Line data    Source code

       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * rewriteRemove.c
       4             :  *    routines for removing rewrite rules
       5             :  *
       6             :  * Portions Copyright (c) 1996-2017, 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/heapam.h"
      19             : #include "access/htup_details.h"
      20             : #include "access/sysattr.h"
      21             : #include "catalog/dependency.h"
      22             : #include "catalog/indexing.h"
      23             : #include "catalog/namespace.h"
      24             : #include "catalog/pg_rewrite.h"
      25             : #include "miscadmin.h"
      26             : #include "rewrite/rewriteRemove.h"
      27             : #include "utils/acl.h"
      28             : #include "utils/fmgroids.h"
      29             : #include "utils/inval.h"
      30             : #include "utils/lsyscache.h"
      31             : #include "utils/syscache.h"
      32             : #include "utils/tqual.h"
      33             : 
      34             : /*
      35             :  * Guts of rule deletion.
      36             :  */
      37             : void
      38         311 : RemoveRewriteRuleById(Oid ruleOid)
      39             : {
      40             :     Relation    RewriteRelation;
      41             :     ScanKeyData skey[1];
      42             :     SysScanDesc rcscan;
      43             :     Relation    event_relation;
      44             :     HeapTuple   tuple;
      45             :     Oid         eventRelationOid;
      46             : 
      47             :     /*
      48             :      * Open the pg_rewrite relation.
      49             :      */
      50         311 :     RewriteRelation = heap_open(RewriteRelationId, RowExclusiveLock);
      51             : 
      52             :     /*
      53             :      * Find the tuple for the target rule.
      54             :      */
      55         311 :     ScanKeyInit(&skey[0],
      56             :                 ObjectIdAttributeNumber,
      57             :                 BTEqualStrategyNumber, F_OIDEQ,
      58             :                 ObjectIdGetDatum(ruleOid));
      59             : 
      60         311 :     rcscan = systable_beginscan(RewriteRelation, RewriteOidIndexId, true,
      61             :                                 NULL, 1, skey);
      62             : 
      63         311 :     tuple = systable_getnext(rcscan);
      64             : 
      65         311 :     if (!HeapTupleIsValid(tuple))
      66           0 :         elog(ERROR, "could not find tuple for rule %u", ruleOid);
      67             : 
      68             :     /*
      69             :      * We had better grab AccessExclusiveLock to ensure that no queries are
      70             :      * going on that might depend on this rule.  (Note: a weaker lock would
      71             :      * suffice if it's not an ON SELECT rule.)
      72             :      */
      73         311 :     eventRelationOid = ((Form_pg_rewrite) GETSTRUCT(tuple))->ev_class;
      74         311 :     event_relation = heap_open(eventRelationOid, AccessExclusiveLock);
      75             : 
      76             :     /*
      77             :      * Now delete the pg_rewrite tuple for the rule
      78             :      */
      79         311 :     CatalogTupleDelete(RewriteRelation, &tuple->t_self);
      80             : 
      81         311 :     systable_endscan(rcscan);
      82             : 
      83         311 :     heap_close(RewriteRelation, RowExclusiveLock);
      84             : 
      85             :     /*
      86             :      * Issue shared-inval notice to force all backends (including me!) to
      87             :      * update relcache entries with the new rule set.
      88             :      */
      89         311 :     CacheInvalidateRelcache(event_relation);
      90             : 
      91             :     /* Close rel, but keep lock till commit... */
      92         311 :     heap_close(event_relation, NoLock);
      93         311 : }