Line data    Source code

       1              : /*-------------------------------------------------------------------------
       2              :  *
       3              :  * rewriteRemove.c
       4              :  *    routines for removing rewrite rules
       5              :  *
       6              :  * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
       7              :  * Portions Copyright (c) 1994, Regents of the University of California
       8              :  *
       9              :  *
      10              :  * IDENTIFICATION
      11              :  *    src/backend/rewrite/rewriteRemove.c
      12              :  *
      13              :  *-------------------------------------------------------------------------
      14              :  */
      15              : #include "postgres.h"
      16              : 
      17              : #include "access/genam.h"
      18              : #include "access/htup_details.h"
      19              : #include "access/table.h"
      20              : #include "catalog/catalog.h"
      21              : #include "catalog/indexing.h"
      22              : #include "catalog/pg_rewrite.h"
      23              : #include "miscadmin.h"
      24              : #include "rewrite/rewriteRemove.h"
      25              : #include "utils/fmgroids.h"
      26              : #include "utils/inval.h"
      27              : #include "utils/rel.h"
      28              : 
      29              : /*
      30              :  * Guts of rule deletion.
      31              :  */
      32              : void
      33         1471 : RemoveRewriteRuleById(Oid ruleOid)
      34              : {
      35              :     Relation    RewriteRelation;
      36              :     ScanKeyData skey[1];
      37              :     SysScanDesc rcscan;
      38              :     Relation    event_relation;
      39              :     HeapTuple   tuple;
      40              :     Oid         eventRelationOid;
      41              : 
      42              :     /*
      43              :      * Open the pg_rewrite relation.
      44              :      */
      45         1471 :     RewriteRelation = table_open(RewriteRelationId, RowExclusiveLock);
      46              : 
      47              :     /*
      48              :      * Find the tuple for the target rule.
      49              :      */
      50         1471 :     ScanKeyInit(&skey[0],
      51              :                 Anum_pg_rewrite_oid,
      52              :                 BTEqualStrategyNumber, F_OIDEQ,
      53              :                 ObjectIdGetDatum(ruleOid));
      54              : 
      55         1471 :     rcscan = systable_beginscan(RewriteRelation, RewriteOidIndexId, true,
      56              :                                 NULL, 1, skey);
      57              : 
      58         1471 :     tuple = systable_getnext(rcscan);
      59              : 
      60         1471 :     if (!HeapTupleIsValid(tuple))
      61            0 :         elog(ERROR, "could not find tuple for rule %u", ruleOid);
      62              : 
      63              :     /*
      64              :      * We had better grab AccessExclusiveLock to ensure that no queries are
      65              :      * going on that might depend on this rule.  (Note: a weaker lock would
      66              :      * suffice if it's not an ON SELECT rule.)
      67              :      */
      68         1471 :     eventRelationOid = ((Form_pg_rewrite) GETSTRUCT(tuple))->ev_class;
      69         1471 :     event_relation = table_open(eventRelationOid, AccessExclusiveLock);
      70              : 
      71         1471 :     if (!allowSystemTableMods && IsSystemRelation(event_relation))
      72            1 :         ereport(ERROR,
      73              :                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
      74              :                  errmsg("permission denied: \"%s\" is a system catalog",
      75              :                         RelationGetRelationName(event_relation))));
      76              : 
      77              :     /*
      78              :      * Now delete the pg_rewrite tuple for the rule
      79              :      */
      80         1470 :     CatalogTupleDelete(RewriteRelation, &tuple->t_self);
      81              : 
      82         1470 :     systable_endscan(rcscan);
      83              : 
      84         1470 :     table_close(RewriteRelation, RowExclusiveLock);
      85              : 
      86              :     /*
      87              :      * Issue shared-inval notice to force all backends (including me!) to
      88              :      * update relcache entries with the new rule set.
      89              :      */
      90         1470 :     CacheInvalidateRelcache(event_relation);
      91              : 
      92              :     /* Close rel, but keep lock till commit... */
      93         1470 :     table_close(event_relation, NoLock);
      94         1470 : }