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Commit39ee0f5

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Fix relation-to-view conversion so that it doesn't try to convert a plain
relation to a view when you create an ON INSERT/UPDATE/DELETE rule ...
1 parent367bc8f commit39ee0f5

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1 file changed

+33
-35
lines changed

1 file changed

+33
-35
lines changed

‎src/backend/rewrite/rewriteDefine.c

Lines changed: 33 additions & 35 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.51 2000/09/1204:49:09momjian Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.52 2000/09/1220:38:09tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -200,40 +200,16 @@ DefineQueryRewrite(RuleStmt *stmt)
200200
foreach(l,action)
201201
{
202202
query= (Query*)lfirst(l);
203-
if (query->resultRelation==1)
203+
if (query->resultRelation==PRS2_OLD_VARNO)
204204
{
205205
elog(ERROR,"rule actions on OLD currently not supported"
206206
"\n\tuse views or triggers instead");
207207
}
208-
if (query->resultRelation==2)
208+
if (query->resultRelation==PRS2_NEW_VARNO)
209209
{
210210
elog(ERROR,"rule actions on NEW currently not supported"
211211
"\n\tuse triggers instead");
212212
}
213-
214-
if (event_relation->rd_rel->relkind!=RELKIND_VIEW)
215-
{
216-
HeapScanDescscanDesc;
217-
HeapTupletuple;
218-
/*
219-
* A relation is about to become a view.
220-
* check that the relation is empty because
221-
* the storage for the relation is going to
222-
* be deleted.
223-
*/
224-
225-
scanDesc=heap_beginscan(event_relation,0,SnapshotNow,0,NULL);
226-
tuple=heap_getnext(scanDesc,0);
227-
if (HeapTupleIsValid(tuple))
228-
elog(ERROR,"relation %s is not empty. Cannot convert to view",event_obj->relname);
229-
230-
/* don't need heap_freetuple because we never got a valid tuple */
231-
heap_endscan(scanDesc);
232-
233-
234-
RelisBecomingView= true;
235-
}
236-
237213
}
238214

239215
/*
@@ -333,14 +309,36 @@ DefineQueryRewrite(RuleStmt *stmt)
333309
/*
334310
* ... and finally the rule must be named _RETviewname.
335311
*/
336-
337312
expected_name=MakeRetrieveViewRuleName(event_obj->relname);
338313
if (strcmp(expected_name,stmt->rulename)!=0)
339314
{
340315
elog(ERROR,"view rule for %s must be named %s",
341316
event_obj->relname,expected_name);
342317
}
343318
pfree(expected_name);
319+
320+
/*
321+
* Are we converting a relation to a view?
322+
*
323+
* If so, check that the relation is empty because the storage
324+
* for the relation is going to be deleted.
325+
*/
326+
if (event_relation->rd_rel->relkind!=RELKIND_VIEW)
327+
{
328+
HeapScanDescscanDesc;
329+
HeapTupletuple;
330+
331+
scanDesc=heap_beginscan(event_relation,0,SnapshotNow,0,NULL);
332+
tuple=heap_getnext(scanDesc,0);
333+
if (HeapTupleIsValid(tuple))
334+
elog(ERROR,"Relation \"%s\" is not empty. Cannot convert it to view",
335+
event_obj->relname);
336+
337+
/* don't need heap_freetuple because we never got a valid tuple */
338+
heap_endscan(scanDesc);
339+
340+
RelisBecomingView= true;
341+
}
344342
}
345343

346344
/*
@@ -363,7 +361,7 @@ DefineQueryRewrite(RuleStmt *stmt)
363361
is_instead,event_attype);
364362

365363
/* discard rule if it's null action and not INSTEAD; it's a no-op */
366-
if (action!=NULL||is_instead)
364+
if (action!=NIL||is_instead)
367365
{
368366
RelationrelationRelation;
369367
HeapTupletuple;
@@ -382,8 +380,8 @@ DefineQueryRewrite(RuleStmt *stmt)
382380

383381
/*
384382
* Set pg_class 'relhasrules' field TRUE for event relation.
385-
*Alsomodify the 'relkind' field to show that the relation is
386-
* now a view.
383+
*If appropriate, alsomodify the 'relkind' field to show that
384+
*the relation isnow a view.
387385
*
388386
* Important side effect: an SI notice is broadcast to force all
389387
* backends (including me!) to update relcache entries with the new
@@ -398,8 +396,8 @@ DefineQueryRewrite(RuleStmt *stmt)
398396
*/
399397
relationRelation=heap_openr(RelationRelationName,RowExclusiveLock);
400398
tuple=SearchSysCacheTupleCopy(RELOID,
401-
ObjectIdGetDatum(ev_relid),
402-
0,0,0);
399+
ObjectIdGetDatum(ev_relid),
400+
0,0,0);
403401
Assert(HeapTupleIsValid(tuple));
404402

405403
/* Do the update */
@@ -420,12 +418,12 @@ DefineQueryRewrite(RuleStmt *stmt)
420418

421419
/*
422420
* IF the relation is becoming a view, delete the storage
423-
* files associated with it.
421+
* files associated with it. NB: we had better have AccessExclusiveLock
422+
* to do this ...
424423
*/
425424
if (RelisBecomingView)
426425
smgrunlink(DEFAULT_SMGR,event_relation);
427426

428-
429427
/* Close rel, but keep lock till commit... */
430428
heap_close(event_relation,NoLock);
431429
}

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