diff options
Diffstat (limited to 'src/backend/optimizer/plan/planmain.c')
| -rw-r--r-- | src/backend/optimizer/plan/planmain.c | 52 |
1 files changed, 14 insertions, 38 deletions
diff --git a/src/backend/optimizer/plan/planmain.c b/src/backend/optimizer/plan/planmain.c index a919914f944..42a98945a38 100644 --- a/src/backend/optimizer/plan/planmain.c +++ b/src/backend/optimizer/plan/planmain.c @@ -30,10 +30,6 @@ #include "utils/selfuncs.h" -/* Local functions */ -static void canonicalize_all_pathkeys(PlannerInfo *root); - - /* * query_planner * Generate a path (that is, a simplified plan) for a basic query, @@ -55,6 +51,8 @@ static void canonicalize_all_pathkeys(PlannerInfo *root); * tuple_fraction is the fraction of tuples we expect will be retrieved * limit_tuples is a hard limit on number of tuples to retrieve, * or -1 if no limit + * qp_callback is a function to compute query_pathkeys once it's safe to do so + * qp_extra is optional extra data to pass to qp_callback * * Output parameters: * *cheapest_path receives the overall-cheapest path for the query @@ -63,18 +61,11 @@ static void canonicalize_all_pathkeys(PlannerInfo *root); * *num_groups receives the estimated number of groups, or 1 if query * does not use grouping * - * Note: the PlannerInfo node also includes a query_pathkeys field, which is - * both an input and an output of query_planner(). The input value signals - * query_planner that the indicated sort order is wanted in the final output - * plan. But this value has not yet been "canonicalized", since the needed - * info does not get computed until we scan the qual clauses. We canonicalize - * it as soon as that task is done. (The main reason query_pathkeys is a - * PlannerInfo field and not a passed parameter is that the low-level routines - * in indxpath.c need to see it.) - * - * Note: the PlannerInfo node includes other pathkeys fields besides - * query_pathkeys, all of which need to be canonicalized once the info is - * available. See canonicalize_all_pathkeys. + * Note: the PlannerInfo node also includes a query_pathkeys field, which + * tells query_planner the sort order that is desired in the final output + * plan. This value is *not* available at call time, but is computed by + * qp_callback once we have completed merging the query's equivalence classes. + * (We cannot construct canonical pathkeys until that's done.) * * tuple_fraction is interpreted as follows: * 0: expect all tuples to be retrieved (normal case) @@ -89,6 +80,7 @@ static void canonicalize_all_pathkeys(PlannerInfo *root); void query_planner(PlannerInfo *root, List *tlist, double tuple_fraction, double limit_tuples, + query_pathkeys_callback qp_callback, void *qp_extra, Path **cheapest_path, Path **sorted_path, double *num_groups) { @@ -118,11 +110,11 @@ query_planner(PlannerInfo *root, List *tlist, *sorted_path = NULL; /* - * We still are required to canonicalize any pathkeys, in case it's - * something like "SELECT 2+2 ORDER BY 1". + * We still are required to call qp_callback, in case it's something + * like "SELECT 2+2 ORDER BY 1". */ root->canon_pathkeys = NIL; - canonicalize_all_pathkeys(root); + (*qp_callback) (root, qp_extra); return; } @@ -205,10 +197,10 @@ query_planner(PlannerInfo *root, List *tlist, /* * We have completed merging equivalence sets, so it's now possible to - * convert previously generated pathkeys (in particular, the requested - * query_pathkeys) to canonical form. + * generate pathkeys in canonical form; so compute query_pathkeys and + * other pathkeys fields in PlannerInfo. */ - canonicalize_all_pathkeys(root); + (*qp_callback) (root, qp_extra); /* * Examine any "placeholder" expressions generated during subquery pullup. @@ -429,19 +421,3 @@ query_planner(PlannerInfo *root, List *tlist, *cheapest_path = cheapestpath; *sorted_path = sortedpath; } - - -/* - * canonicalize_all_pathkeys - * Canonicalize all pathkeys that were generated before entering - * query_planner and then stashed in PlannerInfo. - */ -static void -canonicalize_all_pathkeys(PlannerInfo *root) -{ - root->query_pathkeys = canonicalize_pathkeys(root, root->query_pathkeys); - root->group_pathkeys = canonicalize_pathkeys(root, root->group_pathkeys); - root->window_pathkeys = canonicalize_pathkeys(root, root->window_pathkeys); - root->distinct_pathkeys = canonicalize_pathkeys(root, root->distinct_pathkeys); - root->sort_pathkeys = canonicalize_pathkeys(root, root->sort_pathkeys); -} |