diff options
Diffstat (limited to 'src/backend/optimizer/plan/planner.c')
| -rw-r--r-- | src/backend/optimizer/plan/planner.c | 116 |
1 files changed, 95 insertions, 21 deletions
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index ddd23878409..032818423f6 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -54,6 +54,7 @@ #include "optimizer/tlist.h" #include "parser/analyze.h" #include "parser/parse_agg.h" +#include "parser/parse_clause.h" #include "parser/parse_relation.h" #include "parser/parsetree.h" #include "partitioning/partdesc.h" @@ -119,12 +120,15 @@ typedef struct { List *activeWindows; /* active windows, if any */ grouping_sets_data *gset_data; /* grouping sets data, if any */ + SetOperationStmt *setop; /* parent set operation or NULL if not a + * subquery belonging to a set operation */ } standard_qp_extra; /* Local functions */ static Node *preprocess_expression(PlannerInfo *root, Node *expr, int kind); static void preprocess_qual_conditions(PlannerInfo *root, Node *jtnode); -static void grouping_planner(PlannerInfo *root, double tuple_fraction); +static void grouping_planner(PlannerInfo *root, double tuple_fraction, + SetOperationStmt *setops); static grouping_sets_data *preprocess_grouping_sets(PlannerInfo *root); static List *remap_to_groupclause_idx(List *groupClause, List *gsets, int *tleref_to_colnum_map); @@ -249,6 +253,8 @@ static bool group_by_has_partkey(RelOptInfo *input_rel, List *targetList, List *groupClause); static int common_prefix_cmp(const void *a, const void *b); +static List *generate_setop_child_grouplist(SetOperationStmt *op, + List *targetlist); /***************************************************************************** @@ -406,8 +412,7 @@ standard_planner(Query *parse, const char *query_string, int cursorOptions, } /* primary planning entry point (may recurse for subqueries) */ - root = subquery_planner(glob, parse, NULL, - false, tuple_fraction); + root = subquery_planner(glob, parse, NULL, false, tuple_fraction, NULL); /* Select best Path and turn it into a Plan */ final_rel = fetch_upper_rel(root, UPPERREL_FINAL, NULL); @@ -598,6 +603,10 @@ standard_planner(Query *parse, const char *query_string, int cursorOptions, * hasRecursion is true if this is a recursive WITH query. * tuple_fraction is the fraction of tuples we expect will be retrieved. * tuple_fraction is interpreted as explained for grouping_planner, below. + * setops is used for set operation subqueries to provide the subquery with + * the context in which it's being used so that Paths correctly sorted for the + * set operation can be generated. NULL when not planning a set operation + * child. * * Basically, this routine does the stuff that should only be done once * per Query object. It then calls grouping_planner. At one time, @@ -616,9 +625,9 @@ standard_planner(Query *parse, const char *query_string, int cursorOptions, *-------------------- */ PlannerInfo * -subquery_planner(PlannerGlobal *glob, Query *parse, - PlannerInfo *parent_root, - bool hasRecursion, double tuple_fraction) +subquery_planner(PlannerGlobal *glob, Query *parse, PlannerInfo *parent_root, + bool hasRecursion, double tuple_fraction, + SetOperationStmt *setops) { PlannerInfo *root; List *newWithCheckOptions; @@ -1077,7 +1086,7 @@ subquery_planner(PlannerGlobal *glob, Query *parse, /* * Do the main planning. */ - grouping_planner(root, tuple_fraction); + grouping_planner(root, tuple_fraction, setops); /* * Capture the set of outer-level param IDs we have access to, for use in @@ -1275,7 +1284,11 @@ preprocess_phv_expression(PlannerInfo *root, Expr *expr) * 0 < tuple_fraction < 1: expect the given fraction of tuples available * from the plan to be retrieved * tuple_fraction >= 1: tuple_fraction is the absolute number of tuples - * expected to be retrieved (ie, a LIMIT specification) + * expected to be retrieved (ie, a LIMIT specification). + * setops is used for set operation subqueries to provide the subquery with + * the context in which it's being used so that Paths correctly sorted for the + * set operation can be generated. NULL when not planning a set operation + * child. * * Returns nothing; the useful output is in the Paths we attach to the * (UPPERREL_FINAL, NULL) upperrel in *root. In addition, @@ -1286,7 +1299,8 @@ preprocess_phv_expression(PlannerInfo *root, Expr *expr) *-------------------- */ static void -grouping_planner(PlannerInfo *root, double tuple_fraction) +grouping_planner(PlannerInfo *root, double tuple_fraction, + SetOperationStmt *setops) { Query *parse = root->parse; int64 offset_est = 0; @@ -1322,17 +1336,6 @@ grouping_planner(PlannerInfo *root, double tuple_fraction) if (parse->setOperations) { /* - * If there's a top-level ORDER BY, assume we have to fetch all the - * tuples. This might be too simplistic given all the hackery below - * to possibly avoid the sort; but the odds of accurate estimates here - * are pretty low anyway. XXX try to get rid of this in favor of - * letting plan_set_operations generate both fast-start and - * cheapest-total paths. - */ - if (parse->sortClause) - root->tuple_fraction = 0.0; - - /* * Construct Paths for set operations. The results will not need any * work except perhaps a top-level sort and/or LIMIT. Note that any * special work for recursive unions is the responsibility of @@ -1502,6 +1505,12 @@ grouping_planner(PlannerInfo *root, double tuple_fraction) qp_extra.gset_data = gset_data; /* + * If we're a subquery for a set operation, store the SetOperationStmt + * in qp_extra. + */ + qp_extra.setop = setops; + + /* * Generate the best unsorted and presorted paths for the scan/join * portion of this Query, ie the processing represented by the * FROM/WHERE clauses. (Note there may not be any presorted paths.) @@ -3453,6 +3462,27 @@ standard_qp_callback(PlannerInfo *root, void *extra) parse->sortClause, tlist); + /* setting setop_pathkeys might be useful to the union planner */ + if (qp_extra->setop != NULL && + set_operation_ordered_results_useful(qp_extra->setop)) + { + List *groupClauses; + bool sortable; + + groupClauses = generate_setop_child_grouplist(qp_extra->setop, tlist); + + root->setop_pathkeys = + make_pathkeys_for_sortclauses_extended(root, + &groupClauses, + tlist, + false, + &sortable); + if (!sortable) + root->setop_pathkeys = NIL; + } + else + root->setop_pathkeys = NIL; + /* * Figure out whether we want a sorted result from query_planner. * @@ -3462,7 +3492,9 @@ standard_qp_callback(PlannerInfo *root, void *extra) * sortable DISTINCT clause that's more rigorous than the ORDER BY clause, * we try to produce output that's sufficiently well sorted for the * DISTINCT. Otherwise, if there is an ORDER BY clause, we want to sort - * by the ORDER BY clause. + * by the ORDER BY clause. Otherwise, if we're a subquery being planned + * for a set operation which can benefit from presorted results and have a + * sortable targetlist, we want to sort by the target list. * * Note: if we have both ORDER BY and GROUP BY, and ORDER BY is a superset * of GROUP BY, it would be tempting to request sort by ORDER BY --- but @@ -3480,6 +3512,8 @@ standard_qp_callback(PlannerInfo *root, void *extra) root->query_pathkeys = root->distinct_pathkeys; else if (root->sort_pathkeys) root->query_pathkeys = root->sort_pathkeys; + else if (root->setop_pathkeys != NIL) + root->query_pathkeys = root->setop_pathkeys; else root->query_pathkeys = NIL; } @@ -7923,3 +7957,43 @@ group_by_has_partkey(RelOptInfo *input_rel, return true; } + +/* + * generate_setop_child_grouplist + * Build a SortGroupClause list defining the sort/grouping properties + * of the child of a set operation. + * + * This is similar to generate_setop_grouplist() but differs as the setop + * child query's targetlist entries may already have a tleSortGroupRef + * assigned for other purposes, such as GROUP BYs. Here we keep the + * SortGroupClause list in the same order as 'op' groupClauses and just adjust + * the tleSortGroupRef to reference the TargetEntry's 'ressortgroupref'. + */ +static List * +generate_setop_child_grouplist(SetOperationStmt *op, List *targetlist) +{ + List *grouplist = copyObject(op->groupClauses); + ListCell *lg; + ListCell *lt; + + lg = list_head(grouplist); + foreach(lt, targetlist) + { + TargetEntry *tle = (TargetEntry *) lfirst(lt); + SortGroupClause *sgc; + + /* resjunk columns could have sortgrouprefs. Leave these alone */ + if (tle->resjunk) + continue; + + /* we expect every non-resjunk target to have a SortGroupClause */ + Assert(lg != NULL); + sgc = (SortGroupClause *) lfirst(lg); + lg = lnext(grouplist, lg); + + /* assign a tleSortGroupRef, or reuse the existing one */ + sgc->tleSortGroupRef = assignSortGroupRef(tle, targetlist); + } + Assert(lg == NULL); + return grouplist; +} |