diff --git a/src/backend/partitioning/partprune.c b/src/backend/partitioning/partprune.c index cdc61a8997..e44df8ac94 100644 --- a/src/backend/partitioning/partprune.c +++ b/src/backend/partitioning/partprune.c @@ -853,54 +853,62 @@ 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 may be able to (1) generate pruning steps based on IS NULL clauses, + * if there are enough of them: + * a) For list partitioning, null partition keys can only be found in the + * designated partition, so if there are IS NULL clauses containing + * partition keys we should generate a pruning step that gets rid of + * all partitions but the special null-accepting partitions. + * b) For range partitioning, the same applies. Doing this check first + * means we'll disregard OpExprs that may have been found for other + * keys, but that's fine, because it is not possible to prune range + * partitions with a combination of null and non-null keys. + * c) For hash partitioning, we only apply this strategy if we have + * IS NULL clauses for all the keys. Strategy 2 will take care of the + * case where some keys have OpExprs and others have IS NULL clauses. + * + * If not, then (2) generate steps based on OpExprs we have (if any). + * + * If this doesn't work either, we may be able to (3) 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) - { - /* - * 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; - - step = gen_prune_step_op(context, InvalidStrategy, - false, NIL, NIL, NULL); - result = lappend(result, step); - } - } - else + 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))) { PartitionPruneStep *step; - /* Generate pruning steps from OpExpr clauses in keyclauses. */ + /* Strategy 1 */ + step = gen_prune_step_op(context, InvalidStrategy, + false, NIL, NIL, nullkeys); + result = lappend(result, step); + } + else if (generate_opsteps) + { + PartitionPruneStep *step; + + /* Strategy 2 */ step = gen_prune_steps_from_opexps(part_scheme, context, keyclauses, nullkeys); if (step != NULL) result = lappend(result, step); } + else if (!bms_is_empty(notnullkeys) && + 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 d15f1d37f1..022b7c55c7 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 b8e823d562..2357f02cde 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;