Line data    Source code

       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * rewriteSupport.c
       4             :  *
       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/rewriteSupport.c
      12             :  *
      13             :  *-------------------------------------------------------------------------
      14             :  */
      15             : #include "postgres.h"
      16             : 
      17             : #include "access/heapam.h"
      18             : #include "access/htup_details.h"
      19             : #include "catalog/indexing.h"
      20             : #include "catalog/pg_rewrite.h"
      21             : #include "rewrite/rewriteSupport.h"
      22             : #include "utils/fmgroids.h"
      23             : #include "utils/inval.h"
      24             : #include "utils/lsyscache.h"
      25             : #include "utils/rel.h"
      26             : #include "utils/syscache.h"
      27             : #include "utils/tqual.h"
      28             : 
      29             : 
      30             : /*
      31             :  * Is there a rule by the given name?
      32             :  */
      33             : bool
      34           4 : IsDefinedRewriteRule(Oid owningRel, const char *ruleName)
      35             : {
      36           4 :     return SearchSysCacheExists2(RULERELNAME,
      37             :                                  ObjectIdGetDatum(owningRel),
      38             :                                  PointerGetDatum(ruleName));
      39             : }
      40             : 
      41             : 
      42             : /*
      43             :  * SetRelationRuleStatus
      44             :  *      Set the value of the relation's relhasrules field in pg_class.
      45             :  *
      46             :  * NOTE: caller must be holding an appropriate lock on the relation.
      47             :  *
      48             :  * NOTE: an important side-effect of this operation is that an SI invalidation
      49             :  * message is sent out to all backends --- including me --- causing relcache
      50             :  * entries to be flushed or updated with the new set of rules for the table.
      51             :  * This must happen even if we find that no change is needed in the pg_class
      52             :  * row.
      53             :  */
      54             : void
      55         523 : SetRelationRuleStatus(Oid relationId, bool relHasRules)
      56             : {
      57             :     Relation    relationRelation;
      58             :     HeapTuple   tuple;
      59             :     Form_pg_class classForm;
      60             : 
      61             :     /*
      62             :      * Find the tuple to update in pg_class, using syscache for the lookup.
      63             :      */
      64         523 :     relationRelation = heap_open(RelationRelationId, RowExclusiveLock);
      65         523 :     tuple = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relationId));
      66         523 :     if (!HeapTupleIsValid(tuple))
      67           0 :         elog(ERROR, "cache lookup failed for relation %u", relationId);
      68         523 :     classForm = (Form_pg_class) GETSTRUCT(tuple);
      69             : 
      70         523 :     if (classForm->relhasrules != relHasRules)
      71             :     {
      72             :         /* Do the update */
      73         438 :         classForm->relhasrules = relHasRules;
      74             : 
      75         438 :         CatalogTupleUpdate(relationRelation, &tuple->t_self, tuple);
      76             :     }
      77             :     else
      78             :     {
      79             :         /* no need to change tuple, but force relcache rebuild anyway */
      80          85 :         CacheInvalidateRelcacheByTuple(tuple);
      81             :     }
      82             : 
      83         523 :     heap_freetuple(tuple);
      84         523 :     heap_close(relationRelation, RowExclusiveLock);
      85         523 : }
      86             : 
      87             : /*
      88             :  * Find rule oid.
      89             :  *
      90             :  * If missing_ok is false, throw an error if rule name not found.  If
      91             :  * true, just return InvalidOid.
      92             :  */
      93             : Oid
      94          30 : get_rewrite_oid(Oid relid, const char *rulename, bool missing_ok)
      95             : {
      96             :     HeapTuple   tuple;
      97             :     Oid         ruleoid;
      98             : 
      99             :     /* Find the rule's pg_rewrite tuple, get its OID */
     100          30 :     tuple = SearchSysCache2(RULERELNAME,
     101             :                             ObjectIdGetDatum(relid),
     102             :                             PointerGetDatum(rulename));
     103          30 :     if (!HeapTupleIsValid(tuple))
     104             :     {
     105           3 :         if (missing_ok)
     106           1 :             return InvalidOid;
     107           2 :         ereport(ERROR,
     108             :                 (errcode(ERRCODE_UNDEFINED_OBJECT),
     109             :                  errmsg("rule \"%s\" for relation \"%s\" does not exist",
     110             :                         rulename, get_rel_name(relid))));
     111             :     }
     112          27 :     Assert(relid == ((Form_pg_rewrite) GETSTRUCT(tuple))->ev_class);
     113          27 :     ruleoid = HeapTupleGetOid(tuple);
     114          27 :     ReleaseSysCache(tuple);
     115          27 :     return ruleoid;
     116             : }