/*------------------------------------------------------------------------- * * rewriteHandler.c * * Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.44 1999/05/25 13:16:10 wieck Exp $ * *------------------------------------------------------------------------- */ #include #include "postgres.h" #include "miscadmin.h" #include "utils/palloc.h" #include "utils/elog.h" #include "utils/rel.h" #include "nodes/pg_list.h" #include "nodes/primnodes.h" #include "nodes/relation.h" #include "parser/parsetree.h" /* for parsetree manipulation */ #include "parser/parse_relation.h" #include "nodes/parsenodes.h" /***S*I***/ #include "parser/parse_node.h" #include "parser/parse_target.h" #include "parser/analyze.h" #include "optimizer/prep.h" #include "rewrite/rewriteSupport.h" #include "rewrite/rewriteHandler.h" #include "rewrite/rewriteManip.h" #include "rewrite/locks.h" #include "commands/creatinh.h" #include "access/heapam.h" #include "utils/lsyscache.h" #include "utils/syscache.h" #include "utils/acl.h" #include "catalog/pg_shadow.h" #include "catalog/pg_type.h" static RewriteInfo *gatherRewriteMeta(Query *parsetree, Query *rule_action, Node *rule_qual, int rt_index, CmdType event, bool *instead_flag); static bool rangeTableEntry_used(Node *node, int rt_index, int sublevels_up); static bool attribute_used(Node *node, int rt_index, int attno, int sublevels_up); static void modifyAggrefUplevel(Node *node); static void modifyAggrefChangeVarnodes(Node **nodePtr, int rt_index, int new_index, int sublevels_up); static void modifyAggrefDropQual(Node **nodePtr, Node *orignode, Expr *expr); static SubLink *modifyAggrefMakeSublink(Expr *origexp, Query *parsetree); static void modifyAggrefQual(Node **nodePtr, Query *parsetree); static bool checkQueryHasAggs(Node *node); static Query *fireRIRrules(Query *parsetree); /* * 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 */ static RewriteInfo * gatherRewriteMeta(Query *parsetree, Query *rule_action, Node *rule_qual, int rt_index, CmdType event, bool *instead_flag) { 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 { 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); /* * bug here about replace CURRENT -- sort of replace current is * deprecated now so this code shouldn't really need to be so * clutzy but..... */ if (info->action != CMD_SELECT) { /* i.e update XXXXX */ int new_result_reln = 0; result_reln = info->rule_action->resultRelation; switch (result_reln) { case PRS2_CURRENT_VARNO: new_result_reln = rt_index; break; case PRS2_NEW_VARNO: /* XXX */ default: new_result_reln = result_reln + rt_length; break; } info->rule_action->resultRelation = new_result_reln; } } return info; } /* * rangeTableEntry_used - * we need to process a RTE for RIR rules only if it is * referenced somewhere in var nodes of the query. */ static bool rangeTableEntry_used(Node *node, int rt_index, int sublevels_up) { if (node == NULL) return FALSE; switch(nodeTag(node)) { case T_TargetEntry: { TargetEntry *tle = (TargetEntry *)node; return rangeTableEntry_used( (Node *)(tle->expr), rt_index, sublevels_up); } break; case T_Aggref: { Aggref *aggref = (Aggref *)node; return rangeTableEntry_used( (Node *)(aggref->target), rt_index, sublevels_up); } break; case T_GroupClause: return FALSE; case T_Expr: { Expr *exp = (Expr *)node; return rangeTableEntry_used( (Node *)(exp->args), rt_index, sublevels_up); } break; case T_Iter: { Iter *iter = (Iter *)node; return rangeTableEntry_used( (Node *)(iter->iterexpr), rt_index, sublevels_up); } break; case T_ArrayRef: { ArrayRef *ref = (ArrayRef *)node; if (rangeTableEntry_used( (Node *)(ref->refupperindexpr), rt_index, sublevels_up)) return TRUE; if (rangeTableEntry_used( (Node *)(ref->reflowerindexpr), rt_index, sublevels_up)) return TRUE; if (rangeTableEntry_used( (Node *)(ref->refexpr), rt_index, sublevels_up)) return TRUE; if (rangeTableEntry_used( (Node *)(ref->refassgnexpr), rt_index, sublevels_up)) return TRUE; return FALSE; } break; case T_Var: { Var *var = (Var *)node; if (var->varlevelsup == sublevels_up) return var->varno == rt_index; else return FALSE; } break; case T_Param: return FALSE; case T_Const: return FALSE; case T_List: { List *l; foreach (l, (List *)node) { if (rangeTableEntry_used( (Node *)lfirst(l), rt_index, sublevels_up)) return TRUE; } return FALSE; } break; case T_SubLink: { SubLink *sub = (SubLink *)node; if (rangeTableEntry_used( (Node *)(sub->lefthand), rt_index, sublevels_up)) return TRUE; if (rangeTableEntry_used( (Node *)(sub->subselect), rt_index, sublevels_up + 1)) return TRUE; return FALSE; } break; case T_CaseExpr: { CaseExpr *exp = (CaseExpr *)node; if (rangeTableEntry_used( (Node *)(exp->args), rt_index, sublevels_up)) return TRUE; if (rangeTableEntry_used( (Node *)(exp->defresult), rt_index, sublevels_up)) return TRUE; return FALSE; } break; case T_CaseWhen: { CaseWhen *when = (CaseWhen *)node; if (rangeTableEntry_used( (Node *)(when->expr), rt_index, sublevels_up)) return TRUE; if (rangeTableEntry_used( (Node *)(when->result), rt_index, sublevels_up)) return TRUE; return FALSE; } break; case T_Query: { Query *qry = (Query *)node; if (rangeTableEntry_used( (Node *)(qry->targetList), rt_index, sublevels_up)) return TRUE; if (rangeTableEntry_used( (Node *)(qry->qual), rt_index, sublevels_up)) return TRUE; if (rangeTableEntry_used( (Node *)(qry->havingQual), rt_index, sublevels_up)) return TRUE; return FALSE; } break; default: elog(NOTICE, "unknown node tag %d in rangeTableEntry_used()", nodeTag(node)); elog(NOTICE, "Node is: %s", nodeToString(node)); break; } return FALSE; } /* * attribute_used - * Check if a specific attribute number of a RTE is used * somewhere in the query */ static bool attribute_used(Node *node, int rt_index, int attno, int sublevels_up) { if (node == NULL) return FALSE; switch(nodeTag(node)) { case T_TargetEntry: { TargetEntry *tle = (TargetEntry *)node; return attribute_used( (Node *)(tle->expr), rt_index, attno, sublevels_up); } break; case T_Aggref: { Aggref *aggref = (Aggref *)node; return attribute_used( (Node *)(aggref->target), rt_index, attno, sublevels_up); } break; case T_GroupClause: return FALSE; case T_Expr: { Expr *exp = (Expr *)node; return attribute_used( (Node *)(exp->args), rt_index, attno, sublevels_up); } break; case T_Iter: { Iter *iter = (Iter *)node; return attribute_used( (Node *)(iter->iterexpr), rt_index, attno, sublevels_up); } break; case T_ArrayRef: { ArrayRef *ref = (ArrayRef *)node; if (attribute_used( (Node *)(ref->refupperindexpr), rt_index, attno, sublevels_up)) return TRUE; if (attribute_used( (Node *)(ref->reflowerindexpr), rt_index, attno, sublevels_up)) return TRUE; if (attribute_used( (Node *)(ref->refexpr), rt_index, attno, sublevels_up)) return TRUE; if (attribute_used( (Node *)(ref->refassgnexpr), rt_index, attno, sublevels_up)) return TRUE; return FALSE; } break; case T_Var: { Var *var = (Var *)node; if (var->varlevelsup == sublevels_up) return var->varno == rt_index; else return FALSE; } break; case T_Param: return FALSE; case T_Const: return FALSE; case T_List: { List *l; foreach (l, (List *)node) { if (attribute_used( (Node *)lfirst(l), rt_index, attno, sublevels_up)) return TRUE; } return FALSE; } break; case T_SubLink: { SubLink *sub = (SubLink *)node; if (attribute_used( (Node *)(sub->lefthand), rt_index, attno, sublevels_up)) return TRUE; if (attribute_used( (Node *)(sub->subselect), rt_index, attno, sublevels_up + 1)) return TRUE; return FALSE; } break; case T_Query: { Query *qry = (Query *)node; if (attribute_used( (Node *)(qry->targetList), rt_index, attno, sublevels_up)) return TRUE; if (attribute_used( (Node *)(qry->qual), rt_index, attno, sublevels_up)) return TRUE; if (attribute_used( (Node *)(qry->havingQual), rt_index, attno, sublevels_up)) return TRUE; return FALSE; } break; default: elog(NOTICE, "unknown node tag %d in attribute_used()", nodeTag(node)); elog(NOTICE, "Node is: %s", nodeToString(node)); break; } return FALSE; } /* * modifyAggrefUplevel - * In the newly created sublink for an aggregate column used in * the qualification, we must adjust the varlevelsup in all the * var nodes. */ static void modifyAggrefUplevel(Node *node) { if (node == NULL) return; switch(nodeTag(node)) { case T_TargetEntry: { TargetEntry *tle = (TargetEntry *)node; modifyAggrefUplevel( (Node *)(tle->expr)); } break; case T_Aggref: { Aggref *aggref = (Aggref *)node; modifyAggrefUplevel( (Node *)(aggref->target)); } break; case T_Expr: { Expr *exp = (Expr *)node; modifyAggrefUplevel( (Node *)(exp->args)); } break; case T_Iter: { Iter *iter = (Iter *)node; modifyAggrefUplevel( (Node *)(iter->iterexpr)); } break; case T_ArrayRef: { ArrayRef *ref = (ArrayRef *)node; modifyAggrefUplevel( (Node *)(ref->refupperindexpr)); modifyAggrefUplevel( (Node *)(ref->reflowerindexpr)); modifyAggrefUplevel( (Node *)(ref->refexpr)); modifyAggrefUplevel( (Node *)(ref->refassgnexpr)); } break; case T_Var: { Var *var = (Var *)node; var->varlevelsup++; } break; case T_Param: break; case T_Const: break; case T_List: { List *l; foreach (l, (List *)node) modifyAggrefUplevel( (Node *)lfirst(l)); } break; case T_SubLink: { SubLink *sub = (SubLink *)node; modifyAggrefUplevel( (Node *)(sub->lefthand)); modifyAggrefUplevel( (Node *)(sub->oper)); modifyAggrefUplevel( (Node *)(sub->subselect)); } break; case T_Query: { Query *qry = (Query *)node; modifyAggrefUplevel( (Node *)(qry->targetList)); modifyAggrefUplevel( (Node *)(qry->qual)); modifyAggrefUplevel( (Node *)(qry->havingQual)); } break; default: elog(NOTICE, "unknown node tag %d in modifyAggrefUplevel()", nodeTag(node)); elog(NOTICE, "Node is: %s", nodeToString(node)); break; } } /* * modifyAggrefChangeVarnodes - * Change the var nodes in a sublink created for an aggregate column * used in the qualification that is subject of the aggregate * function to point to the correct local RTE. */ static void modifyAggrefChangeVarnodes(Node **nodePtr, int rt_index, int new_index, int sublevels_up) { Node *node = *nodePtr; if (node == NULL) return; switch(nodeTag(node)) { case T_TargetEntry: { TargetEntry *tle = (TargetEntry *)node; modifyAggrefChangeVarnodes( (Node **)(&(tle->expr)), rt_index, new_index, sublevels_up); } break; case T_Aggref: { Aggref *aggref = (Aggref *)node; modifyAggrefChangeVarnodes( (Node **)(&(aggref->target)), rt_index, new_index, sublevels_up); } break; case T_GroupClause: break; case T_Expr: { Expr *exp = (Expr *)node; modifyAggrefChangeVarnodes( (Node **)(&(exp->args)), rt_index, new_index, sublevels_up); } break; case T_Iter: { Iter *iter = (Iter *)node; modifyAggrefChangeVarnodes( (Node **)(&(iter->iterexpr)), rt_index, new_index, sublevels_up); } break; case T_ArrayRef: { ArrayRef *ref = (ArrayRef *)node; modifyAggrefChangeVarnodes( (Node **)(&(ref->refupperindexpr)), rt_index, new_index, sublevels_up); modifyAggrefChangeVarnodes( (Node **)(&(ref->reflowerindexpr)), rt_index, new_index, sublevels_up); modifyAggrefChangeVarnodes( (Node **)(&(ref->refexpr)), rt_index, new_index, sublevels_up); modifyAggrefChangeVarnodes( (Node **)(&(ref->refassgnexpr)), rt_index, new_index, sublevels_up); } break; case T_Var: { Var *var = (Var *)node; if (var->varlevelsup == sublevels_up && var->varno == rt_index) { var = copyObject(var); var->varno = new_index; var->varnoold = new_index; var->varlevelsup = 0; *nodePtr = (Node *)var; } } break; case T_Param: break; case T_Const: break; case T_List: { List *l; foreach (l, (List *)node) modifyAggrefChangeVarnodes( (Node **)(&lfirst(l)), rt_index, new_index, sublevels_up); } break; case T_SubLink: { SubLink *sub = (SubLink *)node; modifyAggrefChangeVarnodes( (Node **)(&(sub->lefthand)), rt_index, new_index, sublevels_up); modifyAggrefChangeVarnodes( (Node **)(&(sub->oper)), rt_index, new_index, sublevels_up); modifyAggrefChangeVarnodes( (Node **)(&(sub->subselect)), rt_index, new_index, sublevels_up + 1); } break; case T_Query: { Query *qry = (Query *)node; modifyAggrefChangeVarnodes( (Node **)(&(qry->targetList)), rt_index, new_index, sublevels_up); modifyAggrefChangeVarnodes( (Node **)(&(qry->qual)), rt_index, new_index, sublevels_up); modifyAggrefChangeVarnodes( (Node **)(&(qry->havingQual)), rt_index, new_index, sublevels_up); } break; default: elog(NOTICE, "unknown node tag %d in modifyAggrefChangeVarnodes()", nodeTag(node)); elog(NOTICE, "Node is: %s", nodeToString(node)); break; } } /* * modifyAggrefDropQual - * remove the pure aggref clase from a qualification */ static void modifyAggrefDropQual(Node **nodePtr, Node *orignode, Expr *expr) { Node *node = *nodePtr; if (node == NULL) return; switch(nodeTag(node)) { case T_Var: break; case T_Aggref: { Aggref *aggref = (Aggref *)node; Aggref *oaggref = (Aggref *)orignode; modifyAggrefDropQual( (Node **)(&(aggref->target)), (Node *)(oaggref->target), expr); } break; case T_Param: break; case T_Const: break; case T_GroupClause: break; case T_Expr: { Expr *this_expr = (Expr *)node; Expr *orig_expr = (Expr *)orignode; if (orig_expr == expr) { Const *ctrue; if (expr->typeOid != BOOLOID) elog(ERROR, "aggregate expression in qualification isn't of type bool"); ctrue = makeNode(Const); ctrue->consttype = BOOLOID; ctrue->constlen = 1; ctrue->constisnull = FALSE; ctrue->constvalue = (Datum)TRUE; ctrue->constbyval = TRUE; *nodePtr = (Node *)ctrue; } else modifyAggrefDropQual( (Node **)(&(this_expr->args)), (Node *)(orig_expr->args), expr); } break; case T_Iter: { Iter *iter = (Iter *)node; Iter *oiter = (Iter *)orignode; modifyAggrefDropQual( (Node **)(&(iter->iterexpr)), (Node *)(oiter->iterexpr), expr); } break; case T_ArrayRef: { ArrayRef *ref = (ArrayRef *)node; ArrayRef *oref = (ArrayRef *)orignode; modifyAggrefDropQual( (Node **)(&(ref->refupperindexpr)), (Node *)(oref->refupperindexpr), expr); modifyAggrefDropQual( (Node **)(&(ref->reflowerindexpr)), (Node *)(oref->reflowerindexpr), expr); modifyAggrefDropQual( (Node **)(&(ref->refexpr)), (Node *)(oref->refexpr), expr); modifyAggrefDropQual( (Node **)(&(ref->refassgnexpr)), (Node *)(oref->refassgnexpr), expr); } break; case T_List: { List *l; List *ol = (List *)orignode; int li = 0; foreach (l, (List *)node) { modifyAggrefDropQual( (Node **)(&(lfirst(l))), (Node *)nth(li, ol), expr); li++; } } break; case T_SubLink: { SubLink *sub = (SubLink *)node; SubLink *osub = (SubLink *)orignode; modifyAggrefDropQual( (Node **)(&(sub->subselect)), (Node *)(osub->subselect), expr); } break; case T_Query: { Query *qry = (Query *)node; Query *oqry = (Query *)orignode; modifyAggrefDropQual( (Node **)(&(qry->qual)), (Node *)(oqry->qual), expr); modifyAggrefDropQual( (Node **)(&(qry->havingQual)), (Node *)(oqry->havingQual), expr); } break; default: elog(NOTICE, "unknown node tag %d in modifyAggrefDropQual()", nodeTag(node)); elog(NOTICE, "Node is: %s", nodeToString(node)); break; } } /* * modifyAggrefMakeSublink - * Create a sublink node for a qualification expression that * uses an aggregate column of a view */ static SubLink * modifyAggrefMakeSublink(Expr *origexp, Query *parsetree) { SubLink *sublink; Query *subquery; Node *subqual; RangeTblEntry *rte; Aggref *aggref; Var *target; TargetEntry *tle; Resdom *resdom; Expr *exp = copyObject(origexp); if (nodeTag(nth(0, exp->args)) == T_Aggref) { if (nodeTag(nth(1, exp->args)) == T_Aggref) elog(ERROR, "rewrite: comparision of 2 aggregate columns not supported"); else elog(ERROR, "rewrite: aggregate column of view must be at rigth side in qual"); } aggref = (Aggref *)nth(1, exp->args); target = (Var *)(aggref->target); rte = (RangeTblEntry *)nth(target->varno - 1, parsetree->rtable); tle = makeNode(TargetEntry); resdom = makeNode(Resdom); aggref->usenulls = TRUE; resdom->resno = 1; resdom->restype = ((Oper *)(exp->oper))->opresulttype; resdom->restypmod = -1; resdom->resname = pstrdup(""); resdom->reskey = 0; resdom->reskeyop = 0; resdom->resjunk = false; tle->resdom = resdom; tle->expr = (Node *)aggref; subqual = copyObject(parsetree->qual); modifyAggrefDropQual((Node **)&subqual, (Node *)parsetree->qual, origexp); sublink = makeNode(SubLink); sublink->subLinkType = EXPR_SUBLINK; sublink->useor = FALSE; sublink->lefthand = lappend(NIL, copyObject(lfirst(exp->args))); sublink->oper = lappend(NIL, copyObject(exp)); sublink->subselect = NULL; subquery = makeNode(Query); sublink->subselect = (Node *)subquery; subquery->commandType = CMD_SELECT; subquery->utilityStmt = NULL; subquery->resultRelation = 0; subquery->into = NULL; subquery->isPortal = FALSE; subquery->isBinary = FALSE; subquery->isTemp = FALSE; subquery->unionall = FALSE; subquery->uniqueFlag = NULL; subquery->sortClause = NULL; subquery->rtable = lappend(NIL, rte); subquery->targetList = lappend(NIL, tle); subquery->qual = subqual; subquery->groupClause = NIL; subquery->havingQual = NULL; subquery->hasAggs = TRUE; subquery->hasSubLinks = FALSE; subquery->unionClause = NULL; modifyAggrefUplevel((Node *)sublink); modifyAggrefChangeVarnodes((Node **)&(sublink->lefthand), target->varno, 1, target->varlevelsup); modifyAggrefChangeVarnodes((Node **)&(sublink->oper), target->varno, 1, target->varlevelsup); modifyAggrefChangeVarnodes((Node **)&(sublink->subselect), target->varno, 1, target->varlevelsup); return sublink; } /* * modifyAggrefQual - * Search for qualification expressions that contain aggregate * functions and substiture them by sublinks. These expressions * originally come from qualifications that use aggregate columns * of a view. */ static void modifyAggrefQual(Node **nodePtr, Query *parsetree) { Node *node = *nodePtr; if (node == NULL) return; switch(nodeTag(node)) { case T_Var: break; case T_Param: break; case T_Const: break; case T_GroupClause: break; case T_Expr: { Expr *exp = (Expr *)node; SubLink *sub; if (length(exp->args) != 2) { modifyAggrefQual( (Node **)(&(exp->args)), parsetree); break; } if (nodeTag(nth(0, exp->args)) != T_Aggref && nodeTag(nth(1, exp->args)) != T_Aggref) { modifyAggrefQual( (Node **)(&(exp->args)), parsetree); break; } sub = modifyAggrefMakeSublink(exp, parsetree); *nodePtr = (Node *)sub; parsetree->hasSubLinks = TRUE; } break; case T_CaseExpr: { /* We're calling recursively, * and this routine knows how to handle lists * so let it do the work to handle the WHEN clauses... */ modifyAggrefQual( (Node **)(&(((CaseExpr *)node)->args)), parsetree); modifyAggrefQual( (Node **)(&(((CaseExpr *)node)->defresult)), parsetree); } break; case T_CaseWhen: { modifyAggrefQual( (Node **)(&(((CaseWhen *)node)->expr)), parsetree); modifyAggrefQual( (Node **)(&(((CaseWhen *)node)->result)), parsetree); } break; case T_Iter: { Iter *iter = (Iter *)node; modifyAggrefQual( (Node **)(&(iter->iterexpr)), parsetree); } break; case T_ArrayRef: { ArrayRef *ref = (ArrayRef *)node; modifyAggrefQual( (Node **)(&(ref->refupperindexpr)), parsetree); modifyAggrefQual( (Node **)(&(ref->reflowerindexpr)), parsetree); modifyAggrefQual( (Node **)(&(ref->refexpr)), parsetree); modifyAggrefQual( (Node **)(&(ref->refassgnexpr)), parsetree); } break; case T_List: { List *l; foreach (l, (List *)node) modifyAggrefQual( (Node **)(&(lfirst(l))), parsetree); } break; case T_SubLink: { SubLink *sub = (SubLink *)node; modifyAggrefQual( (Node **)(&(sub->subselect)), (Query *)(sub->subselect)); } break; case T_Query: { Query *qry = (Query *)node; modifyAggrefQual( (Node **)(&(qry->qual)), parsetree); modifyAggrefQual( (Node **)(&(qry->havingQual)), parsetree); } break; default: elog(NOTICE, "unknown node tag %d in modifyAggrefQual()", nodeTag(node)); elog(NOTICE, "Node is: %s", nodeToString(node)); break; } } /* * checkQueryHasAggs - * Queries marked hasAggs might not have them any longer after * rewriting. Check it. */ static bool checkQueryHasAggs(Node *node) { if (node == NULL) return FALSE; switch(nodeTag(node)) { case T_TargetEntry: { TargetEntry *tle = (TargetEntry *)node; return checkQueryHasAggs((Node *)(tle->expr)); } break; case T_Aggref: return TRUE; case T_Expr: { Expr *exp = (Expr *)node; return checkQueryHasAggs((Node *)(exp->args)); } break; case T_Iter: { Iter *iter = (Iter *)node; return checkQueryHasAggs((Node *)(iter->iterexpr)); } break; case T_ArrayRef: { ArrayRef *ref = (ArrayRef *)node; if (checkQueryHasAggs((Node *)(ref->refupperindexpr))) return TRUE; if (checkQueryHasAggs((Node *)(ref->reflowerindexpr))) return TRUE; if (checkQueryHasAggs((Node *)(ref->refexpr))) return TRUE; if (checkQueryHasAggs((Node *)(ref->refassgnexpr))) return TRUE; return FALSE; } break; case T_Var: return FALSE; case T_Param: return FALSE; case T_Const: return FALSE; case T_List: { List *l; foreach (l, (List *)node) { if (checkQueryHasAggs((Node *)lfirst(l))) return TRUE; } return FALSE; } break; case T_CaseExpr: { CaseExpr *exp = (CaseExpr *)node; if (checkQueryHasAggs((Node *)(exp->args))) return TRUE; if (checkQueryHasAggs((Node *)(exp->defresult))) return TRUE; return FALSE; } break; case T_CaseWhen: { CaseWhen *when = (CaseWhen *)node; if (checkQueryHasAggs((Node *)(when->expr))) return TRUE; if (checkQueryHasAggs((Node *)(when->result))) return TRUE; return FALSE; } break; default: elog(NOTICE, "unknown node tag %d in checkQueryHasAggs()", nodeTag(node)); elog(NOTICE, "Node is: %s", nodeToString(node)); break; } return FALSE; } /* * checkQueryHasSubLink - * Queries marked hasAggs might not have them any longer after * rewriting. Check it. */ static bool checkQueryHasSubLink(Node *node) { if (node == NULL) return FALSE; switch(nodeTag(node)) { case T_TargetEntry: { TargetEntry *tle = (TargetEntry *)node; return checkQueryHasSubLink((Node *)(tle->expr)); } break; case T_Aggref: return TRUE; case T_Expr: { Expr *exp = (Expr *)node; return checkQueryHasSubLink((Node *)(exp->args)); } break; case T_Iter: { Iter *iter = (Iter *)node; return checkQueryHasSubLink((Node *)(iter->iterexpr)); } break; case T_ArrayRef: { ArrayRef *ref = (ArrayRef *)node; if (checkQueryHasSubLink((Node *)(ref->refupperindexpr))) return TRUE; if (checkQueryHasSubLink((Node *)(ref->reflowerindexpr))) return TRUE; if (checkQueryHasSubLink((Node *)(ref->refexpr))) return TRUE; if (checkQueryHasSubLink((Node *)(ref->refassgnexpr))) return TRUE; return FALSE; } break; case T_Var: return FALSE; case T_Param: return FALSE; case T_Const: return FALSE; case T_List: { List *l; foreach (l, (List *)node) { if (checkQueryHasSubLink((Node *)lfirst(l))) return TRUE; } return FALSE; } break; case T_CaseExpr: { CaseExpr *exp = (CaseExpr *)node; if (checkQueryHasSubLink((Node *)(exp->args))) return TRUE; if (checkQueryHasSubLink((Node *)(exp->defresult))) return TRUE; return FALSE; } break; case T_CaseWhen: { CaseWhen *when = (CaseWhen *)node; if (checkQueryHasSubLink((Node *)(when->expr))) return TRUE; if (checkQueryHasSubLink((Node *)(when->result))) return TRUE; return FALSE; } break; case T_SubLink: return TRUE; default: elog(NOTICE, "unknown node tag %d in checkQueryHasSubLink()", nodeTag(node)); elog(NOTICE, "Node is: %s", nodeToString(node)); break; } return FALSE; } static Node * FindMatchingTLEntry(List *tlist, char *e_attname) { List *i; foreach(i, tlist) { TargetEntry *tle = lfirst(i); char *resname; resname = tle->resdom->resname; if (!strcmp(e_attname, resname)) return (tle->expr); } return NULL; } 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; } static void apply_RIR_adjust_sublevel(Node *node, int sublevels_up) { if (node == NULL) return; switch(nodeTag(node)) { case T_TargetEntry: { TargetEntry *tle = (TargetEntry *)node; apply_RIR_adjust_sublevel( (Node *)(tle->expr), sublevels_up); } break; case T_Aggref: { Aggref *aggref = (Aggref *)node; apply_RIR_adjust_sublevel( (Node *)(aggref->target), sublevels_up); } break; case T_GroupClause: break; case T_Expr: { Expr *exp = (Expr *)node; apply_RIR_adjust_sublevel( (Node *)(exp->args), sublevels_up); } break; case T_Iter: { Iter *iter = (Iter *)node; apply_RIR_adjust_sublevel( (Node *)(iter->iterexpr), sublevels_up); } break; case T_ArrayRef: { ArrayRef *ref = (ArrayRef *)node; apply_RIR_adjust_sublevel( (Node *)(ref->refupperindexpr), sublevels_up); apply_RIR_adjust_sublevel( (Node *)(ref->reflowerindexpr), sublevels_up); apply_RIR_adjust_sublevel( (Node *)(ref->refexpr), sublevels_up); apply_RIR_adjust_sublevel( (Node *)(ref->refassgnexpr), sublevels_up); } break; case T_Var: { Var *var = (Var *)node; var->varlevelsup = sublevels_up; } break; case T_Param: break; case T_Const: break; case T_List: { List *l; foreach (l, (List *)node) { apply_RIR_adjust_sublevel( (Node *)lfirst(l), sublevels_up); } } break; case T_CaseExpr: { CaseExpr *exp = (CaseExpr *)node; apply_RIR_adjust_sublevel( (Node *)(exp->args), sublevels_up); apply_RIR_adjust_sublevel( (Node *)(exp->defresult), sublevels_up); } break; case T_CaseWhen: { CaseWhen *exp = (CaseWhen *)node; apply_RIR_adjust_sublevel( (Node *)(exp->expr), sublevels_up); apply_RIR_adjust_sublevel( (Node *)(exp->result), sublevels_up); } break; default: elog(NOTICE, "unknown node tag %d in attribute_used()", nodeTag(node)); elog(NOTICE, "Node is: %s", nodeToString(node)); break; } } static void apply_RIR_view(Node **nodePtr, int rt_index, RangeTblEntry *rte, List *tlist, int *modified, int sublevels_up) { Node *node = *nodePtr; if (node == NULL) return; switch(nodeTag(node)) { case T_TargetEntry: { TargetEntry *tle = (TargetEntry *)node; apply_RIR_view( (Node **)(&(tle->expr)), rt_index, rte, tlist, modified, sublevels_up); } break; case T_Aggref: { Aggref *aggref = (Aggref *)node; apply_RIR_view( (Node **)(&(aggref->target)), rt_index, rte, tlist, modified, sublevels_up); } break; case T_GroupClause: break; case T_Expr: { Expr *exp = (Expr *)node; apply_RIR_view( (Node **)(&(exp->args)), rt_index, rte, tlist, modified, sublevels_up); } break; case T_Iter: { Iter *iter = (Iter *)node; apply_RIR_view( (Node **)(&(iter->iterexpr)), rt_index, rte, tlist, modified, sublevels_up); } break; case T_ArrayRef: { ArrayRef *ref = (ArrayRef *)node; apply_RIR_view( (Node **)(&(ref->refupperindexpr)), rt_index, rte, tlist, modified, sublevels_up); apply_RIR_view( (Node **)(&(ref->reflowerindexpr)), rt_index, rte, tlist, modified, sublevels_up); apply_RIR_view( (Node **)(&(ref->refexpr)), rt_index, rte, tlist, modified, sublevels_up); apply_RIR_view( (Node **)(&(ref->refassgnexpr)), rt_index, rte, tlist, modified, sublevels_up); } break; case T_Var: { Var *var = (Var *)node; if (var->varlevelsup == sublevels_up && var->varno == rt_index) { Node *exp; if (var->varattno < 0) elog(ERROR, "system column %s not available - %s is a view", get_attname(rte->relid, var->varattno), rte->relname); exp = FindMatchingTLEntry( tlist, get_attname(rte->relid, var->varattno)); if (exp == NULL) { *nodePtr = make_null(var->vartype); return; } exp = copyObject(exp); if (var->varlevelsup > 0) apply_RIR_adjust_sublevel(exp, var->varlevelsup); *nodePtr = exp; *modified = TRUE; } } break; case T_Param: break; case T_Const: break; case T_List: { List *l; foreach (l, (List *)node) apply_RIR_view( (Node **)(&(lfirst(l))), rt_index, rte, tlist, modified, sublevels_up); } break; case T_SubLink: { SubLink *sub = (SubLink *)node; List *tmp_lefthand, *tmp_oper; apply_RIR_view( (Node **)(&(sub->lefthand)), rt_index, rte, tlist, modified, sublevels_up); apply_RIR_view( (Node **)(&(sub->subselect)), rt_index, rte, tlist, modified, sublevels_up + 1); /***S*I***/ tmp_lefthand = sub->lefthand; foreach(tmp_oper, sub->oper) { lfirst(((Expr *) lfirst(tmp_oper))->args) = lfirst(tmp_lefthand); tmp_lefthand = lnext(tmp_lefthand); } } break; case T_Query: { Query *qry = (Query *)node; apply_RIR_view( (Node **)(&(qry->targetList)), rt_index, rte, tlist, modified, sublevels_up); apply_RIR_view( (Node **)(&(qry->qual)), rt_index, rte, tlist, modified, sublevels_up); apply_RIR_view( (Node **)(&(qry->havingQual)), rt_index, rte, tlist, modified, sublevels_up); } break; case T_CaseExpr: { CaseExpr *exp = (CaseExpr *)node; apply_RIR_view( (Node **)(&(exp->args)), rt_index, rte, tlist, modified, sublevels_up); apply_RIR_view( (Node **)(&(exp->defresult)), rt_index, rte, tlist, modified, sublevels_up); } break; case T_CaseWhen: { CaseWhen *exp = (CaseWhen *)node; apply_RIR_view( (Node **)(&(exp->expr)), rt_index, rte, tlist, modified, sublevels_up); apply_RIR_view( (Node **)(&(exp->result)), rt_index, rte, tlist, modified, sublevels_up); } break; default: elog(NOTICE, "unknown node tag %d in apply_RIR_view()", nodeTag(node)); elog(NOTICE, "Node is: %s", nodeToString(node)); break; } } extern void CheckSelectForUpdate(Query *rule_action); /* in analyze.c */ static void ApplyRetrieveRule(Query *parsetree, RewriteRule *rule, int rt_index, int relation_level, Relation relation, int *modified) { Query *rule_action = NULL; Node *rule_qual; List *rtable, *rt, *l; int nothing, rt_length; int badsql = FALSE; rule_qual = rule->qual; if (rule->actions) { if (length(rule->actions) > 1) /* ??? because we don't handle * rules with more than one * action? -ay */ return; rule_action = copyObject(lfirst(rule->actions)); nothing = FALSE; } else nothing = TRUE; rtable = copyObject(parsetree->rtable); foreach(rt, rtable) { RangeTblEntry *rte = lfirst(rt); /* * this is to prevent add_missing_vars_to_base_rels() from adding * a bogus entry to the new target list. */ rte->inFromCl = false; } rt_length = length(rtable); rtable = nconc(rtable, copyObject(rule_action->rtable)); parsetree->rtable = rtable; /* 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; CheckSelectForUpdate(rule_action); /* * 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; foreach (l2, rule_action->rtable) { /* * RTable of VIEW has two entries of VIEW itself - * we use relid to skip them. */ if (relation->rd_id != ((RangeTblEntry*)lfirst(l2))->relid) { newrm = makeNode(RowMark); newrm->rti = rti + rt_length; newrm->info = ROW_MARK_FOR_UPDATE; lnext(l) = lcons(newrm, lnext(l)); l = lnext(l); } rti++; } } rule_action->rtable = rtable; OffsetVarNodes((Node *) rule_qual, rt_length, 0); OffsetVarNodes((Node *) rule_action, rt_length, 0); 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 (relation_level) { apply_RIR_view((Node **) &parsetree, rt_index, (RangeTblEntry *)nth(rt_index - 1, rtable), rule_action->targetList, modified, 0); apply_RIR_view((Node **) &rule_action, rt_index, (RangeTblEntry *)nth(rt_index - 1, rtable), rule_action->targetList, modified, 0); } else { HandleRIRAttributeRule(parsetree, rtable, rule_action->targetList, rt_index, rule->attrno, modified, &badsql); } if (*modified && !badsql) { AddQual(parsetree, rule_action->qual); 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); } } static void fireRIRonSubselect(Node *node) { if (node == NULL) return; switch(nodeTag(node)) { case T_TargetEntry: { TargetEntry *tle = (TargetEntry *)node; fireRIRonSubselect( (Node *)(tle->expr)); } break; case T_Aggref: { Aggref *aggref = (Aggref *)node; fireRIRonSubselect( (Node *)(aggref->target)); } break; case T_GroupClause: break; case T_Expr: { Expr *exp = (Expr *)node; fireRIRonSubselect( (Node *)(exp->args)); } break; case T_Iter: { Iter *iter = (Iter *)node; fireRIRonSubselect( (Node *)(iter->iterexpr)); } break; case T_ArrayRef: { ArrayRef *ref = (ArrayRef *)node; fireRIRonSubselect( (Node *)(ref->refupperindexpr)); fireRIRonSubselect( (Node *)(ref->reflowerindexpr)); fireRIRonSubselect( (Node *)(ref->refexpr)); fireRIRonSubselect( (Node *)(ref->refassgnexpr)); } break; case T_Var: break; case T_Param: break; case T_Const: break; case T_List: { List *l; foreach (l, (List *)node) fireRIRonSubselect( (Node *)(lfirst(l))); } break; case T_SubLink: { SubLink *sub = (SubLink *)node; Query *qry; fireRIRonSubselect( (Node *)(sub->lefthand)); qry = fireRIRrules((Query *)(sub->subselect)); fireRIRonSubselect( (Node *)qry); sub->subselect = (Node *) qry; } break; case T_CaseExpr: { CaseExpr *exp = (CaseExpr *)node; fireRIRonSubselect( (Node *)(exp->args)); fireRIRonSubselect( (Node *)(exp->defresult)); } break; case T_CaseWhen: { CaseWhen *exp = (CaseWhen *)node; fireRIRonSubselect( (Node *)(exp->expr)); fireRIRonSubselect( (Node *)(exp->result)); } break; case T_Query: { Query *qry = (Query *)node; fireRIRonSubselect( (Node *)(qry->targetList)); fireRIRonSubselect( (Node *)(qry->qual)); fireRIRonSubselect( (Node *)(qry->havingQual)); } break; default: elog(NOTICE, "unknown node tag %d in fireRIRonSubselect()", nodeTag(node)); elog(NOTICE, "Node is: %s", nodeToString(node)); break; } } /* * fireRIRrules - * Apply all RIR rules on each rangetable entry in a query */ static Query * fireRIRrules(Query *parsetree) { int rt_index; RangeTblEntry *rte; Relation rel; List *locks; RuleLock *rules; RewriteRule *rule; RewriteRule RIRonly; int modified; int i; List *l; rt_index = 0; while(rt_index < length(parsetree->rtable)) { ++rt_index; rte = nth(rt_index - 1, parsetree->rtable); if (!rangeTableEntry_used((Node *)parsetree, rt_index, 0)) { /* * Unused range table entries must not be marked as coming * from a clause. Otherwise the planner will generate * joins over relations that in fact shouldn't be scanned * at all and the result will contain duplicates * * Jan * */ rte->inFromCl = FALSE; continue; } rel = heap_openr(rte->relname); if (rel->rd_rules == NULL) { heap_close(rel); continue; } rules = rel->rd_rules; locks = NIL; /* * Collect the RIR rules that we must apply */ for (i = 0; i < rules->numLocks; i++) { rule = rules->rules[i]; if (rule->event != CMD_SELECT) continue; if (rule->attrno > 0 && !attribute_used((Node *)parsetree, rt_index, rule->attrno, 0)) continue; locks = lappend(locks, rule); } /* * Check permissions */ checkLockPerms(locks, parsetree, rt_index); /* * Now apply them */ foreach (l, locks) { rule = lfirst(l); RIRonly.event = rule->event; RIRonly.attrno = rule->attrno; RIRonly.qual = rule->qual; RIRonly.actions = rule->actions; ApplyRetrieveRule(parsetree, &RIRonly, rt_index, RIRonly.attrno == -1, rel, &modified); } heap_close(rel); } fireRIRonSubselect((Node *) parsetree); modifyAggrefQual((Node **) &(parsetree->qual), parsetree); return parsetree; } /* * idea is to fire regular rules first, then qualified instead * rules and unqualified instead rules last. Any lemming is counted for. */ static List * orderRules(List *locks) { List *regular = NIL; List *instead_rules = NIL; List *instead_qualified = NIL; List *i; foreach(i, locks) { RewriteRule *rule_lock = (RewriteRule *) lfirst(i); if (rule_lock->isInstead) { if (rule_lock->qual == NULL) instead_rules = lappend(instead_rules, rule_lock); else instead_qualified = lappend(instead_qualified, rule_lock); } else regular = lappend(regular, rule_lock); } regular = nconc(regular, instead_qualified); return nconc(regular, instead_rules); } 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); return new_tree; } /* * fireRules - * Iterate through rule locks applying rules. * All rules create their own parsetrees. Instead rules * with rule qualification save the original parsetree * and add their negated qualification to it. Real instead * rules finally throw away the original parsetree. * * remember: reality is for dead birds -- glass * */ static List * fireRules(Query *parsetree, int rt_index, CmdType event, bool *instead_flag, List *locks, List **qual_products) { 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) { RewriteRule *rule_lock = (RewriteRule *) lfirst(i); Node *qual, *event_qual; List *actions; List *r; /* * Instead rules change the resultRelation of the query. So the * permission checks on the initial resultRelation would never be * done (this is normally done in the executor deep down). So we * must do it here. The result relations resulting from earlier * rewrites are already checked against the rules eventrelation * owner (during matchLocks) and have the skipAcl flag set. */ if (rule_lock->isInstead && parsetree->commandType != CMD_SELECT) { RangeTblEntry *rte; int32 acl_rc; int32 reqperm; switch (parsetree->commandType) { case CMD_INSERT: reqperm = ACL_AP; break; default: reqperm = ACL_WR; break; } rte = (RangeTblEntry *) nth(parsetree->resultRelation - 1, parsetree->rtable); if (!rte->skipAcl) { acl_rc = pg_aclcheck(rte->relname, GetPgUserName(), reqperm); if (acl_rc != ACLCHECK_OK) { elog(ERROR, "%s: %s", rte->relname, aclcheck_error_strings[acl_rc]); } } } /* multiple rule action time */ *instead_flag = rule_lock->isInstead; event_qual = rule_lock->qual; actions = rule_lock->actions; if (event_qual != NULL && *instead_flag) { 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); } 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); } /* ---------- * If this was an unqualified instead rule, * throw away an eventually saved 'default' parsetree * ---------- */ if (event_qual == NULL && *instead_flag) *qual_products = NIL; } return results; } static List * RewriteQuery(Query *parsetree, bool *instead_flag, List **qual_products) { CmdType event; List *product_queries = NIL; int result_relation = 0; RangeTblEntry *rt_entry; Relation rt_entry_relation = NULL; RuleLock *rt_entry_locks = NULL; Assert(parsetree != NULL); event = parsetree->commandType; /* * SELECT rules are handled later when we have all the * queries that should get executed */ if (event == CMD_SELECT) return NIL; /* * Utilities aren't rewritten at all - why is this here? */ if (event == CMD_UTILITY) return NIL; /* * only for a delete may the targetlist be NULL */ if (event != CMD_DELETE) Assert(parsetree->targetList != NULL); result_relation = parsetree->resultRelation; /* * the statement is an update, insert or delete - fire rules * on it. */ rt_entry = rt_fetch(result_relation, parsetree->rtable); rt_entry_relation = heap_openr(rt_entry->relname); rt_entry_locks = rt_entry_relation->rd_rules; heap_close(rt_entry_relation); 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; } /* * 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 */ static List * deepRewriteQuery(Query *parsetree) { List *n; List *rewritten = NIL; List *result = NIL; bool instead; List *qual_products = NIL; if (++numQueryRewriteInvoked > REWRITE_INVOKE_MAX) { elog(ERROR, "query rewritten %d times, may contain cycles", numQueryRewriteInvoked - 1); } instead = FALSE; result = RewriteQuery(parsetree, &instead, &qual_products); foreach(n, result) { Query *pt = lfirst(n); List *newstuff = NIL; newstuff = deepRewriteQuery(pt); if (newstuff != NIL) rewritten = nconc(rewritten, newstuff); } /* ---------- * qual_products are the original query with the negated * rule qualification of an instead rule * ---------- */ if (qual_products != NIL) rewritten = nconc(rewritten, qual_products); /* ---------- * The original query is appended last if not instead * because update and delete rule actions might not do * anything if they are invoked after the update or * delete is performed. The command counter increment * between the query execution makes the deleted (and * maybe the updated) tuples disappear so the scans * for them in the rule actions cannot find them. * ---------- */ if (!instead) rewritten = lappend(rewritten, parsetree); return rewritten; } /* * QueryOneRewrite - * rewrite one query */ static List * QueryRewriteOne(Query *parsetree) { numQueryRewriteInvoked = 0; /* * take a deep breath and apply all the rewrite rules - ay */ return deepRewriteQuery(parsetree); } /* ---------- * RewritePreprocessQuery - * adjust details in the parsetree, the rule system * depends on * ---------- */ static void RewritePreprocessQuery(Query *parsetree) { /* ---------- * if the query has a resultRelation, reassign the * result domain numbers to the attribute numbers in the * target relation. FixNew() depends on it when replacing * *new* references in a rule action by the expressions * from the rewritten query. * ---------- */ if (parsetree->resultRelation > 0) { RangeTblEntry *rte; Relation rd; List *tl; TargetEntry *tle; int resdomno; rte = (RangeTblEntry *) nth(parsetree->resultRelation - 1, parsetree->rtable); rd = heap_openr(rte->relname); foreach(tl, parsetree->targetList) { tle = (TargetEntry *) lfirst(tl); resdomno = attnameAttNum(rd, tle->resdom->resname); tle->resdom->resno = resdomno; } heap_close(rd); } } /* * 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; /* * Step 1 * * There still seems something broken with the resdom numbers * so we reassign them first. */ RewritePreprocessQuery(parsetree); /* * Step 2 * * Apply all non-SELECT rules possibly getting 0 or many queries */ querylist = QueryRewriteOne(parsetree); /* * Step 3 * * Apply all the RIR rules on each query */ foreach (l, querylist) { query = fireRIRrules((Query *)lfirst(l)); /* * 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; } /* * QueryRewrite - * Primary entry point to the query rewriter. * Rewrite one query via query rewrite system, possibly returning 0 * or many queries. * * 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. */ List * QueryRewrite(Query *parsetree) { List *rewritten, *rewritten_item; /***S*I***/ /* Rewrite Union, Intersect and Except Queries * to normal Union Queries using IN and NOT IN subselects */ if (parsetree->intersectClause) parsetree = Except_Intersect_Rewrite(parsetree); /* 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; } /***S*I***/ /* 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 */ 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."); foreach(next_target, current_target) { Oid itype; Oid otype; otype = ((TargetEntry *) lfirst(prev_target))->resdom->restype; itype = ((TargetEntry *) lfirst(next_target))->resdom->restype; /* one or both is a NULL column? then don't convert... */ if (otype == InvalidOid) { /* propagate a known type forward, if available */ if (itype != InvalidOid) ((TargetEntry *) lfirst(prev_target))->resdom->restype = itype; #ifdef NOT_USED else { ((TargetEntry *) lfirst(prev_target))->resdom->restype = UNKNOWNOID; ((TargetEntry *) lfirst(next_target))->resdom->restype = UNKNOWNOID; } #endif } else if (itype == InvalidOid) { } /* they don't match in type? then convert... */ else if (itype != otype) { Node *expr; expr = ((TargetEntry *) lfirst(next_target))->expr; expr = CoerceTargetExpr(NULL, expr, itype, otype); if (expr == NULL) { elog(ERROR, "Unable to transform %s to %s" "\n\tEach UNION | EXCEPT | INTERSECT clause must have compatible target types", typeidTypeName(itype), typeidTypeName(otype)); } ((TargetEntry *) lfirst(next_target))->expr = expr; ((TargetEntry *) lfirst(next_target))->resdom->restype = otype; } /* both are UNKNOWN? then evaluate as text... */ else if (itype == UNKNOWNOID) { ((TargetEntry *) lfirst(next_target))->resdom->restype = TEXTOID; ((TargetEntry *) lfirst(prev_target))->resdom->restype = TEXTOID; } prev_target = lnext(prev_target); } } /***S*I***/ /* 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!) */ 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; /* 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); resnames = lappend(resnames, tent->resdom->resname); } /* 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; /* 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); } /* 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); /* 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; /* Transform the operator tree to DNF (remember ANDs and ORs have been exchanged, * that's why we get DNF by using cnfify) * * After the call, explicit ANDs are removed and all AND operands * are simply items in the intersectClause list */ intersectClause = cnfify((Expr *)intersectClause, true); /* For every entry of the intersectClause list we generate one entry in * the union_list */ foreach(intersect, intersectClause) { /* 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_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); /* Check if all Select Statements use the same number of attributes and * if all corresponding attributes are of the same type */ if (prev_target) check_targetlists_are_compatible(prev_target, intersect_node->targetList); prev_target = intersect_node->targetList; /* End of check for corresponding targetlists */ /* Transform all nodes remaining into subselects and add them to * the qualifications of the Select Query node */ while(intersect_list != NIL) { n = makeNode(SubLink); /* Here we got an OR so transform it to an IN subselect */ if(IsA(lfirst(intersect_list), Query)) { /* 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; } /* Here we got an OR NOT node so transform it to a NOT IN subselect */ else { /* 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; } /* Prepare the lefthand side of the Sublinks: All the entries of the * targetlist must be (IN) or must not be (NOT IN) the subselect */ foreach(elist, intersect_node->targetList) { Node *expr = lfirst(elist); TargetEntry *tent = (TargetEntry *)expr; n->lefthand = lappend(n->lefthand, tent->expr); } /* The first arguments of oper also have to be created for the * sublink (they are the same as the lefthand side!) */ left_expr = n->lefthand; right_expr = ((Query *)(n->subselect))->targetList; foreach(elist, left_expr) { Node *lexpr = lfirst(elist); Node *rexpr = lfirst(right_expr); TargetEntry *tent = (TargetEntry *) rexpr; Expr *op_expr; op_expr = make_op(op, lexpr, tent->expr); n->oper = lappend(n->oper, op_expr); right_expr = lnext(right_expr); } /* 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 == false) { AddQual(intersect_node, (Node *)n); } else { AddHavingQual(intersect_node, (Node *)n); } /* Now we got sublinks */ intersect_node->hasSubLinks = true; intersect_list = lnext(intersect_list); } 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; /* 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; } /* The resnames of the originally first SelectStatement are * attached to the new first SelectStatement */ foreach(elist, result->targetList) { TargetEntry *tent = (TargetEntry *)lfirst(elist); tent->resdom->resname = lfirst(resnames); resnames = lnext(resnames); } return result; } /* 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 */ void create_list(Node *ptr, List **intersect_list) { List *arg; if(IsA(ptr,Query)) { /* The non negated node is attached at the beginning (lcons) */ *intersect_list = lcons(ptr, *intersect_list); return; } if(IsA(ptr,Expr)) { 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_list(lfirst(arg), intersect_list); } return; } return; } } /* 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. */ Node *intersect_tree_analyze(Node *tree, Node *first_select, Node *parsetree) { Node *result = (Node *) NIL; List *arg; if (IsA(tree, SelectStmt)) { /* If we get to the tree given in first_select return * parsetree instead of performing parse_analyze() */ if (tree == first_select) { result = parsetree; } else { /* transform the 'raw' nodes to 'cooked' Query nodes */ List *qtree = parse_analyze(lcons(tree, NIL), NULL); result = (Node *) lfirst(qtree); } } 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; }