/*-------------------------------------------------------------------------
*
- * rewriteHandler.c--
- *
- * Copyright (c) 1994, Regents of the University of California
+ * rewriteHandler.c
+ * Primary module of query rewriter.
*
+ * Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.23 1998/10/02 21:53:39 momjian Exp $
+ * src/backend/rewrite/rewriteHandler.c
*
*-------------------------------------------------------------------------
*/
-#include <string.h>
#include "postgres.h"
-#include "miscadmin.h"
-#include "utils/palloc.h"
-#include "utils/elog.h"
-#include "utils/rel.h"
-#include "nodes/pg_list.h"
-#include "nodes/primnodes.h"
-#include "nodes/relation.h"
-
-#include "parser/parsetree.h" /* for parsetree manipulation */
-#include "parser/parse_relation.h"
-#include "nodes/parsenodes.h"
-
-#include "rewrite/rewriteSupport.h"
-#include "rewrite/rewriteHandler.h"
-#include "rewrite/rewriteManip.h"
-#include "rewrite/locks.h"
-#include "commands/creatinh.h"
#include "access/heapam.h"
-
-#include "utils/lsyscache.h"
-#include "utils/syscache.h"
-#include "utils/acl.h"
-#include "catalog/pg_shadow.h"
+#include "access/sysattr.h"
#include "catalog/pg_type.h"
+#include "nodes/makefuncs.h"
+#include "nodes/nodeFuncs.h"
+#include "parser/analyze.h"
+#include "parser/parse_coerce.h"
+#include "parser/parsetree.h"
+#include "rewrite/rewriteDefine.h"
+#include "rewrite/rewriteHandler.h"
+#include "rewrite/rewriteManip.h"
+#include "utils/builtins.h"
+#include "utils/lsyscache.h"
+#include "commands/trigger.h"
+/* We use a list of these to detect recursion in RewriteQuery */
+typedef struct rewrite_event
+{
+ Oid relation; /* OID of relation having rules */
+ CmdType event; /* type of rule being fired */
+} rewrite_event;
-static RewriteInfo *gatherRewriteMeta(Query *parsetree,
+static bool acquireLocksOnSubLinks(Node *node, void *context);
+static Query *rewriteRuleAction(Query *parsetree,
Query *rule_action,
Node *rule_qual,
int rt_index,
CmdType event,
- bool *instead_flag);
-static bool rangeTableEntry_used(Node *node, int rt_index, int sublevels_up);
-static bool attribute_used(Node *node, int rt_index, int attno, int sublevels_up);
-static void offset_varnodes(Node *node, int offset, int sublevels_up);
-static void change_varnodes(Node *node, int rt_index, int new_index, int sublevels_up);
-static void modifyAggregUplevel(Node *node);
-static void modifyAggregChangeVarnodes(Node **nodePtr, int rt_index, int new_index, int sublevels_up);
-static void modifyAggregDropQual(Node **nodePtr, Node *orignode, Expr *expr);
-static SubLink *modifyAggregMakeSublink(Expr *origexp, Query *parsetree);
-static void modifyAggregQual(Node **nodePtr, Query *parsetree);
-
-
-
+ bool *returning_flag);
+static List *adjustJoinTreeList(Query *parsetree, bool removert, int rt_index);
+static void rewriteTargetListIU(Query *parsetree, Relation target_relation,
+ List **attrno_list);
+static TargetEntry *process_matched_tle(TargetEntry *src_tle,
+ TargetEntry *prior_tle,
+ const char *attrName);
+static Node *get_assignment_input(Node *node);
+static void rewriteValuesRTE(RangeTblEntry *rte, Relation target_relation,
+ List *attrnos);
+static void rewriteTargetListUD(Query *parsetree, RangeTblEntry *target_rte,
+ Relation target_relation);
+static void markQueryForLocking(Query *qry, Node *jtnode,
+ bool forUpdate, bool noWait, bool pushedDown);
+static List *matchLocks(CmdType event, RuleLock *rulelocks,
+ int varno, Query *parsetree);
+static Query *fireRIRrules(Query *parsetree, List *activeRIRs,
+ bool forUpdatePushedDown);
+/*
+ * AcquireRewriteLocks -
+ * Acquire suitable locks on all the relations mentioned in the Query.
+ * These locks will ensure that the relation schemas don't change under us
+ * while we are rewriting and planning the query.
+ *
+ * forUpdatePushedDown indicates that a pushed-down FOR UPDATE/SHARE applies
+ * to the current subquery, requiring all rels to be opened with RowShareLock.
+ * This should always be false at the start of the recursion.
+ *
+ * A secondary purpose of this routine is to fix up JOIN RTE references to
+ * dropped columns (see details below). Because the RTEs are modified in
+ * place, it is generally appropriate for the caller of this routine to have
+ * first done a copyObject() to make a writable copy of the querytree in the
+ * current memory context.
+ *
+ * This processing can, and for efficiency's sake should, be skipped when the
+ * querytree has just been built by the parser: parse analysis already got
+ * all the same locks we'd get here, and the parser will have omitted dropped
+ * columns from JOINs to begin with. But we must do this whenever we are
+ * dealing with a querytree produced earlier than the current command.
+ *
+ * About JOINs and dropped columns: although the parser never includes an
+ * already-dropped column in a JOIN RTE's alias var list, it is possible for
+ * such a list in a stored rule to include references to dropped columns.
+ * (If the column is not explicitly referenced anywhere else in the query,
+ * the dependency mechanism won't consider it used by the rule and so won't
+ * prevent the column drop.) To support get_rte_attribute_is_dropped(),
+ * we replace join alias vars that reference dropped columns with NULL Const
+ * nodes.
+ *
+ * (In PostgreSQL 8.0, we did not do this processing but instead had
+ * get_rte_attribute_is_dropped() recurse to detect dropped columns in joins.
+ * That approach had horrible performance unfortunately; in particular
+ * construction of a nested join was O(N^2) in the nesting depth.)
+ */
+void
+AcquireRewriteLocks(Query *parsetree, bool forUpdatePushedDown)
+{
+ ListCell *l;
+ int rt_index;
+ /*
+ * First, process RTEs of the current query level.
+ */
+ rt_index = 0;
+ foreach(l, parsetree->rtable)
+ {
+ RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
+ Relation rel;
+ LOCKMODE lockmode;
+ List *newaliasvars;
+ Index curinputvarno;
+ RangeTblEntry *curinputrte;
+ ListCell *ll;
+ ++rt_index;
+ switch (rte->rtekind)
+ {
+ case RTE_RELATION:
+
+ /*
+ * Grab the appropriate lock type for the relation, and do not
+ * release it until end of transaction. This protects the
+ * rewriter and planner against schema changes mid-query.
+ *
+ * If the relation is the query's result relation, then we
+ * need RowExclusiveLock. Otherwise, check to see if the
+ * relation is accessed FOR UPDATE/SHARE or not. We can't
+ * just grab AccessShareLock because then the executor would
+ * be trying to upgrade the lock, leading to possible
+ * deadlocks.
+ */
+ if (rt_index == parsetree->resultRelation)
+ lockmode = RowExclusiveLock;
+ else if (forUpdatePushedDown ||
+ get_parse_rowmark(parsetree, rt_index) != NULL)
+ lockmode = RowShareLock;
+ else
+ lockmode = AccessShareLock;
+
+ rel = heap_open(rte->relid, lockmode);
+ heap_close(rel, NoLock);
+ break;
+
+ case RTE_JOIN:
+
+ /*
+ * Scan the join's alias var list to see if any columns have
+ * been dropped, and if so replace those Vars with NULL
+ * Consts.
+ *
+ * Since a join has only two inputs, we can expect to see
+ * multiple references to the same input RTE; optimize away
+ * multiple fetches.
+ */
+ newaliasvars = NIL;
+ curinputvarno = 0;
+ curinputrte = NULL;
+ foreach(ll, rte->joinaliasvars)
+ {
+ Var *aliasvar = (Var *) lfirst(ll);
+
+ /*
+ * If the list item isn't a simple Var, then it must
+ * represent a merged column, ie a USING column, and so it
+ * couldn't possibly be dropped, since it's referenced in
+ * the join clause. (Conceivably it could also be a NULL
+ * constant already? But that's OK too.)
+ */
+ if (IsA(aliasvar, Var))
+ {
+ /*
+ * The elements of an alias list have to refer to
+ * earlier RTEs of the same rtable, because that's the
+ * order the planner builds things in. So we already
+ * processed the referenced RTE, and so it's safe to
+ * use get_rte_attribute_is_dropped on it. (This might
+ * not hold after rewriting or planning, but it's OK
+ * to assume here.)
+ */
+ Assert(aliasvar->varlevelsup == 0);
+ if (aliasvar->varno != curinputvarno)
+ {
+ curinputvarno = aliasvar->varno;
+ if (curinputvarno >= rt_index)
+ elog(ERROR, "unexpected varno %d in JOIN RTE %d",
+ curinputvarno, rt_index);
+ curinputrte = rt_fetch(curinputvarno,
+ parsetree->rtable);
+ }
+ if (get_rte_attribute_is_dropped(curinputrte,
+ aliasvar->varattno))
+ {
+ /*
+ * can't use vartype here, since that might be a
+ * now-dropped type OID, but it doesn't really
+ * matter what type the Const claims to be.
+ */
+ aliasvar = (Var *) makeNullConst(INT4OID, -1);
+ }
+ }
+ newaliasvars = lappend(newaliasvars, aliasvar);
+ }
+ rte->joinaliasvars = newaliasvars;
+ break;
+
+ case RTE_SUBQUERY:
+
+ /*
+ * The subquery RTE itself is all right, but we have to
+ * recurse to process the represented subquery.
+ */
+ AcquireRewriteLocks(rte->subquery,
+ (forUpdatePushedDown ||
+ get_parse_rowmark(parsetree, rt_index) != NULL));
+ break;
+
+ default:
+ /* ignore other types of RTEs */
+ break;
+ }
+ }
+ /* Recurse into subqueries in WITH */
+ foreach(l, parsetree->cteList)
+ {
+ CommonTableExpr *cte = (CommonTableExpr *) lfirst(l);
+ AcquireRewriteLocks((Query *) cte->ctequery, false);
+ }
+ /*
+ * Recurse into sublink subqueries, too. But we already did the ones in
+ * the rtable and cteList.
+ */
+ if (parsetree->hasSubLinks)
+ query_tree_walker(parsetree, acquireLocksOnSubLinks, NULL,
+ QTW_IGNORE_RC_SUBQUERIES);
+}
+/*
+ * Walker to find sublink subqueries for AcquireRewriteLocks
+ */
+static bool
+acquireLocksOnSubLinks(Node *node, void *context)
+{
+ if (node == NULL)
+ return false;
+ if (IsA(node, SubLink))
+ {
+ SubLink *sub = (SubLink *) node;
+ /* Do what we came for */
+ AcquireRewriteLocks((Query *) sub->subselect, false);
+ /* Fall through to process lefthand args of SubLink */
+ }
-static Query *fireRIRrules(Query *parsetree);
+ /*
+ * Do NOT recurse into Query nodes, because AcquireRewriteLocks already
+ * processed subselects of subselects for us.
+ */
+ return expression_tree_walker(node, acquireLocksOnSubLinks, context);
+}
/*
- * gatherRewriteMeta -
- * Gather meta information about parsetree, and rule. Fix rule body
- * and qualifier so that they can be mixed with the parsetree and
- * maintain semantic validity
+ * rewriteRuleAction -
+ * Rewrite the rule action with appropriate qualifiers (taken from
+ * the triggering query).
+ *
+ * Input arguments:
+ * parsetree - original query
+ * rule_action - one action (query) of a rule
+ * rule_qual - WHERE condition of rule, or NULL if unconditional
+ * rt_index - RT index of result relation in original query
+ * event - type of rule event
+ * Output arguments:
+ * *returning_flag - set TRUE if we rewrite RETURNING clause in rule_action
+ * (must be initialized to FALSE)
+ * Return value:
+ * rewritten form of rule_action
*/
-static RewriteInfo *
-gatherRewriteMeta(Query *parsetree,
+static Query *
+rewriteRuleAction(Query *parsetree,
Query *rule_action,
Node *rule_qual,
int rt_index,
CmdType event,
- bool *instead_flag)
+ bool *returning_flag)
{
- RewriteInfo *info;
+ int current_varno,
+ new_varno;
int rt_length;
- int result_reln;
-
- info = (RewriteInfo *) palloc(sizeof(RewriteInfo));
- info->rt_index = rt_index;
- info->event = event;
- info->instead_flag = *instead_flag;
- info->rule_action = (Query *) copyObject(rule_action);
- info->rule_qual = (Node *) copyObject(rule_qual);
- if (info->rule_action == NULL)
- info->nothing = TRUE;
- else
- {
- info->nothing = FALSE;
- info->action = info->rule_action->commandType;
- info->current_varno = rt_index;
- info->rt = parsetree->rtable;
- rt_length = length(info->rt);
- info->rt = append(info->rt, info->rule_action->rtable);
-
- info->new_varno = PRS2_NEW_VARNO + rt_length;
- OffsetVarNodes(info->rule_action->qual, rt_length);
- OffsetVarNodes((Node *) info->rule_action->targetList, rt_length);
- OffsetVarNodes(info->rule_qual, rt_length);
- ChangeVarNodes((Node *) info->rule_action->qual,
- PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
- ChangeVarNodes((Node *) info->rule_action->targetList,
- PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
- ChangeVarNodes(info->rule_qual,
- PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
-
- /*
- * bug here about replace CURRENT -- sort of replace current is
- * deprecated now so this code shouldn't really need to be so
- * clutzy but.....
- */
- if (info->action != CMD_SELECT)
- { /* i.e update XXXXX */
- int new_result_reln = 0;
-
- result_reln = info->rule_action->resultRelation;
- switch (result_reln)
- {
- case PRS2_CURRENT_VARNO:
- new_result_reln = rt_index;
- break;
- case PRS2_NEW_VARNO: /* XXX */
- default:
- new_result_reln = result_reln + rt_length;
- break;
- }
- info->rule_action->resultRelation = new_result_reln;
- }
- }
- return info;
-}
+ Query *sub_action;
+ Query **sub_action_ptr;
+ /*
+ * Make modifiable copies of rule action and qual (what we're passed are
+ * the stored versions in the relcache; don't touch 'em!).
+ */
+ rule_action = (Query *) copyObject(rule_action);
+ rule_qual = (Node *) copyObject(rule_qual);
-/*
- * rangeTableEntry_used -
- * we need to process a RTE for RIR rules only if it is
- * referenced somewhere in var nodes of the query.
- */
-static bool
-rangeTableEntry_used(Node *node, int rt_index, int sublevels_up)
-{
- if (node == NULL)
- return FALSE;
+ /*
+ * Acquire necessary locks and fix any deleted JOIN RTE entries.
+ */
+ AcquireRewriteLocks(rule_action, false);
+ (void) acquireLocksOnSubLinks(rule_qual, NULL);
- switch(nodeTag(node)) {
- case T_TargetEntry:
- {
- TargetEntry *tle = (TargetEntry *)node;
+ current_varno = rt_index;
+ rt_length = list_length(parsetree->rtable);
+ new_varno = PRS2_NEW_VARNO + rt_length;
- return rangeTableEntry_used(
- (Node *)(tle->expr),
- rt_index,
- sublevels_up);
- }
- break;
+ /*
+ * Adjust rule action and qual to offset its varnos, so that we can merge
+ * its rtable with the main parsetree's rtable.
+ *
+ * If the rule action is an INSERT...SELECT, the OLD/NEW rtable entries
+ * will be in the SELECT part, and we have to modify that rather than the
+ * top-level INSERT (kluge!).
+ */
+ sub_action = getInsertSelectQuery(rule_action, &sub_action_ptr);
- case T_Aggreg:
- {
- Aggreg *agg = (Aggreg *)node;
+ OffsetVarNodes((Node *) sub_action, rt_length, 0);
+ OffsetVarNodes(rule_qual, rt_length, 0);
+ /* but references to OLD should point at original rt_index */
+ ChangeVarNodes((Node *) sub_action,
+ PRS2_OLD_VARNO + rt_length, rt_index, 0);
+ ChangeVarNodes(rule_qual,
+ PRS2_OLD_VARNO + rt_length, rt_index, 0);
- return rangeTableEntry_used(
- (Node *)(agg->target),
- rt_index,
- sublevels_up);
- }
- break;
+ /*
+ * Generate expanded rtable consisting of main parsetree's rtable plus
+ * rule action's rtable; this becomes the complete rtable for the rule
+ * action. Some of the entries may be unused after we finish rewriting,
+ * but we leave them all in place for two reasons:
+ *
+ * We'd have a much harder job to adjust the query's varnos if we
+ * selectively removed RT entries.
+ *
+ * If the rule is INSTEAD, then the original query won't be executed at
+ * all, and so its rtable must be preserved so that the executor will do
+ * the correct permissions checks on it.
+ *
+ * RT entries that are not referenced in the completed jointree will be
+ * ignored by the planner, so they do not affect query semantics. But any
+ * permissions checks specified in them will be applied during executor
+ * startup (see ExecCheckRTEPerms()). This allows us to check that the
+ * caller has, say, insert-permission on a view, when the view is not
+ * semantically referenced at all in the resulting query.
+ *
+ * When a rule is not INSTEAD, the permissions checks done on its copied
+ * RT entries will be redundant with those done during execution of the
+ * original query, but we don't bother to treat that case differently.
+ *
+ * NOTE: because planner will destructively alter rtable, we must ensure
+ * that rule action's rtable is separate and shares no substructure with
+ * the main rtable. Hence do a deep copy here.
+ */
+ sub_action->rtable = list_concat((List *) copyObject(parsetree->rtable),
+ sub_action->rtable);
- case T_GroupClause:
- {
- GroupClause *grp = (GroupClause *)node;
+ /*
+ * There could have been some SubLinks in parsetree's rtable, in which
+ * case we'd better mark the sub_action correctly.
+ */
+ if (parsetree->hasSubLinks && !sub_action->hasSubLinks)
+ {
+ ListCell *lc;
- return rangeTableEntry_used(
- (Node *)(grp->entry),
- rt_index,
- sublevels_up);
- }
- break;
+ foreach(lc, parsetree->rtable)
+ {
+ RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
- case T_Expr:
+ switch (rte->rtekind)
{
- Expr *exp = (Expr *)node;
-
- return rangeTableEntry_used(
- (Node *)(exp->args),
- rt_index,
- sublevels_up);
+ case RTE_FUNCTION:
+ sub_action->hasSubLinks =
+ checkExprHasSubLink(rte->funcexpr);
+ break;
+ case RTE_VALUES:
+ sub_action->hasSubLinks =
+ checkExprHasSubLink((Node *) rte->values_lists);
+ break;
+ default:
+ /* other RTE types don't contain bare expressions */
+ break;
}
- break;
-
- case T_Iter:
- {
- Iter *iter = (Iter *)node;
+ if (sub_action->hasSubLinks)
+ break; /* no need to keep scanning rtable */
+ }
+ }
- return rangeTableEntry_used(
- (Node *)(iter->iterexpr),
- rt_index,
- sublevels_up);
- }
- break;
+ /*
+ * Each rule action's jointree should be the main parsetree's jointree
+ * plus that rule's jointree, but usually *without* the original rtindex
+ * that we're replacing (if present, which it won't be for INSERT). Note
+ * that if the rule action refers to OLD, its jointree will add a
+ * reference to rt_index. If the rule action doesn't refer to OLD, but
+ * either the rule_qual or the user query quals do, then we need to keep
+ * the original rtindex in the jointree to provide data for the quals. We
+ * don't want the original rtindex to be joined twice, however, so avoid
+ * keeping it if the rule action mentions it.
+ *
+ * As above, the action's jointree must not share substructure with the
+ * main parsetree's.
+ */
+ if (sub_action->commandType != CMD_UTILITY)
+ {
+ bool keeporig;
+ List *newjointree;
+
+ Assert(sub_action->jointree != NULL);
+ keeporig = (!rangeTableEntry_used((Node *) sub_action->jointree,
+ rt_index, 0)) &&
+ (rangeTableEntry_used(rule_qual, rt_index, 0) ||
+ rangeTableEntry_used(parsetree->jointree->quals, rt_index, 0));
+ newjointree = adjustJoinTreeList(parsetree, !keeporig, rt_index);
+ if (newjointree != NIL)
+ {
+ /*
+ * If sub_action is a setop, manipulating its jointree will do no
+ * good at all, because the jointree is dummy. (Perhaps someday
+ * we could push the joining and quals down to the member
+ * statements of the setop?)
+ */
+ if (sub_action->setOperations != NULL)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("conditional UNION/INTERSECT/EXCEPT statements are not implemented")));
- case T_ArrayRef:
- {
- ArrayRef *ref = (ArrayRef *)node;
-
- if (rangeTableEntry_used(
- (Node *)(ref->refupperindexpr),
- rt_index,
- sublevels_up))
- return TRUE;
-
- if (rangeTableEntry_used(
- (Node *)(ref->reflowerindexpr),
- rt_index,
- sublevels_up))
- return TRUE;
-
- if (rangeTableEntry_used(
- (Node *)(ref->refexpr),
- rt_index,
- sublevels_up))
- return TRUE;
-
- if (rangeTableEntry_used(
- (Node *)(ref->refassgnexpr),
- rt_index,
- sublevels_up))
- return TRUE;
-
- return FALSE;
- }
- break;
+ sub_action->jointree->fromlist =
+ list_concat(newjointree, sub_action->jointree->fromlist);
- case T_Var:
- {
- Var *var = (Var *)node;
+ /*
+ * There could have been some SubLinks in newjointree, in which
+ * case we'd better mark the sub_action correctly.
+ */
+ if (parsetree->hasSubLinks && !sub_action->hasSubLinks)
+ sub_action->hasSubLinks =
+ checkExprHasSubLink((Node *) newjointree);
+ }
+ }
- if (var->varlevelsup == sublevels_up)
- return var->varno == rt_index;
- else
- return FALSE;
- }
- break;
+ /*
+ * Event Qualification forces copying of parsetree and splitting into two
+ * queries one w/rule_qual, one w/NOT rule_qual. Also add user query qual
+ * onto rule action
+ */
+ AddQual(sub_action, rule_qual);
- case T_Param:
- return FALSE;
+ AddQual(sub_action, parsetree->jointree->quals);
- case T_Const:
- return FALSE;
+ /*
+ * Rewrite new.attribute w/ right hand side of target-list entry for
+ * appropriate field name in insert/update.
+ *
+ * KLUGE ALERT: since ResolveNew returns a mutated copy, we can't just
+ * apply it to sub_action; we have to remember to update the sublink
+ * inside rule_action, too.
+ */
+ if ((event == CMD_INSERT || event == CMD_UPDATE) &&
+ sub_action->commandType != CMD_UTILITY)
+ {
+ sub_action = (Query *) ResolveNew((Node *) sub_action,
+ new_varno,
+ 0,
+ rt_fetch(new_varno,
+ sub_action->rtable),
+ parsetree->targetList,
+ event,
+ current_varno,
+ NULL);
+ if (sub_action_ptr)
+ *sub_action_ptr = sub_action;
+ else
+ rule_action = sub_action;
+ }
- case T_List:
- {
- List *l;
-
- foreach (l, (List *)node) {
- if (rangeTableEntry_used(
- (Node *)lfirst(l),
- rt_index,
- sublevels_up))
- return TRUE;
- }
- return FALSE;
- }
- break;
+ /*
+ * If rule_action has a RETURNING clause, then either throw it away if the
+ * triggering query has no RETURNING clause, or rewrite it to emit what
+ * the triggering query's RETURNING clause asks for. Throw an error if
+ * more than one rule has a RETURNING clause.
+ */
+ if (!parsetree->returningList)
+ rule_action->returningList = NIL;
+ else if (rule_action->returningList)
+ {
+ if (*returning_flag)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot have RETURNING lists in multiple rules")));
+ *returning_flag = true;
+ rule_action->returningList = (List *)
+ ResolveNew((Node *) parsetree->returningList,
+ parsetree->resultRelation,
+ 0,
+ rt_fetch(parsetree->resultRelation,
+ parsetree->rtable),
+ rule_action->returningList,
+ CMD_SELECT,
+ 0,
+ &rule_action->hasSubLinks);
- case T_SubLink:
- {
- SubLink *sub = (SubLink *)node;
+ /*
+ * There could have been some SubLinks in parsetree's returningList,
+ * in which case we'd better mark the rule_action correctly.
+ */
+ if (parsetree->hasSubLinks && !rule_action->hasSubLinks)
+ rule_action->hasSubLinks =
+ checkExprHasSubLink((Node *) rule_action->returningList);
+ }
- if (rangeTableEntry_used(
- (Node *)(sub->lefthand),
- rt_index,
- sublevels_up))
- return TRUE;
+ return rule_action;
+}
- if (rangeTableEntry_used(
- (Node *)(sub->subselect),
- rt_index,
- sublevels_up + 1))
- return TRUE;
+/*
+ * Copy the query's jointree list, and optionally attempt to remove any
+ * occurrence of the given rt_index as a top-level join item (we do not look
+ * for it within join items; this is OK because we are only expecting to find
+ * it as an UPDATE or DELETE target relation, which will be at the top level
+ * of the join). Returns modified jointree list --- this is a separate copy
+ * sharing no nodes with the original.
+ */
+static List *
+adjustJoinTreeList(Query *parsetree, bool removert, int rt_index)
+{
+ List *newjointree = copyObject(parsetree->jointree->fromlist);
+ ListCell *l;
- return FALSE;
- }
- break;
+ if (removert)
+ {
+ foreach(l, newjointree)
+ {
+ RangeTblRef *rtr = lfirst(l);
- case T_Query:
+ if (IsA(rtr, RangeTblRef) &&
+ rtr->rtindex == rt_index)
{
- Query *qry = (Query *)node;
-
- if (rangeTableEntry_used(
- (Node *)(qry->targetList),
- rt_index,
- sublevels_up))
- return TRUE;
-
- if (rangeTableEntry_used(
- (Node *)(qry->qual),
- rt_index,
- sublevels_up))
- return TRUE;
-
- if (rangeTableEntry_used(
- (Node *)(qry->havingQual),
- rt_index,
- sublevels_up))
- return TRUE;
-
- if (rangeTableEntry_used(
- (Node *)(qry->groupClause),
- rt_index,
- sublevels_up))
- return TRUE;
-
- return FALSE;
- }
- break;
-
- default:
- elog(NOTICE, "unknown node tag %d in rangeTableEntry_used()", nodeTag(node));
- elog(NOTICE, "Node is: %s", nodeToString(node));
- break;
-
+ newjointree = list_delete_ptr(newjointree, rtr);
+ /*
+ * foreach is safe because we exit loop after list_delete...
+ */
+ break;
+ }
+ }
}
-
- return FALSE;
+ return newjointree;
}
/*
- * attribute_used -
- * Check if a specific attribute number of a RTE is used
- * somewhere in the query
+ * rewriteTargetListIU - rewrite INSERT/UPDATE targetlist into standard form
+ *
+ * This has the following responsibilities:
+ *
+ * 1. For an INSERT, add tlist entries to compute default values for any
+ * attributes that have defaults and are not assigned to in the given tlist.
+ * (We do not insert anything for default-less attributes, however. The
+ * planner will later insert NULLs for them, but there's no reason to slow
+ * down rewriter processing with extra tlist nodes.) Also, for both INSERT
+ * and UPDATE, replace explicit DEFAULT specifications with column default
+ * expressions.
+ *
+ * 2. For an UPDATE on a view, add tlist entries for any unassigned-to
+ * attributes, assigning them their old values. These will later get
+ * expanded to the output values of the view. (This is equivalent to what
+ * the planner's expand_targetlist() will do for UPDATE on a regular table,
+ * but it's more convenient to do it here while we still have easy access
+ * to the view's original RT index.)
+ *
+ * 3. Merge multiple entries for the same target attribute, or declare error
+ * if we can't. Multiple entries are only allowed for INSERT/UPDATE of
+ * portions of an array or record field, for example
+ * UPDATE table SET foo[2] = 42, foo[4] = 43;
+ * We can merge such operations into a single assignment op. Essentially,
+ * the expression we want to produce in this case is like
+ * foo = array_set(array_set(foo, 2, 42), 4, 43)
+ *
+ * 4. Sort the tlist into standard order: non-junk fields in order by resno,
+ * then junk fields (these in no particular order).
+ *
+ * We must do items 1,2,3 before firing rewrite rules, else rewritten
+ * references to NEW.foo will produce wrong or incomplete results. Item 4
+ * is not needed for rewriting, but will be needed by the planner, and we
+ * can do it essentially for free while handling the other items.
+ *
+ * If attrno_list isn't NULL, we return an additional output besides the
+ * rewritten targetlist: an integer list of the assigned-to attnums, in
+ * order of the original tlist's non-junk entries. This is needed for
+ * processing VALUES RTEs.
*/
-static bool
-attribute_used(Node *node, int rt_index, int attno, int sublevels_up)
+static void
+rewriteTargetListIU(Query *parsetree, Relation target_relation,
+ List **attrno_list)
{
- if (node == NULL)
- return FALSE;
+ CmdType commandType = parsetree->commandType;
+ TargetEntry **new_tles;
+ List *new_tlist = NIL;
+ List *junk_tlist = NIL;
+ Form_pg_attribute att_tup;
+ int attrno,
+ next_junk_attrno,
+ numattrs;
+ ListCell *temp;
+
+ if (attrno_list) /* initialize optional result list */
+ *attrno_list = NIL;
- switch(nodeTag(node)) {
- case T_TargetEntry:
- {
- TargetEntry *tle = (TargetEntry *)node;
+ /*
+ * We process the normal (non-junk) attributes by scanning the input tlist
+ * once and transferring TLEs into an array, then scanning the array to
+ * build an output tlist. This avoids O(N^2) behavior for large numbers
+ * of attributes.
+ *
+ * Junk attributes are tossed into a separate list during the same tlist
+ * scan, then appended to the reconstructed tlist.
+ */
+ numattrs = RelationGetNumberOfAttributes(target_relation);
+ new_tles = (TargetEntry **) palloc0(numattrs * sizeof(TargetEntry *));
+ next_junk_attrno = numattrs + 1;
- return attribute_used(
- (Node *)(tle->expr),
- rt_index,
- attno,
- sublevels_up);
- }
- break;
+ foreach(temp, parsetree->targetList)
+ {
+ TargetEntry *old_tle = (TargetEntry *) lfirst(temp);
- case T_Aggreg:
- {
- Aggreg *agg = (Aggreg *)node;
+ if (!old_tle->resjunk)
+ {
+ /* Normal attr: stash it into new_tles[] */
+ attrno = old_tle->resno;
+ if (attrno < 1 || attrno > numattrs)
+ elog(ERROR, "bogus resno %d in targetlist", attrno);
+ att_tup = target_relation->rd_att->attrs[attrno - 1];
+
+ /* put attrno into attrno_list even if it's dropped */
+ if (attrno_list)
+ *attrno_list = lappend_int(*attrno_list, attrno);
+
+ /* We can (and must) ignore deleted attributes */
+ if (att_tup->attisdropped)
+ continue;
- return attribute_used(
- (Node *)(agg->target),
- rt_index,
- attno,
- sublevels_up);
- }
- break;
+ /* Merge with any prior assignment to same attribute */
+ new_tles[attrno - 1] =
+ process_matched_tle(old_tle,
+ new_tles[attrno - 1],
+ NameStr(att_tup->attname));
+ }
+ else
+ {
+ /*
+ * Copy all resjunk tlist entries to junk_tlist, and assign them
+ * resnos above the last real resno.
+ *
+ * Typical junk entries include ORDER BY or GROUP BY expressions
+ * (are these actually possible in an INSERT or UPDATE?), system
+ * attribute references, etc.
+ */
- case T_GroupClause:
+ /* Get the resno right, but don't copy unnecessarily */
+ if (old_tle->resno != next_junk_attrno)
{
- GroupClause *grp = (GroupClause *)node;
-
- return attribute_used(
- (Node *)(grp->entry),
- rt_index,
- attno,
- sublevels_up);
+ old_tle = flatCopyTargetEntry(old_tle);
+ old_tle->resno = next_junk_attrno;
}
- break;
+ junk_tlist = lappend(junk_tlist, old_tle);
+ next_junk_attrno++;
+ }
+ }
- case T_Expr:
- {
- Expr *exp = (Expr *)node;
+ for (attrno = 1; attrno <= numattrs; attrno++)
+ {
+ TargetEntry *new_tle = new_tles[attrno - 1];
- return attribute_used(
- (Node *)(exp->args),
- rt_index,
- attno,
- sublevels_up);
- }
- break;
+ att_tup = target_relation->rd_att->attrs[attrno - 1];
- case T_Iter:
- {
- Iter *iter = (Iter *)node;
+ /* We can (and must) ignore deleted attributes */
+ if (att_tup->attisdropped)
+ continue;
- return attribute_used(
- (Node *)(iter->iterexpr),
- rt_index,
- attno,
- sublevels_up);
- }
- break;
+ /*
+ * Handle the two cases where we need to insert a default expression:
+ * it's an INSERT and there's no tlist entry for the column, or the
+ * tlist entry is a DEFAULT placeholder node.
+ */
+ if ((new_tle == NULL && commandType == CMD_INSERT) ||
+ (new_tle && new_tle->expr && IsA(new_tle->expr, SetToDefault)))
+ {
+ Node *new_expr;
- case T_ArrayRef:
- {
- ArrayRef *ref = (ArrayRef *)node;
-
- if (attribute_used(
- (Node *)(ref->refupperindexpr),
- rt_index,
- attno,
- sublevels_up))
- return TRUE;
-
- if (attribute_used(
- (Node *)(ref->reflowerindexpr),
- rt_index,
- attno,
- sublevels_up))
- return TRUE;
-
- if (attribute_used(
- (Node *)(ref->refexpr),
- rt_index,
- attno,
- sublevels_up))
- return TRUE;
-
- if (attribute_used(
- (Node *)(ref->refassgnexpr),
- rt_index,
- attno,
- sublevels_up))
- return TRUE;
-
- return FALSE;
- }
- break;
+ new_expr = build_column_default(target_relation, attrno);
- case T_Var:
+ /*
+ * If there is no default (ie, default is effectively NULL), we
+ * can omit the tlist entry in the INSERT case, since the planner
+ * can insert a NULL for itself, and there's no point in spending
+ * any more rewriter cycles on the entry. But in the UPDATE case
+ * we've got to explicitly set the column to NULL.
+ */
+ if (!new_expr)
{
- Var *var = (Var *)node;
-
- if (var->varlevelsup == sublevels_up)
- return var->varno == rt_index;
+ if (commandType == CMD_INSERT)
+ new_tle = NULL;
else
- return FALSE;
- }
- break;
-
- case T_Param:
- return FALSE;
-
- case T_Const:
- return FALSE;
-
- case T_List:
- {
- List *l;
-
- foreach (l, (List *)node) {
- if (attribute_used(
- (Node *)lfirst(l),
- rt_index,
- attno,
- sublevels_up))
- return TRUE;
+ {
+ new_expr = (Node *) makeConst(att_tup->atttypid,
+ -1,
+ att_tup->attlen,
+ (Datum) 0,
+ true, /* isnull */
+ att_tup->attbyval);
+ /* this is to catch a NOT NULL domain constraint */
+ new_expr = coerce_to_domain(new_expr,
+ InvalidOid, -1,
+ att_tup->atttypid,
+ COERCE_IMPLICIT_CAST,
+ -1,
+ false,
+ false);
}
- return FALSE;
- }
- break;
-
- case T_SubLink:
- {
- SubLink *sub = (SubLink *)node;
-
- if (attribute_used(
- (Node *)(sub->lefthand),
- rt_index,
- attno,
- sublevels_up))
- return TRUE;
-
- if (attribute_used(
- (Node *)(sub->subselect),
- rt_index,
- attno,
- sublevels_up + 1))
- return TRUE;
-
- return FALSE;
- }
- break;
-
- case T_Query:
- {
- Query *qry = (Query *)node;
-
- if (attribute_used(
- (Node *)(qry->targetList),
- rt_index,
- attno,
- sublevels_up))
- return TRUE;
-
- if (attribute_used(
- (Node *)(qry->qual),
- rt_index,
- attno,
- sublevels_up))
- return TRUE;
-
- if (attribute_used(
- (Node *)(qry->havingQual),
- rt_index,
- attno,
- sublevels_up))
- return TRUE;
-
- if (attribute_used(
- (Node *)(qry->groupClause),
- rt_index,
- attno,
- sublevels_up))
- return TRUE;
-
- return FALSE;
}
- break;
- default:
- elog(NOTICE, "unknown node tag %d in attribute_used()", nodeTag(node));
- elog(NOTICE, "Node is: %s", nodeToString(node));
- break;
+ if (new_expr)
+ new_tle = makeTargetEntry((Expr *) new_expr,
+ attrno,
+ pstrdup(NameStr(att_tup->attname)),
+ false);
+ }
+ /*
+ * For an UPDATE on a view, provide a dummy entry whenever there is
+ * no explicit assignment.
+ */
+ if (new_tle == NULL && commandType == CMD_UPDATE &&
+ target_relation->rd_rel->relkind == RELKIND_VIEW)
+ {
+ Node *new_expr;
+
+ new_expr = (Node *) makeVar(parsetree->resultRelation,
+ attrno,
+ att_tup->atttypid,
+ att_tup->atttypmod,
+ att_tup->attcollation,
+ 0);
+
+ new_tle = makeTargetEntry((Expr *) new_expr,
+ attrno,
+ pstrdup(NameStr(att_tup->attname)),
+ false);
+ }
+ if (new_tle)
+ new_tlist = lappend(new_tlist, new_tle);
}
- return FALSE;
+ pfree(new_tles);
+
+ parsetree->targetList = list_concat(new_tlist, junk_tlist);
}
/*
- * offset_varnodes -
- * We need another version of OffsetVarNodes() when processing
- * RIR rules
+ * Convert a matched TLE from the original tlist into a correct new TLE.
+ *
+ * This routine detects and handles multiple assignments to the same target
+ * attribute. (The attribute name is needed only for error messages.)
*/
-static void
-offset_varnodes(Node *node, int offset, int sublevels_up)
+static TargetEntry *
+process_matched_tle(TargetEntry *src_tle,
+ TargetEntry *prior_tle,
+ const char *attrName)
{
- if (node == NULL)
- return;
+ TargetEntry *result;
+ Node *src_expr;
+ Node *prior_expr;
+ Node *src_input;
+ Node *prior_input;
+ Node *priorbottom;
+ Node *newexpr;
+
+ if (prior_tle == NULL)
+ {
+ /*
+ * Normal case where this is the first assignment to the attribute.
+ */
+ return src_tle;
+ }
- switch(nodeTag(node)) {
- case T_TargetEntry:
- {
- TargetEntry *tle = (TargetEntry *)node;
+ /*----------
+ * Multiple assignments to same attribute. Allow only if all are
+ * FieldStore or ArrayRef assignment operations. This is a bit
+ * tricky because what we may actually be looking at is a nest of
+ * such nodes; consider
+ * UPDATE tab SET col.fld1.subfld1 = x, col.fld2.subfld2 = y
+ * The two expressions produced by the parser will look like
+ * FieldStore(col, fld1, FieldStore(placeholder, subfld1, x))
+ * FieldStore(col, fld2, FieldStore(placeholder, subfld2, x))
+ * However, we can ignore the substructure and just consider the top
+ * FieldStore or ArrayRef from each assignment, because it works to
+ * combine these as
+ * FieldStore(FieldStore(col, fld1,
+ * FieldStore(placeholder, subfld1, x)),
+ * fld2, FieldStore(placeholder, subfld2, x))
+ * Note the leftmost expression goes on the inside so that the
+ * assignments appear to occur left-to-right.
+ *
+ * For FieldStore, instead of nesting we can generate a single
+ * FieldStore with multiple target fields. We must nest when
+ * ArrayRefs are involved though.
+ *----------
+ */
+ src_expr = (Node *) src_tle->expr;
+ prior_expr = (Node *) prior_tle->expr;
+ src_input = get_assignment_input(src_expr);
+ prior_input = get_assignment_input(prior_expr);
+ if (src_input == NULL ||
+ prior_input == NULL ||
+ exprType(src_expr) != exprType(prior_expr))
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("multiple assignments to same column \"%s\"",
+ attrName)));
- offset_varnodes(
- (Node *)(tle->expr),
- offset,
- sublevels_up);
- }
- break;
+ /*
+ * Prior TLE could be a nest of assignments if we do this more than once.
+ */
+ priorbottom = prior_input;
+ for (;;)
+ {
+ Node *newbottom = get_assignment_input(priorbottom);
- case T_Aggreg:
- {
- Aggreg *agg = (Aggreg *)node;
-
- offset_varnodes(
- (Node *)(agg->target),
- offset,
- sublevels_up);
- }
- break;
-
- case T_GroupClause:
- {
- GroupClause *grp = (GroupClause *)node;
-
- offset_varnodes(
- (Node *)(grp->entry),
- offset,
- sublevels_up);
- }
- break;
-
- case T_Expr:
- {
- Expr *exp = (Expr *)node;
-
- offset_varnodes(
- (Node *)(exp->args),
- offset,
- sublevels_up);
- }
- break;
-
- case T_Iter:
- {
- Iter *iter = (Iter *)node;
-
- offset_varnodes(
- (Node *)(iter->iterexpr),
- offset,
- sublevels_up);
- }
- break;
-
- case T_ArrayRef:
- {
- ArrayRef *ref = (ArrayRef *)node;
-
- offset_varnodes(
- (Node *)(ref->refupperindexpr),
- offset,
- sublevels_up);
- offset_varnodes(
- (Node *)(ref->reflowerindexpr),
- offset,
- sublevels_up);
- offset_varnodes(
- (Node *)(ref->refexpr),
- offset,
- sublevels_up);
- offset_varnodes(
- (Node *)(ref->refassgnexpr),
- offset,
- sublevels_up);
- }
- break;
-
- case T_Var:
- {
- Var *var = (Var *)node;
-
- if (var->varlevelsup == sublevels_up) {
- var->varno += offset;
- var->varnoold += offset;
- }
- }
- break;
-
- case T_Param:
- break;
-
- case T_Const:
- break;
-
- case T_List:
- {
- List *l;
-
- foreach (l, (List *)node)
- offset_varnodes(
- (Node *)lfirst(l),
- offset,
- sublevels_up);
- }
- break;
-
- case T_SubLink:
- {
- SubLink *sub = (SubLink *)node;
-
- offset_varnodes(
- (Node *)(sub->lefthand),
- offset,
- sublevels_up);
-
- offset_varnodes(
- (Node *)(sub->subselect),
- offset,
- sublevels_up + 1);
- }
- break;
-
- case T_Query:
- {
- Query *qry = (Query *)node;
-
- offset_varnodes(
- (Node *)(qry->targetList),
- offset,
- sublevels_up);
-
- offset_varnodes(
- (Node *)(qry->qual),
- offset,
- sublevels_up);
-
- offset_varnodes(
- (Node *)(qry->havingQual),
- offset,
- sublevels_up);
-
- offset_varnodes(
- (Node *)(qry->groupClause),
- offset,
- sublevels_up);
- }
- break;
-
- default:
- elog(NOTICE, "unknown node tag %d in offset_varnodes()", nodeTag(node));
- elog(NOTICE, "Node is: %s", nodeToString(node));
- break;
-
-
- }
-}
-
-
-/*
- * change_varnodes -
- * and another ChangeVarNodes() too
- */
-static void
-change_varnodes(Node *node, int rt_index, int new_index, int sublevels_up)
-{
- if (node == NULL)
- return;
-
- switch(nodeTag(node)) {
- case T_TargetEntry:
- {
- TargetEntry *tle = (TargetEntry *)node;
-
- change_varnodes(
- (Node *)(tle->expr),
- rt_index,
- new_index,
- sublevels_up);
- }
- break;
-
- case T_Aggreg:
- {
- Aggreg *agg = (Aggreg *)node;
-
- change_varnodes(
- (Node *)(agg->target),
- rt_index,
- new_index,
- sublevels_up);
- }
- break;
-
- case T_GroupClause:
- {
- GroupClause *grp = (GroupClause *)node;
-
- change_varnodes(
- (Node *)(grp->entry),
- rt_index,
- new_index,
- sublevels_up);
- }
- break;
-
- case T_Expr:
- {
- Expr *exp = (Expr *)node;
-
- change_varnodes(
- (Node *)(exp->args),
- rt_index,
- new_index,
- sublevels_up);
- }
- break;
-
- case T_Iter:
- {
- Iter *iter = (Iter *)node;
-
- change_varnodes(
- (Node *)(iter->iterexpr),
- rt_index,
- new_index,
- sublevels_up);
- }
- break;
-
- case T_ArrayRef:
- {
- ArrayRef *ref = (ArrayRef *)node;
-
- change_varnodes(
- (Node *)(ref->refupperindexpr),
- rt_index,
- new_index,
- sublevels_up);
- change_varnodes(
- (Node *)(ref->reflowerindexpr),
- rt_index,
- new_index,
- sublevels_up);
- change_varnodes(
- (Node *)(ref->refexpr),
- rt_index,
- new_index,
- sublevels_up);
- change_varnodes(
- (Node *)(ref->refassgnexpr),
- rt_index,
- new_index,
- sublevels_up);
- }
- break;
-
- case T_Var:
- {
- Var *var = (Var *)node;
-
- if (var->varlevelsup == sublevels_up &&
- var->varno == rt_index) {
- var->varno = new_index;
- var->varnoold = new_index;
- }
- }
- break;
-
- case T_Param:
- break;
-
- case T_Const:
- break;
-
- case T_List:
- {
- List *l;
-
- foreach (l, (List *)node)
- change_varnodes(
- (Node *)lfirst(l),
- rt_index,
- new_index,
- sublevels_up);
- }
- break;
-
- case T_SubLink:
- {
- SubLink *sub = (SubLink *)node;
-
- change_varnodes(
- (Node *)(sub->lefthand),
- rt_index,
- new_index,
- sublevels_up);
-
- change_varnodes(
- (Node *)(sub->subselect),
- rt_index,
- new_index,
- sublevels_up + 1);
- }
- break;
-
- case T_Query:
- {
- Query *qry = (Query *)node;
-
- change_varnodes(
- (Node *)(qry->targetList),
- rt_index,
- new_index,
- sublevels_up);
-
- change_varnodes(
- (Node *)(qry->qual),
- rt_index,
- new_index,
- sublevels_up);
-
- change_varnodes(
- (Node *)(qry->havingQual),
- rt_index,
- new_index,
- sublevels_up);
-
- change_varnodes(
- (Node *)(qry->groupClause),
- rt_index,
- new_index,
- sublevels_up);
- }
- break;
-
- default:
- elog(NOTICE, "unknown node tag %d in change_varnodes()", nodeTag(node));
- elog(NOTICE, "Node is: %s", nodeToString(node));
- break;
-
-
- }
-}
-
-
-/*
- * modifyAggregUplevel -
- * In the newly created sublink for an aggregate column used in
- * the qualification, we must adjust the varlevelsup in all the
- * var nodes.
- */
-static void
-modifyAggregUplevel(Node *node)
-{
- if (node == NULL)
- return;
-
- switch(nodeTag(node)) {
- case T_TargetEntry:
- {
- TargetEntry *tle = (TargetEntry *)node;
-
- modifyAggregUplevel(
- (Node *)(tle->expr));
- }
- break;
-
- case T_Aggreg:
- {
- Aggreg *agg = (Aggreg *)node;
-
- modifyAggregUplevel(
- (Node *)(agg->target));
- }
- break;
-
- case T_Expr:
- {
- Expr *exp = (Expr *)node;
-
- modifyAggregUplevel(
- (Node *)(exp->args));
- }
- break;
-
- case T_Iter:
- {
- Iter *iter = (Iter *)node;
-
- modifyAggregUplevel(
- (Node *)(iter->iterexpr));
- }
- break;
-
- case T_ArrayRef:
- {
- ArrayRef *ref = (ArrayRef *)node;
-
- modifyAggregUplevel(
- (Node *)(ref->refupperindexpr));
- modifyAggregUplevel(
- (Node *)(ref->reflowerindexpr));
- modifyAggregUplevel(
- (Node *)(ref->refexpr));
- modifyAggregUplevel(
- (Node *)(ref->refassgnexpr));
- }
- break;
-
- case T_Var:
- {
- Var *var = (Var *)node;
-
- var->varlevelsup++;
- }
- break;
-
- case T_Param:
- break;
-
- case T_Const:
- break;
-
- case T_List:
- {
- List *l;
-
- foreach (l, (List *)node)
- modifyAggregUplevel(
- (Node *)lfirst(l));
- }
- break;
-
- case T_SubLink:
- {
- SubLink *sub = (SubLink *)node;
-
- modifyAggregUplevel(
- (Node *)(sub->lefthand));
-
- modifyAggregUplevel(
- (Node *)(sub->oper));
-
- modifyAggregUplevel(
- (Node *)(sub->subselect));
- }
- break;
-
- case T_Query:
- {
- Query *qry = (Query *)node;
-
- modifyAggregUplevel(
- (Node *)(qry->targetList));
-
- modifyAggregUplevel(
- (Node *)(qry->qual));
-
- modifyAggregUplevel(
- (Node *)(qry->havingQual));
-
- modifyAggregUplevel(
- (Node *)(qry->groupClause));
- }
- break;
-
- default:
- elog(NOTICE, "unknown node tag %d in modifyAggregUplevel()", nodeTag(node));
- elog(NOTICE, "Node is: %s", nodeToString(node));
- break;
+ if (newbottom == NULL)
+ break; /* found the original Var reference */
+ priorbottom = newbottom;
+ }
+ if (!equal(priorbottom, src_input))
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("multiple assignments to same column \"%s\"",
+ attrName)));
+ /*
+ * Looks OK to nest 'em.
+ */
+ if (IsA(src_expr, FieldStore))
+ {
+ FieldStore *fstore = makeNode(FieldStore);
+ if (IsA(prior_expr, FieldStore))
+ {
+ /* combine the two */
+ memcpy(fstore, prior_expr, sizeof(FieldStore));
+ fstore->newvals =
+ list_concat(list_copy(((FieldStore *) prior_expr)->newvals),
+ list_copy(((FieldStore *) src_expr)->newvals));
+ fstore->fieldnums =
+ list_concat(list_copy(((FieldStore *) prior_expr)->fieldnums),
+ list_copy(((FieldStore *) src_expr)->fieldnums));
+ }
+ else
+ {
+ /* general case, just nest 'em */
+ memcpy(fstore, src_expr, sizeof(FieldStore));
+ fstore->arg = (Expr *) prior_expr;
+ }
+ newexpr = (Node *) fstore;
}
-}
-
-
-/*
- * modifyAggregChangeVarnodes -
- * Change the var nodes in a sublink created for an aggregate column
- * used in the qualification that is subject of the aggregate
- * function to point to the correct local RTE.
- */
-static void
-modifyAggregChangeVarnodes(Node **nodePtr, int rt_index, int new_index, int sublevels_up)
-{
- Node *node = *nodePtr;
-
- if (node == NULL)
- return;
-
- switch(nodeTag(node)) {
- case T_TargetEntry:
- {
- TargetEntry *tle = (TargetEntry *)node;
-
- modifyAggregChangeVarnodes(
- (Node **)(&(tle->expr)),
- rt_index,
- new_index,
- sublevels_up);
- }
- break;
-
- case T_Aggreg:
- {
- Aggreg *agg = (Aggreg *)node;
-
- modifyAggregChangeVarnodes(
- (Node **)(&(agg->target)),
- rt_index,
- new_index,
- sublevels_up);
- }
- break;
-
- case T_GroupClause:
- {
- GroupClause *grp = (GroupClause *)node;
-
- modifyAggregChangeVarnodes(
- (Node **)(&(grp->entry)),
- rt_index,
- new_index,
- sublevels_up);
- }
- break;
-
- case T_Expr:
- {
- Expr *exp = (Expr *)node;
-
- modifyAggregChangeVarnodes(
- (Node **)(&(exp->args)),
- rt_index,
- new_index,
- sublevels_up);
- }
- break;
-
- case T_Iter:
- {
- Iter *iter = (Iter *)node;
-
- modifyAggregChangeVarnodes(
- (Node **)(&(iter->iterexpr)),
- rt_index,
- new_index,
- sublevels_up);
- }
- break;
-
- case T_ArrayRef:
- {
- ArrayRef *ref = (ArrayRef *)node;
-
- modifyAggregChangeVarnodes(
- (Node **)(&(ref->refupperindexpr)),
- rt_index,
- new_index,
- sublevels_up);
- modifyAggregChangeVarnodes(
- (Node **)(&(ref->reflowerindexpr)),
- rt_index,
- new_index,
- sublevels_up);
- modifyAggregChangeVarnodes(
- (Node **)(&(ref->refexpr)),
- rt_index,
- new_index,
- sublevels_up);
- modifyAggregChangeVarnodes(
- (Node **)(&(ref->refassgnexpr)),
- rt_index,
- new_index,
- sublevels_up);
- }
- break;
-
- case T_Var:
- {
- Var *var = (Var *)node;
-
- if (var->varlevelsup == sublevels_up &&
- var->varno == rt_index) {
- var = copyObject(var);
- var->varno = new_index;
- var->varnoold = new_index;
- var->varlevelsup = 0;
-
- *nodePtr = (Node *)var;
- }
- }
- break;
-
- case T_Param:
- break;
-
- case T_Const:
- break;
-
- case T_List:
- {
- List *l;
-
- foreach (l, (List *)node)
- modifyAggregChangeVarnodes(
- (Node **)(&lfirst(l)),
- rt_index,
- new_index,
- sublevels_up);
- }
- break;
-
- case T_SubLink:
- {
- SubLink *sub = (SubLink *)node;
-
- modifyAggregChangeVarnodes(
- (Node **)(&(sub->lefthand)),
- rt_index,
- new_index,
- sublevels_up);
-
- modifyAggregChangeVarnodes(
- (Node **)(&(sub->oper)),
- rt_index,
- new_index,
- sublevels_up);
-
- modifyAggregChangeVarnodes(
- (Node **)(&(sub->subselect)),
- rt_index,
- new_index,
- sublevels_up + 1);
- }
- break;
-
- case T_Query:
- {
- Query *qry = (Query *)node;
-
- modifyAggregChangeVarnodes(
- (Node **)(&(qry->targetList)),
- rt_index,
- new_index,
- sublevels_up);
-
- modifyAggregChangeVarnodes(
- (Node **)(&(qry->qual)),
- rt_index,
- new_index,
- sublevels_up);
-
- modifyAggregChangeVarnodes(
- (Node **)(&(qry->havingQual)),
- rt_index,
- new_index,
- sublevels_up);
-
- modifyAggregChangeVarnodes(
- (Node **)(&(qry->groupClause)),
- rt_index,
- new_index,
- sublevels_up);
- }
- break;
-
- default:
- elog(NOTICE, "unknown node tag %d in modifyAggregChangeVarnodes()", nodeTag(node));
- elog(NOTICE, "Node is: %s", nodeToString(node));
- break;
-
+ else if (IsA(src_expr, ArrayRef))
+ {
+ ArrayRef *aref = makeNode(ArrayRef);
+ memcpy(aref, src_expr, sizeof(ArrayRef));
+ aref->refexpr = (Expr *) prior_expr;
+ newexpr = (Node *) aref;
}
-}
-
-
-/*
- * modifyAggregDropQual -
- * remove the pure aggreg clase from a qualification
- */
-static void
-modifyAggregDropQual(Node **nodePtr, Node *orignode, Expr *expr)
-{
- Node *node = *nodePtr;
-
- if (node == NULL)
- return;
-
- switch(nodeTag(node)) {
- case T_Var:
- break;
-
- case T_Aggreg:
- {
- Aggreg *agg = (Aggreg *)node;
- Aggreg *oagg = (Aggreg *)orignode;
-
- modifyAggregDropQual(
- (Node **)(&(agg->target)),
- (Node *)(oagg->target),
- expr);
- }
- break;
-
- case T_Param:
- break;
-
- case T_Const:
- break;
-
- case T_GroupClause:
- break;
-
- case T_Expr:
- {
- Expr *this_expr = (Expr *)node;
- Expr *orig_expr = (Expr *)orignode;
-
- if (orig_expr == expr) {
- Const *ctrue;
-
- if (expr->typeOid != BOOLOID)
- elog(ERROR,
- "aggregate expression in qualification isn't of type bool");
- ctrue = makeNode(Const);
- ctrue->consttype = BOOLOID;
- ctrue->constlen = 1;
- ctrue->constisnull = FALSE;
- ctrue->constvalue = (Datum)TRUE;
- ctrue->constbyval = TRUE;
-
- *nodePtr = (Node *)ctrue;
- }
- else
- modifyAggregDropQual(
- (Node **)(&(this_expr->args)),
- (Node *)(orig_expr->args),
- expr);
- }
- break;
-
- case T_Iter:
- {
- Iter *iter = (Iter *)node;
- Iter *oiter = (Iter *)orignode;
-
- modifyAggregDropQual(
- (Node **)(&(iter->iterexpr)),
- (Node *)(oiter->iterexpr),
- expr);
- }
- break;
-
- case T_ArrayRef:
- {
- ArrayRef *ref = (ArrayRef *)node;
- ArrayRef *oref = (ArrayRef *)orignode;
-
- modifyAggregDropQual(
- (Node **)(&(ref->refupperindexpr)),
- (Node *)(oref->refupperindexpr),
- expr);
- modifyAggregDropQual(
- (Node **)(&(ref->reflowerindexpr)),
- (Node *)(oref->reflowerindexpr),
- expr);
- modifyAggregDropQual(
- (Node **)(&(ref->refexpr)),
- (Node *)(oref->refexpr),
- expr);
- modifyAggregDropQual(
- (Node **)(&(ref->refassgnexpr)),
- (Node *)(oref->refassgnexpr),
- expr);
- }
- break;
-
- case T_List:
- {
- List *l;
- List *ol = (List *)orignode;
- int li = 0;
-
- foreach (l, (List *)node) {
- modifyAggregDropQual(
- (Node **)(&(lfirst(l))),
- (Node *)nth(li, ol),
- expr);
- li++;
- }
- }
- break;
-
- case T_SubLink:
- {
- SubLink *sub = (SubLink *)node;
- SubLink *osub = (SubLink *)orignode;
-
- modifyAggregDropQual(
- (Node **)(&(sub->subselect)),
- (Node *)(osub->subselect),
- expr);
- }
- break;
-
- case T_Query:
- {
- Query *qry = (Query *)node;
- Query *oqry = (Query *)orignode;
-
- modifyAggregDropQual(
- (Node **)(&(qry->qual)),
- (Node *)(oqry->qual),
- expr);
-
- modifyAggregDropQual(
- (Node **)(&(qry->havingQual)),
- (Node *)(oqry->havingQual),
- expr);
- }
- break;
-
- default:
- elog(NOTICE, "unknown node tag %d in modifyAggregDropQual()", nodeTag(node));
- elog(NOTICE, "Node is: %s", nodeToString(node));
- break;
-
-
+ else
+ {
+ elog(ERROR, "cannot happen");
+ newexpr = NULL;
}
-}
-
-
-/*
- * modifyAggregMakeSublink -
- * Create a sublink node for a qualification expression that
- * uses an aggregate column of a view
- */
-static SubLink *
-modifyAggregMakeSublink(Expr *origexp, Query *parsetree)
-{
- SubLink *sublink;
- Query *subquery;
- Node *subqual;
- RangeTblEntry *rte;
- Aggreg *aggreg;
- Var *target;
- TargetEntry *tle;
- Resdom *resdom;
- Expr *exp = copyObject(origexp);
-
- if (nodeTag(nth(0, exp->args)) == T_Aggreg)
- if (nodeTag(nth(1, exp->args)) == T_Aggreg)
- elog(ERROR, "rewrite: comparision of 2 aggregate columns not supported");
- else
- elog(ERROR, "rewrite: aggregate column of view must be at rigth side in qual");
-
- aggreg = (Aggreg *)nth(1, exp->args);
- target = (Var *)(aggreg->target);
- rte = (RangeTblEntry *)nth(target->varno - 1, parsetree->rtable);
- tle = makeNode(TargetEntry);
- resdom = makeNode(Resdom);
-
- aggreg->usenulls = TRUE;
-
- resdom->resno = 1;
- resdom->restype = ((Oper *)(exp->oper))->opresulttype;
- resdom->restypmod = -1;
- resdom->resname = pstrdup("<noname>");
- resdom->reskey = 0;
- resdom->reskeyop = 0;
- resdom->resjunk = 0;
-
- tle->resdom = resdom;
- tle->expr = (Node *)aggreg;
-
- subqual = copyObject(parsetree->qual);
- modifyAggregDropQual((Node **)&subqual, (Node *)parsetree->qual, origexp);
-
- sublink = makeNode(SubLink);
- sublink->subLinkType = EXPR_SUBLINK;
- sublink->useor = FALSE;
- sublink->lefthand = lappend(NIL, copyObject(lfirst(exp->args)));
- sublink->oper = lappend(NIL, copyObject(exp));
- sublink->subselect = NULL;
-
- subquery = makeNode(Query);
- sublink->subselect = (Node *)subquery;
-
- subquery->commandType = CMD_SELECT;
- subquery->utilityStmt = NULL;
- subquery->resultRelation = 0;
- subquery->into = NULL;
- subquery->isPortal = FALSE;
- subquery->isBinary = FALSE;
- subquery->unionall = FALSE;
- subquery->uniqueFlag = NULL;
- subquery->sortClause = NULL;
- subquery->rtable = lappend(NIL, rte);
- subquery->targetList = lappend(NIL, tle);
- subquery->qual = subqual;
- subquery->groupClause = NIL;
- subquery->havingQual = NULL;
- subquery->hasAggs = TRUE;
- subquery->hasSubLinks = FALSE;
- subquery->unionClause = NULL;
-
-
- modifyAggregUplevel((Node *)sublink);
-
- modifyAggregChangeVarnodes((Node **)&(sublink->lefthand), target->varno,
- 1, target->varlevelsup);
- modifyAggregChangeVarnodes((Node **)&(sublink->oper), target->varno,
- 1, target->varlevelsup);
- modifyAggregChangeVarnodes((Node **)&(sublink->subselect), target->varno,
- 1, target->varlevelsup);
-
- return sublink;
-}
-
-
-/*
- * modifyAggregQual -
- * Search for qualification expressions that contain aggregate
- * functions and substiture them by sublinks. These expressions
- * originally come from qualifications that use aggregate columns
- * of a view.
- */
-static void
-modifyAggregQual(Node **nodePtr, Query *parsetree)
-{
- Node *node = *nodePtr;
-
- if (node == NULL)
- return;
-
- switch(nodeTag(node)) {
- case T_Var:
- break;
-
- case T_Param:
- break;
-
- case T_Const:
- break;
-
- case T_GroupClause:
- {
- GroupClause *grp = (GroupClause *)node;
-
- modifyAggregQual(
- (Node **)(&(grp->entry)),
- parsetree);
- }
- break;
-
- case T_Expr:
- {
- Expr *exp = (Expr *)node;
- SubLink *sub;
-
-
- if (length(exp->args) != 2) {
- modifyAggregQual(
- (Node **)(&(exp->args)),
- parsetree);
- break;
- }
-
- if (nodeTag(nth(0, exp->args)) != T_Aggreg &&
- nodeTag(nth(1, exp->args)) != T_Aggreg) {
-
- modifyAggregQual(
- (Node **)(&(exp->args)),
- parsetree);
- break;
- }
-
- sub = modifyAggregMakeSublink(exp,
- parsetree);
-
- *nodePtr = (Node *)sub;
- parsetree->hasSubLinks = TRUE;
- }
- break;
-
- case T_Iter:
- {
- Iter *iter = (Iter *)node;
- modifyAggregQual(
- (Node **)(&(iter->iterexpr)),
- parsetree);
- }
- break;
+ result = flatCopyTargetEntry(src_tle);
+ result->expr = (Expr *) newexpr;
+ return result;
+}
- case T_ArrayRef:
- {
- ArrayRef *ref = (ArrayRef *)node;
-
- modifyAggregQual(
- (Node **)(&(ref->refupperindexpr)),
- parsetree);
- modifyAggregQual(
- (Node **)(&(ref->reflowerindexpr)),
- parsetree);
- modifyAggregQual(
- (Node **)(&(ref->refexpr)),
- parsetree);
- modifyAggregQual(
- (Node **)(&(ref->refassgnexpr)),
- parsetree);
- }
- break;
+/*
+ * If node is an assignment node, return its input; else return NULL
+ */
+static Node *
+get_assignment_input(Node *node)
+{
+ if (node == NULL)
+ return NULL;
+ if (IsA(node, FieldStore))
+ {
+ FieldStore *fstore = (FieldStore *) node;
- case T_List:
- {
- List *l;
+ return (Node *) fstore->arg;
+ }
+ else if (IsA(node, ArrayRef))
+ {
+ ArrayRef *aref = (ArrayRef *) node;
- foreach (l, (List *)node)
- modifyAggregQual(
- (Node **)(&(lfirst(l))),
- parsetree);
- }
- break;
+ if (aref->refassgnexpr == NULL)
+ return NULL;
+ return (Node *) aref->refexpr;
+ }
+ return NULL;
+}
- case T_SubLink:
- {
- SubLink *sub = (SubLink *)node;
+/*
+ * Make an expression tree for the default value for a column.
+ *
+ * If there is no default, return a NULL instead.
+ */
+Node *
+build_column_default(Relation rel, int attrno)
+{
+ TupleDesc rd_att = rel->rd_att;
+ Form_pg_attribute att_tup = rd_att->attrs[attrno - 1];
+ Oid atttype = att_tup->atttypid;
+ int32 atttypmod = att_tup->atttypmod;
+ Node *expr = NULL;
+ Oid exprtype;
- modifyAggregQual(
- (Node **)(&(sub->subselect)),
- (Query *)(sub->subselect));
- }
- break;
+ /*
+ * Scan to see if relation has a default for this column.
+ */
+ if (rd_att->constr && rd_att->constr->num_defval > 0)
+ {
+ AttrDefault *defval = rd_att->constr->defval;
+ int ndef = rd_att->constr->num_defval;
- case T_Query:
+ while (--ndef >= 0)
+ {
+ if (attrno == defval[ndef].adnum)
{
- Query *qry = (Query *)node;
-
- modifyAggregQual(
- (Node **)(&(qry->qual)),
- parsetree);
-
- modifyAggregQual(
- (Node **)(&(qry->havingQual)),
- parsetree);
+ /*
+ * Found it, convert string representation to node tree.
+ */
+ expr = stringToNode(defval[ndef].adbin);
+ break;
}
- break;
+ }
+ }
- default:
- elog(NOTICE, "unknown node tag %d in modifyAggregQual()", nodeTag(node));
- elog(NOTICE, "Node is: %s", nodeToString(node));
- break;
+ if (expr == NULL)
+ {
+ /*
+ * No per-column default, so look for a default for the type itself.
+ */
+ expr = get_typdefault(atttype);
+ }
+ if (expr == NULL)
+ return NULL; /* No default anywhere */
- }
+ /*
+ * Make sure the value is coerced to the target column type; this will
+ * generally be true already, but there seem to be some corner cases
+ * involving domain defaults where it might not be true. This should match
+ * the parser's processing of non-defaulted expressions --- see
+ * transformAssignedExpr().
+ */
+ exprtype = exprType(expr);
+
+ expr = coerce_to_target_type(NULL, /* no UNKNOWN params here */
+ expr, exprtype,
+ atttype, atttypmod,
+ COERCION_ASSIGNMENT,
+ COERCE_IMPLICIT_CAST,
+ -1);
+ if (expr == NULL)
+ ereport(ERROR,
+ (errcode(ERRCODE_DATATYPE_MISMATCH),
+ errmsg("column \"%s\" is of type %s"
+ " but default expression is of type %s",
+ NameStr(att_tup->attname),
+ format_type_be(atttype),
+ format_type_be(exprtype)),
+ errhint("You will need to rewrite or cast the expression.")));
+
+ return expr;
}
-static Node *
-FindMatchingTLEntry(List *tlist, char *e_attname)
+/* Does VALUES RTE contain any SetToDefault items? */
+static bool
+searchForDefault(RangeTblEntry *rte)
{
- List *i;
+ ListCell *lc;
- foreach(i, tlist)
+ foreach(lc, rte->values_lists)
{
- TargetEntry *tle = lfirst(i);
- char *resname;
-
- resname = tle->resdom->resname;
- if (!strcmp(e_attname, resname))
- return (tle->expr);
- }
- return NULL;
-}
+ List *sublist = (List *) lfirst(lc);
+ ListCell *lc2;
+ foreach(lc2, sublist)
+ {
+ Node *col = (Node *) lfirst(lc2);
-static Node *
-make_null(Oid type)
-{
- Const *c = makeNode(Const);
-
- c->consttype = type;
- c->constlen = get_typlen(type);
- c->constvalue = PointerGetDatum(NULL);
- c->constisnull = true;
- c->constbyval = get_typbyval(type);
- return (Node *) c;
+ if (IsA(col, SetToDefault))
+ return true;
+ }
+ }
+ return false;
}
-
+/*
+ * When processing INSERT ... VALUES with a VALUES RTE (ie, multiple VALUES
+ * lists), we have to replace any DEFAULT items in the VALUES lists with
+ * the appropriate default expressions. The other aspects of targetlist
+ * rewriting need be applied only to the query's targetlist proper.
+ *
+ * Note that we currently can't support subscripted or field assignment
+ * in the multi-VALUES case. The targetlist will contain simple Vars
+ * referencing the VALUES RTE, and therefore process_matched_tle() will
+ * reject any such attempt with "multiple assignments to same column".
+ */
static void
-apply_RIR_view(Node **nodePtr, int rt_index, RangeTblEntry *rte, List *tlist, int *modified, int sublevels_up)
+rewriteValuesRTE(RangeTblEntry *rte, Relation target_relation, List *attrnos)
{
- Node *node = *nodePtr;
-
- if (node == NULL)
- return;
+ List *newValues;
+ ListCell *lc;
- switch(nodeTag(node)) {
- case T_TargetEntry:
- {
- TargetEntry *tle = (TargetEntry *)node;
-
- apply_RIR_view(
- (Node **)(&(tle->expr)),
- rt_index,
- rte,
- tlist,
- modified,
- sublevels_up);
- }
- break;
+ /*
+ * Rebuilding all the lists is a pretty expensive proposition in a big
+ * VALUES list, and it's a waste of time if there aren't any DEFAULT
+ * placeholders. So first scan to see if there are any.
+ */
+ if (!searchForDefault(rte))
+ return; /* nothing to do */
- case T_Aggreg:
- {
- Aggreg *agg = (Aggreg *)node;
-
- apply_RIR_view(
- (Node **)(&(agg->target)),
- rt_index,
- rte,
- tlist,
- modified,
- sublevels_up);
- }
- break;
+ /* Check list lengths (we can assume all the VALUES sublists are alike) */
+ Assert(list_length(attrnos) == list_length(linitial(rte->values_lists)));
- case T_GroupClause:
- {
- GroupClause *grp = (GroupClause *)node;
-
- apply_RIR_view(
- (Node **)(&(grp->entry)),
- rt_index,
- rte,
- tlist,
- modified,
- sublevels_up);
- }
- break;
+ newValues = NIL;
+ foreach(lc, rte->values_lists)
+ {
+ List *sublist = (List *) lfirst(lc);
+ List *newList = NIL;
+ ListCell *lc2;
+ ListCell *lc3;
- case T_Expr:
- {
- Expr *exp = (Expr *)node;
-
- apply_RIR_view(
- (Node **)(&(exp->args)),
- rt_index,
- rte,
- tlist,
- modified,
- sublevels_up);
- }
- break;
+ forboth(lc2, sublist, lc3, attrnos)
+ {
+ Node *col = (Node *) lfirst(lc2);
+ int attrno = lfirst_int(lc3);
- case T_Iter:
+ if (IsA(col, SetToDefault))
{
- Iter *iter = (Iter *)node;
-
- apply_RIR_view(
- (Node **)(&(iter->iterexpr)),
- rt_index,
- rte,
- tlist,
- modified,
- sublevels_up);
- }
- break;
+ Form_pg_attribute att_tup;
+ Node *new_expr;
- case T_ArrayRef:
- {
- ArrayRef *ref = (ArrayRef *)node;
-
- apply_RIR_view(
- (Node **)(&(ref->refupperindexpr)),
- rt_index,
- rte,
- tlist,
- modified,
- sublevels_up);
- apply_RIR_view(
- (Node **)(&(ref->reflowerindexpr)),
- rt_index,
- rte,
- tlist,
- modified,
- sublevels_up);
- apply_RIR_view(
- (Node **)(&(ref->refexpr)),
- rt_index,
- rte,
- tlist,
- modified,
- sublevels_up);
- apply_RIR_view(
- (Node **)(&(ref->refassgnexpr)),
- rt_index,
- rte,
- tlist,
- modified,
- sublevels_up);
- }
- break;
+ att_tup = target_relation->rd_att->attrs[attrno - 1];
- case T_Var:
- {
- Var *var = (Var *)node;
-
- if (var->varlevelsup == sublevels_up &&
- var->varno == rt_index) {
- Node *exp;
-
- if (var->varattno < 0)
- elog(ERROR, "system column %s not available - %s is a view", get_attname(rte->relid, var->varattno), rte->relname);
- exp = FindMatchingTLEntry(
- tlist,
- get_attname(rte->relid,
- var->varattno));
-
- if (exp == NULL) {
- *nodePtr = make_null(var->vartype);
- return;
- }
+ if (!att_tup->attisdropped)
+ new_expr = build_column_default(target_relation, attrno);
+ else
+ new_expr = NULL; /* force a NULL if dropped */
- if (var->varlevelsup > 0 &&
- nodeTag(exp) == T_Var) {
- exp = copyObject(exp);
- ((Var *)exp)->varlevelsup = var->varlevelsup;
- }
- *nodePtr = exp;
- *modified = TRUE;
+ /*
+ * If there is no default (ie, default is effectively NULL),
+ * we've got to explicitly set the column to NULL.
+ */
+ if (!new_expr)
+ {
+ new_expr = (Node *) makeConst(att_tup->atttypid,
+ -1,
+ att_tup->attlen,
+ (Datum) 0,
+ true, /* isnull */
+ att_tup->attbyval);
+ /* this is to catch a NOT NULL domain constraint */
+ new_expr = coerce_to_domain(new_expr,
+ InvalidOid, -1,
+ att_tup->atttypid,
+ COERCE_IMPLICIT_CAST,
+ -1,
+ false,
+ false);
}
+ newList = lappend(newList, new_expr);
}
- break;
-
- case T_Param:
- break;
-
- case T_Const:
- break;
-
- case T_List:
- {
- List *l;
-
- foreach (l, (List *)node)
- apply_RIR_view(
- (Node **)(&(lfirst(l))),
- rt_index,
- rte,
- tlist,
- modified,
- sublevels_up);
- }
- break;
-
- case T_SubLink:
- {
- SubLink *sub = (SubLink *)node;
-
- apply_RIR_view(
- (Node **)(&(sub->lefthand)),
- rt_index,
- rte,
- tlist,
- modified,
- sublevels_up);
-
- apply_RIR_view(
- (Node **)(&(sub->subselect)),
- rt_index,
- rte,
- tlist,
- modified,
- sublevels_up + 1);
- }
- break;
-
- case T_Query:
- {
- Query *qry = (Query *)node;
-
- apply_RIR_view(
- (Node **)(&(qry->targetList)),
- rt_index,
- rte,
- tlist,
- modified,
- sublevels_up);
-
- apply_RIR_view(
- (Node **)(&(qry->qual)),
- rt_index,
- rte,
- tlist,
- modified,
- sublevels_up);
-
- apply_RIR_view(
- (Node **)(&(qry->havingQual)),
- rt_index,
- rte,
- tlist,
- modified,
- sublevels_up);
-
- apply_RIR_view(
- (Node **)(&(qry->groupClause)),
- rt_index,
- rte,
- tlist,
- modified,
- sublevels_up);
- }
- break;
-
- default:
- elog(NOTICE, "unknown node tag %d in apply_RIR_view()", nodeTag(node));
- elog(NOTICE, "Node is: %s", nodeToString(node));
- break;
-
-
+ else
+ newList = lappend(newList, col);
+ }
+ newValues = lappend(newValues, newList);
}
+ rte->values_lists = newValues;
}
+/*
+ * rewriteTargetListUD - rewrite UPDATE/DELETE targetlist as needed
+ *
+ * This function adds a "junk" TLE that is needed to allow the executor to
+ * find the original row for the update or delete. When the target relation
+ * is a regular table, the junk TLE emits the ctid attribute of the original
+ * row. When the target relation is a view, there is no ctid, so we instead
+ * emit a whole-row Var that will contain the "old" values of the view row.
+ *
+ * For UPDATE queries, this is applied after rewriteTargetListIU. The
+ * ordering isn't actually critical at the moment.
+ */
static void
-ApplyRetrieveRule(Query *parsetree,
- RewriteRule *rule,
- int rt_index,
- int relation_level,
- Relation relation,
- int *modified)
+rewriteTargetListUD(Query *parsetree, RangeTblEntry *target_rte,
+ Relation target_relation)
{
- Query *rule_action = NULL;
- Node *rule_qual;
- List *rtable,
- *rt;
- int nothing,
- rt_length;
- int badsql = FALSE;
-
- rule_qual = rule->qual;
- if (rule->actions)
- {
- if (length(rule->actions) > 1) /* ??? because we don't handle
- * rules with more than one
- * action? -ay */
+ Var *var;
+ const char *attrname;
+ TargetEntry *tle;
- return;
- rule_action = copyObject(lfirst(rule->actions));
- nothing = FALSE;
+ if (target_relation->rd_rel->relkind == RELKIND_RELATION)
+ {
+ /*
+ * Emit CTID so that executor can find the row to update or delete.
+ */
+ var = makeVar(parsetree->resultRelation,
+ SelfItemPointerAttributeNumber,
+ TIDOID,
+ -1,
+ InvalidOid,
+ 0);
+
+ attrname = "ctid";
}
else
- nothing = TRUE;
-
- rtable = copyObject(parsetree->rtable);
- foreach(rt, rtable)
{
- RangeTblEntry *rte = lfirst(rt);
-
/*
- * this is to prevent add_missing_vars_to_base_rels() from adding
- * a bogus entry to the new target list.
+ * Emit whole-row Var so that executor will have the "old" view row
+ * to pass to the INSTEAD OF trigger.
*/
- rte->inFromCl = false;
- }
- rt_length = length(rtable);
+ var = makeWholeRowVar(target_rte,
+ parsetree->resultRelation,
+ 0);
- rtable = nconc(rtable, copyObject(rule_action->rtable));
- parsetree->rtable = rtable;
-
- rule_action->rtable = rtable;
- offset_varnodes((Node *) rule_qual, rt_length, 0);
- offset_varnodes((Node *) rule_action, rt_length, 0);
+ attrname = "wholerow";
+ }
- change_varnodes((Node *) rule_qual,
- PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
- change_varnodes((Node *) rule_action,
- PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
+ tle = makeTargetEntry((Expr *) var,
+ list_length(parsetree->targetList) + 1,
+ pstrdup(attrname),
+ true);
- if (relation_level)
- {
- apply_RIR_view((Node **) &parsetree, rt_index,
- (RangeTblEntry *)nth(rt_index - 1, rtable),
- rule_action->targetList, modified, 0);
- apply_RIR_view((Node **) &rule_action, rt_index,
- (RangeTblEntry *)nth(rt_index - 1, rtable),
- rule_action->targetList, modified, 0);
- }
- else
- {
- HandleRIRAttributeRule(parsetree, rtable, rule_action->targetList,
- rt_index, rule->attrno, modified, &badsql);
- }
- if (*modified && !badsql) {
- AddQual(parsetree, rule_action->qual);
- /* This will only work if the query made to the view defined by the following
- * groupClause groups by the same attributes or does not use group at all! */
- if (parsetree->groupClause == NULL)
- parsetree->groupClause=rule_action->groupClause;
- AddHavingQual(parsetree, rule_action->havingQual);
- parsetree->hasAggs = (rule_action->hasAggs || parsetree->hasAggs);
- parsetree->hasSubLinks = (rule_action->hasSubLinks || parsetree->hasSubLinks);
- }
+ parsetree->targetList = lappend(parsetree->targetList, tle);
}
-static void
-fireRIRonSubselect(Node *node)
+/*
+ * matchLocks -
+ * match the list of locks and returns the matching rules
+ */
+static List *
+matchLocks(CmdType event,
+ RuleLock *rulelocks,
+ int varno,
+ Query *parsetree)
{
- if (node == NULL)
- return;
+ List *matching_locks = NIL;
+ int nlocks;
+ int i;
- switch(nodeTag(node)) {
- case T_TargetEntry:
- {
- TargetEntry *tle = (TargetEntry *)node;
+ if (rulelocks == NULL)
+ return NIL;
- fireRIRonSubselect(
- (Node *)(tle->expr));
- }
- break;
+ if (parsetree->commandType != CMD_SELECT)
+ {
+ if (parsetree->resultRelation != varno)
+ return NIL;
+ }
- case T_Aggreg:
- {
- Aggreg *agg = (Aggreg *)node;
+ nlocks = rulelocks->numLocks;
- fireRIRonSubselect(
- (Node *)(agg->target));
- }
- break;
+ for (i = 0; i < nlocks; i++)
+ {
+ RewriteRule *oneLock = rulelocks->rules[i];
- case T_GroupClause:
+ /*
+ * Suppress ON INSERT/UPDATE/DELETE rules that are disabled or
+ * configured to not fire during the current sessions replication
+ * role. ON SELECT rules will always be applied in order to keep views
+ * working even in LOCAL or REPLICA role.
+ */
+ if (oneLock->event != CMD_SELECT)
+ {
+ if (SessionReplicationRole == SESSION_REPLICATION_ROLE_REPLICA)
{
- GroupClause *grp = (GroupClause *)node;
-
- fireRIRonSubselect(
- (Node *)(grp->entry));
+ if (oneLock->enabled == RULE_FIRES_ON_ORIGIN ||
+ oneLock->enabled == RULE_DISABLED)
+ continue;
}
- break;
-
- case T_Expr:
+ else /* ORIGIN or LOCAL ROLE */
{
- Expr *exp = (Expr *)node;
-
- fireRIRonSubselect(
- (Node *)(exp->args));
+ if (oneLock->enabled == RULE_FIRES_ON_REPLICA ||
+ oneLock->enabled == RULE_DISABLED)
+ continue;
}
- break;
+ }
- case T_Iter:
- {
- Iter *iter = (Iter *)node;
+ if (oneLock->event == event)
+ {
+ if (parsetree->commandType != CMD_SELECT ||
+ (oneLock->attrno == -1 ?
+ rangeTableEntry_used((Node *) parsetree, varno, 0) :
+ attribute_used((Node *) parsetree,
+ varno, oneLock->attrno, 0)))
+ matching_locks = lappend(matching_locks, oneLock);
+ }
+ }
- fireRIRonSubselect(
- (Node *)(iter->iterexpr));
- }
- break;
+ return matching_locks;
+}
- case T_ArrayRef:
- {
- ArrayRef *ref = (ArrayRef *)node;
-
- fireRIRonSubselect(
- (Node *)(ref->refupperindexpr));
- fireRIRonSubselect(
- (Node *)(ref->reflowerindexpr));
- fireRIRonSubselect(
- (Node *)(ref->refexpr));
- fireRIRonSubselect(
- (Node *)(ref->refassgnexpr));
- }
- break;
- case T_Var:
- break;
+/*
+ * ApplyRetrieveRule - expand an ON SELECT rule
+ */
+static Query *
+ApplyRetrieveRule(Query *parsetree,
+ RewriteRule *rule,
+ int rt_index,
+ bool relation_level,
+ Relation relation,
+ List *activeRIRs,
+ bool forUpdatePushedDown)
+{
+ Query *rule_action;
+ RangeTblEntry *rte,
+ *subrte;
+ RowMarkClause *rc;
+
+ if (list_length(rule->actions) != 1)
+ elog(ERROR, "expected just one rule action");
+ if (rule->qual != NULL)
+ elog(ERROR, "cannot handle qualified ON SELECT rule");
+ if (!relation_level)
+ elog(ERROR, "cannot handle per-attribute ON SELECT rule");
+
+ if (rt_index == parsetree->resultRelation)
+ {
+ /*
+ * We have a view as the result relation of the query, and it wasn't
+ * rewritten by any rule. This case is supported if there is an
+ * INSTEAD OF trigger that will trap attempts to insert/update/delete
+ * view rows. The executor will check that; for the moment just plow
+ * ahead. We have two cases:
+ *
+ * For INSERT, we needn't do anything. The unmodified RTE will serve
+ * fine as the result relation.
+ *
+ * For UPDATE/DELETE, we need to expand the view so as to have source
+ * data for the operation. But we also need an unmodified RTE to
+ * serve as the target. So, copy the RTE and add the copy to the
+ * rangetable. Note that the copy does not get added to the jointree.
+ * Also note that there's a hack in fireRIRrules to avoid calling
+ * this function again when it arrives at the copied RTE.
+ */
+ if (parsetree->commandType == CMD_INSERT)
+ return parsetree;
+ else if (parsetree->commandType == CMD_UPDATE ||
+ parsetree->commandType == CMD_DELETE)
+ {
+ RangeTblEntry *newrte;
- case T_Param:
- break;
+ rte = rt_fetch(rt_index, parsetree->rtable);
+ newrte = copyObject(rte);
+ parsetree->rtable = lappend(parsetree->rtable, newrte);
+ parsetree->resultRelation = list_length(parsetree->rtable);
- case T_Const:
- break;
+ /*
+ * There's no need to do permissions checks twice, so wipe out
+ * the permissions info for the original RTE (we prefer to keep
+ * the bits set on the result RTE).
+ */
+ rte->requiredPerms = 0;
+ rte->checkAsUser = InvalidOid;
+ rte->selectedCols = NULL;
+ rte->modifiedCols = NULL;
- case T_List:
- {
- List *l;
+ /*
+ * For the most part, Vars referencing the view should remain as
+ * they are, meaning that they implicitly represent OLD values.
+ * But in the RETURNING list if any, we want such Vars to
+ * represent NEW values, so change them to reference the new RTE.
+ *
+ * Since ChangeVarNodes scribbles on the tree in-place, copy the
+ * RETURNING list first for safety.
+ */
+ parsetree->returningList = copyObject(parsetree->returningList);
+ ChangeVarNodes((Node *) parsetree->returningList, rt_index,
+ parsetree->resultRelation, 0);
- foreach (l, (List *)node)
- fireRIRonSubselect(
- (Node *)(lfirst(l)));
- }
- break;
+ /* Now, continue with expanding the original view RTE */
+ }
+ else
+ elog(ERROR, "unrecognized commandType: %d",
+ (int) parsetree->commandType);
+ }
- case T_SubLink:
- {
- SubLink *sub = (SubLink *)node;
- Query *qry;
+ /*
+ * If FOR UPDATE/SHARE of view, be sure we get right initial lock on the
+ * relations it references.
+ */
+ rc = get_parse_rowmark(parsetree, rt_index);
+ forUpdatePushedDown |= (rc != NULL);
+
+ /*
+ * Make a modifiable copy of the view query, and acquire needed locks on
+ * the relations it mentions.
+ */
+ rule_action = copyObject(linitial(rule->actions));
- fireRIRonSubselect(
- (Node *)(sub->lefthand));
+ AcquireRewriteLocks(rule_action, forUpdatePushedDown);
- qry = fireRIRrules((Query *)(sub->subselect));
+ /*
+ * Recursively expand any view references inside the view.
+ */
+ rule_action = fireRIRrules(rule_action, activeRIRs, forUpdatePushedDown);
- fireRIRonSubselect(
- (Node *)qry);
+ /*
+ * Now, plug the view query in as a subselect, replacing the relation's
+ * original RTE.
+ */
+ rte = rt_fetch(rt_index, parsetree->rtable);
- sub->subselect = (Node *) qry;
- }
- break;
+ rte->rtekind = RTE_SUBQUERY;
+ rte->relid = InvalidOid;
+ rte->subquery = rule_action;
+ rte->inh = false; /* must not be set for a subquery */
- case T_Query:
- {
- Query *qry = (Query *)node;
+ /*
+ * We move the view's permission check data down to its rangetable. The
+ * checks will actually be done against the OLD entry therein.
+ */
+ subrte = rt_fetch(PRS2_OLD_VARNO, rule_action->rtable);
+ Assert(subrte->relid == relation->rd_id);
+ subrte->requiredPerms = rte->requiredPerms;
+ subrte->checkAsUser = rte->checkAsUser;
+ subrte->selectedCols = rte->selectedCols;
+ subrte->modifiedCols = rte->modifiedCols;
+
+ rte->requiredPerms = 0; /* no permission check on subquery itself */
+ rte->checkAsUser = InvalidOid;
+ rte->selectedCols = NULL;
+ rte->modifiedCols = NULL;
- fireRIRonSubselect(
- (Node *)(qry->targetList));
+ /*
+ * If FOR UPDATE/SHARE of view, mark all the contained tables as implicit
+ * FOR UPDATE/SHARE, the same as the parser would have done if the view's
+ * subquery had been written out explicitly.
+ *
+ * Note: we don't consider forUpdatePushedDown here; such marks will be
+ * made by recursing from the upper level in markQueryForLocking.
+ */
+ if (rc != NULL)
+ markQueryForLocking(rule_action, (Node *) rule_action->jointree,
+ rc->forUpdate, rc->noWait, true);
- fireRIRonSubselect(
- (Node *)(qry->qual));
+ return parsetree;
+}
- fireRIRonSubselect(
- (Node *)(qry->havingQual));
+/*
+ * Recursively mark all relations used by a view as FOR UPDATE/SHARE.
+ *
+ * This may generate an invalid query, eg if some sub-query uses an
+ * aggregate. We leave it to the planner to detect that.
+ *
+ * NB: this must agree with the parser's transformLockingClause() routine.
+ * However, unlike the parser we have to be careful not to mark a view's
+ * OLD and NEW rels for updating. The best way to handle that seems to be
+ * to scan the jointree to determine which rels are used.
+ */
+static void
+markQueryForLocking(Query *qry, Node *jtnode,
+ bool forUpdate, bool noWait, bool pushedDown)
+{
+ if (jtnode == NULL)
+ return;
+ if (IsA(jtnode, RangeTblRef))
+ {
+ int rti = ((RangeTblRef *) jtnode)->rtindex;
+ RangeTblEntry *rte = rt_fetch(rti, qry->rtable);
- fireRIRonSubselect(
- (Node *)(qry->groupClause));
+ if (rte->rtekind == RTE_RELATION)
+ {
+ /* ignore foreign tables */
+ if (get_rel_relkind(rte->relid) != RELKIND_FOREIGN_TABLE)
+ {
+ applyLockingClause(qry, rti, forUpdate, noWait, pushedDown);
+ rte->requiredPerms |= ACL_SELECT_FOR_UPDATE;
}
- break;
+ }
+ else if (rte->rtekind == RTE_SUBQUERY)
+ {
+ applyLockingClause(qry, rti, forUpdate, noWait, pushedDown);
+ /* FOR UPDATE/SHARE of subquery is propagated to subquery's rels */
+ markQueryForLocking(rte->subquery, (Node *) rte->subquery->jointree,
+ forUpdate, noWait, true);
+ }
+ /* other RTE types are unaffected by FOR UPDATE */
+ }
+ else if (IsA(jtnode, FromExpr))
+ {
+ FromExpr *f = (FromExpr *) jtnode;
+ ListCell *l;
- default:
- elog(NOTICE, "unknown node tag %d in fireRIRonSubselect()", nodeTag(node));
- elog(NOTICE, "Node is: %s", nodeToString(node));
- break;
+ foreach(l, f->fromlist)
+ markQueryForLocking(qry, lfirst(l), forUpdate, noWait, pushedDown);
+ }
+ else if (IsA(jtnode, JoinExpr))
+ {
+ JoinExpr *j = (JoinExpr *) jtnode;
+
+ markQueryForLocking(qry, j->larg, forUpdate, noWait, pushedDown);
+ markQueryForLocking(qry, j->rarg, forUpdate, noWait, pushedDown);
+ }
+ else
+ elog(ERROR, "unrecognized node type: %d",
+ (int) nodeTag(jtnode));
+}
+/*
+ * fireRIRonSubLink -
+ * Apply fireRIRrules() to each SubLink (subselect in expression) found
+ * in the given tree.
+ *
+ * NOTE: although this has the form of a walker, we cheat and modify the
+ * SubLink nodes in-place. It is caller's responsibility to ensure that
+ * no unwanted side-effects occur!
+ *
+ * This is unlike most of the other routines that recurse into subselects,
+ * because we must take control at the SubLink node in order to replace
+ * the SubLink's subselect link with the possibly-rewritten subquery.
+ */
+static bool
+fireRIRonSubLink(Node *node, List *activeRIRs)
+{
+ if (node == NULL)
+ return false;
+ if (IsA(node, SubLink))
+ {
+ SubLink *sub = (SubLink *) node;
+
+ /* Do what we came for */
+ sub->subselect = (Node *) fireRIRrules((Query *) sub->subselect,
+ activeRIRs, false);
+ /* Fall through to process lefthand args of SubLink */
}
+
+ /*
+ * Do NOT recurse into Query nodes, because fireRIRrules already processed
+ * subselects of subselects for us.
+ */
+ return expression_tree_walker(node, fireRIRonSubLink,
+ (void *) activeRIRs);
}
* Apply all RIR rules on each rangetable entry in a query
*/
static Query *
-fireRIRrules(Query *parsetree)
+fireRIRrules(Query *parsetree, List *activeRIRs, bool forUpdatePushedDown)
{
- int rt_index;
- RangeTblEntry *rte;
- Relation rel;
- List *locks;
- RuleLock *rules;
- RewriteRule *rule;
- RewriteRule RIRonly;
- int modified;
- int i;
- List *l;
+ int origResultRelation = parsetree->resultRelation;
+ int rt_index;
+ ListCell *lc;
+
+ /*
+ * don't try to convert this into a foreach loop, because rtable list can
+ * get changed each time through...
+ */
+ rt_index = 0;
+ while (rt_index < list_length(parsetree->rtable))
+ {
+ RangeTblEntry *rte;
+ Relation rel;
+ List *locks;
+ RuleLock *rules;
+ RewriteRule *rule;
+ int i;
- rt_index = 0;
- while(rt_index < length(parsetree->rtable)) {
++rt_index;
- if (!rangeTableEntry_used((Node *)parsetree, rt_index, 0))
- continue;
-
- rte = nth(rt_index - 1, parsetree->rtable);
- rel = heap_openr(rte->relname);
- if (rel->rd_rules == NULL) {
- heap_close(rel);
+ rte = rt_fetch(rt_index, parsetree->rtable);
+
+ /*
+ * A subquery RTE can't have associated rules, so there's nothing to
+ * do to this level of the query, but we must recurse into the
+ * subquery to expand any rule references in it.
+ */
+ if (rte->rtekind == RTE_SUBQUERY)
+ {
+ rte->subquery = fireRIRrules(rte->subquery, activeRIRs,
+ (forUpdatePushedDown ||
+ get_parse_rowmark(parsetree, rt_index) != NULL));
continue;
}
- rules = rel->rd_rules;
- locks = NIL;
+ /*
+ * Joins and other non-relation RTEs can be ignored completely.
+ */
+ if (rte->rtekind != RTE_RELATION)
+ continue;
+
+ /*
+ * If the table is not referenced in the query, then we ignore it.
+ * This prevents infinite expansion loop due to new rtable entries
+ * inserted by expansion of a rule. A table is referenced if it is
+ * part of the join set (a source table), or is referenced by any Var
+ * nodes, or is the result table.
+ */
+ if (rt_index != parsetree->resultRelation &&
+ !rangeTableEntry_used((Node *) parsetree, rt_index, 0))
+ continue;
+
+ /*
+ * Also, if this is a new result relation introduced by
+ * ApplyRetrieveRule, we don't want to do anything more with it.
+ */
+ if (rt_index == parsetree->resultRelation &&
+ rt_index != origResultRelation)
+ continue;
+
+ /*
+ * We can use NoLock here since either the parser or
+ * AcquireRewriteLocks should have locked the rel already.
+ */
+ rel = heap_open(rte->relid, NoLock);
/*
* Collect the RIR rules that we must apply
*/
- for (i = 0; i < rules->numLocks; i++) {
+ rules = rel->rd_rules;
+ if (rules == NULL)
+ {
+ heap_close(rel, NoLock);
+ continue;
+ }
+ locks = NIL;
+ for (i = 0; i < rules->numLocks; i++)
+ {
rule = rules->rules[i];
if (rule->event != CMD_SELECT)
continue;
-
- if (rule->attrno > 0 &&
- !attribute_used((Node *)parsetree,
- rt_index,
- rule->attrno, 0))
- continue;
+
+ if (rule->attrno > 0)
+ {
+ /* per-attr rule; do we need it? */
+ if (!attribute_used((Node *) parsetree, rt_index,
+ rule->attrno, 0))
+ continue;
+ }
locks = lappend(locks, rule);
}
/*
- * Check permissions
- */
- checkLockPerms(locks, parsetree, rt_index);
-
- /*
- * Now apply them
+ * If we found any, apply them --- but first check for recursion!
*/
- foreach (l, locks) {
- rule = lfirst(l);
-
- RIRonly.event = rule->event;
- RIRonly.attrno = rule->attrno;
- RIRonly.qual = rule->qual;
- RIRonly.actions = rule->actions;
-
- ApplyRetrieveRule(parsetree,
- &RIRonly,
- rt_index,
- RIRonly.attrno == -1,
- rel,
- &modified);
- }
+ if (locks != NIL)
+ {
+ ListCell *l;
- heap_close(rel);
- }
+ if (list_member_oid(activeRIRs, RelationGetRelid(rel)))
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
+ errmsg("infinite recursion detected in rules for relation \"%s\"",
+ RelationGetRelationName(rel))));
+ activeRIRs = lcons_oid(RelationGetRelid(rel), activeRIRs);
- fireRIRonSubselect((Node *) parsetree);
- modifyAggregQual((Node **) &(parsetree->qual), parsetree);
+ foreach(l, locks)
+ {
+ rule = lfirst(l);
- return parsetree;
-}
+ parsetree = ApplyRetrieveRule(parsetree,
+ rule,
+ rt_index,
+ rule->attrno == -1,
+ rel,
+ activeRIRs,
+ forUpdatePushedDown);
+ }
+ activeRIRs = list_delete_first(activeRIRs);
+ }
-/*
- * idea is to fire regular rules first, then qualified instead
- * rules and unqualified instead rules last. Any lemming is counted for.
- */
-static List *
-orderRules(List *locks)
-{
- List *regular = NIL;
- List *instead_rules = NIL;
- List *instead_qualified = NIL;
- List *i;
+ heap_close(rel, NoLock);
+ }
- foreach(i, locks)
+ /* Recurse into subqueries in WITH */
+ foreach(lc, parsetree->cteList)
{
- RewriteRule *rule_lock = (RewriteRule *) lfirst(i);
+ CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
- if (rule_lock->isInstead)
- {
- if (rule_lock->qual == NULL)
- instead_rules = lappend(instead_rules, rule_lock);
- else
- instead_qualified = lappend(instead_qualified, rule_lock);
- }
- else
- regular = lappend(regular, rule_lock);
+ cte->ctequery = (Node *)
+ fireRIRrules((Query *) cte->ctequery, activeRIRs, false);
}
- regular = nconc(regular, instead_qualified);
- return nconc(regular, instead_rules);
-}
+ /*
+ * Recurse into sublink subqueries, too. But we already did the ones in
+ * the rtable and cteList.
+ */
+ if (parsetree->hasSubLinks)
+ query_tree_walker(parsetree, fireRIRonSubLink, (void *) activeRIRs,
+ QTW_IGNORE_RC_SUBQUERIES);
+
+ return parsetree;
+}
+/*
+ * Modify the given query by adding 'AND rule_qual IS NOT TRUE' to its
+ * qualification. This is used to generate suitable "else clauses" for
+ * conditional INSTEAD rules. (Unfortunately we must use "x IS NOT TRUE",
+ * not just "NOT x" which the planner is much smarter about, else we will
+ * do the wrong thing when the qual evaluates to NULL.)
+ *
+ * The rule_qual may contain references to OLD or NEW. OLD references are
+ * replaced by references to the specified rt_index (the relation that the
+ * rule applies to). NEW references are only possible for INSERT and UPDATE
+ * queries on the relation itself, and so they should be replaced by copies
+ * of the related entries in the query's own targetlist.
+ */
static Query *
-CopyAndAddQual(Query *parsetree,
- List *actions,
- Node *rule_qual,
- int rt_index,
- CmdType event)
+CopyAndAddInvertedQual(Query *parsetree,
+ Node *rule_qual,
+ int rt_index,
+ CmdType event)
{
- Query *new_tree = (Query *) copyObject(parsetree);
- Node *new_qual = NULL;
- Query *rule_action = NULL;
-
- if (actions)
- rule_action = lfirst(actions);
- if (rule_qual != NULL)
- new_qual = (Node *) copyObject(rule_qual);
- if (rule_action != NULL)
- {
- List *rtable;
- int rt_length;
-
- rtable = new_tree->rtable;
- rt_length = length(rtable);
- rtable = append(rtable, listCopy(rule_action->rtable));
- new_tree->rtable = rtable;
- OffsetVarNodes(new_qual, rt_length);
- ChangeVarNodes(new_qual, PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
- }
- /* XXX -- where current doesn't work for instead nothing.... yet */
- AddNotQual(new_tree, new_qual);
+ /* Don't scribble on the passed qual (it's in the relcache!) */
+ Node *new_qual = (Node *) copyObject(rule_qual);
- return new_tree;
-}
+ /*
+ * In case there are subqueries in the qual, acquire necessary locks and
+ * fix any deleted JOIN RTE entries. (This is somewhat redundant with
+ * rewriteRuleAction, but not entirely ... consider restructuring so that
+ * we only need to process the qual this way once.)
+ */
+ (void) acquireLocksOnSubLinks(new_qual, NULL);
+
+ /* Fix references to OLD */
+ ChangeVarNodes(new_qual, PRS2_OLD_VARNO, rt_index, 0);
+ /* Fix references to NEW */
+ if (event == CMD_INSERT || event == CMD_UPDATE)
+ new_qual = ResolveNew(new_qual,
+ PRS2_NEW_VARNO,
+ 0,
+ rt_fetch(rt_index, parsetree->rtable),
+ parsetree->targetList,
+ event,
+ rt_index,
+ &parsetree->hasSubLinks);
+ /* And attach the fixed qual */
+ AddInvertedQual(parsetree, new_qual);
+ return parsetree;
+}
/*
* fireRules -
* Iterate through rule locks applying rules.
- * All rules create their own parsetrees. Instead rules
- * with rule qualification save the original parsetree
- * and add their negated qualification to it. Real instead
- * rules finally throw away the original parsetree.
*
- * remember: reality is for dead birds -- glass
+ * Input arguments:
+ * parsetree - original query
+ * rt_index - RT index of result relation in original query
+ * event - type of rule event
+ * locks - list of rules to fire
+ * Output arguments:
+ * *instead_flag - set TRUE if any unqualified INSTEAD rule is found
+ * (must be initialized to FALSE)
+ * *returning_flag - set TRUE if we rewrite RETURNING clause in any rule
+ * (must be initialized to FALSE)
+ * *qual_product - filled with modified original query if any qualified
+ * INSTEAD rule is found (must be initialized to NULL)
+ * Return value:
+ * list of rule actions adjusted for use with this query
*
+ * Qualified INSTEAD rules generate their action with the qualification
+ * condition added. They also generate a modified version of the original
+ * query with the negated qualification added, so that it will run only for
+ * rows that the qualified action doesn't act on. (If there are multiple
+ * qualified INSTEAD rules, we AND all the negated quals onto a single
+ * modified original query.) We won't execute the original, unmodified
+ * query if we find either qualified or unqualified INSTEAD rules. If
+ * we find both, the modified original query is discarded too.
*/
static List *
fireRules(Query *parsetree,
int rt_index,
CmdType event,
- bool *instead_flag,
List *locks,
- List **qual_products)
+ bool *instead_flag,
+ bool *returning_flag,
+ Query **qual_product)
{
- RewriteInfo *info;
List *results = NIL;
- List *i;
+ ListCell *l;
- /* choose rule to fire from list of rules */
- if (locks == NIL)
+ foreach(l, locks)
{
- return NIL;
- }
-
- locks = orderRules(locks); /* real instead rules last */
- foreach(i, locks)
- {
- RewriteRule *rule_lock = (RewriteRule *) lfirst(i);
- Node *qual,
- *event_qual;
- List *actions;
- List *r;
+ RewriteRule *rule_lock = (RewriteRule *) lfirst(l);
+ Node *event_qual = rule_lock->qual;
+ List *actions = rule_lock->actions;
+ QuerySource qsrc;
+ ListCell *r;
- /*
- * Instead rules change the resultRelation of the query. So the
- * permission checks on the initial resultRelation would never be
- * done (this is normally done in the executor deep down). So we
- * must do it here. The result relations resulting from earlier
- * rewrites are already checked against the rules eventrelation
- * owner (during matchLocks) and have the skipAcl flag set.
- */
- if (rule_lock->isInstead &&
- parsetree->commandType != CMD_SELECT)
+ /* Determine correct QuerySource value for actions */
+ if (rule_lock->isInstead)
{
- RangeTblEntry *rte;
- int32 acl_rc;
- int32 reqperm;
-
- switch (parsetree->commandType)
- {
- case CMD_INSERT:
- reqperm = ACL_AP;
- break;
- default:
- reqperm = ACL_WR;
- break;
- }
-
- rte = (RangeTblEntry *) nth(parsetree->resultRelation - 1,
- parsetree->rtable);
- if (!rte->skipAcl)
+ if (event_qual != NULL)
+ qsrc = QSRC_QUAL_INSTEAD_RULE;
+ else
{
- acl_rc = pg_aclcheck(rte->relname,
- GetPgUserName(), reqperm);
- if (acl_rc != ACLCHECK_OK)
- {
- elog(ERROR, "%s: %s",
- rte->relname,
- aclcheck_error_strings[acl_rc]);
- }
+ qsrc = QSRC_INSTEAD_RULE;
+ *instead_flag = true; /* report unqualified INSTEAD */
}
}
+ else
+ qsrc = QSRC_NON_INSTEAD_RULE;
- /* multiple rule action time */
- *instead_flag = rule_lock->isInstead;
- event_qual = rule_lock->qual;
- actions = rule_lock->actions;
- if (event_qual != NULL && *instead_flag)
+ if (qsrc == QSRC_QUAL_INSTEAD_RULE)
{
- Query *qual_product;
- RewriteInfo qual_info;
-
- /* ----------
- * If there are instead rules with qualifications,
- * the original query is still performed. But all
- * the negated rule qualifications of the instead
- * rules are added so it does it's actions only
- * in cases where the rule quals of all instead
- * rules are false. Think of it as the default
- * action in a case. We save this in *qual_products
- * so deepRewriteQuery() can add it to the query
+ /*
+ * If there are INSTEAD rules with qualifications, the original
+ * query is still performed. But all the negated rule
+ * qualifications of the INSTEAD rules are added so it does its
+ * actions only in cases where the rule quals of all INSTEAD rules
+ * are false. Think of it as the default action in a case. We save
+ * this in *qual_product so RewriteQuery() can add it to the query
* list after we mangled it up enough.
- * ----------
+ *
+ * If we have already found an unqualified INSTEAD rule, then
+ * *qual_product won't be used, so don't bother building it.
*/
- if (*qual_products == NIL)
- qual_product = parsetree;
- else
- qual_product = (Query *) nth(0, *qual_products);
-
- qual_info.event = qual_product->commandType;
- qual_info.new_varno = length(qual_product->rtable) + 2;
- qual_product = CopyAndAddQual(qual_product,
- actions,
- event_qual,
- rt_index,
- event);
-
- qual_info.rule_action = qual_product;
-
- if (event == CMD_INSERT || event == CMD_UPDATE)
- FixNew(&qual_info, qual_product);
-
- *qual_products = lappend(NIL, qual_product);
+ if (!*instead_flag)
+ {
+ if (*qual_product == NULL)
+ *qual_product = copyObject(parsetree);
+ *qual_product = CopyAndAddInvertedQual(*qual_product,
+ event_qual,
+ rt_index,
+ event);
+ }
}
+ /* Now process the rule's actions and add them to the result list */
foreach(r, actions)
{
Query *rule_action = lfirst(r);
- Node *rule_qual = copyObject(event_qual);
if (rule_action->commandType == CMD_NOTHING)
continue;
- /*--------------------------------------------------
- * Step 1:
- * Rewrite current.attribute or current to tuple variable
- * this appears to be done in parser?
- *--------------------------------------------------
- */
- info = gatherRewriteMeta(parsetree, rule_action, rule_qual,
- rt_index, event, instead_flag);
-
- /* handle escapable cases, or those handled by other code */
- if (info->nothing)
- {
- if (*instead_flag)
- return NIL;
- else
- continue;
- }
-
- if (info->action == info->event &&
- info->event == CMD_SELECT)
- continue;
-
- /*
- * Event Qualification forces copying of parsetree and
- * splitting into two queries one w/rule_qual, one w/NOT
- * rule_qual. Also add user query qual onto rule action
- */
- qual = parsetree->qual;
- AddQual(info->rule_action, qual);
-
- if (info->rule_qual != NULL)
- AddQual(info->rule_action, info->rule_qual);
-
- /*--------------------------------------------------
- * Step 2:
- * Rewrite new.attribute w/ right hand side of target-list
- * entry for appropriate field name in insert/update
- *--------------------------------------------------
- */
- if ((info->event == CMD_INSERT) || (info->event == CMD_UPDATE))
- FixNew(info, parsetree);
+ rule_action = rewriteRuleAction(parsetree, rule_action,
+ event_qual, rt_index, event,
+ returning_flag);
- /*--------------------------------------------------
- * Step 3:
- * rewriting due to retrieve rules
- *--------------------------------------------------
- */
- info->rule_action->rtable = info->rt;
- /*
- ProcessRetrieveQuery(info->rule_action, info->rt,
- &orig_instead_flag, TRUE);
- */
-
- /*--------------------------------------------------
- * Step 4
- * Simplify? hey, no algorithm for simplification... let
- * the planner do it.
- *--------------------------------------------------
- */
- results = lappend(results, info->rule_action);
+ rule_action->querySource = qsrc;
+ rule_action->canSetTag = false; /* might change later */
- pfree(info);
+ results = lappend(results, rule_action);
}
-
- /* ----------
- * If this was an unqualified instead rule,
- * throw away an eventually saved 'default' parsetree
- * ----------
- */
- if (event_qual == NULL && *instead_flag)
- *qual_products = NIL;
}
+
return results;
}
-
+/*
+ * RewriteQuery -
+ * rewrites the query and apply the rules again on the queries rewritten
+ *
+ * rewrite_events is a list of open query-rewrite actions, so we can detect
+ * infinite recursion.
+ */
static List *
-RewriteQuery(Query *parsetree, bool *instead_flag, List **qual_products)
+RewriteQuery(Query *parsetree, List *rewrite_events)
{
- CmdType event;
- List *product_queries = NIL;
- int result_relation = 0;
- RangeTblEntry *rt_entry;
- Relation rt_entry_relation = NULL;
- RuleLock *rt_entry_locks = NULL;
-
- Assert(parsetree != NULL);
-
- event = parsetree->commandType;
-
- /*
- * SELECT rules are handled later when we have all the
- * queries that should get executed
- */
- if (event == CMD_SELECT)
- return NIL;
-
- /*
- * Utilities aren't rewritten at all - why is this here?
- */
- if (event == CMD_UTILITY)
- return NIL;
+ CmdType event = parsetree->commandType;
+ bool instead = false;
+ bool returning = false;
+ Query *qual_product = NULL;
+ List *rewritten = NIL;
/*
- * only for a delete may the targetlist be NULL
+ * If the statement is an insert, update, or delete, adjust its targetlist
+ * as needed, and then fire INSERT/UPDATE/DELETE rules on it.
+ *
+ * SELECT rules are handled later when we have all the queries that should
+ * get executed. Also, utilities aren't rewritten at all (do we still
+ * need that check?)
*/
- if (event != CMD_DELETE)
- Assert(parsetree->targetList != NULL);
+ if (event != CMD_SELECT && event != CMD_UTILITY)
+ {
+ int result_relation;
+ RangeTblEntry *rt_entry;
+ Relation rt_entry_relation;
+ List *locks;
- result_relation = parsetree->resultRelation;
+ result_relation = parsetree->resultRelation;
+ Assert(result_relation != 0);
+ rt_entry = rt_fetch(result_relation, parsetree->rtable);
+ Assert(rt_entry->rtekind == RTE_RELATION);
- /*
- * the statement is an update, insert or delete - fire rules
- * on it.
- */
- rt_entry = rt_fetch(result_relation, parsetree->rtable);
- rt_entry_relation = heap_openr(rt_entry->relname);
- rt_entry_locks = rt_entry_relation->rd_rules;
- heap_close(rt_entry_relation);
+ /*
+ * We can use NoLock here since either the parser or
+ * AcquireRewriteLocks should have locked the rel already.
+ */
+ rt_entry_relation = heap_open(rt_entry->relid, NoLock);
- if (rt_entry_locks != NULL)
- {
- List *locks =
- matchLocks(event, rt_entry_locks, result_relation, parsetree);
-
- product_queries =
- fireRules(parsetree,
- result_relation,
- event,
- instead_flag,
- locks,
- qual_products);
- }
+ /*
+ * Rewrite the targetlist as needed for the command type.
+ */
+ if (event == CMD_INSERT)
+ {
+ RangeTblEntry *values_rte = NULL;
- return product_queries;
+ /*
+ * If it's an INSERT ... VALUES (...), (...), ... there will be a
+ * single RTE for the VALUES targetlists.
+ */
+ if (list_length(parsetree->jointree->fromlist) == 1)
+ {
+ RangeTblRef *rtr = (RangeTblRef *) linitial(parsetree->jointree->fromlist);
-}
+ if (IsA(rtr, RangeTblRef))
+ {
+ RangeTblEntry *rte = rt_fetch(rtr->rtindex,
+ parsetree->rtable);
+ if (rte->rtekind == RTE_VALUES)
+ values_rte = rte;
+ }
+ }
-/*
- * to avoid infinite recursion, we restrict the number of times a query
- * can be rewritten. Detecting cycles is left for the reader as an excercise.
- */
-#ifndef REWRITE_INVOKE_MAX
-#define REWRITE_INVOKE_MAX 10
-#endif
+ if (values_rte)
+ {
+ List *attrnos;
-static int numQueryRewriteInvoked = 0;
+ /* Process the main targetlist ... */
+ rewriteTargetListIU(parsetree, rt_entry_relation, &attrnos);
+ /* ... and the VALUES expression lists */
+ rewriteValuesRTE(values_rte, rt_entry_relation, attrnos);
+ }
+ else
+ {
+ /* Process just the main targetlist */
+ rewriteTargetListIU(parsetree, rt_entry_relation, NULL);
+ }
+ }
+ else if (event == CMD_UPDATE)
+ {
+ rewriteTargetListIU(parsetree, rt_entry_relation, NULL);
+ rewriteTargetListUD(parsetree, rt_entry, rt_entry_relation);
+ }
+ else if (event == CMD_DELETE)
+ {
+ rewriteTargetListUD(parsetree, rt_entry, rt_entry_relation);
+ }
+ else
+ elog(ERROR, "unrecognized commandType: %d", (int) event);
-/*
- * deepRewriteQuery -
- * rewrites the query and apply the rules again on the queries rewritten
- */
-static List *
-deepRewriteQuery(Query *parsetree)
-{
- List *n;
- List *rewritten = NIL;
- List *result = NIL;
- bool instead;
- List *qual_products = NIL;
+ /*
+ * Collect and apply the appropriate rules.
+ */
+ locks = matchLocks(event, rt_entry_relation->rd_rules,
+ result_relation, parsetree);
+ if (locks != NIL)
+ {
+ List *product_queries;
+ product_queries = fireRules(parsetree,
+ result_relation,
+ event,
+ locks,
+ &instead,
+ &returning,
+ &qual_product);
- if (++numQueryRewriteInvoked > REWRITE_INVOKE_MAX)
- {
- elog(ERROR, "query rewritten %d times, may contain cycles",
- numQueryRewriteInvoked - 1);
- }
+ /*
+ * If we got any product queries, recursively rewrite them --- but
+ * first check for recursion!
+ */
+ if (product_queries != NIL)
+ {
+ ListCell *n;
+ rewrite_event *rev;
- instead = FALSE;
- result = RewriteQuery(parsetree, &instead, &qual_products);
+ foreach(n, rewrite_events)
+ {
+ rev = (rewrite_event *) lfirst(n);
+ if (rev->relation == RelationGetRelid(rt_entry_relation) &&
+ rev->event == event)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
+ errmsg("infinite recursion detected in rules for relation \"%s\"",
+ RelationGetRelationName(rt_entry_relation))));
+ }
- foreach(n, result)
- {
- Query *pt = lfirst(n);
- List *newstuff = NIL;
+ rev = (rewrite_event *) palloc(sizeof(rewrite_event));
+ rev->relation = RelationGetRelid(rt_entry_relation);
+ rev->event = event;
+ rewrite_events = lcons(rev, rewrite_events);
- newstuff = deepRewriteQuery(pt);
- if (newstuff != NIL)
- rewritten = nconc(rewritten, newstuff);
- }
+ foreach(n, product_queries)
+ {
+ Query *pt = (Query *) lfirst(n);
+ List *newstuff;
- /* ----------
- * qual_products are the original query with the negated
- * rule qualification of an instead rule
- * ----------
- */
- if (qual_products != NIL)
- rewritten = nconc(rewritten, qual_products);
-
- /* ----------
- * The original query is appended last if not instead
- * because update and delete rule actions might not do
- * anything if they are invoked after the update or
- * delete is performed. The command counter increment
- * between the query execution makes the deleted (and
- * maybe the updated) tuples disappear so the scans
- * for them in the rule actions cannot find them.
- * ----------
- */
- if (!instead)
- rewritten = lappend(rewritten, parsetree);
+ newstuff = RewriteQuery(pt, rewrite_events);
+ rewritten = list_concat(rewritten, newstuff);
+ }
- return rewritten;
-}
+ rewrite_events = list_delete_first(rewrite_events);
+ }
+ }
+ /*
+ * If there is an INSTEAD, and the original query has a RETURNING, we
+ * have to have found a RETURNING in the rule(s), else fail. (Because
+ * DefineQueryRewrite only allows RETURNING in unconditional INSTEAD
+ * rules, there's no need to worry whether the substituted RETURNING
+ * will actually be executed --- it must be.)
+ */
+ if ((instead || qual_product != NULL) &&
+ parsetree->returningList &&
+ !returning)
+ {
+ switch (event)
+ {
+ case CMD_INSERT:
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot perform INSERT RETURNING on relation \"%s\"",
+ RelationGetRelationName(rt_entry_relation)),
+ errhint("You need an unconditional ON INSERT DO INSTEAD rule with a RETURNING clause.")));
+ break;
+ case CMD_UPDATE:
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot perform UPDATE RETURNING on relation \"%s\"",
+ RelationGetRelationName(rt_entry_relation)),
+ errhint("You need an unconditional ON UPDATE DO INSTEAD rule with a RETURNING clause.")));
+ break;
+ case CMD_DELETE:
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot perform DELETE RETURNING on relation \"%s\"",
+ RelationGetRelationName(rt_entry_relation)),
+ errhint("You need an unconditional ON DELETE DO INSTEAD rule with a RETURNING clause.")));
+ break;
+ default:
+ elog(ERROR, "unrecognized commandType: %d",
+ (int) event);
+ break;
+ }
+ }
-/*
- * QueryOneRewrite -
- * rewrite one query
- */
-static List *
-QueryRewriteOne(Query *parsetree)
-{
- numQueryRewriteInvoked = 0;
+ heap_close(rt_entry_relation, NoLock);
+ }
/*
- * take a deep breath and apply all the rewrite rules - ay
- */
- return deepRewriteQuery(parsetree);
-}
-
-
-/* ----------
- * RewritePreprocessQuery -
- * adjust details in the parsetree, the rule system
- * depends on
- * ----------
- */
-static void
-RewritePreprocessQuery(Query *parsetree)
-{
- /* ----------
- * if the query has a resultRelation, reassign the
- * result domain numbers to the attribute numbers in the
- * target relation. FixNew() depends on it when replacing
- * *new* references in a rule action by the expressions
- * from the rewritten query.
- * ----------
+ * For INSERTs, the original query is done first; for UPDATE/DELETE, it is
+ * done last. This is needed because update and delete rule actions might
+ * not do anything if they are invoked after the update or delete is
+ * performed. The command counter increment between the query executions
+ * makes the deleted (and maybe the updated) tuples disappear so the scans
+ * for them in the rule actions cannot find them.
+ *
+ * If we found any unqualified INSTEAD, the original query is not done at
+ * all, in any form. Otherwise, we add the modified form if qualified
+ * INSTEADs were found, else the unmodified form.
*/
- if (parsetree->resultRelation > 0)
+ if (!instead)
{
- RangeTblEntry *rte;
- Relation rd;
- List *tl;
- TargetEntry *tle;
- int resdomno;
-
- rte = (RangeTblEntry *) nth(parsetree->resultRelation - 1,
- parsetree->rtable);
- rd = heap_openr(rte->relname);
-
- foreach(tl, parsetree->targetList)
+ if (parsetree->commandType == CMD_INSERT)
{
- tle = (TargetEntry *) lfirst(tl);
- resdomno = attnameAttNum(rd, tle->resdom->resname);
- tle->resdom->resno = resdomno;
+ if (qual_product != NULL)
+ rewritten = lcons(qual_product, rewritten);
+ else
+ rewritten = lcons(parsetree, rewritten);
+ }
+ else
+ {
+ if (qual_product != NULL)
+ rewritten = lappend(rewritten, qual_product);
+ else
+ rewritten = lappend(rewritten, parsetree);
}
-
- heap_close(rd);
}
+
+ return rewritten;
}
/*
* QueryRewrite -
- * rewrite one query via query rewrite system, possibly returning 0
- * or many queries
+ * Primary entry point to the query rewriter.
+ * Rewrite one query via query rewrite system, possibly returning 0
+ * or many queries.
+ *
+ * NOTE: the parsetree must either have come straight from the parser,
+ * or have been scanned by AcquireRewriteLocks to acquire suitable locks.
*/
List *
QueryRewrite(Query *parsetree)
{
- List *querylist;
- List *results = NIL;
- List *l;
- Query *query;
+ List *querylist;
+ List *results;
+ ListCell *l;
+ CmdType origCmdType;
+ bool foundOriginalQuery;
+ Query *lastInstead;
/*
* Step 1
*
- * There still seems something broken with the resdom numbers
- * so we reassign them first.
+ * Apply all non-SELECT rules possibly getting 0 or many queries
*/
- RewritePreprocessQuery(parsetree);
+ querylist = RewriteQuery(parsetree, NIL);
/*
* Step 2
*
- * Apply all non-SELECT rules possibly getting 0 or many queries
+ * Apply all the RIR rules on each query
*/
- querylist = QueryRewriteOne(parsetree);
+ results = NIL;
+ foreach(l, querylist)
+ {
+ Query *query = (Query *) lfirst(l);
+
+ query = fireRIRrules(query, NIL, false);
+ results = lappend(results, query);
+ }
/*
* Step 3
*
- * Apply all the RIR rules on each query
+ * Determine which, if any, of the resulting queries is supposed to set
+ * the command-result tag; and update the canSetTag fields accordingly.
+ *
+ * If the original query is still in the list, it sets the command tag.
+ * Otherwise, the last INSTEAD query of the same kind as the original is
+ * allowed to set the tag. (Note these rules can leave us with no query
+ * setting the tag. The tcop code has to cope with this by setting up a
+ * default tag based on the original un-rewritten query.)
+ *
+ * The Asserts verify that at most one query in the result list is marked
+ * canSetTag. If we aren't checking asserts, we can fall out of the loop
+ * as soon as we find the original query.
*/
- foreach (l, querylist) {
- query = (Query *)lfirst(l);
- results = lappend(results, fireRIRrules(query));
+ origCmdType = parsetree->commandType;
+ foundOriginalQuery = false;
+ lastInstead = NULL;
+
+ foreach(l, results)
+ {
+ Query *query = (Query *) lfirst(l);
+
+ if (query->querySource == QSRC_ORIGINAL)
+ {
+ Assert(query->canSetTag);
+ Assert(!foundOriginalQuery);
+ foundOriginalQuery = true;
+#ifndef USE_ASSERT_CHECKING
+ break;
+#endif
+ }
+ else
+ {
+ Assert(!query->canSetTag);
+ if (query->commandType == origCmdType &&
+ (query->querySource == QSRC_INSTEAD_RULE ||
+ query->querySource == QSRC_QUAL_INSTEAD_RULE))
+ lastInstead = query;
+ }
}
+ if (!foundOriginalQuery && lastInstead != NULL)
+ lastInstead->canSetTag = true;
+
return results;
}
-
-
projects / postgresql / blobdiff