diff options
Diffstat (limited to 'src/backend/optimizer/plan/planner.c')
| -rw-r--r-- | src/backend/optimizer/plan/planner.c | 63 |
1 files changed, 33 insertions, 30 deletions
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index c7c072fe2eb..9fa78b8a237 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.150 2003/03/05 20:01:03 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.151 2003/03/10 03:53:50 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -19,6 +19,7 @@ #include "catalog/pg_operator.h" #include "catalog/pg_type.h" +#include "executor/executor.h" #include "miscadmin.h" #include "nodes/makefuncs.h" #ifdef OPTIMIZER_DEBUG @@ -73,8 +74,9 @@ static List *postprocess_setop_tlist(List *new_tlist, List *orig_tlist); * *****************************************************************************/ Plan * -planner(Query *parse) +planner(Query *parse, bool isCursor, int cursorOptions) { + double tuple_fraction; Plan *result_plan; Index save_PlannerQueryLevel; List *save_PlannerParamVar; @@ -99,11 +101,38 @@ planner(Query *parse) PlannerQueryLevel = 0; /* will be 1 in top-level subquery_planner */ PlannerParamVar = NIL; + /* Determine what fraction of the plan is likely to be scanned */ + if (isCursor) + { + /* + * We have no real idea how many tuples the user will ultimately + * FETCH from a cursor, but it seems a good bet that he + * doesn't want 'em all. Optimize for 10% retrieval (you + * gotta better number? Should this be a SETtable parameter?) + */ + tuple_fraction = 0.10; + } + else + { + /* Default assumption is we need all the tuples */ + tuple_fraction = 0.0; + } + /* primary planning entry point (may recurse for subqueries) */ - result_plan = subquery_planner(parse, -1.0 /* default case */ ); + result_plan = subquery_planner(parse, tuple_fraction); Assert(PlannerQueryLevel == 0); + /* + * If creating a plan for a scrollable cursor, make sure it can + * run backwards on demand. Add a Material node at the top at need. + */ + if (isCursor && (cursorOptions & CURSOR_OPT_SCROLL)) + { + if (!ExecSupportsBackwardScan(result_plan)) + result_plan = materialize_finished_plan(result_plan); + } + /* executor wants to know total number of Params used overall */ result_plan->nParamExec = length(PlannerParamVar); @@ -505,14 +534,11 @@ inheritance_planner(Query *parse, List *inheritlist) * tuple_fraction is the fraction of tuples we expect will be retrieved * * tuple_fraction is interpreted as follows: - * < 0: determine fraction by inspection of query (normal case) - * 0: expect all tuples to be retrieved + * 0: expect all tuples to be retrieved (normal case) * 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) - * The normal case is to pass -1, but some callers pass values >= 0 to - * override this routine's determination of the appropriate fraction. * * Returns a query plan. Also, parse->query_pathkeys is returned as the * actual output ordering of the plan (in pathkey format). @@ -694,29 +720,6 @@ grouping_planner(Query *parse, double tuple_fraction) parse->query_pathkeys = NIL; /* - * Figure out whether we expect to retrieve all the tuples that - * the plan can generate, or to stop early due to outside factors - * such as a cursor. If the caller passed a value >= 0, believe - * that value, else do our own examination of the query context. - */ - if (tuple_fraction < 0.0) - { - /* Initial assumption is we need all the tuples */ - tuple_fraction = 0.0; - - /* - * Check for retrieve-into-portal, ie DECLARE CURSOR. - * - * We have no real idea how many tuples the user will ultimately - * FETCH from a cursor, but it seems a good bet that he - * doesn't want 'em all. Optimize for 10% retrieval (you - * gotta better number? Should this be a SETtable parameter?) - */ - if (parse->isPortal) - tuple_fraction = 0.10; - } - - /* * Adjust tuple_fraction if we see that we are going to apply * limiting/grouping/aggregation/etc. This is not overridable by * the caller, since it reflects plan actions that this routine |