345 lines
10 KiB
C
345 lines
10 KiB
C
/*-------------------------------------------------------------------------
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*
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* rename.c
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* renameatt() and renamerel() reside here.
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*
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* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
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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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* $Header: /cvsroot/pgsql/src/backend/commands/Attic/rename.c,v 1.46 2000/06/20 06:41:13 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include <errno.h>
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#include "access/heapam.h"
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#include "catalog/catname.h"
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#include "catalog/pg_type.h"
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#include "catalog/heap.h"
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#include "catalog/indexing.h"
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#include "catalog/catalog.h"
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#include "commands/rename.h"
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#include "miscadmin.h"
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#include "storage/smgr.h"
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#include "optimizer/prep.h"
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#include "utils/acl.h"
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#include "utils/relcache.h"
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#include "utils/syscache.h"
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#include "utils/temprel.h"
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/*
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* renameatt - changes the name of a attribute in a relation
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*
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* Attname attribute is changed in attribute catalog.
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* No record of the previous attname is kept (correct?).
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*
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* get proper relrelation from relation catalog (if not arg)
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* scan attribute catalog
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* for name conflict (within rel)
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* for original attribute (if not arg)
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* modify attname in attribute tuple
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* insert modified attribute in attribute catalog
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* delete original attribute from attribute catalog
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*
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* XXX Renaming an indexed attribute must (eventually) also change
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* the attribute name in the associated indexes.
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*/
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void
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renameatt(char *relname,
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char *oldattname,
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char *newattname,
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char *userName,
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int recurse)
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{
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Relation targetrelation;
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Relation attrelation;
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HeapTuple reltup,
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oldatttup,
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newatttup;
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Oid relid;
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/*
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* permissions checking. this would normally be done in utility.c,
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* but this particular routine is recursive.
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*
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* normally, only the owner of a class can change its schema.
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*/
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if (!allowSystemTableMods && IsSystemRelationName(relname))
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elog(ERROR, "renameatt: class \"%s\" is a system catalog",
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relname);
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#ifndef NO_SECURITY
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if (!IsBootstrapProcessingMode() &&
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!pg_ownercheck(userName, relname, RELNAME))
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elog(ERROR, "renameatt: you do not own class \"%s\"",
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relname);
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#endif
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/*
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* Grab an exclusive lock on the target table, which we will NOT
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* release until end of transaction.
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*/
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targetrelation = heap_openr(relname, AccessExclusiveLock);
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relid = RelationGetRelid(targetrelation);
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heap_close(targetrelation, NoLock); /* close rel but keep lock! */
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/*
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* if the 'recurse' flag is set then we are supposed to rename this
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* attribute in all classes that inherit from 'relname' (as well as in
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* 'relname').
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*
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* any permissions or problems with duplicate attributes will cause the
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* whole transaction to abort, which is what we want -- all or
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* nothing.
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*/
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if (recurse)
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{
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List *child,
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*children;
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/* this routine is actually in the planner */
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children = find_all_inheritors(relid);
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/*
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* find_all_inheritors does the recursive search of the
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* inheritance hierarchy, so all we have to do is process all of
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* the relids in the list that it returns.
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*/
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foreach(child, children)
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{
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Oid childrelid = lfirsti(child);
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char childname[NAMEDATALEN];
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if (childrelid == relid)
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continue;
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reltup = SearchSysCacheTuple(RELOID,
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ObjectIdGetDatum(childrelid),
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0, 0, 0);
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if (!HeapTupleIsValid(reltup))
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{
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elog(ERROR, "renameatt: can't find catalog entry for inheriting class with oid %u",
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childrelid);
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}
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/* make copy of cache value, could disappear in call */
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StrNCpy(childname,
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NameStr(((Form_pg_class) GETSTRUCT(reltup))->relname),
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NAMEDATALEN);
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/* note we need not recurse again! */
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renameatt(childname, oldattname, newattname, userName, 0);
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}
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}
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attrelation = heap_openr(AttributeRelationName, RowExclusiveLock);
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oldatttup = SearchSysCacheTupleCopy(ATTNAME,
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ObjectIdGetDatum(relid),
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PointerGetDatum(oldattname),
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0, 0);
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if (!HeapTupleIsValid(oldatttup))
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elog(ERROR, "renameatt: attribute \"%s\" nonexistent", oldattname);
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if (((Form_pg_attribute) GETSTRUCT(oldatttup))->attnum < 0)
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elog(ERROR, "renameatt: system attribute \"%s\" not renamed", oldattname);
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newatttup = SearchSysCacheTuple(ATTNAME,
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ObjectIdGetDatum(relid),
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PointerGetDatum(newattname),
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0, 0);
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/* should not already exist */
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if (HeapTupleIsValid(newatttup))
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{
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heap_freetuple(oldatttup);
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elog(ERROR, "renameatt: attribute \"%s\" exists", newattname);
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}
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StrNCpy(NameStr(((Form_pg_attribute) GETSTRUCT(oldatttup))->attname),
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newattname, NAMEDATALEN);
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heap_update(attrelation, &oldatttup->t_self, oldatttup, NULL);
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/* keep system catalog indices current */
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{
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Relation irelations[Num_pg_attr_indices];
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CatalogOpenIndices(Num_pg_attr_indices, Name_pg_attr_indices, irelations);
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CatalogIndexInsert(irelations, Num_pg_attr_indices, attrelation, oldatttup);
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CatalogCloseIndices(Num_pg_attr_indices, irelations);
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}
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heap_freetuple(oldatttup);
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heap_close(attrelation, RowExclusiveLock);
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}
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/*
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* renamerel - change the name of a relation
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*/
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void
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renamerel(const char *oldrelname, const char *newrelname)
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{
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int i;
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Relation targetrelation;
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Relation relrelation; /* for RELATION relation */
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HeapTuple oldreltup;
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Oid reloid;
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char relkind;
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char oldpath[MAXPGPATH],
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newpath[MAXPGPATH],
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toldpath[MAXPGPATH + 10],
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tnewpath[MAXPGPATH + 10];
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Relation irelations[Num_pg_class_indices];
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if (!allowSystemTableMods && IsSystemRelationName(oldrelname))
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elog(ERROR, "renamerel: system relation \"%s\" not renamed",
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oldrelname);
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if (!allowSystemTableMods && IsSystemRelationName(newrelname))
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elog(ERROR, "renamerel: Illegal class name: \"%s\" -- pg_ is reserved for system catalogs",
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newrelname);
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/*
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* Check for renaming a temp table, which only requires altering
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* the temp-table mapping, not the physical table.
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*/
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if (rename_temp_relation(oldrelname, newrelname))
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return; /* all done... */
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/*
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* Instead of using heap_openr(), do it the hard way, so that we
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* can rename indexes as well as regular relations.
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*/
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targetrelation = RelationNameGetRelation(oldrelname);
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if (!RelationIsValid(targetrelation))
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elog(ERROR, "Relation '%s' does not exist", oldrelname);
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/*
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* Grab an exclusive lock on the target table, which we will NOT
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* release until end of transaction.
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*/
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LockRelation(targetrelation, AccessExclusiveLock);
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/* ----------------
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* RENAME TABLE within a transaction block is dangerous, because
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* if the transaction is later rolled back we have no way to
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* undo the rename of the relation's physical file. For now, allow it
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* but emit a warning message.
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* Someday we might want to consider postponing the physical rename
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* until transaction commit, but that's a lot of work...
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* The only case that actually works right is for relations created
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* in the current transaction, since the post-abort state would be that
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* they don't exist anyway. So, no warning in that case.
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* ----------------
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*/
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if (IsTransactionBlock() && !targetrelation->rd_myxactonly)
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elog(NOTICE, "Caution: RENAME TABLE cannot be rolled back, so don't abort now");
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reloid = RelationGetRelid(targetrelation);
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relkind = targetrelation->rd_rel->relkind;
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/*
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* Flush all blocks of the relation out of the buffer pool. We need
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* this because the blocks are marked with the relation's name as well
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* as OID. If some backend tries to write a dirty buffer with
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* mdblindwrt after we've renamed the physical file, we'll be in big
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* trouble.
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*
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* Since we hold the exclusive lock on the relation, we don't have to
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* worry about more blocks being read in while we finish the rename.
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*/
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if (FlushRelationBuffers(targetrelation, (BlockNumber) 0) < 0)
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elog(ERROR, "renamerel: unable to flush relation from buffer pool");
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/*
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* Make sure smgr and lower levels close the relation's files. (Next
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* access to rel will reopen them.)
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*
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* Note: we rely on shared cache invalidation message to make other
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* backends close and re-open the files.
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*/
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smgrclose(DEFAULT_SMGR, targetrelation);
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/*
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* Close rel, but keep exclusive lock!
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*/
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heap_close(targetrelation, NoLock);
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/*
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* Flush the relcache entry (easier than trying to change it at exactly
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* the right instant). It'll get rebuilt on next access to relation.
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*
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* XXX What if relation is myxactonly?
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*/
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targetrelation = NULL; /* make sure I don't touch it again */
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RelationIdInvalidateRelationCacheByRelationId(reloid);
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/*
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* Find relation's pg_class tuple, and make sure newrelname isn't in
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* use.
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*/
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relrelation = heap_openr(RelationRelationName, RowExclusiveLock);
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oldreltup = SearchSysCacheTupleCopy(RELNAME,
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PointerGetDatum(oldrelname),
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0, 0, 0);
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if (!HeapTupleIsValid(oldreltup))
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elog(ERROR, "renamerel: relation \"%s\" does not exist", oldrelname);
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if (RelnameFindRelid(newrelname) != InvalidOid)
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elog(ERROR, "renamerel: relation \"%s\" exists", newrelname);
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/*
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* Update pg_class tuple with new relname.
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*/
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StrNCpy(NameStr(((Form_pg_class) GETSTRUCT(oldreltup))->relname),
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newrelname, NAMEDATALEN);
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heap_update(relrelation, &oldreltup->t_self, oldreltup, NULL);
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/* keep the system catalog indices current */
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CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, irelations);
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CatalogIndexInsert(irelations, Num_pg_class_indices, relrelation, oldreltup);
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CatalogCloseIndices(Num_pg_class_indices, irelations);
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heap_close(relrelation, NoLock);
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/*
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* Also rename the associated type, if any.
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*/
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if (relkind != RELKIND_INDEX)
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TypeRename(oldrelname, newrelname);
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/*
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* Perform physical rename of files. If this fails, we haven't yet
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* done anything irreversible. NOTE that this MUST be the last step;
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* an error occurring afterwards would leave the relation hosed!
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*
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* XXX smgr.c ought to provide an interface for this; doing it directly
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* is bletcherous.
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*/
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strcpy(oldpath, relpath(oldrelname));
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strcpy(newpath, relpath(newrelname));
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if (rename(oldpath, newpath) < 0)
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elog(ERROR, "renamerel: unable to rename %s to %s: %m",
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oldpath, newpath);
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/* rename additional segments of relation, too */
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for (i = 1;; i++)
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{
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sprintf(toldpath, "%s.%d", oldpath, i);
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sprintf(tnewpath, "%s.%d", newpath, i);
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if (rename(toldpath, tnewpath) < 0)
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{
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/* expected case is that there's not another segment file */
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if (errno == ENOENT)
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break;
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/* otherwise we're up the creek... */
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elog(ERROR, "renamerel: unable to rename %s to %s: %m",
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toldpath, tnewpath);
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}
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}
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}
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