diff options
Diffstat (limited to 'src/backend/optimizer/plan/initsplan.c')
| -rw-r--r-- | src/backend/optimizer/plan/initsplan.c | 64 |
1 files changed, 50 insertions, 14 deletions
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c index cf05f033b9a..952fd7649fd 100644 --- a/src/backend/optimizer/plan/initsplan.c +++ b/src/backend/optimizer/plan/initsplan.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/plan/initsplan.c,v 1.149 2009/02/27 22:41:38 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/plan/initsplan.c,v 1.150 2009/04/16 20:42:16 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -53,7 +53,7 @@ static void distribute_qual_to_rels(PlannerInfo *root, Node *clause, Relids ojscope, Relids outerjoin_nonnullable); static bool check_outerjoin_delay(PlannerInfo *root, Relids *relids_p, - bool is_pushed_down); + Relids *nullable_relids_p, bool is_pushed_down); static bool check_redundant_nullability_qual(PlannerInfo *root, Node *clause); static void check_mergejoinable(RestrictInfo *restrictinfo); static void check_hashjoinable(RestrictInfo *restrictinfo); @@ -755,6 +755,7 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause, bool pseudoconstant = false; bool maybe_equivalence; bool maybe_outer_join; + Relids nullable_relids; RestrictInfo *restrictinfo; /* @@ -861,6 +862,7 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause, Assert(!ojscope); is_pushed_down = true; outerjoin_delayed = false; + nullable_relids = NULL; /* Don't feed it back for more deductions */ maybe_equivalence = false; maybe_outer_join = false; @@ -882,7 +884,10 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause, maybe_outer_join = true; /* Check to see if must be delayed by lower outer join */ - outerjoin_delayed = check_outerjoin_delay(root, &relids, false); + outerjoin_delayed = check_outerjoin_delay(root, + &relids, + &nullable_relids, + false); /* * Now force the qual to be evaluated exactly at the level of joining @@ -907,7 +912,10 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause, is_pushed_down = true; /* Check to see if must be delayed by lower outer join */ - outerjoin_delayed = check_outerjoin_delay(root, &relids, true); + outerjoin_delayed = check_outerjoin_delay(root, + &relids, + &nullable_relids, + true); if (outerjoin_delayed) { @@ -957,7 +965,8 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause, is_pushed_down, outerjoin_delayed, pseudoconstant, - relids); + relids, + nullable_relids); /* * If it's a join clause (either naturally, or because delayed by @@ -1064,7 +1073,9 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause, * If the qual must be delayed, add relids to *relids_p to reflect the lowest * safe level for evaluating the qual, and return TRUE. Any extra delay for * higher-level joins is reflected by setting delay_upper_joins to TRUE in - * SpecialJoinInfo structs. + * SpecialJoinInfo structs. We also compute nullable_relids, the set of + * referenced relids that are nullable by lower outer joins (note that this + * can be nonempty even for a non-delayed qual). * * For an is_pushed_down qual, we can evaluate the qual as soon as (1) we have * all the rels it mentions, and (2) we are at or above any outer joins that @@ -1087,8 +1098,8 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause, * mentioning only C cannot be applied below the join to A. * * For a non-pushed-down qual, this isn't going to determine where we place the - * qual, but we need to determine outerjoin_delayed anyway for possible use - * in reconsider_outer_join_clauses(). + * qual, but we need to determine outerjoin_delayed and nullable_relids anyway + * for use later in the planning process. * * Lastly, a pushed-down qual that references the nullable side of any current * join_info_list member and has to be evaluated above that OJ (because its @@ -1104,13 +1115,26 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause, * two OJs to commute.) */ static bool -check_outerjoin_delay(PlannerInfo *root, Relids *relids_p, +check_outerjoin_delay(PlannerInfo *root, + Relids *relids_p, /* in/out parameter */ + Relids *nullable_relids_p, /* output parameter */ bool is_pushed_down) { - Relids relids = *relids_p; + Relids relids; + Relids nullable_relids; bool outerjoin_delayed; bool found_some; + /* fast path if no special joins */ + if (root->join_info_list == NIL) + { + *nullable_relids_p = NULL; + return false; + } + + /* must copy relids because we need the original value at the end */ + relids = bms_copy(*relids_p); + nullable_relids = NULL; outerjoin_delayed = false; do { @@ -1126,18 +1150,23 @@ check_outerjoin_delay(PlannerInfo *root, Relids *relids_p, (sjinfo->jointype == JOIN_FULL && bms_overlap(relids, sjinfo->min_lefthand))) { - /* yes, so set the result flag */ - outerjoin_delayed = true; - /* have we included all its rels in relids? */ + /* yes; have we included all its rels in relids? */ if (!bms_is_subset(sjinfo->min_lefthand, relids) || !bms_is_subset(sjinfo->min_righthand, relids)) { /* no, so add them in */ relids = bms_add_members(relids, sjinfo->min_lefthand); relids = bms_add_members(relids, sjinfo->min_righthand); + outerjoin_delayed = true; /* we'll need another iteration */ found_some = true; } + /* track all the nullable rels of relevant OJs */ + nullable_relids = bms_add_members(nullable_relids, + sjinfo->min_righthand); + if (sjinfo->jointype == JOIN_FULL) + nullable_relids = bms_add_members(nullable_relids, + sjinfo->min_lefthand); /* set delay_upper_joins if needed */ if (is_pushed_down && sjinfo->jointype != JOIN_FULL && bms_overlap(relids, sjinfo->min_lefthand)) @@ -1146,7 +1175,13 @@ check_outerjoin_delay(PlannerInfo *root, Relids *relids_p, } } while (found_some); + /* identify just the actually-referenced nullable rels */ + nullable_relids = bms_int_members(nullable_relids, *relids_p); + + /* replace *relids_p, and return nullable_relids */ + bms_free(*relids_p); *relids_p = relids; + *nullable_relids_p = nullable_relids; return outerjoin_delayed; } @@ -1352,7 +1387,8 @@ build_implied_join_equality(Oid opno, true, /* is_pushed_down */ false, /* outerjoin_delayed */ false, /* pseudoconstant */ - qualscope); + qualscope, /* required_relids */ + NULL); /* nullable_relids */ /* Set mergejoinability info always, and hashjoinability if enabled */ check_mergejoinable(restrictinfo); |