/*-------------------------------------------------------------------------
*
* rewriteHandler.c
+ * Primary module of query rewriter.
*
- * Copyright (c) 1994, Regents of the University of California
- *
+ * 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 1.60 1999/10/07 04:23:15 tgl Exp $
+ * src/backend/rewrite/rewriteHandler.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/heapam.h"
-#include "catalog/pg_operator.h"
+#include "access/sysattr.h"
#include "catalog/pg_type.h"
-#include "miscadmin.h"
#include "nodes/makefuncs.h"
-#include "optimizer/clauses.h"
-#include "optimizer/prep.h"
+#include "nodes/nodeFuncs.h"
#include "parser/analyze.h"
-#include "parser/parse_expr.h"
-#include "parser/parse_relation.h"
-#include "parser/parse_oper.h"
-#include "parser/parse_target.h"
-#include "parser/parse_type.h"
+#include "parser/parse_coerce.h"
#include "parser/parsetree.h"
-#include "rewrite/locks.h"
+#include "rewrite/rewriteDefine.h"
+#include "rewrite/rewriteHandler.h"
#include "rewrite/rewriteManip.h"
-#include "utils/acl.h"
+#include "utils/builtins.h"
#include "utils/lsyscache.h"
+#include "commands/trigger.h"
-extern void CheckSelectForUpdate(Query *rule_action); /* in analyze.c */
-
-
-/* macros borrowed from expression_tree_mutator */
-
-#define FLATCOPY(newnode, node, nodetype) \
- ( (newnode) = makeNode(nodetype), \
- memcpy((newnode), (node), sizeof(nodetype)) )
-
-#define MUTATE(newfield, oldfield, fieldtype, mutator, context) \
- ( (newfield) = (fieldtype) mutator((Node *) (oldfield), (context)) )
-
+/* 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 bool modifyAggrefUplevel(Node *node, void *context);
-static bool modifyAggrefChangeVarnodes(Node *node, int rt_index, int new_index,
- int sublevels_up);
-static Node *modifyAggrefDropQual(Node *node, Node *targetNode);
-static SubLink *modifyAggrefMakeSublink(Expr *origexp, Query *parsetree);
-static Node *modifyAggrefQual(Node *node, Query *parsetree);
-static bool checkQueryHasAggs(Node *node);
-static bool checkQueryHasAggs_walker(Node *node, void *context);
-static bool checkQueryHasSubLink(Node *node);
-static bool checkQueryHasSubLink_walker(Node *node, void *context);
-static Query *fireRIRrules(Query *parsetree);
-static Query *Except_Intersect_Rewrite(Query *parsetree);
-static void check_targetlists_are_compatible(List *prev_target,
- List *current_target);
-static void create_intersect_list(Node *ptr, List **intersect_list);
-static Node *intersect_tree_analyze(Node *tree, Node *first_select,
- Node *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);
+
/*
- * 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
+ * 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.)
*/
-static RewriteInfo *
-gatherRewriteMeta(Query *parsetree,
- Query *rule_action,
- Node *rule_qual,
- int rt_index,
- CmdType event,
- bool *instead_flag)
+void
+AcquireRewriteLocks(Query *parsetree, bool forUpdatePushedDown)
{
- RewriteInfo *info;
- 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
+ ListCell *l;
+ int rt_index;
+
+ /*
+ * First, process RTEs of the current query level.
+ */
+ rt_index = 0;
+ foreach(l, parsetree->rtable)
{
- 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 = nconc(info->rt, copyObject(info->rule_action->rtable));
-
- info->new_varno = PRS2_NEW_VARNO + rt_length;
- OffsetVarNodes(info->rule_action->qual, rt_length, 0);
- OffsetVarNodes((Node *) info->rule_action->targetList, rt_length, 0);
- OffsetVarNodes(info->rule_qual, rt_length, 0);
- 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);
+ RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
+ Relation rel;
+ LOCKMODE lockmode;
+ List *newaliasvars;
+ Index curinputvarno;
+ RangeTblEntry *curinputrte;
+ ListCell *ll;
- /*
- * 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;
+ ++rt_index;
+ switch (rte->rtekind)
+ {
+ case RTE_RELATION:
- 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;
-}
+ /*
+ * 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;
-/*
- * rangeTableEntry_used -
- * we need to process a RTE for RIR rules only if it is
- * referenced somewhere in var nodes of the query.
- */
+ case RTE_JOIN:
-typedef struct {
- int rt_index;
- int sublevels_up;
-} rangeTableEntry_used_context;
+ /*
+ * 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;
-static bool
-rangeTableEntry_used_walker (Node *node,
- rangeTableEntry_used_context *context)
-{
- if (node == NULL)
- return false;
- if (IsA(node, Var))
- {
- Var *var = (Var *) node;
+ case RTE_SUBQUERY:
- if (var->varlevelsup == context->sublevels_up &&
- var->varno == context->rt_index)
- return true;
- return false;
+ /*
+ * 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;
+ }
}
- if (IsA(node, SubLink))
- {
- /*
- * Standard expression_tree_walker will not recurse into subselect,
- * but here we must do so.
- */
- SubLink *sub = (SubLink *) node;
- if (rangeTableEntry_used_walker((Node *) (sub->lefthand), context))
- return true;
- if (rangeTableEntry_used((Node *) (sub->subselect),
- context->rt_index,
- context->sublevels_up + 1))
- return true;
- return false;
- }
- if (IsA(node, Query))
+ /* Recurse into subqueries in WITH */
+ foreach(l, parsetree->cteList)
{
- /* Reach here after recursing down into subselect above... */
- Query *qry = (Query *) node;
-
- if (rangeTableEntry_used_walker((Node *) (qry->targetList), context))
- return true;
- if (rangeTableEntry_used_walker((Node *) (qry->qual), context))
- return true;
- if (rangeTableEntry_used_walker((Node *) (qry->havingQual), context))
- return true;
- return false;
- }
- return expression_tree_walker(node, rangeTableEntry_used_walker,
- (void *) context);
-}
+ CommonTableExpr *cte = (CommonTableExpr *) lfirst(l);
-static bool
-rangeTableEntry_used(Node *node, int rt_index, int sublevels_up)
-{
- rangeTableEntry_used_context context;
+ AcquireRewriteLocks((Query *) cte->ctequery, false);
+ }
- context.rt_index = rt_index;
- context.sublevels_up = sublevels_up;
- return rangeTableEntry_used_walker(node, &context);
+ /*
+ * 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);
}
-
/*
- * attribute_used -
- * Check if a specific attribute number of a RTE is used
- * somewhere in the query
+ * Walker to find sublink subqueries for AcquireRewriteLocks
*/
-
-typedef struct {
- int rt_index;
- int attno;
- int sublevels_up;
-} attribute_used_context;
-
static bool
-attribute_used_walker (Node *node,
- attribute_used_context *context)
+acquireLocksOnSubLinks(Node *node, void *context)
{
if (node == NULL)
return false;
- if (IsA(node, Var))
- {
- Var *var = (Var *) node;
-
- if (var->varlevelsup == context->sublevels_up &&
- var->varno == context->rt_index &&
- var->varattno == context->attno)
- return true;
- return false;
- }
if (IsA(node, SubLink))
{
- /*
- * Standard expression_tree_walker will not recurse into subselect,
- * but here we must do so.
- */
SubLink *sub = (SubLink *) node;
- if (attribute_used_walker((Node *) (sub->lefthand), context))
- return true;
- if (attribute_used((Node *) (sub->subselect),
- context->rt_index,
- context->attno,
- context->sublevels_up + 1))
- return true;
- return false;
- }
- if (IsA(node, Query))
- {
- /* Reach here after recursing down into subselect above... */
- Query *qry = (Query *) node;
-
- if (attribute_used_walker((Node *) (qry->targetList), context))
- return true;
- if (attribute_used_walker((Node *) (qry->qual), context))
- return true;
- if (attribute_used_walker((Node *) (qry->havingQual), context))
- return true;
- return false;
+ /* Do what we came for */
+ AcquireRewriteLocks((Query *) sub->subselect, false);
+ /* Fall through to process lefthand args of SubLink */
}
- return expression_tree_walker(node, attribute_used_walker,
- (void *) context);
-}
-
-static bool
-attribute_used(Node *node, int rt_index, int attno, int sublevels_up)
-{
- attribute_used_context context;
- context.rt_index = rt_index;
- context.attno = attno;
- context.sublevels_up = sublevels_up;
- return attribute_used_walker(node, &context);
+ /*
+ * Do NOT recurse into Query nodes, because AcquireRewriteLocks already
+ * processed subselects of subselects for us.
+ */
+ return expression_tree_walker(node, acquireLocksOnSubLinks, context);
}
/*
- * modifyAggrefUplevel -
- * In the newly created sublink for an aggregate column used in
- * the qualification, we must increment the varlevelsup in all the
- * var nodes.
+ * rewriteRuleAction -
+ * Rewrite the rule action with appropriate qualifiers (taken from
+ * the triggering query).
*
- * NOTE: although this has the form of a walker, we cheat and modify the
- * Var nodes in-place. The given expression tree should have been copied
- * earlier to ensure that no unwanted side-effects occur!
+ * 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 bool
-modifyAggrefUplevel(Node *node, void *context)
+static Query *
+rewriteRuleAction(Query *parsetree,
+ Query *rule_action,
+ Node *rule_qual,
+ int rt_index,
+ CmdType event,
+ bool *returning_flag)
{
- if (node == NULL)
- return false;
- if (IsA(node, Var))
- {
- Var *var = (Var *) node;
+ int current_varno,
+ new_varno;
+ int rt_length;
+ Query *sub_action;
+ Query **sub_action_ptr;
- var->varlevelsup++;
- return false;
- }
- if (IsA(node, SubLink))
- {
- /*
- * Standard expression_tree_walker will not recurse into subselect,
- * but here we must do so.
- */
- SubLink *sub = (SubLink *) node;
+ /*
+ * 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);
- if (modifyAggrefUplevel((Node *) (sub->lefthand), context))
- return true;
- if (modifyAggrefUplevel((Node *) (sub->subselect), context))
- return true;
- return false;
- }
- if (IsA(node, Query))
- {
- /* Reach here after recursing down into subselect above... */
- Query *qry = (Query *) node;
-
- if (modifyAggrefUplevel((Node *) (qry->targetList), context))
- return true;
- if (modifyAggrefUplevel((Node *) (qry->qual), context))
- return true;
- if (modifyAggrefUplevel((Node *) (qry->havingQual), context))
- return true;
- return false;
- }
- return expression_tree_walker(node, modifyAggrefUplevel,
- (void *) context);
-}
+ /*
+ * Acquire necessary locks and fix any deleted JOIN RTE entries.
+ */
+ AcquireRewriteLocks(rule_action, false);
+ (void) acquireLocksOnSubLinks(rule_qual, NULL);
+ current_varno = rt_index;
+ rt_length = list_length(parsetree->rtable);
+ new_varno = PRS2_NEW_VARNO + rt_length;
-/*
- * modifyAggrefChangeVarnodes -
- * Change the var nodes in a sublink created for an aggregate column
- * used in the qualification to point to the correct local RTE.
- *
- * NOTE: although this has the form of a walker, we cheat and modify the
- * Var nodes in-place. The given expression tree should have been copied
- * earlier to ensure that no unwanted side-effects occur!
- */
+ /*
+ * 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);
-typedef struct {
- int rt_index;
- int new_index;
- int sublevels_up;
-} modifyAggrefChangeVarnodes_context;
+ 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);
-static bool
-modifyAggrefChangeVarnodes_walker(Node *node,
- modifyAggrefChangeVarnodes_context *context)
-{
- if (node == NULL)
- return false;
- if (IsA(node, Var))
+ /*
+ * 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);
+
+ /*
+ * 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)
{
- Var *var = (Var *) node;
+ ListCell *lc;
- if (var->varlevelsup == context->sublevels_up &&
- var->varno == context->rt_index)
+ foreach(lc, parsetree->rtable)
{
- var->varno = context->new_index;
- var->varnoold = context->new_index;
- var->varlevelsup = 0;
+ RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+
+ switch (rte->rtekind)
+ {
+ 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;
+ }
+ if (sub_action->hasSubLinks)
+ break; /* no need to keep scanning rtable */
}
- return false;
}
- if (IsA(node, SubLink))
- {
- /*
- * Standard expression_tree_walker will not recurse into subselect,
- * but here we must do so.
- */
- SubLink *sub = (SubLink *) node;
- if (modifyAggrefChangeVarnodes_walker((Node *) (sub->lefthand),
- context))
- return true;
- if (modifyAggrefChangeVarnodes((Node *) (sub->subselect),
- context->rt_index,
- context->new_index,
- context->sublevels_up + 1))
- return true;
- return false;
- }
- if (IsA(node, Query))
+ /*
+ * 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)
{
- /* Reach here after recursing down into subselect above... */
- Query *qry = (Query *) node;
-
- if (modifyAggrefChangeVarnodes_walker((Node *) (qry->targetList),
- context))
- return true;
- if (modifyAggrefChangeVarnodes_walker((Node *) (qry->qual),
- context))
- return true;
- if (modifyAggrefChangeVarnodes_walker((Node *) (qry->havingQual),
- context))
- return true;
- return false;
+ 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")));
+
+ sub_action->jointree->fromlist =
+ list_concat(newjointree, sub_action->jointree->fromlist);
+
+ /*
+ * 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);
+ }
}
- return expression_tree_walker(node, modifyAggrefChangeVarnodes_walker,
- (void *) context);
-}
-static bool
-modifyAggrefChangeVarnodes(Node *node, int rt_index, int new_index,
- int sublevels_up)
-{
- modifyAggrefChangeVarnodes_context context;
+ /*
+ * 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);
- context.rt_index = rt_index;
- context.new_index = new_index;
- context.sublevels_up = sublevels_up;
- return modifyAggrefChangeVarnodes_walker(node, &context);
-}
+ AddQual(sub_action, parsetree->jointree->quals);
+ /*
+ * 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;
+ }
-/*
- * modifyAggrefDropQual -
- * remove the pure aggref clause from a qualification
- *
- * targetNode is a boolean expression node somewhere within the given
- * expression tree. When we find it, replace it with a constant TRUE.
- * The return tree is a modified copy of the given tree; the given tree
- * is not altered.
- *
- * Note: we don't recurse into subselects looking for targetNode; that's
- * not necessary in the current usage, since in fact targetNode will be
- * within the same select level as the given toplevel node.
- */
-static Node *
-modifyAggrefDropQual(Node *node, Node *targetNode)
-{
- if (node == NULL)
- return NULL;
- if (node == targetNode)
+ /*
+ * 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)
{
- Expr *expr = (Expr *) node;
+ 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);
- if (! IsA(expr, Expr) || expr->typeOid != BOOLOID)
- elog(ERROR,
- "aggregate expression in qualification isn't of type bool");
- return (Node *) makeConst(BOOLOID, 1, (Datum) true,
- false, true, false, false);
+ /*
+ * 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);
}
- return expression_tree_mutator(node, modifyAggrefDropQual,
- (void *) targetNode);
+
+ return rule_action;
}
/*
- * modifyAggrefMakeSublink -
- * Create a sublink node for a qualification expression that
- * uses an aggregate column of a view
+ * 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 SubLink *
-modifyAggrefMakeSublink(Expr *origexp, Query *parsetree)
+static List *
+adjustJoinTreeList(Query *parsetree, bool removert, int rt_index)
{
- SubLink *sublink;
- Query *subquery;
- RangeTblEntry *rte;
- Aggref *aggref;
- Var *target;
- TargetEntry *tle;
- Resdom *resdom;
- Expr *exp = copyObject(origexp);
+ List *newjointree = copyObject(parsetree->jointree->fromlist);
+ ListCell *l;
- if (IsA(nth(0, exp->args), Aggref))
+ if (removert)
{
- if (IsA(nth(1, exp->args), Aggref))
- elog(ERROR, "rewrite: comparison of 2 aggregate columns not supported");
- else
- elog(ERROR, "rewrite: aggregate column of view must be at right side in qual");
- /* XXX could try to commute operator, instead of failing */
- }
+ foreach(l, newjointree)
+ {
+ RangeTblRef *rtr = lfirst(l);
- aggref = (Aggref *) nth(1, exp->args);
- target = (Var *) (aggref->target);
- if (! IsA(target, Var))
- elog(ERROR, "rewrite: aggregates of views only allowed on simple variables for now");
- rte = (RangeTblEntry *) nth(target->varno - 1, parsetree->rtable);
-
- resdom = makeNode(Resdom);
- resdom->resno = 1;
- resdom->restype = aggref->aggtype;
- resdom->restypmod = -1;
- resdom->resname = pstrdup("<noname>");
- resdom->reskey = 0;
- resdom->reskeyop = 0;
- resdom->resjunk = false;
-
- tle = makeNode(TargetEntry);
- tle->resdom = resdom;
- tle->expr = (Node *) aggref; /* note this is from the copied expr */
-
- sublink = makeNode(SubLink);
- sublink->subLinkType = EXPR_SUBLINK;
- sublink->useor = false;
- /* note lefthand and oper are made from the copied expr */
- sublink->lefthand = lcons(lfirst(exp->args), NIL);
- sublink->oper = lcons(exp->oper, NIL);
-
- 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->isTemp = FALSE;
- subquery->unionall = FALSE;
- subquery->uniqueFlag = NULL;
- subquery->sortClause = NULL;
- subquery->rtable = lcons(rte, NIL);
- subquery->targetList = lcons(tle, NIL);
- subquery->qual = modifyAggrefDropQual((Node *) parsetree->qual,
- (Node *) origexp);
- /*
- * If there are still aggs in the subselect's qual, give up.
- * Recursing would be a bad idea --- we'd likely produce an
- * infinite recursion. This whole technique is a crock, really...
- */
- if (checkQueryHasAggs(subquery->qual))
- elog(ERROR, "Cannot handle aggregate function inserted at this place in WHERE clause");
- subquery->groupClause = NIL;
- subquery->havingQual = NULL;
- subquery->hasAggs = TRUE;
- subquery->hasSubLinks = FALSE;
- subquery->unionClause = NULL;
-
- modifyAggrefUplevel((Node *) subquery, NULL);
- /*
- * Note: it might appear that we should be passing target->varlevelsup+1
- * here, since modifyAggrefUplevel has increased all the varlevelsup
- * values in the subquery. However, target itself is a pointer to a
- * Var node in the subquery, so it's been incremented too! What a kluge
- * this all is ... we need to make subquery RTEs so it can go away...
- */
- modifyAggrefChangeVarnodes((Node *) subquery, target->varno,
- 1, target->varlevelsup);
+ if (IsA(rtr, RangeTblRef) &&
+ rtr->rtindex == rt_index)
+ {
+ newjointree = list_delete_ptr(newjointree, rtr);
- return sublink;
+ /*
+ * foreach is safe because we exit loop after list_delete...
+ */
+ break;
+ }
+ }
+ }
+ return newjointree;
}
/*
- * modifyAggrefQual -
- * Search for qualification expressions that contain aggregate
- * functions and substitute them by sublinks. These expressions
- * originally come from qualifications that use aggregate columns
- * of a view.
+ * rewriteTargetListIU - rewrite INSERT/UPDATE targetlist into standard form
*
- * The return value is a modified copy of the given expression tree.
+ * 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 Node *
-modifyAggrefQual(Node *node, Query *parsetree)
+static void
+rewriteTargetListIU(Query *parsetree, Relation target_relation,
+ List **attrno_list)
{
- if (node == NULL)
- return NULL;
- if (IsA(node, Expr))
+ 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;
+
+ /*
+ * 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;
+
+ foreach(temp, parsetree->targetList)
{
- Expr *expr = (Expr *) node;
+ TargetEntry *old_tle = (TargetEntry *) lfirst(temp);
+
+ 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;
- if (length(expr->args) == 2 &&
- (IsA(lfirst(expr->args), Aggref) ||
- IsA(lsecond(expr->args), Aggref)))
+ /* 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
{
- SubLink *sub = modifyAggrefMakeSublink(expr,
- parsetree);
- parsetree->hasSubLinks = true;
- /* check for aggs in resulting lefthand... */
- sub->lefthand = (List *) modifyAggrefQual((Node *) sub->lefthand,
- parsetree);
- return (Node *) sub;
+ /*
+ * 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.
+ */
+
+ /* Get the resno right, but don't copy unnecessarily */
+ if (old_tle->resno != next_junk_attrno)
+ {
+ old_tle = flatCopyTargetEntry(old_tle);
+ old_tle->resno = next_junk_attrno;
+ }
+ junk_tlist = lappend(junk_tlist, old_tle);
+ next_junk_attrno++;
}
- /* otherwise, fall through and copy the expr normally */
}
- if (IsA(node, Aggref))
+
+ for (attrno = 1; attrno <= numattrs; attrno++)
{
- /* Oops, found one that's not inside an Expr we can rearrange... */
- elog(ERROR, "Cannot handle aggregate function inserted at this place in WHERE clause");
- }
- /* We do NOT recurse into subselects in this routine. It's sufficient
- * to get rid of aggregates that are in the qual expression proper.
- */
- return expression_tree_mutator(node, modifyAggrefQual,
- (void *) parsetree);
-}
+ TargetEntry *new_tle = new_tles[attrno - 1];
+ att_tup = target_relation->rd_att->attrs[attrno - 1];
-/*
- * checkQueryHasAggs -
- * Queries marked hasAggs might not have them any longer after
- * rewriting. Check it.
- */
-static bool
-checkQueryHasAggs(Node *node)
-{
- return checkQueryHasAggs_walker(node, NULL);
-}
+ /* We can (and must) ignore deleted attributes */
+ if (att_tup->attisdropped)
+ continue;
-static bool
-checkQueryHasAggs_walker(Node *node, void *context)
-{
- if (node == NULL)
- return false;
- if (IsA(node, Aggref))
- return true; /* abort the tree traversal and return true */
- return expression_tree_walker(node, checkQueryHasAggs_walker, context);
-}
+ /*
+ * 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;
-/*
- * checkQueryHasSubLink -
- * Queries marked hasSubLinks might not have them any longer after
- * rewriting. Check it.
- */
-static bool
-checkQueryHasSubLink(Node *node)
-{
- return checkQueryHasSubLink_walker(node, NULL);
-}
-
-static bool
-checkQueryHasSubLink_walker(Node *node, void *context)
-{
- if (node == NULL)
- return false;
- if (IsA(node, SubLink))
- return true; /* abort the tree traversal and return true */
- return expression_tree_walker(node, checkQueryHasSubLink_walker, context);
-}
+ new_expr = build_column_default(target_relation, attrno);
+ /*
+ * 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)
+ {
+ if (commandType == CMD_INSERT)
+ new_tle = NULL;
+ else
+ {
+ 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);
+ }
+ }
-static Node *
-FindMatchingTLEntry(List *tlist, char *e_attname)
-{
- List *i;
+ if (new_expr)
+ new_tle = makeTargetEntry((Expr *) new_expr,
+ attrno,
+ pstrdup(NameStr(att_tup->attname)),
+ false);
+ }
- foreach(i, tlist)
- {
- TargetEntry *tle = lfirst(i);
- char *resname;
+ /*
+ * 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);
+ }
- resname = tle->resdom->resname;
- if (!strcmp(e_attname, resname))
- return (tle->expr);
+ if (new_tle)
+ new_tlist = lappend(new_tlist, new_tle);
}
- return NULL;
-}
+ pfree(new_tles);
-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;
+ parsetree->targetList = list_concat(new_tlist, junk_tlist);
}
/*
- * apply_RIR_adjust_sublevel -
- * Set the varlevelsup field of all Var nodes in the given expression tree
- * to sublevels_up. We do NOT recurse into subselects.
+ * Convert a matched TLE from the original tlist into a correct new TLE.
*
- * NOTE: although this has the form of a walker, we cheat and modify the
- * Var nodes in-place. The given expression tree should have been copied
- * earlier to ensure that no unwanted side-effects occur!
+ * This routine detects and handles multiple assignments to the same target
+ * attribute. (The attribute name is needed only for error messages.)
*/
-static bool
-apply_RIR_adjust_sublevel_walker(Node *node, int *sublevels_up)
+static TargetEntry *
+process_matched_tle(TargetEntry *src_tle,
+ TargetEntry *prior_tle,
+ const char *attrName)
{
- if (node == NULL)
- return false;
- if (IsA(node, Var))
+ TargetEntry *result;
+ Node *src_expr;
+ Node *prior_expr;
+ Node *src_input;
+ Node *prior_input;
+ Node *priorbottom;
+ Node *newexpr;
+
+ if (prior_tle == NULL)
{
- Var *var = (Var *) node;
-
- var->varlevelsup = *sublevels_up;
- return false;
+ /*
+ * Normal case where this is the first assignment to the attribute.
+ */
+ return src_tle;
}
- return expression_tree_walker(node, apply_RIR_adjust_sublevel_walker,
- (void *) sublevels_up);
-}
-
-static void
-apply_RIR_adjust_sublevel(Node *node, int sublevels_up)
-{
- apply_RIR_adjust_sublevel_walker(node, &sublevels_up);
-}
+ /*----------
+ * 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)));
-/*
- * apply_RIR_view
- * Replace Vars matching a given RT index with copies of TL expressions.
- */
+ /*
+ * 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);
-typedef struct {
- int rt_index;
- int sublevels_up;
- RangeTblEntry *rte;
- List *tlist;
- int *modified;
-} apply_RIR_view_context;
+ 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)));
-static Node *
-apply_RIR_view_mutator(Node *node,
- apply_RIR_view_context *context)
-{
- if (node == NULL)
- return NULL;
- if (IsA(node, Var))
+ /*
+ * Looks OK to nest 'em.
+ */
+ if (IsA(src_expr, FieldStore))
{
- Var *var = (Var *) node;
+ FieldStore *fstore = makeNode(FieldStore);
- if (var->varlevelsup == context->sublevels_up &&
- var->varno == context->rt_index)
+ if (IsA(prior_expr, FieldStore))
{
- Node *expr;
-
- if (var->varattno < 0)
- elog(ERROR, "system column %s not available - %s is a view",
- get_attname(context->rte->relid, var->varattno),
- context->rte->relname);
-
- expr = FindMatchingTLEntry(context->tlist,
- get_attname(context->rte->relid,
- var->varattno));
- if (expr == NULL)
- {
- /* XXX shouldn't this be an error condition? */
- return make_null(var->vartype);
- }
-
- expr = copyObject(expr);
- if (var->varlevelsup > 0)
- apply_RIR_adjust_sublevel(expr, var->varlevelsup);
- *(context->modified) = true;
- return (Node *) expr;
+ /* 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;
}
- /* otherwise fall through to copy the var normally */
+ newexpr = (Node *) fstore;
}
- /*
- * Since expression_tree_mutator won't touch subselects, we have to
- * handle them specially.
- */
- if (IsA(node, SubLink))
+ else if (IsA(src_expr, ArrayRef))
{
- SubLink *sublink = (SubLink *) node;
- SubLink *newnode;
-
- FLATCOPY(newnode, sublink, SubLink);
- MUTATE(newnode->lefthand, sublink->lefthand, List *,
- apply_RIR_view_mutator, context);
- context->sublevels_up++;
- MUTATE(newnode->subselect, sublink->subselect, Node *,
- apply_RIR_view_mutator, context);
- context->sublevels_up--;
- return (Node *) newnode;
+ ArrayRef *aref = makeNode(ArrayRef);
+
+ memcpy(aref, src_expr, sizeof(ArrayRef));
+ aref->refexpr = (Expr *) prior_expr;
+ newexpr = (Node *) aref;
}
- if (IsA(node, Query))
+ else
{
- Query *query = (Query *) node;
- Query *newnode;
-
- FLATCOPY(newnode, query, Query);
- MUTATE(newnode->targetList, query->targetList, List *,
- apply_RIR_view_mutator, context);
- MUTATE(newnode->qual, query->qual, Node *,
- apply_RIR_view_mutator, context);
- MUTATE(newnode->havingQual, query->havingQual, Node *,
- apply_RIR_view_mutator, context);
- return (Node *) newnode;
+ elog(ERROR, "cannot happen");
+ newexpr = NULL;
}
- return expression_tree_mutator(node, apply_RIR_view_mutator,
- (void *) context);
+
+ result = flatCopyTargetEntry(src_tle);
+ result->expr = (Expr *) newexpr;
+ return result;
}
+/*
+ * If node is an assignment node, return its input; else return NULL
+ */
static Node *
-apply_RIR_view(Node *node, int rt_index, RangeTblEntry *rte, List *tlist,
- int *modified, int sublevels_up)
+get_assignment_input(Node *node)
{
- apply_RIR_view_context context;
+ if (node == NULL)
+ return NULL;
+ if (IsA(node, FieldStore))
+ {
+ FieldStore *fstore = (FieldStore *) node;
- context.rt_index = rt_index;
- context.sublevels_up = sublevels_up;
- context.rte = rte;
- context.tlist = tlist;
- context.modified = modified;
+ return (Node *) fstore->arg;
+ }
+ else if (IsA(node, ArrayRef))
+ {
+ ArrayRef *aref = (ArrayRef *) node;
- return apply_RIR_view_mutator(node, &context);
+ if (aref->refassgnexpr == NULL)
+ return NULL;
+ return (Node *) aref->refexpr;
+ }
+ return NULL;
}
-
-static Query *
-ApplyRetrieveRule(Query *parsetree,
- RewriteRule *rule,
- int rt_index,
- int relation_level,
- Relation relation,
- bool relWasInJoinSet,
- int *modified)
+/*
+ * 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)
{
- Query *rule_action = NULL;
- Node *rule_qual;
- List *rtable,
- *addedrtable,
- *l;
- int nothing,
- rt_length;
- int badsql = false;
-
- rule_qual = rule->qual;
- if (rule->actions)
+ 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;
+
+ /*
+ * Scan to see if relation has a default for this column.
+ */
+ if (rd_att->constr && rd_att->constr->num_defval > 0)
{
- if (length(rule->actions) > 1) /* ??? because we don't handle
- * rules with more than one
- * action? -ay */
+ AttrDefault *defval = rd_att->constr->defval;
+ int ndef = rd_att->constr->num_defval;
- return parsetree;
- rule_action = copyObject(lfirst(rule->actions));
- nothing = FALSE;
+ while (--ndef >= 0)
+ {
+ if (attrno == defval[ndef].adnum)
+ {
+ /*
+ * Found it, convert string representation to node tree.
+ */
+ expr = stringToNode(defval[ndef].adbin);
+ break;
+ }
+ }
}
- else
- nothing = TRUE;
- rtable = copyObject(parsetree->rtable);
- rt_length = length(rtable); /* original length, not counting rule */
+ if (expr == NULL)
+ {
+ /*
+ * No per-column default, so look for a default for the type itself.
+ */
+ expr = get_typdefault(atttype);
+ }
- addedrtable = copyObject(rule_action->rtable);
+ if (expr == NULL)
+ return NULL; /* No default anywhere */
- /* If the original rel wasn't in the join set, none of its spawn is.
- * If it was, then leave the spawn's flags as they are.
+ /*
+ * 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().
*/
- if (! relWasInJoinSet)
+ 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;
+}
+
+
+/* Does VALUES RTE contain any SetToDefault items? */
+static bool
+searchForDefault(RangeTblEntry *rte)
+{
+ ListCell *lc;
+
+ foreach(lc, rte->values_lists)
{
- foreach(l, addedrtable)
+ List *sublist = (List *) lfirst(lc);
+ ListCell *lc2;
+
+ foreach(lc2, sublist)
{
- RangeTblEntry *rte = lfirst(l);
- rte->inJoinSet = false;
+ Node *col = (Node *) lfirst(lc2);
+
+ if (IsA(col, SetToDefault))
+ return true;
}
}
+ return false;
+}
- rtable = nconc(rtable, addedrtable);
- parsetree->rtable = rtable;
+/*
+ * 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
+rewriteValuesRTE(RangeTblEntry *rte, Relation target_relation, List *attrnos)
+{
+ List *newValues;
+ ListCell *lc;
- /* FOR UPDATE of view... */
- foreach(l, parsetree->rowMark)
- {
- if (((RowMark *) lfirst(l))->rti == rt_index)
- break;
- }
- if (l != NULL) /* oh, hell -:) */
- {
- RowMark *newrm;
- Index rti = 1;
- List *l2;
+ /*
+ * 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 */
- CheckSelectForUpdate(rule_action);
+ /* Check list lengths (we can assume all the VALUES sublists are alike) */
+ Assert(list_length(attrnos) == list_length(linitial(rte->values_lists)));
- /*
- * We believe that rt_index is VIEW - nothing should be marked for
- * VIEW, but ACL check must be done. As for real tables of VIEW -
- * their rows must be marked, but we have to skip ACL check for
- * them.
- */
- ((RowMark *) lfirst(l))->info &= ~ROW_MARK_FOR_UPDATE;
+ newValues = NIL;
+ foreach(lc, rte->values_lists)
+ {
+ List *sublist = (List *) lfirst(lc);
+ List *newList = NIL;
+ ListCell *lc2;
+ ListCell *lc3;
- foreach(l2, rule_action->rtable)
+ forboth(lc2, sublist, lc3, attrnos)
{
+ Node *col = (Node *) lfirst(lc2);
+ int attrno = lfirst_int(lc3);
- /*
- * RTable of VIEW has two entries of VIEW itself - we use
- * relid to skip them.
- */
- if (relation->rd_id != ((RangeTblEntry *) lfirst(l2))->relid)
+ if (IsA(col, SetToDefault))
{
- newrm = makeNode(RowMark);
- newrm->rti = rti + rt_length;
- newrm->info = ROW_MARK_FOR_UPDATE;
- lnext(l) = lcons(newrm, lnext(l));
- l = lnext(l);
- }
- rti++;
- }
- }
+ Form_pg_attribute att_tup;
+ Node *new_expr;
- rule_action->rtable = rtable;
- OffsetVarNodes((Node *) rule_qual, rt_length, 0);
- OffsetVarNodes((Node *) rule_action, rt_length, 0);
+ att_tup = target_relation->rd_att->attrs[attrno - 1];
- ChangeVarNodes((Node *) rule_qual,
- PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
- ChangeVarNodes((Node *) rule_action,
- PRS2_CURRENT_VARNO + rt_length, rt_index, 0);
+ if (!att_tup->attisdropped)
+ new_expr = build_column_default(target_relation, attrno);
+ else
+ new_expr = NULL; /* force a NULL if dropped */
- if (relation_level)
- {
- RangeTblEntry *rte = (RangeTblEntry *) nth(rt_index - 1, rtable);
-
- parsetree = (Query *) apply_RIR_view((Node *) parsetree,
- rt_index, rte,
- rule_action->targetList,
- modified, 0);
- rule_action = (Query *) apply_RIR_view((Node *) rule_action,
- rt_index, rte,
- 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);
- AddGroupClause(parsetree, rule_action->groupClause,
- rule_action->targetList);
- AddHavingQual(parsetree, rule_action->havingQual);
- parsetree->hasAggs = (rule_action->hasAggs || parsetree->hasAggs);
- parsetree->hasSubLinks = (rule_action->hasSubLinks || parsetree->hasSubLinks);
+ /*
+ * 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);
+ }
+ else
+ newList = lappend(newList, col);
+ }
+ newValues = lappend(newValues, newList);
}
-
- return parsetree;
+ rte->values_lists = newValues;
}
/*
- * fireRIRonSubselect -
- * Apply fireRIRrules() to each subselect found in the given tree.
+ * rewriteTargetListUD - rewrite UPDATE/DELETE targetlist as needed
*
- * 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 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 bool
-fireRIRonSubselect(Node *node, void *context)
+static void
+rewriteTargetListUD(Query *parsetree, RangeTblEntry *target_rte,
+ Relation target_relation)
{
- if (node == NULL)
- return false;
- if (IsA(node, SubLink))
+ Var *var;
+ const char *attrname;
+ TargetEntry *tle;
+
+ if (target_relation->rd_rel->relkind == RELKIND_RELATION)
{
/*
- * Standard expression_tree_walker will not recurse into subselect,
- * but here we must do so.
+ * Emit CTID so that executor can find the row to update or delete.
*/
- SubLink *sub = (SubLink *) node;
- Query *qry;
-
- /* Process lefthand args */
- if (fireRIRonSubselect((Node *) (sub->lefthand), context))
- return true;
- /* Do what we came for */
- qry = fireRIRrules((Query *) (sub->subselect));
- sub->subselect = (Node *) qry;
- /* Must recurse to handle any sub-subselects! */
- if (fireRIRonSubselect((Node *) qry, context))
- return true;
- return false;
+ var = makeVar(parsetree->resultRelation,
+ SelfItemPointerAttributeNumber,
+ TIDOID,
+ -1,
+ InvalidOid,
+ 0);
+
+ attrname = "ctid";
}
- if (IsA(node, Query))
+ else
{
- /* Reach here after recursing down into subselect above... */
- Query *qry = (Query *) node;
-
- if (fireRIRonSubselect((Node *) (qry->targetList), context))
- return true;
- if (fireRIRonSubselect((Node *) (qry->qual), context))
- return true;
- if (fireRIRonSubselect((Node *) (qry->havingQual), context))
- return true;
- return false;
+ /*
+ * Emit whole-row Var so that executor will have the "old" view row
+ * to pass to the INSTEAD OF trigger.
+ */
+ var = makeWholeRowVar(target_rte,
+ parsetree->resultRelation,
+ 0);
+
+ attrname = "wholerow";
}
- return expression_tree_walker(node, fireRIRonSubselect,
- (void *) context);
+
+ tle = makeTargetEntry((Expr *) var,
+ list_length(parsetree->targetList) + 1,
+ pstrdup(attrname),
+ true);
+
+ parsetree->targetList = lappend(parsetree->targetList, tle);
}
/*
- * fireRIRrules -
- * Apply all RIR rules on each rangetable entry in a query
+ * matchLocks -
+ * match the list of locks and returns the matching rules
*/
-static Query *
-fireRIRrules(Query *parsetree)
+static List *
+matchLocks(CmdType event,
+ RuleLock *rulelocks,
+ int varno,
+ Query *parsetree)
{
- int rt_index;
- RangeTblEntry *rte;
- Relation rel;
- List *locks;
- RuleLock *rules;
- RewriteRule *rule;
- RewriteRule RIRonly;
- bool relWasInJoinSet;
- int modified = false;
+ List *matching_locks = NIL;
+ int nlocks;
int i;
- List *l;
-
- /* 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 < length(parsetree->rtable))
- {
- ++rt_index;
- rte = nth(rt_index - 1, parsetree->rtable);
+ if (rulelocks == NULL)
+ return NIL;
- /*
- * If the table is not one named in the original FROM clause
- * then it must be referenced in the query, or we ignore it.
- * This prevents infinite expansion loop due to new rtable
- * entries inserted by expansion of a rule.
- */
- if (! rte->inFromCl && rt_index != parsetree->resultRelation &&
- ! rangeTableEntry_used((Node *) parsetree, rt_index, 0))
- {
- /* Make sure the planner ignores it too... */
- rte->inJoinSet = false;
- continue;
- }
+ if (parsetree->commandType != CMD_SELECT)
+ {
+ if (parsetree->resultRelation != varno)
+ return NIL;
+ }
- rel = heap_openr(rte->relname, AccessShareLock);
- rules = rel->rd_rules;
- if (rules == NULL)
- {
- heap_close(rel, AccessShareLock);
- continue;
- }
+ nlocks = rulelocks->numLocks;
- relWasInJoinSet = rte->inJoinSet; /* save before possibly clearing */
+ for (i = 0; i < nlocks; i++)
+ {
+ RewriteRule *oneLock = rulelocks->rules[i];
/*
- * Collect the RIR rules that we must apply
+ * 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.
*/
- locks = NIL;
- for (i = 0; i < rules->numLocks; i++)
+ if (oneLock->event != CMD_SELECT)
{
- rule = rules->rules[i];
- if (rule->event != CMD_SELECT)
- continue;
-
- if (rule->attrno > 0)
+ if (SessionReplicationRole == SESSION_REPLICATION_ROLE_REPLICA)
{
- /* per-attr rule; do we need it? */
- if (! attribute_used((Node *) parsetree,
- rt_index,
- rule->attrno, 0))
+ if (oneLock->enabled == RULE_FIRES_ON_ORIGIN ||
+ oneLock->enabled == RULE_DISABLED)
continue;
}
- else
+ else /* ORIGIN or LOCAL ROLE */
{
- /* Rel-wide ON SELECT DO INSTEAD means this is a view.
- * Remove the view from the planner's join target set,
- * or we'll get no rows out because view itself is empty!
- */
- if (rule->isInstead)
- rte->inJoinSet = false;
+ if (oneLock->enabled == RULE_FIRES_ON_REPLICA ||
+ oneLock->enabled == RULE_DISABLED)
+ continue;
}
-
- locks = lappend(locks, rule);
}
- /*
- * Check permissions
- */
- checkLockPerms(locks, parsetree, rt_index);
-
- /*
- * Now apply them
- */
- foreach(l, locks)
+ if (oneLock->event == event)
{
- rule = lfirst(l);
-
- RIRonly.event = rule->event;
- RIRonly.attrno = rule->attrno;
- RIRonly.qual = rule->qual;
- RIRonly.actions = rule->actions;
-
- parsetree = ApplyRetrieveRule(parsetree,
- &RIRonly,
- rt_index,
- RIRonly.attrno == -1,
- rel,
- relWasInJoinSet,
- &modified);
+ 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);
}
-
- heap_close(rel, AccessShareLock);
}
- fireRIRonSubselect((Node *) parsetree, NULL);
-
- parsetree->qual = modifyAggrefQual(parsetree->qual, parsetree);
-
- return parsetree;
+ return matching_locks;
}
/*
- * idea is to fire regular rules first, then qualified instead
- * rules and unqualified instead rules last. Any lemming is counted for.
+ * ApplyRetrieveRule - expand an ON SELECT rule
*/
-static List *
-orderRules(List *locks)
+static Query *
+ApplyRetrieveRule(Query *parsetree,
+ RewriteRule *rule,
+ int rt_index,
+ bool relation_level,
+ Relation relation,
+ List *activeRIRs,
+ bool forUpdatePushedDown)
{
- List *regular = NIL;
- List *instead_rules = NIL;
- List *instead_qualified = NIL;
- List *i;
-
- foreach(i, locks)
+ 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)
{
- RewriteRule *rule_lock = (RewriteRule *) lfirst(i);
-
- if (rule_lock->isInstead)
+ /*
+ * 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)
{
- if (rule_lock->qual == NULL)
- instead_rules = lappend(instead_rules, rule_lock);
- else
- instead_qualified = lappend(instead_qualified, rule_lock);
+ RangeTblEntry *newrte;
+
+ rte = rt_fetch(rt_index, parsetree->rtable);
+ newrte = copyObject(rte);
+ parsetree->rtable = lappend(parsetree->rtable, newrte);
+ parsetree->resultRelation = list_length(parsetree->rtable);
+
+ /*
+ * 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;
+
+ /*
+ * 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);
+
+ /* Now, continue with expanding the original view RTE */
}
else
- regular = lappend(regular, rule_lock);
+ elog(ERROR, "unrecognized commandType: %d",
+ (int) parsetree->commandType);
}
- regular = nconc(regular, instead_qualified);
- return nconc(regular, instead_rules);
-}
+ /*
+ * 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));
-static Query *
-CopyAndAddQual(Query *parsetree,
- List *actions,
- 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 = nconc(rtable, copyObject(rule_action->rtable));
- new_tree->rtable = rtable;
- OffsetVarNodes(new_qual, rt_length, 0);
- 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);
+ AcquireRewriteLocks(rule_action, forUpdatePushedDown);
- return new_tree;
-}
+ /*
+ * Recursively expand any view references inside the view.
+ */
+ rule_action = fireRIRrules(rule_action, activeRIRs, forUpdatePushedDown);
+ /*
+ * Now, plug the view query in as a subselect, replacing the relation's
+ * original RTE.
+ */
+ rte = rt_fetch(rt_index, parsetree->rtable);
+ rte->rtekind = RTE_SUBQUERY;
+ rte->relid = InvalidOid;
+ rte->subquery = rule_action;
+ rte->inh = false; /* must not be set for a subquery */
-/*
- * 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.
+ /*
+ * 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;
+
+ /*
+ * 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);
+
+ return parsetree;
+}
+
+/*
+ * Recursively mark all relations used by a view as FOR UPDATE/SHARE.
*
- * remember: reality is for dead birds -- glass
+ * 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 List *
-fireRules(Query *parsetree,
- int rt_index,
- CmdType event,
- bool *instead_flag,
- List *locks,
- List **qual_products)
+static void
+markQueryForLocking(Query *qry, Node *jtnode,
+ bool forUpdate, bool noWait, bool pushedDown)
{
- RewriteInfo *info;
- List *results = NIL;
- List *i;
-
- /* choose rule to fire from list of rules */
- if (locks == NIL)
- return NIL;
-
- locks = orderRules(locks); /* real instead rules last */
- foreach(i, locks)
+ if (jtnode == NULL)
+ return;
+ if (IsA(jtnode, RangeTblRef))
{
- RewriteRule *rule_lock = (RewriteRule *) lfirst(i);
- Node *qual,
- *event_qual;
- List *actions;
- List *r;
+ int rti = ((RangeTblRef *) jtnode)->rtindex;
+ RangeTblEntry *rte = rt_fetch(rti, qry->rtable);
- /*
- * 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)
+ if (rte->rtekind == RTE_RELATION)
{
- RangeTblEntry *rte;
- int32 acl_rc;
- int32 reqperm;
-
- switch (parsetree->commandType)
+ /* ignore foreign tables */
+ if (get_rel_relkind(rte->relid) != RELKIND_FOREIGN_TABLE)
{
- case CMD_INSERT:
- reqperm = ACL_AP;
- break;
- default:
- reqperm = ACL_WR;
- break;
- }
-
- rte = (RangeTblEntry *) nth(parsetree->resultRelation - 1,
- parsetree->rtable);
- if (!rte->skipAcl)
- {
- acl_rc = pg_aclcheck(rte->relname,
- GetPgUserName(), reqperm);
- if (acl_rc != ACLCHECK_OK)
- {
- elog(ERROR, "%s: %s",
- rte->relname,
- aclcheck_error_strings[acl_rc]);
- }
+ applyLockingClause(qry, rti, forUpdate, noWait, pushedDown);
+ rte->requiredPerms |= ACL_SELECT_FOR_UPDATE;
}
}
-
- /* multiple rule action time */
- *instead_flag = rule_lock->isInstead;
- event_qual = rule_lock->qual;
- actions = rule_lock->actions;
- if (event_qual != NULL && *instead_flag)
+ else if (rte->rtekind == RTE_SUBQUERY)
{
- 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
- * list after we mangled it up enough.
- * ----------
- */
- 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);
+ 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;
- foreach(r, actions)
- {
- Query *rule_action = lfirst(r);
- Node *rule_qual = copyObject(event_qual);
-
- if (rule_action->commandType == CMD_NOTHING)
- continue;
-
- /*--------------------------------------------------
- * We copy the qualifications of the parsetree
- * to the action and vice versa. So force
- * hasSubLinks if one of them has it.
- *
- * As of 6.4 only parsetree qualifications can
- * have sublinks. If this changes, we must make
- * this a node lookup at the end of rewriting.
- *
- * Jan
- *--------------------------------------------------
- */
- if (parsetree->hasSubLinks && !rule_action->hasSubLinks)
- {
- rule_action = copyObject(rule_action);
- rule_action->hasSubLinks = TRUE;
- }
- if (!parsetree->hasSubLinks && rule_action->hasSubLinks)
- parsetree->hasSubLinks = TRUE;
-
- /*--------------------------------------------------
- * 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);
-
- /*--------------------------------------------------
- * 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);
-
- pfree(info);
- }
+ foreach(l, f->fromlist)
+ markQueryForLocking(qry, lfirst(l), forUpdate, noWait, pushedDown);
+ }
+ else if (IsA(jtnode, JoinExpr))
+ {
+ JoinExpr *j = (JoinExpr *) jtnode;
- /* ----------
- * If this was an unqualified instead rule,
- * throw away an eventually saved 'default' parsetree
- * ----------
- */
- if (event_qual == NULL && *instead_flag)
- *qual_products = NIL;
+ markQueryForLocking(qry, j->larg, forUpdate, noWait, pushedDown);
+ markQueryForLocking(qry, j->rarg, forUpdate, noWait, pushedDown);
}
- return results;
+ else
+ elog(ERROR, "unrecognized node type: %d",
+ (int) nodeTag(jtnode));
}
-
-static List *
-RewriteQuery(Query *parsetree, bool *instead_flag, List **qual_products)
+/*
+ * 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)
{
- 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;
+ if (node == NULL)
+ return false;
+ if (IsA(node, SubLink))
+ {
+ SubLink *sub = (SubLink *) node;
- /*
- * Utilities aren't rewritten at all - why is this here?
- */
- if (event == CMD_UTILITY)
- return NIL;
+ /* Do what we came for */
+ sub->subselect = (Node *) fireRIRrules((Query *) sub->subselect,
+ activeRIRs, false);
+ /* Fall through to process lefthand args of SubLink */
+ }
/*
- * the statement is an update, insert or delete - fire rules on it.
+ * Do NOT recurse into Query nodes, because fireRIRrules already processed
+ * subselects of subselects for us.
*/
- result_relation = parsetree->resultRelation;
- rt_entry = rt_fetch(result_relation, parsetree->rtable);
- rt_entry_relation = heap_openr(rt_entry->relname, AccessShareLock);
- rt_entry_locks = rt_entry_relation->rd_rules;
- heap_close(rt_entry_relation, AccessShareLock);
-
- 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);
- }
-
- return product_queries;
+ return expression_tree_walker(node, fireRIRonSubLink,
+ (void *) activeRIRs);
}
/*
- * 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
-
-static int numQueryRewriteInvoked = 0;
-
-/*
- * deepRewriteQuery -
- * rewrites the query and apply the rules again on the queries rewritten
+ * fireRIRrules -
+ * Apply all RIR rules on each rangetable entry in a query
*/
-static List *
-deepRewriteQuery(Query *parsetree)
+static Query *
+fireRIRrules(Query *parsetree, List *activeRIRs, bool forUpdatePushedDown)
{
- List *n;
- List *rewritten = NIL;
- List *result = NIL;
- bool instead;
- List *qual_products = NIL;
-
-
+ int origResultRelation = parsetree->resultRelation;
+ int rt_index;
+ ListCell *lc;
- if (++numQueryRewriteInvoked > REWRITE_INVOKE_MAX)
+ /*
+ * 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))
{
- elog(ERROR, "query rewritten %d times, may contain cycles",
- numQueryRewriteInvoked - 1);
- }
-
- instead = FALSE;
- result = RewriteQuery(parsetree, &instead, &qual_products);
+ RangeTblEntry *rte;
+ Relation rel;
+ List *locks;
+ RuleLock *rules;
+ RewriteRule *rule;
+ int i;
- foreach(n, result)
- {
- Query *pt = lfirst(n);
- List *newstuff = NIL;
+ ++rt_index;
- newstuff = deepRewriteQuery(pt);
- if (newstuff != NIL)
- rewritten = nconc(rewritten, newstuff);
- }
+ rte = rt_fetch(rt_index, parsetree->rtable);
- /* ----------
- * 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);
+ /*
+ * 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;
+ }
- return rewritten;
-}
+ /*
+ * 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;
-/*
- * QueryOneRewrite -
- * rewrite one query
- */
-static List *
-QueryRewriteOne(Query *parsetree)
-{
- numQueryRewriteInvoked = 0;
+ /*
+ * 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;
- /*
- * take a deep breath and apply all the rewrite rules - ay
- */
- return deepRewriteQuery(parsetree);
-}
+ /*
+ * 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
+ */
+ 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;
-/* ----------
- * 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.
- * resjunk targets are somewhat arbitrarily given a resno of 0;
- * this is to prevent FixNew() from matching them to var nodes.
- * ----------
- */
- if (parsetree->resultRelation > 0)
- {
- RangeTblEntry *rte;
- Relation rd;
- List *tl;
+ if (rule->attrno > 0)
+ {
+ /* per-attr rule; do we need it? */
+ if (!attribute_used((Node *) parsetree, rt_index,
+ rule->attrno, 0))
+ continue;
+ }
- rte = (RangeTblEntry *) nth(parsetree->resultRelation - 1,
- parsetree->rtable);
- rd = heap_openr(rte->relname, AccessShareLock);
+ locks = lappend(locks, rule);
+ }
- foreach(tl, parsetree->targetList)
+ /*
+ * If we found any, apply them --- but first check for recursion!
+ */
+ if (locks != NIL)
{
- TargetEntry *tle = (TargetEntry *) lfirst(tl);
+ ListCell *l;
- if (! tle->resdom->resjunk)
- tle->resdom->resno = attnameAttNum(rd, tle->resdom->resname);
- else
- tle->resdom->resno = 0;
- }
+ 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);
- heap_close(rd, AccessShareLock);
- }
-}
+ foreach(l, locks)
+ {
+ rule = lfirst(l);
+
+ parsetree = ApplyRetrieveRule(parsetree,
+ rule,
+ rt_index,
+ rule->attrno == -1,
+ rel,
+ activeRIRs,
+ forUpdatePushedDown);
+ }
+ activeRIRs = list_delete_first(activeRIRs);
+ }
-/*
- * BasicQueryRewrite -
- * rewrite one query via query rewrite system, possibly returning 0
- * or many queries
- */
-static List *
-BasicQueryRewrite(Query *parsetree)
-{
- List *querylist;
- List *results = NIL;
- List *l;
- Query *query;
+ heap_close(rel, NoLock);
+ }
- /*
- * Step 1
- *
- * There still seems something broken with the resdom numbers so we
- * reassign them first.
- */
- RewritePreprocessQuery(parsetree);
+ /* Recurse into subqueries in WITH */
+ foreach(lc, parsetree->cteList)
+ {
+ CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
- /*
- * Step 2
- *
- * Apply all non-SELECT rules possibly getting 0 or many queries
- */
- querylist = QueryRewriteOne(parsetree);
+ cte->ctequery = (Node *)
+ fireRIRrules((Query *) cte->ctequery, activeRIRs, false);
+ }
/*
- * Step 3
- *
- * Apply all the RIR rules on each query
+ * Recurse into sublink subqueries, too. But we already did the ones in
+ * the rtable and cteList.
*/
- foreach(l, querylist)
- {
- query = fireRIRrules((Query *) lfirst(l));
+ if (parsetree->hasSubLinks)
+ query_tree_walker(parsetree, fireRIRonSubLink, (void *) activeRIRs,
+ QTW_IGNORE_RC_SUBQUERIES);
- /*
- * If the query was marked having aggregates, check if this is
- * still true after rewriting. This check must get expanded when
- * someday aggregates can appear somewhere else than in the
- * targetlist or the having qual.
- */
- if (query->hasAggs)
- query->hasAggs = checkQueryHasAggs((Node *) (query->targetList))
- || checkQueryHasAggs((Node *) (query->havingQual));
- query->hasSubLinks = checkQueryHasSubLink((Node *) (query->qual))
- || checkQueryHasSubLink((Node *) (query->havingQual));
- results = lappend(results, query);
- }
- return results;
+ return parsetree;
}
+
/*
- * QueryRewrite -
- * Primary entry point to the query rewriter.
- * Rewrite one query via query rewrite system, possibly returning 0
- * or many queries.
+ * 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.)
*
- * NOTE: The code in QueryRewrite was formerly in pg_parse_and_plan(), and was
- * moved here so that it would be invoked during EXPLAIN. The division of
- * labor between this routine and BasicQueryRewrite is not obviously correct
- * ... at least not to me ... tgl 5/99.
+ * 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.
*/
-List *
-QueryRewrite(Query *parsetree)
+static Query *
+CopyAndAddInvertedQual(Query *parsetree,
+ Node *rule_qual,
+ int rt_index,
+ CmdType event)
{
- List *rewritten,
- *rewritten_item;
+ /* Don't scribble on the passed qual (it's in the relcache!) */
+ Node *new_qual = (Node *) copyObject(rule_qual);
/*
- * Rewrite Union, Intersect and Except Queries to normal Union Queries
- * using IN and NOT IN subselects
+ * 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.)
*/
- if (parsetree->intersectClause)
- parsetree = Except_Intersect_Rewrite(parsetree);
+ (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);
- /* Rewrite basic queries (retrieve, append, delete, replace) */
- rewritten = BasicQueryRewrite(parsetree);
-
- /*
- * Rewrite the UNIONS.
- */
- foreach(rewritten_item, rewritten)
- {
- Query *qry = (Query *) lfirst(rewritten_item);
- List *union_result = NIL;
- List *union_item;
-
- foreach(union_item, qry->unionClause)
- {
- union_result = nconc(union_result,
- BasicQueryRewrite((Query *) lfirst(union_item)));
- }
- qry->unionClause = union_result;
- }
-
- return rewritten;
+ return parsetree;
}
-/* This function takes two targetlists as arguments and checks if the
- * targetlists are compatible (i.e. both select for the same number of
- * attributes and the types are compatible */
-static void
-check_targetlists_are_compatible(List *prev_target, List *current_target)
-{
- List *tl,
- *next_target;
- int prev_len = 0,
- next_len = 0;
-
- foreach(tl, prev_target)
- if (!((TargetEntry *) lfirst(tl))->resdom->resjunk)
- prev_len++;
- foreach(next_target, current_target)
- if (!((TargetEntry *) lfirst(next_target))->resdom->resjunk)
- next_len++;
-
- if (prev_len != next_len)
- elog(ERROR, "Each UNION | EXCEPT | INTERSECT query must have the same number of columns.");
+/*
+ * fireRules -
+ * Iterate through rule locks applying rules.
+ *
+ * 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,
+ List *locks,
+ bool *instead_flag,
+ bool *returning_flag,
+ Query **qual_product)
+{
+ List *results = NIL;
+ ListCell *l;
- foreach(next_target, current_target)
+ foreach(l, locks)
{
- Oid itype;
- Oid otype;
-
- otype = ((TargetEntry *) lfirst(prev_target))->resdom->restype;
- itype = ((TargetEntry *) lfirst(next_target))->resdom->restype;
+ RewriteRule *rule_lock = (RewriteRule *) lfirst(l);
+ Node *event_qual = rule_lock->qual;
+ List *actions = rule_lock->actions;
+ QuerySource qsrc;
+ ListCell *r;
- /* one or both is a NULL column? then don't convert... */
- if (otype == InvalidOid)
+ /* Determine correct QuerySource value for actions */
+ if (rule_lock->isInstead)
{
- /* propagate a known type forward, if available */
- if (itype != InvalidOid)
- ((TargetEntry *) lfirst(prev_target))->resdom->restype = itype;
-#ifdef NOT_USED
+ if (event_qual != NULL)
+ qsrc = QSRC_QUAL_INSTEAD_RULE;
else
{
- ((TargetEntry *) lfirst(prev_target))->resdom->restype = UNKNOWNOID;
- ((TargetEntry *) lfirst(next_target))->resdom->restype = UNKNOWNOID;
+ qsrc = QSRC_INSTEAD_RULE;
+ *instead_flag = true; /* report unqualified INSTEAD */
}
-#endif
- }
- else if (itype == InvalidOid)
- {
}
- /* they don't match in type? then convert... */
- else if (itype != otype)
- {
- Node *expr;
+ else
+ qsrc = QSRC_NON_INSTEAD_RULE;
- expr = ((TargetEntry *) lfirst(next_target))->expr;
- expr = CoerceTargetExpr(NULL, expr, itype, otype);
- if (expr == NULL)
+ if (qsrc == QSRC_QUAL_INSTEAD_RULE)
+ {
+ /*
+ * 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 (!*instead_flag)
{
- elog(ERROR, "Unable to transform %s to %s"
- "\n\tEach UNION | EXCEPT | INTERSECT clause must have compatible target types",
- typeidTypeName(itype),
- typeidTypeName(otype));
+ if (*qual_product == NULL)
+ *qual_product = copyObject(parsetree);
+ *qual_product = CopyAndAddInvertedQual(*qual_product,
+ event_qual,
+ rt_index,
+ event);
}
- ((TargetEntry *) lfirst(next_target))->expr = expr;
- ((TargetEntry *) lfirst(next_target))->resdom->restype = otype;
}
- /* both are UNKNOWN? then evaluate as text... */
- else if (itype == UNKNOWNOID)
+ /* Now process the rule's actions and add them to the result list */
+ foreach(r, actions)
{
- ((TargetEntry *) lfirst(next_target))->resdom->restype = TEXTOID;
- ((TargetEntry *) lfirst(prev_target))->resdom->restype = TEXTOID;
- }
- prev_target = lnext(prev_target);
- }
-}
-
-/* Rewrites UNION INTERSECT and EXCEPT queries to semantiacally equivalent
- * queries that use IN and NOT IN subselects.
- *
- * The operator tree is attached to 'intersectClause' (see rule
- * 'SelectStmt' in gram.y) of the 'parsetree' given as an
- * argument. First we remember some clauses (the sortClause, the
- * unique flag etc.) Then we translate the operator tree to DNF
- * (disjunctive normal form) by 'cnfify'. (Note that 'cnfify' produces
- * CNF but as we exchanged ANDs with ORs in function A_Expr_to_Expr()
- * earlier we get DNF after exchanging ANDs and ORs again in the
- * result.) Now we create a new query by evaluating the new operator
- * tree which is in DNF now. For every AND we create an entry in the
- * union list and for every OR we create an IN subselect. (NOT IN
- * subselects are created for OR NOT nodes). The first entry of the
- * union list is handed back but before that the remembered clauses
- * (sortClause etc) are attached to the new top Node (Note that the
- * new top Node can differ from the parsetree given as argument because of
- * the translation to DNF. That's why we have to remember the sortClause or
- * unique flag!) */
-static Query *
-Except_Intersect_Rewrite(Query *parsetree)
-{
-
- SubLink *n;
- Query *result,
- *intersect_node;
- List *elist,
- *intersect_list = NIL,
- *intersect,
- *intersectClause;
- List *union_list = NIL,
- *sortClause;
- List *left_expr,
- *right_expr,
- *resnames = NIL;
- char *op,
- *uniqueFlag,
- *into;
- bool isBinary,
- isPortal,
- isTemp;
- CmdType commandType = CMD_SELECT;
- List *rtable_insert = NIL;
-
- List *prev_target = NIL;
+ Query *rule_action = lfirst(r);
- /*
- * Remember the Resnames of the given parsetree's targetlist (these
- * are the resnames of the first Select Statement of the query
- * formulated by the user and he wants the columns named by these
- * strings. The transformation to DNF can cause another Select
- * Statment to be the top one which uses other names for its columns.
- * Therefore we remeber the original names and attach them to the
- * targetlist of the new topmost Node at the end of this function
- */
- foreach(elist, parsetree->targetList)
- {
- TargetEntry *tent = (TargetEntry *) lfirst(elist);
+ if (rule_action->commandType == CMD_NOTHING)
+ continue;
- resnames = lappend(resnames, tent->resdom->resname);
- }
+ rule_action = rewriteRuleAction(parsetree, rule_action,
+ event_qual, rt_index, event,
+ returning_flag);
- /*
- * If the Statement is an INSERT INTO ... (SELECT...) statement using
- * UNIONs, INTERSECTs or EXCEPTs and the transformation to DNF makes
- * another Node to the top node we have to transform the new top node
- * to an INSERT node and the original INSERT node to a SELECT node
- */
- if (parsetree->commandType == CMD_INSERT)
- {
- parsetree->commandType = CMD_SELECT;
- commandType = CMD_INSERT;
- parsetree->resultRelation = 0;
+ rule_action->querySource = qsrc;
+ rule_action->canSetTag = false; /* might change later */
- /*
- * The result relation ( = the one to insert into) has to be
- * attached to the rtable list of the new top node
- */
- rtable_insert = nth(length(parsetree->rtable) - 1, parsetree->rtable);
+ results = lappend(results, rule_action);
+ }
}
- /*
- * Save some items, to be able to attach them to the resulting top
- * node at the end of the function
- */
- sortClause = parsetree->sortClause;
- uniqueFlag = parsetree->uniqueFlag;
- into = parsetree->into;
- isBinary = parsetree->isBinary;
- isPortal = parsetree->isPortal;
- isTemp = parsetree->isTemp;
-
- /*
- * The operator tree attached to parsetree->intersectClause is still
- * 'raw' ( = the leaf nodes are still SelectStmt nodes instead of
- * Query nodes) So step through the tree and transform the nodes using
- * parse_analyze().
- *
- * The parsetree (given as an argument to Except_Intersect_Rewrite()) has
- * already been transformed and transforming it again would cause
- * troubles. So we give the 'raw' version (of the cooked parsetree)
- * to the function to prevent an additional transformation. Instead we
- * hand back the 'cooked' version also given as an argument to
- * intersect_tree_analyze()
- */
- intersectClause =
- (List *) intersect_tree_analyze((Node *) parsetree->intersectClause,
- (Node *) lfirst(parsetree->unionClause),
- (Node *) parsetree);
+ return results;
+}
- /* intersectClause is no longer needed so set it to NIL */
- parsetree->intersectClause = NIL;
- /*
- * unionClause will be needed later on but the list it delivered is no
- * longer needed, so set it to NIL
- */
- parsetree->unionClause = NIL;
+/*
+ * 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, List *rewrite_events)
+{
+ CmdType event = parsetree->commandType;
+ bool instead = false;
+ bool returning = false;
+ Query *qual_product = NULL;
+ List *rewritten = NIL;
/*
- * Transform the operator tree to DNF (remember ANDs and ORs have been
- * exchanged, that's why we get DNF by using cnfify)
+ * If the statement is an insert, update, or delete, adjust its targetlist
+ * as needed, and then fire INSERT/UPDATE/DELETE rules on it.
*
- * After the call, explicit ANDs are removed and all AND operands are
- * simply items in the intersectClause list
+ * 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?)
*/
- intersectClause = cnfify((Expr *) intersectClause, true);
-
- /*
- * For every entry of the intersectClause list we generate one entry
- * in the union_list
- */
- foreach(intersect, intersectClause)
+ if (event != CMD_SELECT && event != CMD_UTILITY)
{
+ int result_relation;
+ RangeTblEntry *rt_entry;
+ Relation rt_entry_relation;
+ List *locks;
- /*
- * for every OR we create an IN subselect and for every OR NOT we
- * create a NOT IN subselect, so first extract all the Select
- * Query nodes from the tree (that contains only OR or OR NOTs any
- * more because we did a transformation to DNF
- *
- * There must be at least one node that is not negated (i.e. just OR
- * and not OR NOT) and this node will be the first in the list
- * returned
- */
- intersect_list = NIL;
- create_intersect_list((Node *) lfirst(intersect), &intersect_list);
-
- /*
- * This one will become the Select Query node, all other nodes are
- * transformed into subselects under this node!
- */
- intersect_node = (Query *) lfirst(intersect_list);
- intersect_list = lnext(intersect_list);
+ result_relation = parsetree->resultRelation;
+ Assert(result_relation != 0);
+ rt_entry = rt_fetch(result_relation, parsetree->rtable);
+ Assert(rt_entry->rtekind == RTE_RELATION);
/*
- * Check if all Select Statements use the same number of
- * attributes and if all corresponding attributes are of the same
- * type
+ * We can use NoLock here since either the parser or
+ * AcquireRewriteLocks should have locked the rel already.
*/
- if (prev_target)
- check_targetlists_are_compatible(prev_target, intersect_node->targetList);
- prev_target = intersect_node->targetList;
- /* End of check for corresponding targetlists */
+ rt_entry_relation = heap_open(rt_entry->relid, NoLock);
/*
- * Transform all nodes remaining into subselects and add them to
- * the qualifications of the Select Query node
+ * Rewrite the targetlist as needed for the command type.
*/
- while (intersect_list != NIL)
+ if (event == CMD_INSERT)
{
+ RangeTblEntry *values_rte = NULL;
- n = makeNode(SubLink);
-
- /* Here we got an OR so transform it to an IN subselect */
- if (IsA(lfirst(intersect_list), Query))
+ /*
+ * 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);
- /*
- * Check if all Select Statements use the same number of
- * attributes and if all corresponding attributes are of
- * the same type
- */
- check_targetlists_are_compatible(prev_target,
- ((Query *) lfirst(intersect_list))->targetList);
- /* End of check for corresponding targetlists */
-
- n->subselect = lfirst(intersect_list);
- op = "=";
- n->subLinkType = ANY_SUBLINK;
- n->useor = false;
+ if (IsA(rtr, RangeTblRef))
+ {
+ RangeTblEntry *rte = rt_fetch(rtr->rtindex,
+ parsetree->rtable);
+
+ if (rte->rtekind == RTE_VALUES)
+ values_rte = rte;
+ }
}
- /*
- * Here we got an OR NOT node so transform it to a NOT IN
- * subselect
- */
- else
+ if (values_rte)
{
+ List *attrnos;
- /*
- * Check if all Select Statements use the same number of
- * attributes and if all corresponding attributes are of
- * the same type
- */
- check_targetlists_are_compatible(prev_target,
- ((Query *) lfirst(((Expr *) lfirst(intersect_list))->args))->targetList);
- /* End of check for corresponding targetlists */
-
- n->subselect = (Node *) lfirst(((Expr *) lfirst(intersect_list))->args);
- op = "<>";
- n->subLinkType = ALL_SUBLINK;
- n->useor = true;
+ /* 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);
+
+ /*
+ * 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);
/*
- * Prepare the lefthand side of the Sublinks: All the entries
- * of the targetlist must be (IN) or must not be (NOT IN) the
- * subselect
+ * If we got any product queries, recursively rewrite them --- but
+ * first check for recursion!
*/
- n->lefthand = NIL;
- foreach(elist, intersect_node->targetList)
+ if (product_queries != NIL)
{
- TargetEntry *tent = (TargetEntry *) lfirst(elist);
+ ListCell *n;
+ rewrite_event *rev;
- n->lefthand = lappend(n->lefthand, tent->expr);
- }
+ 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))));
+ }
- /*
- * Also prepare the list of Opers that must be used for the
- * comparisons (they depend on the specific datatypes involved!)
- */
- left_expr = n->lefthand;
- right_expr = ((Query *) (n->subselect))->targetList;
- n->oper = NIL;
+ rev = (rewrite_event *) palloc(sizeof(rewrite_event));
+ rev->relation = RelationGetRelid(rt_entry_relation);
+ rev->event = event;
+ rewrite_events = lcons(rev, rewrite_events);
- foreach(elist, left_expr)
- {
- Node *lexpr = lfirst(elist);
- TargetEntry *tent = (TargetEntry *) lfirst(right_expr);
- Operator optup;
- Form_pg_operator opform;
- Oper *newop;
-
- optup = oper(op,
- exprType(lexpr),
- exprType(tent->expr),
- FALSE);
- opform = (Form_pg_operator) GETSTRUCT(optup);
-
- if (opform->oprresult != BOOLOID)
- elog(ERROR, "parser: '%s' must return 'bool' to be used with quantified predicate subquery", op);
-
- newop = makeOper(oprid(optup),/* opno */
- InvalidOid, /* opid */
- opform->oprresult,
- 0,
- NULL);
-
- n->oper = lappend(n->oper, newop);
-
- right_expr = lnext(right_expr);
- }
+ foreach(n, product_queries)
+ {
+ Query *pt = (Query *) lfirst(n);
+ List *newstuff;
- /*
- * If the Select Query node has aggregates in use add all the
- * subselects to the HAVING qual else to the WHERE qual
- */
- if (intersect_node->hasAggs)
- AddHavingQual(intersect_node, (Node *) n);
- else
- AddQual(intersect_node, (Node *) n);
+ newstuff = RewriteQuery(pt, rewrite_events);
+ rewritten = list_concat(rewritten, newstuff);
+ }
- /* Now we got sublinks */
- intersect_node->hasSubLinks = true;
- intersect_list = lnext(intersect_list);
+ rewrite_events = list_delete_first(rewrite_events);
+ }
}
- intersect_node->intersectClause = NIL;
- union_list = lappend(union_list, intersect_node);
- }
- /* The first entry to union_list is our new top node */
- result = (Query *) lfirst(union_list);
- /* attach the rest to unionClause */
- result->unionClause = lnext(union_list);
- /* Attach all the items remembered in the beginning of the function */
- result->sortClause = sortClause;
- result->uniqueFlag = uniqueFlag;
- result->into = into;
- result->isPortal = isPortal;
- result->isBinary = isBinary;
- result->isTemp = isTemp;
+ /*
+ * 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;
+ }
+ }
- /*
- * The relation to insert into is attached to the range table of the
- * new top node
- */
- if (commandType == CMD_INSERT)
- {
- result->rtable = lappend(result->rtable, rtable_insert);
- result->resultRelation = length(result->rtable);
- result->commandType = commandType;
+ heap_close(rt_entry_relation, NoLock);
}
/*
- * The resnames of the originally first SelectStatement are attached
- * to the new first SelectStatement
+ * 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.
*/
- foreach(elist, result->targetList)
+ if (!instead)
{
- TargetEntry *tent = (TargetEntry *) lfirst(elist);
-
- tent->resdom->resname = lfirst(resnames);
- resnames = lnext(resnames);
+ if (parsetree->commandType == CMD_INSERT)
+ {
+ 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);
+ }
}
- return result;
+
+ return rewritten;
}
-/* Create a list of nodes that are either Query nodes of NOT Expr
- * nodes followed by a Query node. The tree given in ptr contains at
- * least one non negated Query node. This node is attached to the
- * beginning of the list */
-static void
-create_intersect_list(Node *ptr, List **intersect_list)
+/*
+ * QueryRewrite -
+ * 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 *arg;
+ List *querylist;
+ List *results;
+ ListCell *l;
+ CmdType origCmdType;
+ bool foundOriginalQuery;
+ Query *lastInstead;
- if (IsA(ptr, Query))
- {
- /* The non negated node is attached at the beginning (lcons) */
- *intersect_list = lcons(ptr, *intersect_list);
- return;
- }
+ /*
+ * Step 1
+ *
+ * Apply all non-SELECT rules possibly getting 0 or many queries
+ */
+ querylist = RewriteQuery(parsetree, NIL);
- if (IsA(ptr, Expr))
+ /*
+ * Step 2
+ *
+ * Apply all the RIR rules on each query
+ */
+ results = NIL;
+ foreach(l, querylist)
{
- if (((Expr *) ptr)->opType == NOT_EXPR)
- {
- /* negated nodes are appended to the end (lappend) */
- *intersect_list = lappend(*intersect_list, ptr);
- return;
- }
- else
- {
- foreach(arg, ((Expr *) ptr)->args)
- create_intersect_list(lfirst(arg), intersect_list);
- return;
- }
- return;
+ Query *query = (Query *) lfirst(l);
+
+ query = fireRIRrules(query, NIL, false);
+ results = lappend(results, query);
}
-}
-/* The nodes given in 'tree' are still 'raw' so 'cook' them using parse_analyze().
- * The node given in first_select has already been cooked, so don't transform
- * it again but return a pointer to the previously cooked version given in 'parsetree'
- * instead. */
-static Node *
-intersect_tree_analyze(Node *tree, Node *first_select, Node *parsetree)
-{
- Node *result = (Node *) NIL;
- List *arg;
+ /*
+ * Step 3
+ *
+ * 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.
+ */
+ origCmdType = parsetree->commandType;
+ foundOriginalQuery = false;
+ lastInstead = NULL;
- if (IsA(tree, SelectStmt))
+ foreach(l, results)
{
+ Query *query = (Query *) lfirst(l);
- /*
- * If we get to the tree given in first_select return parsetree
- * instead of performing parse_analyze()
- */
- if (tree == first_select)
- result = parsetree;
+ if (query->querySource == QSRC_ORIGINAL)
+ {
+ Assert(query->canSetTag);
+ Assert(!foundOriginalQuery);
+ foundOriginalQuery = true;
+#ifndef USE_ASSERT_CHECKING
+ break;
+#endif
+ }
else
{
- /* transform the 'raw' nodes to 'cooked' Query nodes */
- List *qtree = parse_analyze(lcons(tree, NIL), NULL);
-
- result = (Node *) lfirst(qtree);
+ Assert(!query->canSetTag);
+ if (query->commandType == origCmdType &&
+ (query->querySource == QSRC_INSTEAD_RULE ||
+ query->querySource == QSRC_QUAL_INSTEAD_RULE))
+ lastInstead = query;
}
}
- if (IsA(tree, Expr))
- {
- /* Call recursively for every argument of the node */
- foreach(arg, ((Expr *) tree)->args)
- lfirst(arg) = intersect_tree_analyze(lfirst(arg), first_select, parsetree);
- result = tree;
- }
- return result;
+ if (!foundOriginalQuery && lastInstead != NULL)
+ lastInstead->canSetTag = true;
+
+ return results;
}
projects / postgresql / blobdiff