TLA  Line data    Source code

       1                 : /*-------------------------------------------------------------------------
       2                 :  *
       3                 :  * rewriteRemove.c
       4                 :  *    routines for removing rewrite rules
       5                 :  *
       6                 :  * Portions Copyright (c) 1996-2023, 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/sysattr.h"
      20                 : #include "access/table.h"
      21                 : #include "catalog/catalog.h"
      22                 : #include "catalog/dependency.h"
      23                 : #include "catalog/indexing.h"
      24                 : #include "catalog/namespace.h"
      25                 : #include "catalog/pg_rewrite.h"
      26                 : #include "miscadmin.h"
      27                 : #include "rewrite/rewriteRemove.h"
      28                 : #include "utils/acl.h"
      29                 : #include "utils/fmgroids.h"
      30                 : #include "utils/inval.h"
      31                 : #include "utils/lsyscache.h"
      32                 : #include "utils/rel.h"
      33                 : #include "utils/syscache.h"
      34                 : 
      35                 : /*
      36                 :  * Guts of rule deletion.
      37                 :  */
      38                 : void
      39 CBC        1331 : RemoveRewriteRuleById(Oid ruleOid)
      40                 : {
      41                 :     Relation    RewriteRelation;
      42                 :     ScanKeyData skey[1];
      43                 :     SysScanDesc rcscan;
      44                 :     Relation    event_relation;
      45                 :     HeapTuple   tuple;
      46                 :     Oid         eventRelationOid;
      47                 : 
      48                 :     /*
      49                 :      * Open the pg_rewrite relation.
      50                 :      */
      51            1331 :     RewriteRelation = table_open(RewriteRelationId, RowExclusiveLock);
      52                 : 
      53                 :     /*
      54                 :      * Find the tuple for the target rule.
      55                 :      */
      56            1331 :     ScanKeyInit(&skey[0],
      57                 :                 Anum_pg_rewrite_oid,
      58                 :                 BTEqualStrategyNumber, F_OIDEQ,
      59                 :                 ObjectIdGetDatum(ruleOid));
      60                 : 
      61            1331 :     rcscan = systable_beginscan(RewriteRelation, RewriteOidIndexId, true,
      62                 :                                 NULL, 1, skey);
      63                 : 
      64            1331 :     tuple = systable_getnext(rcscan);
      65                 : 
      66            1331 :     if (!HeapTupleIsValid(tuple))
      67 UBC           0 :         elog(ERROR, "could not find tuple for rule %u", ruleOid);
      68                 : 
      69                 :     /*
      70                 :      * We had better grab AccessExclusiveLock to ensure that no queries are
      71                 :      * going on that might depend on this rule.  (Note: a weaker lock would
      72                 :      * suffice if it's not an ON SELECT rule.)
      73                 :      */
      74 CBC        1331 :     eventRelationOid = ((Form_pg_rewrite) GETSTRUCT(tuple))->ev_class;
      75            1331 :     event_relation = table_open(eventRelationOid, AccessExclusiveLock);
      76                 : 
      77            1331 :     if (!allowSystemTableMods && IsSystemRelation(event_relation))
      78               1 :         ereport(ERROR,
      79                 :                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
      80                 :                  errmsg("permission denied: \"%s\" is a system catalog",
      81                 :                         RelationGetRelationName(event_relation))));
      82                 : 
      83                 :     /*
      84                 :      * Now delete the pg_rewrite tuple for the rule
      85                 :      */
      86            1330 :     CatalogTupleDelete(RewriteRelation, &tuple->t_self);
      87                 : 
      88            1330 :     systable_endscan(rcscan);
      89                 : 
      90            1330 :     table_close(RewriteRelation, RowExclusiveLock);
      91                 : 
      92                 :     /*
      93                 :      * Issue shared-inval notice to force all backends (including me!) to
      94                 :      * update relcache entries with the new rule set.
      95                 :      */
      96            1330 :     CacheInvalidateRelcache(event_relation);
      97                 : 
      98                 :     /* Close rel, but keep lock till commit... */
      99            1330 :     table_close(event_relation, NoLock);
     100            1330 : }