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Subselects in FROM clause, per ISO syntax: FROM (SELECT ...) [AS] alias.
(Don't forget that an alias is required.) Views reimplemented as expanding to subselect-in-FROM. Grouping, aggregates, DISTINCT in views actually work now (he says optimistically). No UNION support in subselects/views yet, but I have some ideas about that. Rule-related permissions checking moved out of rewriter and into executor. INITDB REQUIRED!
This commit is contained in:
Tom Lane
@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.52 2000/09/12 20:38:09 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.53 2000/09/29 18:21:24 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -16,16 +16,21 @@
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#include "postgres.h"
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#include "access/heapam.h"
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#include "utils/builtins.h"
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#include "catalog/catname.h"
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#include "catalog/indexing.h"
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#include "catalog/pg_rewrite.h"
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#include "commands/view.h"
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#include "miscadmin.h"
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#include "optimizer/clauses.h"
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#include "parser/parse_relation.h"
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#include "rewrite/rewriteDefine.h"
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#include "rewrite/rewriteSupport.h"
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#include "utils/syscache.h"
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#include "storage/smgr.h"
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#include "commands/view.h"
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#include "utils/builtins.h"
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static void setRuleCheckAsUser(Query *qry, Oid userid);
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static bool setRuleCheckAsUser_walker(Node *node, Oid *context);
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/*
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@ -52,7 +57,7 @@ InsertRule(char *rulname,
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Oid rewriteObjectId;
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if (IsDefinedRewriteRule(rulname))
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elog(ERROR, "Attempt to insert rule '%s' failed: already exists",
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elog(ERROR, "Attempt to insert rule \"%s\" failed: already exists",
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rulname);
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/* ----------------
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@ -217,10 +222,7 @@ DefineQueryRewrite(RuleStmt *stmt)
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*/
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if (event_type == CMD_SELECT)
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{
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TargetEntry *tle;
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Resdom *resdom;
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Form_pg_attribute attr;
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char *attname;
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List *tllist;
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int i;
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char *expected_name;
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@ -245,6 +247,10 @@ DefineQueryRewrite(RuleStmt *stmt)
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query = (Query *) lfirst(action);
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if (!is_instead || query->commandType != CMD_SELECT)
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elog(ERROR, "only instead-select rules currently supported on select");
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/*
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* ... there can be no rule qual, ...
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*/
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if (event_qual != NULL)
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elog(ERROR, "event qualifications not supported for rules on select");
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@ -252,26 +258,36 @@ DefineQueryRewrite(RuleStmt *stmt)
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* ... the targetlist of the SELECT action must exactly match the
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* event relation, ...
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*/
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if (event_relation->rd_att->natts != length(query->targetList))
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elog(ERROR, "select rules target list must match event relations structure");
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for (i = 1; i <= event_relation->rd_att->natts; i++)
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i = 0;
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foreach(tllist, query->targetList)
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{
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tle = (TargetEntry *) nth(i - 1, query->targetList);
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resdom = tle->resdom;
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TargetEntry *tle = (TargetEntry *) lfirst(tllist);
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Resdom *resdom = tle->resdom;
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Form_pg_attribute attr;
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char *attname;
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if (resdom->resjunk)
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continue;
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i++;
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if (i > event_relation->rd_att->natts)
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elog(ERROR, "select rule's target list has too many entries");
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attr = event_relation->rd_att->attrs[i - 1];
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attname = NameStr(attr->attname);
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if (strcmp(resdom->resname, attname) != 0)
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elog(ERROR, "select rules target entry %d has different column name from %s", i, attname);
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elog(ERROR, "select rule's target entry %d has different column name from %s", i, attname);
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if (attr->atttypid != resdom->restype)
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elog(ERROR, "select rules target entry %d has different type from attribute %s", i, attname);
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elog(ERROR, "select rule's target entry %d has different type from attribute %s", i, attname);
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if (attr->atttypmod != resdom->restypmod)
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elog(ERROR, "select rules target entry %d has different size from attribute %s", i, attname);
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elog(ERROR, "select rule's target entry %d has different size from attribute %s", i, attname);
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}
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if (i != event_relation->rd_att->natts)
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elog(ERROR, "select rule's target list has too few entries");
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/*
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* ... there must not be another ON SELECT rule already ...
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*/
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@ -283,7 +299,7 @@ DefineQueryRewrite(RuleStmt *stmt)
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rule = event_relation->rd_rules->rules[i];
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if (rule->event == CMD_SELECT)
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elog(ERROR, "%s is already a view",
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elog(ERROR, "\"%s\" is already a view",
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RelationGetRelationName(event_relation));
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}
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}
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@ -294,25 +310,13 @@ DefineQueryRewrite(RuleStmt *stmt)
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if (query->limitOffset != NULL || query->limitCount != NULL)
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elog(ERROR, "LIMIT clause not supported in views");
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/*
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* DISTINCT on view is not supported
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*/
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if (query->distinctClause != NIL)
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elog(ERROR, "DISTINCT not supported in views");
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/*
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* ORDER BY in view is not supported
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*/
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if (query->sortClause != NIL)
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elog(ERROR, "ORDER BY not supported in views");
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/*
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* ... and finally the rule must be named _RETviewname.
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*/
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expected_name = MakeRetrieveViewRuleName(event_obj->relname);
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if (strcmp(expected_name, stmt->rulename) != 0)
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{
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elog(ERROR, "view rule for %s must be named %s",
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elog(ERROR, "view rule for \"%s\" must be named \"%s\"",
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event_obj->relname, expected_name);
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}
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pfree(expected_name);
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@ -342,7 +346,7 @@ DefineQueryRewrite(RuleStmt *stmt)
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}
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/*
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* This rule is allowed - install it.
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* This rule is allowed - prepare to install it.
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*/
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if (eslot_string == NULL)
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{
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@ -360,13 +364,21 @@ DefineQueryRewrite(RuleStmt *stmt)
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eslot_string, event_qual, &action,
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is_instead, event_attype);
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/*
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* We want the rule's table references to be checked as though by
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* the rule owner, not the user referencing the rule. Therefore,
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* scan through the rule's rtables and set the checkAsUser field
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* on all rtable entries (except *OLD* and *NEW*).
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*/
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foreach(l, action)
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{
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query = (Query *) lfirst(l);
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setRuleCheckAsUser(query, GetUserId());
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}
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/* discard rule if it's null action and not INSTEAD; it's a no-op */
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if (action != NIL || is_instead)
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{
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Relation relationRelation;
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HeapTuple tuple;
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Relation idescs[Num_pg_class_indices];
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event_qualP = nodeToString(event_qual);
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actionP = nodeToString(action);
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@ -386,34 +398,8 @@ DefineQueryRewrite(RuleStmt *stmt)
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* Important side effect: an SI notice is broadcast to force all
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* backends (including me!) to update relcache entries with the new
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* rule.
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*
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* NOTE : Used to call setRelhasrulesInRelation. The code
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* was inlined so that two updates were not needed. mhh 31-aug-2000
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*/
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/*
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* Find the tuple to update in pg_class, using syscache for the lookup.
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*/
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relationRelation = heap_openr(RelationRelationName, RowExclusiveLock);
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tuple = SearchSysCacheTupleCopy(RELOID,
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ObjectIdGetDatum(ev_relid),
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0, 0, 0);
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Assert(HeapTupleIsValid(tuple));
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/* Do the update */
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((Form_pg_class) GETSTRUCT(tuple))->relhasrules = true;
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if (RelisBecomingView)
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((Form_pg_class) GETSTRUCT(tuple))->relkind = RELKIND_VIEW;
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heap_update(relationRelation, &tuple->t_self, tuple, NULL);
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/* Keep the catalog indices up to date */
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CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, idescs);
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CatalogIndexInsert(idescs, Num_pg_class_indices, relationRelation, tuple);
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CatalogCloseIndices(Num_pg_class_indices, idescs);
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heap_freetuple(tuple);
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heap_close(relationRelation, RowExclusiveLock);
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SetRelationRuleStatus(ev_relid, true, RelisBecomingView);
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}
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/*
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@ -427,3 +413,60 @@ DefineQueryRewrite(RuleStmt *stmt)
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/* Close rel, but keep lock till commit... */
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heap_close(event_relation, NoLock);
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}
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/*
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* setRuleCheckAsUser
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* Recursively scan a query and set the checkAsUser field to the
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* given userid in all rtable entries except *OLD* and *NEW*.
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*/
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static void
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setRuleCheckAsUser(Query *qry, Oid userid)
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{
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List *l;
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/* Set all the RTEs in this query node, except OLD and NEW */
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foreach(l, qry->rtable)
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{
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RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
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if (strcmp(rte->eref->relname, "*NEW*") == 0)
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continue;
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if (strcmp(rte->eref->relname, "*OLD*") == 0)
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continue;
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if (rte->subquery)
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{
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/*
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* Recurse into subquery in FROM
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*/
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setRuleCheckAsUser(rte->subquery, userid);
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}
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else
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{
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rte->checkAsUser = userid;
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}
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}
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/* If there are sublinks, search for them and process their RTEs */
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if (qry->hasSubLinks)
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query_tree_walker(qry, setRuleCheckAsUser_walker, (void *) &userid);
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}
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/*
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* Expression-tree walker to find sublink queries
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*/
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static bool
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setRuleCheckAsUser_walker(Node *node, Oid *context)
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{
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if (node == NULL)
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return false;
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if (IsA(node, Query))
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{
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Query *qry = (Query *) node;
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setRuleCheckAsUser(qry, *context);
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return false;
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}
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return expression_tree_walker(node, setRuleCheckAsUser_walker,
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(void *) context);
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}
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