Line data    Source code

       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * rewriteRemove.c
       4             :  *    routines for removing rewrite rules
       5             :  *
       6             :  * Portions Copyright (c) 1996-2024, 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        2834 : 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        2834 :     RewriteRelation = table_open(RewriteRelationId, RowExclusiveLock);
      46             : 
      47             :     /*
      48             :      * Find the tuple for the target rule.
      49             :      */
      50        2834 :     ScanKeyInit(&skey[0],
      51             :                 Anum_pg_rewrite_oid,
      52             :                 BTEqualStrategyNumber, F_OIDEQ,
      53             :                 ObjectIdGetDatum(ruleOid));
      54             : 
      55        2834 :     rcscan = systable_beginscan(RewriteRelation, RewriteOidIndexId, true,
      56             :                                 NULL, 1, skey);
      57             : 
      58        2834 :     tuple = systable_getnext(rcscan);
      59             : 
      60        2834 :     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        2834 :     eventRelationOid = ((Form_pg_rewrite) GETSTRUCT(tuple))->ev_class;
      69        2834 :     event_relation = table_open(eventRelationOid, AccessExclusiveLock);
      70             : 
      71        2834 :     if (!allowSystemTableMods && IsSystemRelation(event_relation))
      72           2 :         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        2832 :     CatalogTupleDelete(RewriteRelation, &tuple->t_self);
      81             : 
      82        2832 :     systable_endscan(rcscan);
      83             : 
      84        2832 :     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        2832 :     CacheInvalidateRelcache(event_relation);
      91             : 
      92             :     /* Close rel, but keep lock till commit... */
      93        2832 :     table_close(event_relation, NoLock);
      94        2832 : }