diff options
Diffstat (limited to 'src/backend/optimizer/plan/subselect.c')
| -rw-r--r-- | src/backend/optimizer/plan/subselect.c | 119 |
1 files changed, 83 insertions, 36 deletions
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c index be92049ec4d..3e7dc851579 100644 --- a/src/backend/optimizer/plan/subselect.c +++ b/src/backend/optimizer/plan/subselect.c @@ -55,8 +55,9 @@ typedef struct finalize_primnode_context static Node *build_subplan(PlannerInfo *root, Plan *plan, PlannerInfo *subroot, List *plan_params, - SubLinkType subLinkType, Node *testexpr, - bool adjust_testexpr, bool unknownEqFalse); + SubLinkType subLinkType, int subLinkId, + Node *testexpr, bool adjust_testexpr, + bool unknownEqFalse); static List *generate_subquery_params(PlannerInfo *root, List *tlist, List **paramIds); static List *generate_subquery_vars(PlannerInfo *root, List *tlist, @@ -407,7 +408,7 @@ get_first_col_type(Plan *plan, Oid *coltype, int32 *coltypmod, /* * Convert a SubLink (as created by the parser) into a SubPlan. * - * We are given the SubLink's contained query, type, and testexpr. We are + * We are given the SubLink's contained query, type, ID, and testexpr. We are * also told if this expression appears at top level of a WHERE/HAVING qual. * * Note: we assume that the testexpr has been AND/OR flattened (actually, @@ -415,14 +416,20 @@ get_first_col_type(Plan *plan, Oid *coltype, int32 *coltypmod, * implicit-AND form; and any SubLinks in it should already have been * converted to SubPlans. The subquery is as yet untouched, however. * - * The result is whatever we need to substitute in place of the SubLink - * node in the executable expression. This will be either the SubPlan - * node (if we have to do the subplan as a subplan), or a Param node - * representing the result of an InitPlan, or a row comparison expression - * tree containing InitPlan Param nodes. + * The result is whatever we need to substitute in place of the SubLink node + * in the executable expression. If we're going to do the subplan as a + * regular subplan, this will be the constructed SubPlan node. If we're going + * to do the subplan as an InitPlan, the SubPlan node instead goes into + * root->init_plans, and what we return here is an expression tree + * representing the InitPlan's result: usually just a Param node representing + * a single scalar result, but possibly a row comparison tree containing + * multiple Param nodes, or for a MULTIEXPR subquery a simple NULL constant + * (since the real output Params are elsewhere in the tree, and the MULTIEXPR + * subquery itself is in a resjunk tlist entry whose value is uninteresting). */ static Node * -make_subplan(PlannerInfo *root, Query *orig_subquery, SubLinkType subLinkType, +make_subplan(PlannerInfo *root, Query *orig_subquery, + SubLinkType subLinkType, int subLinkId, Node *testexpr, bool isTopQual) { Query *subquery; @@ -452,8 +459,8 @@ make_subplan(PlannerInfo *root, Query *orig_subquery, SubLinkType subLinkType, * first tuple will be retrieved. For ALL and ANY subplans, we will be * able to stop evaluating if the test condition fails or matches, so very * often not all the tuples will be retrieved; for lack of a better idea, - * specify 50% retrieval. For EXPR and ROWCOMPARE subplans, use default - * behavior (we're only expecting one row out, anyway). + * specify 50% retrieval. For EXPR, MULTIEXPR, and ROWCOMPARE subplans, + * use default behavior (we're only expecting one row out, anyway). * * NOTE: if you change these numbers, also change cost_subplan() in * path/costsize.c. @@ -491,7 +498,8 @@ make_subplan(PlannerInfo *root, Query *orig_subquery, SubLinkType subLinkType, /* And convert to SubPlan or InitPlan format. */ result = build_subplan(root, plan, subroot, plan_params, - subLinkType, testexpr, true, isTopQual); + subLinkType, subLinkId, + testexpr, true, isTopQual); /* * If it's a correlated EXISTS with an unimportant targetlist, we might be @@ -536,7 +544,8 @@ make_subplan(PlannerInfo *root, Query *orig_subquery, SubLinkType subLinkType, /* OK, convert to SubPlan format. */ hashplan = (SubPlan *) build_subplan(root, plan, subroot, plan_params, - ANY_SUBLINK, newtestexpr, + ANY_SUBLINK, 0, + newtestexpr, false, true); /* Check we got what we expected */ Assert(IsA(hashplan, SubPlan)); @@ -559,14 +568,15 @@ make_subplan(PlannerInfo *root, Query *orig_subquery, SubLinkType subLinkType, /* * Build a SubPlan node given the raw inputs --- subroutine for make_subplan * - * Returns either the SubPlan, or an expression using initplan output Params, - * as explained in the comments for make_subplan. + * Returns either the SubPlan, or a replacement expression if we decide to + * make it an InitPlan, as explained in the comments for make_subplan. */ static Node * build_subplan(PlannerInfo *root, Plan *plan, PlannerInfo *subroot, List *plan_params, - SubLinkType subLinkType, Node *testexpr, - bool adjust_testexpr, bool unknownEqFalse) + SubLinkType subLinkType, int subLinkId, + Node *testexpr, bool adjust_testexpr, + bool unknownEqFalse) { Node *result; SubPlan *splan; @@ -615,12 +625,15 @@ build_subplan(PlannerInfo *root, Plan *plan, PlannerInfo *subroot, } /* - * Un-correlated or undirect correlated plans of EXISTS, EXPR, ARRAY, or - * ROWCOMPARE types can be used as initPlans. For EXISTS, EXPR, or ARRAY, - * we just produce a Param referring to the result of evaluating the - * initPlan. For ROWCOMPARE, we must modify the testexpr tree to contain - * PARAM_EXEC Params instead of the PARAM_SUBLINK Params emitted by the - * parser. + * Un-correlated or undirect correlated plans of EXISTS, EXPR, ARRAY, + * ROWCOMPARE, or MULTIEXPR types can be used as initPlans. For EXISTS, + * EXPR, or ARRAY, we return a Param referring to the result of evaluating + * the initPlan. For ROWCOMPARE, we must modify the testexpr tree to + * contain PARAM_EXEC Params instead of the PARAM_SUBLINK Params emitted + * by the parser, and then return that tree. For MULTIEXPR, we return a + * null constant: the resjunk targetlist item containing the SubLink does + * not need to return anything useful, since the referencing Params are + * elsewhere. */ if (splan->parParam == NIL && subLinkType == EXISTS_SUBLINK) { @@ -687,6 +700,42 @@ build_subplan(PlannerInfo *root, Plan *plan, PlannerInfo *subroot, * plan's expression tree; it is not kept in the initplan node. */ } + else if (subLinkType == MULTIEXPR_SUBLINK) + { + /* + * Whether it's an initplan or not, it needs to set a PARAM_EXEC Param + * for each output column. + */ + List *params; + + Assert(testexpr == NULL); + params = generate_subquery_params(root, + plan->targetlist, + &splan->setParam); + + /* + * Save the list of replacement Params in the n'th cell of + * root->multiexpr_params; setrefs.c will use it to replace + * PARAM_MULTIEXPR Params. + */ + while (list_length(root->multiexpr_params) < subLinkId) + root->multiexpr_params = lappend(root->multiexpr_params, NIL); + lc = list_nth_cell(root->multiexpr_params, subLinkId - 1); + Assert(lfirst(lc) == NIL); + lfirst(lc) = params; + + /* It can be an initplan if there are no parParams. */ + if (splan->parParam == NIL) + { + isInitPlan = true; + result = (Node *) makeNullConst(RECORDOID, -1, InvalidOid); + } + else + { + isInitPlan = false; + result = (Node *) splan; + } + } else { /* @@ -760,25 +809,22 @@ build_subplan(PlannerInfo *root, Plan *plan, PlannerInfo *subroot, splan->plan_id); /* Label the subplan for EXPLAIN purposes */ - if (isInitPlan) + splan->plan_name = palloc(32 + 12 * list_length(splan->setParam)); + sprintf(splan->plan_name, "%s %d", + isInitPlan ? "InitPlan" : "SubPlan", + splan->plan_id); + if (splan->setParam) { - ListCell *lc; - int offset; + char *ptr = splan->plan_name + strlen(splan->plan_name); - splan->plan_name = palloc(32 + 12 * list_length(splan->setParam)); - sprintf(splan->plan_name, "InitPlan %d (returns ", splan->plan_id); - offset = strlen(splan->plan_name); + ptr += sprintf(ptr, " (returns "); foreach(lc, splan->setParam) { - sprintf(splan->plan_name + offset, "$%d%s", - lfirst_int(lc), - lnext(lc) ? "," : ""); - offset += strlen(splan->plan_name + offset); + ptr += sprintf(ptr, "$%d%s", + lfirst_int(lc), + lnext(lc) ? "," : ")"); } - sprintf(splan->plan_name + offset, ")"); } - else - splan->plan_name = psprintf("SubPlan %d", splan->plan_id); /* Lastly, fill in the cost estimates for use later */ cost_subplan(root, splan, plan); @@ -1816,6 +1862,7 @@ process_sublinks_mutator(Node *node, process_sublinks_context *context) return make_subplan(context->root, (Query *) sublink->subselect, sublink->subLinkType, + sublink->subLinkId, testexpr, context->isTopQual); } |