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-rw-r--r--src/backend/partitioning/partprune.c78
-rw-r--r--src/test/regress/expected/partition_prune.out41
-rw-r--r--src/test/regress/sql/partition_prune.sql7
3 files changed, 90 insertions, 36 deletions
diff --git a/src/backend/partitioning/partprune.c b/src/backend/partitioning/partprune.c
index cdc61a89974..354eb0d4e60 100644
--- a/src/backend/partitioning/partprune.c
+++ b/src/backend/partitioning/partprune.c
@@ -853,54 +853,60 @@ gen_partprune_steps_internal(GeneratePruningStepsContext *context,
}
}
- /*
- * If generate_opsteps is set to false it means no OpExprs were directly
- * present in the input list.
+ /*-----------
+ * Now generate some (more) pruning steps. We have three strategies:
+ *
+ * 1) Generate pruning steps based on IS NULL clauses:
+ * a) For list partitioning, null partition keys can only be found in
+ * the designated null-accepting partition, so if there are IS NULL
+ * clauses containing partition keys we should generate a pruning
+ * step that gets rid of all partitions but that one. We can
+ * disregard any OpExpr we may have found.
+ * b) For range partitioning, only the default partition can contain
+ * NULL values, so the same rationale applies.
+ * c) For hash partitioning, we only apply this strategy if we have
+ * IS NULL clauses for all the keys. Strategy 2 below will take
+ * care of the case where some keys have OpExprs and others have
+ * IS NULL clauses.
+ *
+ * 2) If not, generate steps based on OpExprs we have (if any).
+ *
+ * 3) If this doesn't work either, we may be able to generate steps to
+ * prune just the null-accepting partition (if one exists), if we have
+ * IS NOT NULL clauses for all partition keys.
*/
- if (!generate_opsteps)
+ if (!bms_is_empty(nullkeys) &&
+ (part_scheme->strategy == PARTITION_STRATEGY_LIST ||
+ part_scheme->strategy == PARTITION_STRATEGY_RANGE ||
+ (part_scheme->strategy == PARTITION_STRATEGY_HASH &&
+ bms_num_members(nullkeys) == part_scheme->partnatts)))
{
- /*
- * Generate one prune step for the information derived from IS NULL,
- * if any. To prune hash partitions, we must have found IS NULL
- * clauses for all partition keys.
- */
- if (!bms_is_empty(nullkeys) &&
- (part_scheme->strategy != PARTITION_STRATEGY_HASH ||
- bms_num_members(nullkeys) == part_scheme->partnatts))
- {
- PartitionPruneStep *step;
-
- step = gen_prune_step_op(context, InvalidStrategy,
- false, NIL, NIL, nullkeys);
- result = lappend(result, step);
- }
-
- /*
- * Note that for IS NOT NULL clauses, simply having step suffices;
- * there is no need to propagate the exact details of which keys are
- * required to be NOT NULL. Hash partitioning expects to see actual
- * values to perform any pruning.
- */
- if (!bms_is_empty(notnullkeys) &&
- part_scheme->strategy != PARTITION_STRATEGY_HASH)
- {
- PartitionPruneStep *step;
+ PartitionPruneStep *step;
- step = gen_prune_step_op(context, InvalidStrategy,
- false, NIL, NIL, NULL);
- result = lappend(result, step);
- }
+ /* Strategy 1 */
+ step = gen_prune_step_op(context, InvalidStrategy,
+ false, NIL, NIL, nullkeys);
+ result = lappend(result, step);
}
- else
+ else if (generate_opsteps)
{
PartitionPruneStep *step;
- /* Generate pruning steps from OpExpr clauses in keyclauses. */
+ /* Strategy 2 */
step = gen_prune_steps_from_opexps(part_scheme, context,
keyclauses, nullkeys);
if (step != NULL)
result = lappend(result, step);
}
+ else if (bms_num_members(notnullkeys) == part_scheme->partnatts)
+ {
+ PartitionPruneStep *step;
+
+ /* Strategy 3 */
+ step = gen_prune_step_op(context, InvalidStrategy,
+ false, NIL, NIL, NULL);
+ result = lappend(result, step);
+ }
/*
* Finally, results from all entries appearing in result should be
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index d15f1d37f13..022b7c55c7d 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -993,6 +993,47 @@ explain (costs off) select * from mc2p where a = 1 and b > 1;
Filter: ((b > 1) AND (a = 1))
(3 rows)
+-- all partitions but the default one should be pruned
+explain (costs off) select * from mc2p where a = 1 and b is null;
+ QUERY PLAN
+-------------------------------------------
+ Append
+ -> Seq Scan on mc2p_default
+ Filter: ((b IS NULL) AND (a = 1))
+(3 rows)
+
+explain (costs off) select * from mc2p where a is null and b is null;
+ QUERY PLAN
+-----------------------------------------------
+ Append
+ -> Seq Scan on mc2p_default
+ Filter: ((a IS NULL) AND (b IS NULL))
+(3 rows)
+
+explain (costs off) select * from mc2p where a is null and b = 1;
+ QUERY PLAN
+-------------------------------------------
+ Append
+ -> Seq Scan on mc2p_default
+ Filter: ((a IS NULL) AND (b = 1))
+(3 rows)
+
+explain (costs off) select * from mc2p where a is null;
+ QUERY PLAN
+--------------------------------
+ Append
+ -> Seq Scan on mc2p_default
+ Filter: (a IS NULL)
+(3 rows)
+
+explain (costs off) select * from mc2p where b is null;
+ QUERY PLAN
+--------------------------------
+ Append
+ -> Seq Scan on mc2p_default
+ Filter: (b IS NULL)
+(3 rows)
+
-- boolean partitioning
create table boolpart (a bool) partition by list (a);
create table boolpart_default partition of boolpart default;
diff --git a/src/test/regress/sql/partition_prune.sql b/src/test/regress/sql/partition_prune.sql
index b8e823d5620..2357f02cde9 100644
--- a/src/test/regress/sql/partition_prune.sql
+++ b/src/test/regress/sql/partition_prune.sql
@@ -137,6 +137,13 @@ explain (costs off) select * from mc2p where a = 2 and b < 1;
explain (costs off) select * from mc2p where a > 1;
explain (costs off) select * from mc2p where a = 1 and b > 1;
+-- all partitions but the default one should be pruned
+explain (costs off) select * from mc2p where a = 1 and b is null;
+explain (costs off) select * from mc2p where a is null and b is null;
+explain (costs off) select * from mc2p where a is null and b = 1;
+explain (costs off) select * from mc2p where a is null;
+explain (costs off) select * from mc2p where b is null;
+
-- boolean partitioning
create table boolpart (a bool) partition by list (a);
create table boolpart_default partition of boolpart default;
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-30 22:47:11 +0000