's a problem upstream.
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*/
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Form_pg_attribute
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SystemAttributeDefinition(AttrNumber attno, bool relhasoids)
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{
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if (attno >= 0 || attno < -(int) lengthof(SysAtt))
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elog(ERROR, "invalid system attribute number %d", attno);
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if (attno == ObjectIdAttributeNumber && !relhasoids)
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elog(ERROR, "invalid system attribute number %d", attno);
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return SysAtt[-attno - 1];
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}
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/*
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* If the given name is a system attribute name, return a Form_pg_attribute
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* pointer for a prototype definition. If not, return NULL.
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*/
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Form_pg_attribute
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SystemAttributeByName(const char *attname, bool relhasoids)
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{
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int j;
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for (j = 0; j < (int) lengthof(SysAtt); j++)
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{
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Form_pg_attribute att = SysAtt[j];
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if (relhasoids || att->attnum != ObjectIdAttributeNumber)
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{
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if (strcmp(NameStr(att->attname), attname) == 0)
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return att;
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}
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}
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return NULL;
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}
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/* ----------------------------------------------------------------
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* XXX END OF UGLY HARD CODED BADNESS XXX
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* ---------------------------------------------------------------- */
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/* ----------------------------------------------------------------
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* heap_create - Create an uncataloged heap relation
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*
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* rel->rd_rel is initialized by RelationBuildLocalRelation,
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* and is mostly zeroes at return.
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*
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* Remove the system relation specific code to elsewhere eventually.
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*
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* If storage_create is TRUE then heap_storage_create is called here,
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* else caller must call heap_storage_create later (or not at all,
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* if the relation doesn't need physical storage).
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* ----------------------------------------------------------------
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*/
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Relation
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heap_create(const char *relname,
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Oid relnamespace,
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TupleDesc tupDesc,
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bool shared_relation,
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bool storage_create,
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bool allow_system_table_mods)
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{
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Oid relid;
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Oid dbid = shared_relation ? InvalidOid : MyDatabaseId;
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bool nailme = false;
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RelFileNode rnode;
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Relation rel;
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/*
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* sanity checks
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*/
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if (!allow_system_table_mods &&
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(IsSystemNamespace(relnamespace) || IsToastNamespace(relnamespace)) &&
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IsNormalProcessingMode())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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errmsg("permission denied to create \"%s.%s\"",
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get_namespace_name(relnamespace), relname),
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errdetail("System catalog modifications are currently disallowed.")));
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/*
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* Real ugly stuff to assign the proper relid in the relation
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* descriptor follows. Note that only "bootstrapped" relations whose
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* OIDs are hard-coded in pg_class.h should be listed here. We also
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* have to recognize those rels that must be nailed in cache.
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*/
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if (IsSystemNamespace(relnamespace))
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{
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if (strcmp(TypeRelationName, relname) == 0)
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{
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nailme = true;
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relid = RelOid_pg_type;
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}
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else if (strcmp(AttributeRelationName, relname) == 0)
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{
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nailme = true;
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relid = RelOid_pg_attribute;
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}
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else if (strcmp(ProcedureRelationName, relname) == 0)
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{
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nailme = true;
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relid = RelOid_pg_proc;
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}
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else if (strcmp(RelationRelationName, relname) == 0)
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{
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nailme = true;
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relid = RelOid_pg_class;
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}
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else if (strcmp(ShadowRelationName, relname) == 0)
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relid = RelOid_pg_shadow;
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else if (strcmp(GroupRelationName, relname) == 0)
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relid = RelOid_pg_group;
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else if (strcmp(DatabaseRelationName, relname) == 0)
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relid = RelOid_pg_database;
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else
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relid = newoid();
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}
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else
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relid = newoid();
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/*
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* For now, the physical identifier of the relation is the same as the
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* logical identifier.
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*/
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rnode.tblNode = dbid;
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rnode.relNode = relid;
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/*
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* build the relcache entry.
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*/
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rel = RelationBuildLocalRelation(relname,
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relnamespace,
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tupDesc,
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relid, dbid,
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rnode,
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nailme);
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/*
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* have the storage manager create the relation's disk file, if
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* wanted.
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*/
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if (storage_create)
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heap_storage_create(rel);
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return rel;
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}
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void
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heap_storage_create(Relation rel)
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{
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Assert(rel->rd_smgr == NULL);
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rel->rd_smgr = smgropen(rel->rd_node);
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smgrcreate(rel->rd_smgr, rel->rd_istemp, false);
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}
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/* ----------------------------------------------------------------
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* heap_create_with_catalog - Create a cataloged relation
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*
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* this is done in 6 steps:
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*
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* 1) CheckAttributeNamesTypes() is used to make certain the tuple
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* descriptor contains a valid set of attribute names and types
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*
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* 2) pg_class is opened and get_relname_relid()
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* performs a scan to ensure that no relation with the
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* same name already exists.
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*
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* 3) heap_create() is called to create the new relation on disk.
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*
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* 4) AddNewRelationTuple() is called to register the
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* relation in pg_class.
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*
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* 5) TypeCreate() is called to define a new type corresponding
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* to the new relation.
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*
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* 6) AddNewAttributeTuples() is called to register the
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* new relation's schema in pg_attribute.
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*
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* 7) StoreConstraints is called () - vadim 08/22/97
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*
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* 8) the relations are closed and the new relation's oid
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* is returned.
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*
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* ----------------------------------------------------------------
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*/
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/* --------------------------------
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* CheckAttributeNamesTypes
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*
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* this is used to make certain the tuple descriptor contains a
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* valid set of attribute names and datatypes. a problem simply
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* generates ereport(ERROR) which aborts the current transaction.
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* --------------------------------
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*/
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void
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CheckAttributeNamesTypes(TupleDesc tupdesc, char relkind)
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{
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int i;
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int j;
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int natts = tupdesc->natts;
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/* Sanity check on column count */
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if (natts < 0 || natts > MaxHeapAttributeNumber)
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ereport(ERROR,
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(errcode(ERRCODE_TOO_MANY_COLUMNS),
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errmsg("tables can have at most %d columns",
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MaxHeapAttributeNumber)));
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/*
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* first check for collision with system attribute names
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*
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* Skip this for a view or type relation, since those don't have system
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* attributes.
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*/
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if (relkind != RELKIND_VIEW && relkind != RELKIND_COMPOSITE_TYPE)
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{
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for (i = 0; i < natts; i++)
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{
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if (SystemAttributeByName(NameStr(tupdesc->attrs[i]->attname),
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tupdesc->tdhasoid) != NULL)
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ereport(ERROR,
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(errcode(ERRCODE_DUPLICATE_COLUMN),
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errmsg("column name \"%s\" conflicts with a system column name",
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NameStr(tupdesc->attrs[i]->attname))));
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}
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}
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/*
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* next check for repeated attribute names
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*/
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for (i = 1; i < natts; i++)
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{
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for (j = 0; j < i; j++)
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{
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if (strcmp(NameStr(tupdesc->attrs[j]->attname),
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NameStr(tupdesc->attrs[i]->attname)) == 0)
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ereport(ERROR,
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(errcode(ERRCODE_DUPLICATE_COLUMN),
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errmsg("column name \"%s\" is duplicated",
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NameStr(tupdesc->attrs[j]->attname))));
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}
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}
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/*
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* next check the attribute types
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*/
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for (i = 0; i < natts; i++)
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{
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CheckAttributeType(NameStr(tupdesc->attrs[i]->attname),
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tupdesc->attrs[i]->atttypid);
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}
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}
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/* --------------------------------
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* CheckAttributeType
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*
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* Verify that the proposed datatype of an attribute is legal.
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* This is needed because there are types (and pseudo-types)
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* in the catalogs that we do not support as elements of real tuples.
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* --------------------------------
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*/
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void
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CheckAttributeType(const char *attname, Oid atttypid)
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{
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char att_typtype = get_typtype(atttypid);
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|
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/*
|
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* Warn user, but don't fail, if column to be created has UNKNOWN type
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* (usually as a result of a 'retrieve into' - jolly)
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*
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* Refuse any attempt to create a pseudo-type column or one that uses a
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* standalone composite type. (Eventually we should probably refuse
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* all references to complex types, but for now there's still some
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* Berkeley-derived code that thinks it can do this...)
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*/
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if (atttypid == UNKNOWNOID)
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ereport(WARNING,
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(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
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errmsg("column \"%s\" has type \"unknown\"", attname),
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errdetail("Proceeding with relation creation anyway.")));
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else if (att_typtype == 'p')
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{
|
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/* Special hack for pg_statistic: allow ANYARRAY during initdb */
|
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if (atttypid != ANYARRAYOID || IsUnderPostmaster)
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ereport(ERROR,
|
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(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
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errmsg("column \"%s\" has pseudo-type %s",
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attname, format_type_be(atttypid))));
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}
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else if (att_typtype == 'c')
|
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{
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Oid typrelid = get_typ_typrelid(atttypid);
|
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|
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if (get_rel_relkind(typrelid) == RELKIND_COMPOSITE_TYPE)
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ereport(ERROR,
|
|
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
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errmsg("column \"%s\" has composite type %s",
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attname, format_type_be(atttypid))));
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}
|
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}
|
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|
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/* --------------------------------
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* AddNewAttributeTuples
|
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*
|
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* this registers the new relation's schema by adding
|
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* tuples to pg_attribute.
|
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* --------------------------------
|
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*/
|
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static void
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AddNewAttributeTuples(Oid new_rel_oid,
|
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TupleDesc tupdesc,
|
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char relkind,
|
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bool oidislocal,
|
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int oidinhcount)
|
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{
|
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Form_pg_attribute *dpp;
|
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int i;
|
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HeapTuple tup;
|
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Relation rel;
|
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CatalogIndexState indstate;
|
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int natts = tupdesc->natts;
|
|
ObjectAddress myself,
|
|
referenced;
|
|
|
|
/*
|
|
* open pg_attribute and its indexes.
|
|
*/
|
|
rel = heap_openr(AttributeRelationName, RowExclusiveLock);
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|
|
|
indstate = CatalogOpenIndexes(rel);
|
|
|
|
/*
|
|
* First we add the user attributes. This is also a convenient place
|
|
* to add dependencies on their datatypes.
|
|
*/
|
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dpp = tupdesc->attrs;
|
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for (i = 0; i < natts; i++)
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{
|
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/* Fill in the correct relation OID */
|
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(*dpp)->attrelid = new_rel_oid;
|
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/* Make sure these are OK, too */
|
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(*dpp)->attstattarget = -1;
|
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(*dpp)->attcacheoff = -1;
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|
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tup = heap_addheader(Natts_pg_attribute,
|
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false,
|
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ATTRIBUTE_TUPLE_SIZE,
|
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(void *) *dpp);
|
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|
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simple_heap_insert(rel, tup);
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|
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CatalogIndexInsert(indstate, tup);
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|
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heap_freetuple(tup);
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|
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myself.classId = RelOid_pg_class;
|
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myself.objectId = new_rel_oid;
|
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myself.objectSubId = i + 1;
|
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referenced.classId = RelOid_pg_type;
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referenced.objectId = (*dpp)->atttypid;
|
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referenced.objectSubId = 0;
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recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
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|
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dpp++;
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}
|
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|
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/*
|
|
* Next we add the system attributes. Skip OID if rel has no OIDs.
|
|
* Skip all for a view or type relation. We don't bother with making
|
|
* datatype dependencies here, since presumably all these types are
|
|
* pinned.
|
|
*/
|
|
if (relkind != RELKIND_VIEW && relkind != RELKIND_COMPOSITE_TYPE)
|
|
{
|
|
dpp = SysAtt;
|
|
for (i = 0; i < -1 - FirstLowInvalidHeapAttributeNumber; i++)
|
|
{
|
|
if (tupdesc->tdhasoid ||
|
|
(*dpp)->attnum != ObjectIdAttributeNumber)
|
|
{
|
|
Form_pg_attribute attStruct;
|
|
|
|
tup = heap_addheader(Natts_pg_attribute,
|
|
false,
|
|
ATTRIBUTE_TUPLE_SIZE,
|
|
(void *) *dpp);
|
|
attStruct = (Form_pg_attribute) GETSTRUCT(tup);
|
|
|
|
/* Fill in the correct relation OID in the copied tuple */
|
|
attStruct->attrelid = new_rel_oid;
|
|
|
|
/* Fill in correct inheritance info for the OID column */
|
|
if (attStruct->attnum == ObjectIdAttributeNumber)
|
|
{
|
|
attStruct->attislocal = oidislocal;
|
|
attStruct->attinhcount = oidinhcount;
|
|
}
|
|
|
|
/*
|
|
* Unneeded since they should be OK in the constant data
|
|
* anyway
|
|
*/
|
|
/* attStruct->attstattarget = 0; */
|
|
/* attStruct->attcacheoff = -1; */
|
|
|
|
simple_heap_insert(rel, tup);
|
|
|
|
CatalogIndexInsert(indstate, tup);
|
|
|
|
heap_freetuple(tup);
|
|
}
|
|
dpp++;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* clean up
|
|
*/
|
|
CatalogCloseIndexes(indstate);
|
|
|
|
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,
|
|
char relkind)
|
|
{
|
|
Form_pg_class new_rel_reltup;
|
|
HeapTuple tup;
|
|
|
|
/*
|
|
* 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_desc->rd_att->tdtypeid = new_type_oid;
|
|
|
|
/* ----------------
|
|
* 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,
|
|
true,
|
|
CLASS_TUPLE_SIZE,
|
|
(void *) new_rel_reltup);
|
|
|
|
/* force tuple to have the desired OID */
|
|
HeapTupleSetOid(tup, new_rel_oid);
|
|
|
|
/*
|
|
* finally insert the new tuple, update the indexes, and clean up.
|
|
*/
|
|
simple_heap_insert(pg_class_desc, tup);
|
|
|
|
CatalogUpdateIndexes(pg_class_desc, tup);
|
|
|
|
heap_freetuple(tup);
|
|
}
|
|
|
|
|
|
/* --------------------------------
|
|
* AddNewRelationType -
|
|
*
|
|
* define a composite type corresponding to the new relation
|
|
* --------------------------------
|
|
*/
|
|
static void
|
|
AddNewRelationType(const char *typeName,
|
|
Oid typeNamespace,
|
|
Oid new_rel_oid,
|
|
char new_rel_kind,
|
|
Oid new_type_oid)
|
|
{
|
|
TypeCreate(typeName, /* type name */
|
|
typeNamespace, /* type namespace */
|
|
new_type_oid, /* preassigned oid for type */
|
|
new_rel_oid, /* relation oid */
|
|
new_rel_kind, /* relation kind */
|
|
-1, /* internal size (varlena) */
|
|
'c', /* type-type (complex) */
|
|
',', /* default array delimiter */
|
|
F_RECORD_IN, /* input procedure */
|
|
F_RECORD_OUT, /* output procedure */
|
|
F_RECORD_RECV, /* receive procedure */
|
|
F_RECORD_SEND, /* send procedure */
|
|
InvalidOid, /* analyze procedure - default */
|
|
InvalidOid, /* array element type - irrelevant */
|
|
InvalidOid, /* domain base type - irrelevant */
|
|
NULL, /* default type value - none */
|
|
NULL, /* default type binary representation */
|
|
false, /* passed by reference */
|
|
'd', /* alignment - must be the largest! */
|
|
'x', /* fully TOASTable */
|
|
-1, /* typmod */
|
|
0, /* array dimensions for typBaseType */
|
|
false); /* Type NOT NULL */
|
|
}
|
|
|
|
/* --------------------------------
|
|
* heap_create_with_catalog
|
|
*
|
|
* creates a new cataloged relation. see comments above.
|
|
* --------------------------------
|
|
*/
|
|
Oid
|
|
heap_create_with_catalog(const char *relname,
|
|
Oid relnamespace,
|
|
TupleDesc tupdesc,
|
|
char relkind,
|
|
bool shared_relation,
|
|
bool oidislocal,
|
|
int oidinhcount,
|
|
OnCommitAction oncommit,
|
|
bool allow_system_table_mods)
|
|
{
|
|
Relation pg_class_desc;
|
|
Relation new_rel_desc;
|
|
Oid new_rel_oid;
|
|
Oid new_type_oid;
|
|
|
|
/*
|
|
* sanity checks
|
|
*/
|
|
Assert(IsNormalProcessingMode() || IsBootstrapProcessingMode());
|
|
|
|
CheckAttributeNamesTypes(tupdesc, relkind);
|
|
|
|
if (get_relname_relid(relname, relnamespace))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DUPLICATE_TABLE),
|
|
errmsg("relation \"%s\" already exists", relname)));
|
|
|
|
/*
|
|
* Create the relcache entry (mostly dummy at this point) and the
|
|
* physical disk file. (If we fail further down, it's the smgr's
|
|
* responsibility to remove the disk file again.)
|
|
*
|
|
* NB: create a physical file only if it's not a view or type relation.
|
|
*/
|
|
new_rel_desc = heap_create(relname,
|
|
relnamespace,
|
|
tupdesc,
|
|
shared_relation,
|
|
(relkind != RELKIND_VIEW &&
|
|
relkind != RELKIND_COMPOSITE_TYPE),
|
|
allow_system_table_mods);
|
|
|
|
/* Fetch the relation OID assigned by heap_create */
|
|
new_rel_oid = RelationGetRelid(new_rel_desc);
|
|
|
|
/* 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,
|
|
relkind);
|
|
|
|
/*
|
|
* 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,
|
|
relnamespace,
|
|
new_rel_oid,
|
|
relkind,
|
|
new_type_oid);
|
|
|
|
/*
|
|
* now add tuples to pg_attribute for the attributes in our new
|
|
* relation.
|
|
*/
|
|
AddNewAttributeTuples(new_rel_oid, new_rel_desc->rd_att, relkind,
|
|
oidislocal, oidinhcount);
|
|
|
|
/*
|
|
* make a dependency link to force the relation to be deleted if its
|
|
* namespace is. Skip this in bootstrap mode, since we don't make
|
|
* dependencies while bootstrapping.
|
|
*/
|
|
if (!IsBootstrapProcessingMode())
|
|
{
|
|
ObjectAddress myself,
|
|
referenced;
|
|
|
|
myself.classId = RelOid_pg_class;
|
|
myself.objectId = new_rel_oid;
|
|
myself.objectSubId = 0;
|
|
referenced.classId = get_system_catalog_relid(NamespaceRelationName);
|
|
referenced.objectId = relnamespace;
|
|
referenced.objectSubId = 0;
|
|
recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
|
|
}
|
|
|
|
/*
|
|
* store constraints and defaults passed in the tupdesc, if any.
|
|
*
|
|
* NB: this may do a CommandCounterIncrement and rebuild the relcache
|
|
* entry, so the relation must be valid and self-consistent at this
|
|
* point. In particular, there are not yet constraints and defaults
|
|
* anywhere.
|
|
*/
|
|
StoreConstraints(new_rel_desc, tupdesc);
|
|
|
|
/*
|
|
* If there's a special on-commit action, remember it
|
|
*/
|
|
if (oncommit != ONCOMMIT_NOOP)
|
|
register_on_commit_action(new_rel_oid, oncommit);
|
|
|
|
/*
|
|
* ok, the relation has been cataloged, so close our relations and
|
|
* return the oid of the newly created relation.
|
|
*/
|
|
heap_close(new_rel_desc, NoLock); /* do not unlock till end of xact */
|
|
heap_close(pg_class_desc, RowExclusiveLock);
|
|
|
|
return new_rel_oid;
|
|
}
|
|
|
|
|
|
/*
|
|
* RelationRemoveInheritance
|
|
*
|
|
* Formerly, this routine checked for child relations and aborted the
|
|
* deletion if any were found. Now we rely on the dependency mechanism
|
|
* to check for or delete child relations. By the time we get here,
|
|
* there are no children and we need only remove any pg_inherits rows
|
|
* linking this relation to its parent(s).
|
|
*/
|
|
static void
|
|
RelationRemoveInheritance(Relation relation)
|
|
{
|
|
Relation catalogRelation;
|
|
SysScanDesc scan;
|
|
ScanKeyData key;
|
|
HeapTuple tuple;
|
|
|
|
catalogRelation = heap_openr(InheritsRelationName, RowExclusiveLock);
|
|
|
|
ScanKeyInit(&key,
|
|
Anum_pg_inherits_inhrelid,
|
|
BTEqualStrategyNumber, F_OIDEQ,
|
|
ObjectIdGetDatum(RelationGetRelid(relation)));
|
|
|
|
scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndex, true,
|
|
SnapshotNow, 1, &key);
|
|
|
|
while (HeapTupleIsValid(tuple = systable_getnext(scan)))
|
|
simple_heap_delete(catalogRelation, &tuple->t_self);
|
|
|
|
systable_endscan(scan);
|
|
heap_close(catalogRelation, RowExclusiveLock);
|
|
}
|
|
|
|
/*
|
|
* DeleteRelationTuple
|
|
*
|
|
* Remove pg_class row for the given relid.
|
|
*
|
|
* Note: this is shared by relation deletion and index deletion. It's
|
|
* not intended for use anyplace else.
|
|
*/
|
|
void
|
|
DeleteRelationTuple(Oid relid)
|
|
{
|
|
Relation pg_class_desc;
|
|
HeapTuple tup;
|
|
|
|
/* Grab an appropriate lock on the pg_class relation */
|
|
pg_class_desc = heap_openr(RelationRelationName, RowExclusiveLock);
|
|
|
|
tup = SearchSysCache(RELOID,
|
|
ObjectIdGetDatum(relid),
|
|
0, 0, 0);
|
|
if (!HeapTupleIsValid(tup))
|
|
elog(ERROR, "cache lookup failed for relation %u", relid);
|
|
|
|
/* delete the relation tuple from pg_class, and finish up */
|
|
simple_heap_delete(pg_class_desc, &tup->t_self);
|
|
|
|
ReleaseSysCache(tup);
|
|
|
|
heap_close(pg_class_desc, RowExclusiveLock);
|
|
}
|
|
|
|
/*
|
|
* DeleteAttributeTuples
|
|
*
|
|
* Remove pg_attribute rows for the given relid.
|
|
*
|
|
* Note: this is shared by relation deletion and index deletion. It's
|
|
* not intended for use anyplace else.
|
|
*/
|
|
void
|
|
DeleteAttributeTuples(Oid relid)
|
|
{
|
|
Relation attrel;
|
|
SysScanDesc scan;
|
|
ScanKeyData key[1];
|
|
HeapTuple atttup;
|
|
|
|
/* Grab an appropriate lock on the pg_attribute relation */
|
|
attrel = heap_openr(AttributeRelationName, RowExclusiveLock);
|
|
|
|
/* Use the index to scan only attributes of the target relation */
|
|
ScanKeyInit(&key[0],
|
|
Anum_pg_attribute_attrelid,
|
|
BTEqualStrategyNumber, F_OIDEQ,
|
|
ObjectIdGetDatum(relid));
|
|
|
|
scan = systable_beginscan(attrel, AttributeRelidNumIndex, true,
|
|
SnapshotNow, 1, key);
|
|
|
|
/* Delete all the matching tuples */
|
|
while ((atttup = systable_getnext(scan)) != NULL)
|
|
simple_heap_delete(attrel, &atttup->t_self);
|
|
|
|
/* Clean up after the scan */
|
|
systable_endscan(scan);
|
|
heap_close(attrel, RowExclusiveLock);
|
|
}
|
|
|
|
/*
|
|
* RemoveAttributeById
|
|
*
|
|
* This is the guts of ALTER TABLE DROP COLUMN: actually mark the attribute
|
|
* deleted in pg_attribute. We also remove pg_statistic entries for it.
|
|
* (Everything else needed, such as getting rid of any pg_attrdef entry,
|
|
* is handled by dependency.c.)
|
|
*/
|
|
void
|
|
RemoveAttributeById(Oid relid, AttrNumber attnum)
|
|
{
|
|
Relation rel;
|
|
Relation attr_rel;
|
|
HeapTuple tuple;
|
|
Form_pg_attribute attStruct;
|
|
char newattname[NAMEDATALEN];
|
|
|
|
/*
|
|
* Grab an exclusive lock on the target table, which we will NOT
|
|
* release until end of transaction. (In the simple case where we are
|
|
* directly dropping this column, AlterTableDropColumn already did
|
|
* this ... but when cascading from a drop of some other object, we
|
|
* may not have any lock.)
|
|
*/
|
|
rel = relation_open(relid, AccessExclusiveLock);
|
|
|
|
attr_rel = heap_openr(AttributeRelationName, RowExclusiveLock);
|
|
|
|
tuple = SearchSysCacheCopy(ATTNUM,
|
|
ObjectIdGetDatum(relid),
|
|
Int16GetDatum(attnum),
|
|
0, 0);
|
|
if (!HeapTupleIsValid(tuple)) /* shouldn't happen */
|
|
elog(ERROR, "cache lookup failed for attribute %d of relation %u",
|
|
attnum, relid);
|
|
attStruct = (Form_pg_attribute) GETSTRUCT(tuple);
|
|
|
|
if (attnum < 0)
|
|
{
|
|
/* System attribute (probably OID) ... just delete the row */
|
|
|
|
simple_heap_delete(attr_rel, &tuple->t_self);
|
|
}
|
|
else
|
|
{
|
|
/* Dropping user attributes is lots harder */
|
|
|
|
/* Mark the attribute as dropped */
|
|
attStruct->attisdropped = true;
|
|
|
|
/*
|
|
* Set the type OID to invalid. A dropped attribute's type link
|
|
* cannot be relied on (once the attribute is dropped, the type might
|
|
* be too). Fortunately we do not need the type row --- the only
|
|
* really essential information is the type's typlen and typalign,
|
|
* which are preserved in the attribute's attlen and attalign. We set
|
|
* atttypid to zero here as a means of catching code that incorrectly
|
|
* expects it to be valid.
|
|
*/
|
|
attStruct->atttypid = InvalidOid;
|
|
|
|
/* Remove any NOT NULL constraint the column may have */
|
|
attStruct->attnotnull = false;
|
|
|
|
/* We don't want to keep stats for it anymore */
|
|
attStruct->attstattarget = 0;
|
|
|
|
/* Change the column name to something that isn't likely to conflict */
|
|
snprintf(newattname, sizeof(newattname),
|
|
"........pg.dropped.%d........", attnum);
|
|
namestrcpy(&(attStruct->attname), newattname);
|
|
|
|
simple_heap_update(attr_rel, &tuple->t_self, tuple);
|
|
|
|
/* keep the system catalog indexes current */
|
|
CatalogUpdateIndexes(attr_rel, tuple);
|
|
}
|
|
|
|
/*
|
|
* Because updating the pg_attribute row will trigger a relcache flush
|
|
* for the target relation, we need not do anything else to notify
|
|
* other backends of the change.
|
|
*/
|
|
|
|
heap_close(attr_rel, RowExclusiveLock);
|
|
|
|
if (attnum > 0)
|
|
RemoveStatistics(rel, attnum);
|
|
|
|
relation_close(rel, NoLock);
|
|
}
|
|
|
|
/*
|
|
* RemoveAttrDefault
|
|
*
|
|
* If the specified relation/attribute has a default, remove it.
|
|
* (If no default, raise error if complain is true, else return quietly.)
|
|
*/
|
|
void
|
|
RemoveAttrDefault(Oid relid, AttrNumber attnum,
|
|
DropBehavior behavior, bool complain)
|
|
{
|
|
Relation attrdef_rel;
|
|
ScanKeyData scankeys[2];
|
|
SysScanDesc scan;
|
|
HeapTuple tuple;
|
|
bool found = false;
|
|
|
|
attrdef_rel = heap_openr(AttrDefaultRelationName, RowExclusiveLock);
|
|
|
|
ScanKeyInit(&scankeys[0],
|
|
Anum_pg_attrdef_adrelid,
|
|
BTEqualStrategyNumber, F_OIDEQ,
|
|
ObjectIdGetDatum(relid));
|
|
ScanKeyInit(&scankeys[1],
|
|
Anum_pg_attrdef_adnum,
|
|
BTEqualStrategyNumber, F_INT2EQ,
|
|
Int16GetDatum(attnum));
|
|
|
|
scan = systable_beginscan(attrdef_rel, AttrDefaultIndex, true,
|
|
SnapshotNow, 2, scankeys);
|
|
|
|
/* There should be at most one matching tuple, but we loop anyway */
|
|
while (HeapTupleIsValid(tuple = systable_getnext(scan)))
|
|
{
|
|
ObjectAddress object;
|
|
|
|
object.classId = RelationGetRelid(attrdef_rel);
|
|
object.objectId = HeapTupleGetOid(tuple);
|
|
object.objectSubId = 0;
|
|
|
|
performDeletion(&object, behavior);
|
|
|
|
found = true;
|
|
}
|
|
|
|
systable_endscan(scan);
|
|
heap_close(attrdef_rel, RowExclusiveLock);
|
|
|
|
if (complain && !found)
|
|
elog(ERROR, "could not find attrdef tuple for relation %u attnum %d",
|
|
relid, attnum);
|
|
}
|
|
|
|
/*
|
|
* RemoveAttrDefaultById
|
|
*
|
|
* Remove a pg_attrdef entry specified by OID. This is the guts of
|
|
* attribute-default removal. Note it should be called via performDeletion,
|
|
* not directly.
|
|
*/
|
|
void
|
|
RemoveAttrDefaultById(Oid attrdefId)
|
|
{
|
|
Relation attrdef_rel;
|
|
Relation attr_rel;
|
|
Relation myrel;
|
|
ScanKeyData scankeys[1];
|
|
SysScanDesc scan;
|
|
HeapTuple tuple;
|
|
Oid myrelid;
|
|
AttrNumber myattnum;
|
|
|
|
/* Grab an appropriate lock on the pg_attrdef relation */
|
|
attrdef_rel = heap_openr(AttrDefaultRelationName, RowExclusiveLock);
|
|
|
|
/* Find the pg_attrdef tuple */
|
|
ScanKeyInit(&scankeys[0],
|
|
ObjectIdAttributeNumber,
|
|
BTEqualStrategyNumber, F_OIDEQ,
|
|
ObjectIdGetDatum(attrdefId));
|
|
|
|
scan = systable_beginscan(attrdef_rel, AttrDefaultOidIndex, true,
|
|
SnapshotNow, 1, scankeys);
|
|
|
|
tuple = systable_getnext(scan);
|
|
if (!HeapTupleIsValid(tuple))
|
|
elog(ERROR, "could not find tuple for attrdef %u", attrdefId);
|
|
|
|
myrelid = ((Form_pg_attrdef) GETSTRUCT(tuple))->adrelid;
|
|
myattnum = ((Form_pg_attrdef) GETSTRUCT(tuple))->adnum;
|
|
|
|
/* Get an exclusive lock on the relation owning the attribute */
|
|
myrel = relation_open(myrelid, AccessExclusiveLock);
|
|
|
|
/* Now we can delete the pg_attrdef row */
|
|
simple_heap_delete(attrdef_rel, &tuple->t_self);
|
|
|
|
systable_endscan(scan);
|
|
heap_close(attrdef_rel, RowExclusiveLock);
|
|
|
|
/* Fix the pg_attribute row */
|
|
attr_rel = heap_openr(AttributeRelationName, RowExclusiveLock);
|
|
|
|
tuple = SearchSysCacheCopy(ATTNUM,
|
|
ObjectIdGetDatum(myrelid),
|
|
Int16GetDatum(myattnum),
|
|
0, 0);
|
|
if (!HeapTupleIsValid(tuple)) /* shouldn't happen */
|
|
elog(ERROR, "cache lookup failed for attribute %d of relation %u",
|
|
myattnum, myrelid);
|
|
|
|
((Form_pg_attribute) GETSTRUCT(tuple))->atthasdef = false;
|
|
|
|
simple_heap_update(attr_rel, &tuple->t_self, tuple);
|
|
|
|
/* keep the system catalog indexes current */
|
|
CatalogUpdateIndexes(attr_rel, tuple);
|
|
|
|
/*
|
|
* Our update of the pg_attribute row will force a relcache rebuild,
|
|
* so there's nothing else to do here.
|
|
*/
|
|
heap_close(attr_rel, RowExclusiveLock);
|
|
|
|
/* Keep lock on attribute's rel until end of xact */
|
|
relation_close(myrel, NoLock);
|
|
}
|
|
|
|
/* ----------------------------------------------------------------
|
|
* heap_drop_with_catalog - removes specified relation from catalogs
|
|
*
|
|
* 1) open relation, acquire exclusive lock.
|
|
* 2) flush relation buffers from bufmgr
|
|
* 3) remove inheritance information
|
|
* 4) remove pg_statistic tuples
|
|
* 5) remove pg_attribute tuples
|
|
* 6) remove pg_class tuple
|
|
* 7) unlink relation file
|
|
*
|
|
* Note that this routine is not responsible for dropping objects that are
|
|
* linked to the pg_class entry via dependencies (for example, indexes and
|
|
* constraints). Those are deleted by the dependency-tracing logic in
|
|
* dependency.c before control gets here. In general, therefore, this routine
|
|
* should never be called directly; go through performDeletion() instead.
|
|
* ----------------------------------------------------------------
|
|
*/
|
|
void
|
|
heap_drop_with_catalog(Oid rid)
|
|
{
|
|
Relation rel;
|
|
int i;
|
|
|
|
/*
|
|
* Open and lock the relation.
|
|
*/
|
|
rel = relation_open(rid, AccessExclusiveLock);
|
|
|
|
/*
|
|
* Release all buffers that belong to this relation, after writing any
|
|
* that are dirty
|
|
*/
|
|
i = FlushRelationBuffers(rel, (BlockNumber) 0);
|
|
if (i < 0)
|
|
elog(ERROR, "FlushRelationBuffers returned %d", i);
|
|
|
|
/*
|
|
* remove inheritance information
|
|
*/
|
|
RelationRemoveInheritance(rel);
|
|
|
|
/*
|
|
* delete statistics
|
|
*/
|
|
RemoveStatistics(rel, 0);
|
|
|
|
/*
|
|
* delete attribute tuples
|
|
*/
|
|
DeleteAttributeTuples(RelationGetRelid(rel));
|
|
|
|
/*
|
|
* delete relation tuple
|
|
*/
|
|
DeleteRelationTuple(RelationGetRelid(rel));
|
|
|
|
/*
|
|
* forget any ON COMMIT action for the rel
|
|
*/
|
|
remove_on_commit_action(rid);
|
|
|
|
/*
|
|
* unlink the relation's physical file and finish up.
|
|
*/
|
|
if (rel->rd_rel->relkind != RELKIND_VIEW &&
|
|
rel->rd_rel->relkind != RELKIND_COMPOSITE_TYPE)
|
|
{
|
|
if (rel->rd_smgr == NULL)
|
|
rel->rd_smgr = smgropen(rel->rd_node);
|
|
smgrscheduleunlink(rel->rd_smgr, rel->rd_istemp);
|
|
rel->rd_smgr = NULL;
|
|
}
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
relation_close(rel, NoLock);
|
|
|
|
/*
|
|
* flush the relation from the relcache
|
|
*/
|
|
RelationForgetRelation(rid);
|
|
}
|
|
|
|
|
|
/*
|
|
* Store a default expression for column attnum of relation rel.
|
|
* The expression must be presented as a nodeToString() string.
|
|
*/
|
|
static void
|
|
StoreAttrDefault(Relation rel, AttrNumber attnum, char *adbin)
|
|
{
|
|
Node *expr;
|
|
char *adsrc;
|
|
Relation adrel;
|
|
HeapTuple tuple;
|
|
Datum values[4];
|
|
static char nulls[4] = {' ', ' ', ' ', ' '};
|
|
Relation attrrel;
|
|
HeapTuple atttup;
|
|
Form_pg_attribute attStruct;
|
|
Oid attrdefOid;
|
|
ObjectAddress colobject,
|
|
defobject;
|
|
|
|
/*
|
|
* 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, false);
|
|
|
|
/*
|
|
* Make the pg_attrdef entry.
|
|
*/
|
|
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);
|
|
attrdefOid = simple_heap_insert(adrel, tuple);
|
|
|
|
CatalogUpdateIndexes(adrel, tuple);
|
|
|
|
defobject.classId = RelationGetRelid(adrel);
|
|
defobject.objectId = attrdefOid;
|
|
defobject.objectSubId = 0;
|
|
|
|
heap_close(adrel, RowExclusiveLock);
|
|
|
|
/* now can free some of the stuff allocated above */
|
|
pfree(DatumGetPointer(values[Anum_pg_attrdef_adbin - 1]));
|
|
pfree(DatumGetPointer(values[Anum_pg_attrdef_adsrc - 1]));
|
|
heap_freetuple(tuple);
|
|
pfree(adsrc);
|
|
|
|
/*
|
|
* Update the pg_attribute entry for the column to show that a default
|
|
* exists.
|
|
*/
|
|
attrrel = heap_openr(AttributeRelationName, RowExclusiveLock);
|
|
atttup = SearchSysCacheCopy(ATTNUM,
|
|
ObjectIdGetDatum(RelationGetRelid(rel)),
|
|
Int16GetDatum(attnum),
|
|
0, 0);
|
|
if (!HeapTupleIsValid(atttup))
|
|
elog(ERROR, "cache lookup failed for attribute %d of relation %u",
|
|
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 indexes current */
|
|
CatalogUpdateIndexes(attrrel, atttup);
|
|
}
|
|
heap_close(attrrel, RowExclusiveLock);
|
|
heap_freetuple(atttup);
|
|
|
|
/*
|
|
* Make a dependency so that the pg_attrdef entry goes away if the
|
|
* column (or whole table) is deleted.
|
|
*/
|
|
colobject.classId = RelOid_pg_class;
|
|
colobject.objectId = RelationGetRelid(rel);
|
|
colobject.objectSubId = attnum;
|
|
|
|
recordDependencyOn(&defobject, &colobject, DEPENDENCY_AUTO);
|
|
|
|
/*
|
|
* Record dependencies on objects used in the expression, too.
|
|
*/
|
|
recordDependencyOnExpr(&defobject, expr, NIL, DEPENDENCY_NORMAL);
|
|
}
|
|
|
|
/*
|
|
* Store a check-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;
|
|
List *varList;
|
|
int keycount;
|
|
int16 *attNos;
|
|
|
|
/*
|
|
* Convert condition to an expression tree.
|
|
*/
|
|
expr = stringToNode(ccbin);
|
|
|
|
/*
|
|
* deparse it
|
|
*/
|
|
ccsrc = deparse_expression(expr,
|
|
deparse_context_for(RelationGetRelationName(rel),
|
|
RelationGetRelid(rel)),
|
|
false, false);
|
|
|
|
/*
|
|
* Find columns of rel that are used in ccbin
|
|
*
|
|
* NB: pull_var_clause is okay here only because we don't allow
|
|
* subselects in check constraints; it would fail to examine the
|
|
* contents of subselects.
|
|
*/
|
|
varList = pull_var_clause(expr, false);
|
|
keycount = length(varList);
|
|
|
|
if (keycount > 0)
|
|
{
|
|
List *vl;
|
|
int i = 0;
|
|
|
|
attNos = (int16 *) palloc(keycount * sizeof(int16));
|
|
foreach(vl, varList)
|
|
{
|
|
Var *var = (Var *) lfirst(vl);
|
|
int j;
|
|
|
|
for (j = 0; j < i; j++)
|
|
if (attNos[j] == var->varattno)
|
|
break;
|
|
if (j == i)
|
|
attNos[i++] = var->varattno;
|
|
}
|
|
keycount = i;
|
|
}
|
|
else
|
|
attNos = NULL;
|
|
|
|
/*
|
|
* Create the Check Constraint
|
|
*/
|
|
CreateConstraintEntry(ccname, /* Constraint Name */
|
|
RelationGetNamespace(rel), /* namespace */
|
|
CONSTRAINT_CHECK, /* Constraint Type */
|
|
false, /* Is Deferrable */
|
|
false, /* Is Deferred */
|
|
RelationGetRelid(rel), /* relation */
|
|
attNos, /* attrs in the constraint */
|
|
keycount, /* # attrs in the constraint */
|
|
InvalidOid, /* not a domain constraint */
|
|
InvalidOid, /* Foreign key fields */
|
|
NULL,
|
|
0,
|
|
' ',
|
|
' ',
|
|
' ',
|
|
InvalidOid, /* no associated index */
|
|
expr, /* Tree form check constraint */
|
|
ccbin, /* Binary form check constraint */
|
|
ccsrc); /* Source form check constraint */
|
|
|
|
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()).
|
|
*/
|
|
static void
|
|
StoreConstraints(Relation rel, TupleDesc tupdesc)
|
|
{
|
|
TupleConstr *constr = tupdesc->constr;
|
|
int i;
|
|
|
|
if (!constr)
|
|
return; /* nothing to do */
|
|
|
|
/*
|
|
* Deparsing of constraint expressions will fail unless the
|
|
* just-created pg_attribute tuples for this relation are made
|
|
* visible. So, bump the command counter. CAUTION: this will cause a
|
|
* relcache entry rebuild.
|
|
*/
|
|
CommandCounterIncrement();
|
|
|
|
for (i = 0; i < constr->num_defval; i++)
|
|
StoreAttrDefault(rel, constr->defval[i].adnum,
|
|
constr->defval[i].adbin);
|
|
|
|
for (i = 0; i < constr->num_check; i++)
|
|
StoreRelCheck(rel, constr->check[i].ccname,
|
|
constr->check[i].ccbin);
|
|
|
|
if (constr->num_check > 0)
|
|
SetRelationNumChecks(rel, constr->num_check);
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
int constr_name_ctr = 0;
|
|
List *listptr;
|
|
Node *expr;
|
|
|
|
/*
|
|
* 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 = addRangeTableEntryForRelation(pstate,
|
|
RelationGetRelid(rel),
|
|
makeAlias(relname, NIL),
|
|
false,
|
|
true);
|
|
addRTEtoQuery(pstate, rte, true, true);
|
|
|
|
/*
|
|
* Process column default expressions.
|
|
*/
|
|
foreach(listptr, rawColDefaults)
|
|
{
|
|
RawColumnDefault *colDef = (RawColumnDefault *) lfirst(listptr);
|
|
Form_pg_attribute atp = rel->rd_att->attrs[colDef->attnum - 1];
|
|
|
|
expr = cookDefault(pstate, colDef->raw_default,
|
|
atp->atttypid, atp->atttypmod,
|
|
NameStr(atp->attname));
|
|
StoreAttrDefault(rel, colDef->attnum, nodeToString(expr));
|
|
}
|
|
|
|
/*
|
|
* Process constraint expressions.
|
|
*/
|
|
numchecks = numoldchecks;
|
|
foreach(listptr, rawConstraints)
|
|
{
|
|
Constraint *cdef = (Constraint *) lfirst(listptr);
|
|
char *ccname;
|
|
|
|
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)
|
|
{
|
|
List *listptr2;
|
|
|
|
ccname = cdef->name;
|
|
/* Check against pre-existing constraints */
|
|
if (ConstraintNameIsUsed(CONSTRAINT_RELATION,
|
|
RelationGetRelid(rel),
|
|
RelationGetNamespace(rel),
|
|
ccname))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DUPLICATE_OBJECT),
|
|
errmsg("constraint \"%s\" for relation \"%s\" already exists",
|
|
ccname, RelationGetRelationName(rel))));
|
|
/* Check against other new constraints */
|
|
/* Needed because we don't do CommandCounterIncrement in loop */
|
|
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)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DUPLICATE_OBJECT),
|
|
errmsg("check constraint \"%s\" already exists",
|
|
ccname)));
|
|
}
|
|
}
|
|
else
|
|
{
|
|
bool success;
|
|
|
|
do
|
|
{
|
|
List *listptr2;
|
|
|
|
/*
|
|
* Generate a name that does not conflict with
|
|
* pre-existing constraints, nor with any auto-generated
|
|
* names so far.
|
|
*/
|
|
ccname = GenerateConstraintName(CONSTRAINT_RELATION,
|
|
RelationGetRelid(rel),
|
|
RelationGetNamespace(rel),
|
|
&constr_name_ctr);
|
|
|
|
/*
|
|
* Check against other new constraints, in case the user
|
|
* has specified a name that looks like an auto-generated
|
|
* name.
|
|
*/
|
|
success = true;
|
|
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;
|
|
}
|
|
}
|
|
} while (!success);
|
|
}
|
|
|
|
/*
|
|
* Transform raw parsetree to executable expression.
|
|
*/
|
|
expr = transformExpr(pstate, cdef->raw_expr);
|
|
|
|
/*
|
|
* Make sure it yields a boolean result.
|
|
*/
|
|
expr = coerce_to_boolean(pstate, expr, "CHECK");
|
|
|
|
/*
|
|
* Make sure no outside relations are referred to.
|
|
*/
|
|
if (length(pstate->p_rtable) != 1)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
|
|
errmsg("only table \"%s\" can be referenced in check constraint",
|
|
relname)));
|
|
|
|
/*
|
|
* No subplans or aggregates, either...
|
|
*/
|
|
if (pstate->p_hasSubLinks)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmsg("cannot use subquery in check constraint")));
|
|
if (pstate->p_hasAggs)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_GROUPING_ERROR),
|
|
errmsg("cannot use aggregate function in check constraint")));
|
|
|
|
/*
|
|
* 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.
|
|
* (This is critical if we added defaults but not constraints.)
|
|
*/
|
|
SetRelationNumChecks(rel, numchecks);
|
|
}
|
|
|
|
/*
|
|
* Update the count of constraints in the relation's pg_class tuple.
|
|
*
|
|
* Caller had better hold exclusive lock on the relation.
|
|
*
|
|
* An important side effect is that a SI update message will be sent out for
|
|
* the pg_class tuple, which will force other backends to rebuild their
|
|
* relcache entries for the rel. Also, this backend will rebuild its
|
|
* own relcache entry at the next CommandCounterIncrement.
|
|
*/
|
|
static void
|
|
SetRelationNumChecks(Relation rel, int numchecks)
|
|
{
|
|
Relation relrel;
|
|
HeapTuple reltup;
|
|
Form_pg_class relStruct;
|
|
|
|
relrel = heap_openr(RelationRelationName, RowExclusiveLock);
|
|
reltup = SearchSysCacheCopy(RELOID,
|
|
ObjectIdGetDatum(RelationGetRelid(rel)),
|
|
0, 0, 0);
|
|
if (!HeapTupleIsValid(reltup))
|
|
elog(ERROR, "cache lookup failed for relation %u",
|
|
RelationGetRelid(rel));
|
|
relStruct = (Form_pg_class) GETSTRUCT(reltup);
|
|
|
|
if (relStruct->relchecks != numchecks)
|
|
{
|
|
relStruct->relchecks = numchecks;
|
|
|
|
simple_heap_update(relrel, &reltup->t_self, reltup);
|
|
|
|
/* keep catalog indexes current */
|
|
CatalogUpdateIndexes(relrel, reltup);
|
|
}
|
|
else
|
|
{
|
|
/* Skip the disk update, but force relcache inval anyway */
|
|
CacheInvalidateRelcache(rel);
|
|
}
|
|
|
|
heap_freetuple(reltup);
|
|
heap_close(relrel, RowExclusiveLock);
|
|
}
|
|
|
|
/*
|
|
* Take a raw default and convert it to a cooked format ready for
|
|
* storage.
|
|
*
|
|
* Parse state should be set up to recognize any vars that might appear
|
|
* in the expression. (Even though we plan to reject vars, it's more
|
|
* user-friendly to give the correct error message than "unknown var".)
|
|
*
|
|
* If atttypid is not InvalidOid, coerce the expression to the specified
|
|
* type (and typmod atttypmod). attname is only needed in this case:
|
|
* it is used in the error message, if any.
|
|
*/
|
|
Node *
|
|
cookDefault(ParseState *pstate,
|
|
Node *raw_default,
|
|
Oid atttypid,
|
|
int32 atttypmod,
|
|
char *attname)
|
|
{
|
|
Node *expr;
|
|
|
|
Assert(raw_default != NULL);
|
|
|
|
/*
|
|
* Transform raw parsetree to executable expression.
|
|
*/
|
|
expr = transformExpr(pstate, raw_default);
|
|
|
|
/*
|
|
* Make sure default expr does not refer to any vars.
|
|
*/
|
|
if (contain_var_clause(expr))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
|
|
errmsg("cannot use column references in default expression")));
|
|
|
|
/*
|
|
* It can't return a set either.
|
|
*/
|
|
if (expression_returns_set(expr))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DATATYPE_MISMATCH),
|
|
errmsg("default 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 default expression")));
|
|
if (pstate->p_hasAggs)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_GROUPING_ERROR),
|
|
errmsg("cannot use aggregate function in default expression")));
|
|
|
|
/*
|
|
* Coerce the expression to the correct type and typmod, if given.
|
|
* This should match the parser's processing of non-defaulted
|
|
* expressions --- see updateTargetListEntry().
|
|
*/
|
|
if (OidIsValid(atttypid))
|
|
{
|
|
Oid type_id = exprType(expr);
|
|
|
|
expr = coerce_to_target_type(pstate, expr, type_id,
|
|
atttypid, atttypmod,
|
|
COERCION_ASSIGNMENT,
|
|
COERCE_IMPLICIT_CAST);
|
|
if (expr == NULL)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DATATYPE_MISMATCH),
|
|
errmsg("column \"%s\" is of type %s"
|
|
" but default expression is of type %s",
|
|
attname,
|
|
format_type_be(atttypid),
|
|
format_type_be(type_id)),
|
|
errhint("You will need to rewrite or cast the expression.")));
|
|
}
|
|
|
|
return expr;
|
|
}
|
|
|
|
|
|
/*
|
|
* Removes all constraints on a relation that match the given name.
|
|
*
|
|
* It is the responsibility of the calling function to acquire a suitable
|
|
* lock on the relation.
|
|
*
|
|
* Returns: The number of constraints removed.
|
|
*/
|
|
int
|
|
RemoveRelConstraints(Relation rel, const char *constrName,
|
|
DropBehavior behavior)
|
|
{
|
|
int ndeleted = 0;
|
|
Relation conrel;
|
|
SysScanDesc conscan;
|
|
ScanKeyData key[1];
|
|
HeapTuple contup;
|
|
|
|
/* Grab an appropriate lock on the pg_constraint relation */
|
|
conrel = heap_openr(ConstraintRelationName, RowExclusiveLock);
|
|
|
|
/* Use the index to scan only constraints of the target relation */
|
|
ScanKeyInit(&key[0],
|
|
Anum_pg_constraint_conrelid,
|
|
BTEqualStrategyNumber, F_OIDEQ,
|
|
ObjectIdGetDatum(RelationGetRelid(rel)));
|
|
|
|
conscan = systable_beginscan(conrel, ConstraintRelidIndex, true,
|
|
SnapshotNow, 1, key);
|
|
|
|
/*
|
|
* Scan over the result set, removing any matching entries.
|
|
*/
|
|
while ((contup = systable_getnext(conscan)) != NULL)
|
|
{
|
|
Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(contup);
|
|
|
|
if (strcmp(NameStr(con->conname), constrName) == 0)
|
|
{
|
|
ObjectAddress conobj;
|
|
|
|
conobj.classId = RelationGetRelid(conrel);
|
|
conobj.objectId = HeapTupleGetOid(contup);
|
|
conobj.objectSubId = 0;
|
|
|
|
performDeletion(&conobj, behavior);
|
|
|
|
ndeleted++;
|
|
}
|
|
}
|
|
|
|
/* Clean up after the scan */
|
|
systable_endscan(conscan);
|
|
heap_close(conrel, RowExclusiveLock);
|
|
|
|
return ndeleted;
|
|
}
|
|
|
|
|
|
/*
|
|
* RemoveStatistics --- remove entries in pg_statistic for a rel or column
|
|
*
|
|
* If attnum is zero, remove all entries for rel; else remove only the one
|
|
* for that column.
|
|
*/
|
|
void
|
|
RemoveStatistics(Relation rel, AttrNumber attnum)
|
|
{
|
|
Relation pgstatistic;
|
|
SysScanDesc scan;
|
|
ScanKeyData key[2];
|
|
int nkeys;
|
|
HeapTuple tuple;
|
|
|
|
pgstatistic = heap_openr(StatisticRelationName, RowExclusiveLock);
|
|
|
|
ScanKeyInit(&key[0],
|
|
Anum_pg_statistic_starelid,
|
|
BTEqualStrategyNumber, F_OIDEQ,
|
|
ObjectIdGetDatum(RelationGetRelid(rel)));
|
|
|
|
if (attnum == 0)
|
|
nkeys = 1;
|
|
else
|
|
{
|
|
ScanKeyInit(&key[1],
|
|
Anum_pg_statistic_staattnum,
|
|
BTEqualStrategyNumber, F_INT2EQ,
|
|
Int16GetDatum(attnum));
|
|
nkeys = 2;
|
|
}
|
|
|
|
scan = systable_beginscan(pgstatistic, StatisticRelidAttnumIndex, true,
|
|
SnapshotNow, nkeys, key);
|
|
|
|
while (HeapTupleIsValid(tuple = systable_getnext(scan)))
|
|
simple_heap_delete(pgstatistic, &tuple->t_self);
|
|
|
|
systable_endscan(scan);
|
|
|
|
heap_close(pgstatistic, RowExclusiveLock);
|
|
}
|
|
|
|
|
|
/*
|
|
* RelationTruncateIndexes - truncate all
|
|
* indexes associated with the heap relation to zero tuples.
|
|
*
|
|
* The routine will truncate and then reconstruct the indexes on
|
|
* the relation specified by the heapId parameter.
|
|
*/
|
|
static void
|
|
RelationTruncateIndexes(Oid heapId)
|
|
{
|
|
Relation heapRelation;
|
|
List *indlist;
|
|
|
|
/*
|
|
* Open the heap rel. We need grab no lock because we assume
|
|
* heap_truncate is holding an exclusive lock on the heap rel.
|
|
*/
|
|
heapRelation = heap_open(heapId, NoLock);
|
|
|
|
/* Ask the relcache to produce a list of the indexes of the rel */
|
|
foreach(indlist, RelationGetIndexList(heapRelation))
|
|
{
|
|
Oid indexId = lfirsto(indlist);
|
|
Relation currentIndex;
|
|
IndexInfo *indexInfo;
|
|
|
|
/* Open the index relation */
|
|
currentIndex = index_open(indexId);
|
|
|
|
/* Obtain exclusive lock on it, just to be sure */
|
|
LockRelation(currentIndex, AccessExclusiveLock);
|
|
|
|
/* Fetch info needed for index_build */
|
|
indexInfo = BuildIndexInfo(currentIndex);
|
|
|
|
/*
|
|
* 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 */
|
|
if (currentIndex->rd_smgr == NULL)
|
|
currentIndex->rd_smgr = smgropen(currentIndex->rd_node);
|
|
smgrtruncate(currentIndex->rd_smgr, 0);
|
|
currentIndex->rd_nblocks = 0;
|
|
currentIndex->rd_targblock = InvalidBlockNumber;
|
|
|
|
/* Initialize the index and rebuild */
|
|
index_build(heapRelation, currentIndex, indexInfo);
|
|
|
|
/*
|
|
* index_build will close both the heap and index relations (but
|
|
* not give up the locks we hold on them). We're done with this
|
|
* index, but we must re-open the heap rel.
|
|
*/
|
|
heapRelation = heap_open(heapId, NoLock);
|
|
}
|
|
|
|
/* Finish by closing the heap rel again */
|
|
heap_close(heapRelation, NoLock);
|
|
}
|
|
|
|
/*
|
|
* heap_truncate
|
|
*
|
|
* This routine deletes all data within the specified relation.
|
|
*
|
|
* This is not transaction-safe! There is another, transaction-safe
|
|
* implementation in commands/cluster.c. We now use this only for
|
|
* ON COMMIT truncation of temporary tables, where it doesn't matter.
|
|
*/
|
|
void
|
|
heap_truncate(Oid rid)
|
|
{
|
|
Relation rel;
|
|
Oid toastrelid;
|
|
|
|
/* Open relation for processing, and grab exclusive access on it. */
|
|
rel = heap_open(rid, AccessExclusiveLock);
|
|
|
|
/* Don't allow truncate on tables that are referenced by foreign keys */
|
|
heap_truncate_check_FKs(rel);
|
|
|
|
/*
|
|
* 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 */
|
|
if (rel->rd_smgr == NULL)
|
|
rel->rd_smgr = smgropen(rel->rd_node);
|
|
smgrtruncate(rel->rd_smgr, 0);
|
|
rel->rd_nblocks = 0;
|
|
rel->rd_targblock = InvalidBlockNumber;
|
|
|
|
/* If this relation has indexes, truncate the indexes too */
|
|
RelationTruncateIndexes(rid);
|
|
|
|
/* If it has a toast table, recursively truncate that too */
|
|
toastrelid = rel->rd_rel->reltoastrelid;
|
|
if (OidIsValid(toastrelid))
|
|
heap_truncate(toastrelid);
|
|
|
|
/*
|
|
* Close the relation, but keep exclusive lock on it until commit.
|
|
*/
|
|
heap_close(rel, NoLock);
|
|
}
|
|
|
|
/*
|
|
* heap_truncate_check_FKs
|
|
* Check for foreign keys referencing a relation that's to be truncated
|
|
*
|
|
* We disallow such FKs (except self-referential ones) since the whole point
|
|
* of TRUNCATE is to not scan the individual rows to be thrown away.
|
|
*
|
|
* This is split out so it can be shared by both implementations of truncate.
|
|
* Caller should already hold a suitable lock on the relation.
|
|
*/
|
|
void
|
|
heap_truncate_check_FKs(Relation rel)
|
|
{
|
|
Oid relid = RelationGetRelid(rel);
|
|
ScanKeyData key;
|
|
Relation fkeyRel;
|
|
SysScanDesc fkeyScan;
|
|
HeapTuple tuple;
|
|
|
|
/*
|
|
* Fast path: if the relation has no triggers, it surely has no FKs
|
|
* either.
|
|
*/
|
|
if (rel->rd_rel->reltriggers == 0)
|
|
return;
|
|
|
|
/*
|
|
* Otherwise, must scan pg_constraint. Right now, this is a seqscan
|
|
* because there is no available index on confrelid.
|
|
*/
|
|
fkeyRel = heap_openr(ConstraintRelationName, AccessShareLock);
|
|
|
|
ScanKeyInit(&key,
|
|
Anum_pg_constraint_confrelid,
|
|
BTEqualStrategyNumber, F_OIDEQ,
|
|
ObjectIdGetDatum(relid));
|
|
|
|
fkeyScan = systable_beginscan(fkeyRel, NULL, false,
|
|
SnapshotNow, 1, &key);
|
|
|
|
while (HeapTupleIsValid(tuple = systable_getnext(fkeyScan)))
|
|
{
|
|
Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(tuple);
|
|
|
|
if (con->contype == CONSTRAINT_FOREIGN && con->conrelid != relid)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmsg("cannot truncate a table referenced in a foreign key constraint"),
|
|
errdetail("Table \"%s\" references \"%s\" via foreign key constraint \"%s\".",
|
|
get_rel_name(con->conrelid),
|
|
RelationGetRelationName(rel),
|
|
NameStr(con->conname))));
|
|
}
|
|
|
|
systable_endscan(fkeyScan);
|
|
heap_close(fkeyRel, AccessShareLock);
|
|
}
|