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Update test cases w.r.to 8113

onur-leftjoin_push-improvements
eaydingol 2025-08-10 15:04:01 +03:00
parent 55bbf08c81
commit 0cf34388e2
6 changed files with 126 additions and 50 deletions
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35
src/backend/distributed/planner/deparse_shard_query.c
View File

@ -320,8 +320,38 @@ DefineQualsForShardInterval(RelationShard *relationShard, int attnum, int rtinde
/*
* UpdateWhereClauseForOuterJoin walks over the query tree and appends quals
* to the WHERE clause to filter w.r.to the distribution column of the corresponding shard.
* UpdateWhereClauseForOuterJoin
*
* Inject shard interval predicates into the query WHERE clause for certain
* outer joins to make the join semantically correct when distributed.
*
* Why this is needed:
* When an inner side of an OUTER JOIN is a distributed table that has been
* routed to a single shard, we cannot simply replace the RTE with the shard
* name and rely on implicit pruning: the preserved (outer) side could still
* produce rows whose join keys would hash to other shards. To keep results
* consistent with the global execution semantics we restrict the preserved
* (outer) side to only those partition key values that would route to the
* chosen shard (plus NULLs, which are assigned to exactly one shard).
*
* What the function does:
* 1. Iterate over the top-level jointree->fromlist.
* 2. For each JoinExpr call CheckPushDownFeasibilityAndComputeIndexes() which:
* - Verifies shape / join type is eligible.
* - Returns:
* outerRtIndex : RT index whose column we will constrain,
* outerRte / innerRte,
* attnum : attribute number (partition column) on outer side.
* 3. Find the RelationShard for the inner distributed table (innerRte->relid)
* in relationShardList; skip if absent (no fixed shard chosen).
* 4. Build the shard qualification with DefineQualsForShardInterval():
* (minValue < hash(partcol) AND hash(partcol) <= maxValue)
* and, for the first shard only, OR (partcol IS NULL).
* The Var refers to (outerRtIndex, attnum) so the restriction applies to
* the preserved outer input.
* 5. AND the new quals into jointree->quals (creating it if NULL).
*
* The function does not return anything, it modifies the query in place.
*/
void
UpdateWhereClauseForOuterJoin(Query *query, List *relationShardList)
@ -387,7 +417,6 @@ UpdateWhereClauseForOuterJoin(Query *query, List *relationShardList)
fromExpr->quals = make_and_qual(fromExpr->quals, shardIntervalBoundQuals);
}
}
return;
}

2
src/include/distributed/listutils.h
View File

@ -160,7 +160,7 @@ typedef struct ListCellAndListWrapper
for (int var ## PositionDoNotUse = 0; \
(var ## PositionDoNotUse) < list_length(l) && \
(((var) = list_nth(l, var ## PositionDoNotUse)) || true); \
var ## PositionDoNotUse++)
var ## PositionDoNotUse ++)
/* utility functions declaration shared within this module */
extern List * SortList(List *pointerList,

4
src/test/regress/citus_tests/run_test.py
View File

@ -237,11 +237,11 @@ DEPS = {
),
"multi_limit_clause_approximate": TestDeps(
"minimal_schedule",
["multi_create_table", "multi_create_users", "multi_multiuser_load_data"],
["multi_create_table", "multi_create_users", "multi_load_data"],
),
"multi_single_relation_subquery": TestDeps(
"minimal_schedule",
["multi_create_table", "multi_create_users", "multi_multiuser_load_data"],
["multi_create_table", "multi_create_users", "multi_load_data"],
),
"multi_subquery_complex_reference_clause": TestDeps(
"minimal_schedule", ["multi_behavioral_analytics_create_table"]

89
src/test/regress/expected/recurring_outer_join.out
View File

@ -560,8 +560,11 @@ LATERAL
---------------------------------------------------------------------
(0 rows)
-- Qual is the same but top-level join is an anti-join. Right join
-- is pushed down.
-- Qual is the same but top-level join is an anti-join.
-- The right join between t2 and t3 is pushed down.
-- Citus determines that the whole query can be pushed down
-- due to the equality constraint between two distributed
-- tables t1 and t2.
SELECT COUNT(*) FROM dist_1 t1
WHERE NOT EXISTS (
SELECT * FROM dist_1 t2
@ -573,22 +576,53 @@ WHERE NOT EXISTS (
8
(1 row)
SET client_min_messages TO DEBUG3;
-- This time the semi-join qual is <t3.a = t1.a> (not <<t2.a = t1.a>)
-- where t3 is the outer rel of the right join. Hence Postgres can't
-- replace right join with an inner join and so we recursively plan
-- inner side of the right join since the outer side is a recurring
-- rel.
-- replace right join with an inner join.
-- Citus pushes down the right join between t2 and t3 with constraints on
-- the recurring outer part (t3). However, it cannnot push down the whole
-- query as it can not establish an equivalence between the distribution
-- tables t1 and t2. Hence, Citus tries to recursively plan the subquery.
-- This attempt fails since the subquery has a reference to outer query.
-- See #8113
SELECT COUNT(*) FROM dist_1 t1
WHERE EXISTS (
SELECT * FROM dist_1 t2
RIGHT JOIN ref_1 t3 USING (a)
WHERE t3.a = t1.a
);
DEBUG: recursively planning left side of the right join since the outer side is a recurring rel
DEBUG: recursively planning distributed relation "dist_1" "t2" since it is part of a distributed join node that is outer joined with a recurring rel
DEBUG: Wrapping relation "dist_1" "t2" to a subquery
DEBUG: generating subplan XXX_1 for subquery SELECT a FROM recurring_outer_join.dist_1 t2 WHERE true
DEBUG: Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM recurring_outer_join.dist_1 t1 WHERE (EXISTS (SELECT t3.a, t2.b, t3.b FROM ((SELECT t2_1.a, NULL::integer AS b FROM (SELECT intermediate_result.a FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(a integer)) t2_1) t2 RIGHT JOIN recurring_outer_join.ref_1 t3 USING (a)) WHERE (t3.a OPERATOR(pg_catalog.=) t1.a)))
DEBUG: no shard pruning constraints on dist_1 found
DEBUG: shard count after pruning for dist_1: 32
DEBUG: no shard pruning constraints on dist_1 found
DEBUG: shard count after pruning for dist_1: 32
DEBUG: Router planner cannot handle multi-shard select queries
DEBUG: a push down safe right join with recurring left side
DEBUG: skipping recursive planning for the subquery since it contains references to outer queries
ERROR: complex joins are only supported when all distributed tables are co-located and joined on their distribution columns
SELECT COUNT(*) FROM dist_1 t1
WHERE NOT EXISTS (
SELECT * FROM dist_1 t2
RIGHT JOIN ref_1 t3 USING (a)
WHERE t3.a = t1.a
);
DEBUG: no shard pruning constraints on dist_1 found
DEBUG: shard count after pruning for dist_1: 32
DEBUG: no shard pruning constraints on dist_1 found
DEBUG: shard count after pruning for dist_1: 32
DEBUG: Router planner cannot handle multi-shard select queries
DEBUG: a push down safe right join with recurring left side
DEBUG: skipping recursive planning for the subquery since it contains references to outer queries
ERROR: complex joins are only supported when all distributed tables are co-located and joined on their distribution columns
SET client_min_messages TO DEBUG1;
-- Force recursive planning of the right join with offset
SELECT COUNT(*) FROM dist_1 t1
WHERE EXISTS (
SELECT * FROM dist_1 t2
RIGHT JOIN ref_1 t3 USING (a)
WHERE t3.a = t1.a
OFFSET 0
);
count
---------------------------------------------------------------------
7
@ -599,12 +633,8 @@ WHERE NOT EXISTS (
SELECT * FROM dist_1 t2
RIGHT JOIN ref_1 t3 USING (a)
WHERE t3.a = t1.a
OFFSET 0
);
DEBUG: recursively planning left side of the right join since the outer side is a recurring rel
DEBUG: recursively planning distributed relation "dist_1" "t2" since it is part of a distributed join node that is outer joined with a recurring rel
DEBUG: Wrapping relation "dist_1" "t2" to a subquery
DEBUG: generating subplan XXX_1 for subquery SELECT a FROM recurring_outer_join.dist_1 t2 WHERE true
DEBUG: Plan XXX query after replacing subqueries and CTEs: SELECT count(*) AS count FROM recurring_outer_join.dist_1 t1 WHERE (NOT (EXISTS (SELECT t3.a, t2.b, t3.b FROM ((SELECT t2_1.a, NULL::integer AS b FROM (SELECT intermediate_result.a FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(a integer)) t2_1) t2 RIGHT JOIN recurring_outer_join.ref_1 t3 USING (a)) WHERE (t3.a OPERATOR(pg_catalog.=) t1.a))))
count
---------------------------------------------------------------------
8
@ -1548,7 +1578,7 @@ SELECT * FROM ref_1 t36 WHERE (b,100,a) IN (
DISTINCT t31.b,
-- 1) we first search for such joins in the target list and recursively plan t33
-- because t32 is recurring
(SELECT max(b) FROM ref_1 t32 LEFT JOIN dist_1 t33 USING(a,b) WHERE t31.a = t32.a),
(SELECT max(b) FROM ref_1 t32 LEFT JOIN dist_1 t33 USING(b) WHERE t31.a = t32.a),
(SELECT t34.a)
FROM ref_1 t35
LEFT JOIN dist_1 t31 USING (a,b)
@ -1599,16 +1629,13 @@ DEBUG: CTE cte_1_inner_cte is going to be inlined via distributed planning
DEBUG: recursively planning right side of the left join since the outer side is a recurring rel
DEBUG: recursively planning distributed relation "dist_1" "t33" since it is part of a distributed join node that is outer joined with a recurring rel
DEBUG: Wrapping relation "dist_1" "t33" to a subquery
DEBUG: generating subplan XXX_1 for subquery SELECT a, b FROM recurring_outer_join.dist_1 t33 WHERE true
DEBUG: recursively planning right side of the left join since the outer side is a recurring rel
DEBUG: recursively planning distributed relation "dist_1" "t12" since it is part of a distributed join node that is outer joined with a recurring rel
DEBUG: Wrapping relation "dist_1" "t12" to a subquery
DEBUG: generating subplan XXX_2 for subquery SELECT a, b FROM recurring_outer_join.dist_1 t12 WHERE true
DEBUG: generating subplan XXX_1 for subquery SELECT b FROM recurring_outer_join.dist_1 t33 WHERE true
DEBUG: generating subplan XXX_2 for subquery SELECT t11.a, t11.b FROM (recurring_outer_join.ref_1 t11 LEFT JOIN recurring_outer_join.dist_1 t12 USING (a, b))
DEBUG: recursively planning right side of the left join since the outer side is a recurring rel
DEBUG: recursively planning distributed relation "dist_1" "t14" since it is part of a distributed join node that is outer joined with a recurring rel
DEBUG: Wrapping relation "dist_1" "t14" to a subquery
DEBUG: generating subplan XXX_3 for subquery SELECT a, b FROM recurring_outer_join.dist_1 t14 WHERE true
DEBUG: generating subplan XXX_4 for subquery SELECT t13.a, t13.b FROM ((recurring_outer_join.ref_1 t13 LEFT JOIN (SELECT t14_1.a, t14_1.b FROM (SELECT intermediate_result.a, intermediate_result.b FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(a integer, b integer)) t14_1) t14 USING (a, b)) JOIN (SELECT t11.a, t11.b FROM (recurring_outer_join.ref_1 t11 LEFT JOIN (SELECT t12_1.a, t12_1.b FROM (SELECT intermediate_result.a, intermediate_result.b FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(a integer, b integer)) t12_1) t12 USING (a, b))) t15 USING (a, b)) OFFSET 0
DEBUG: generating subplan XXX_4 for subquery SELECT t13.a, t13.b FROM ((recurring_outer_join.ref_1 t13 LEFT JOIN (SELECT t14_1.a, t14_1.b FROM (SELECT intermediate_result.a, intermediate_result.b FROM read_intermediate_result('XXX_3'::text, 'binary'::citus_copy_format) intermediate_result(a integer, b integer)) t14_1) t14 USING (a, b)) JOIN (SELECT intermediate_result.a, intermediate_result.b FROM read_intermediate_result('XXX_2'::text, 'binary'::citus_copy_format) intermediate_result(a integer, b integer)) t15 USING (a, b)) OFFSET 0
DEBUG: recursively planning right side of the left join since the outer side is a recurring rel
DEBUG: recursively planning distributed relation "dist_1" "d" since it is part of a distributed join node that is outer joined with a recurring rel
DEBUG: Wrapping relation "dist_1" "d" to a subquery
@ -1658,23 +1685,15 @@ DEBUG: recursively planning right side of the left join since the outer side is
DEBUG: recursively planning distributed relation "dist_1" "t34" since it is part of a distributed join node that is outer joined with a recurring rel
DEBUG: Wrapping relation "dist_1" "t34" to a subquery
DEBUG: generating subplan XXX_17 for subquery SELECT a, b FROM recurring_outer_join.dist_1 t34 WHERE true
DEBUG: generating subplan XXX_18 for subquery SELECT DISTINCT t31.b, (SELECT max(t32.b) AS max FROM (recurring_outer_join.ref_1 t32 LEFT JOIN (SELECT t33_1.a, t33_1.b FROM (SELECT intermediate_result.a, intermediate_result.b FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(a integer, b integer)) t33_1) t33 USING (a, b)) WHERE (t31.a OPERATOR(pg_catalog.=) t32.a)) AS max, (SELECT t34.a) AS a FROM ((((recurring_outer_join.ref_1 t35 LEFT JOIN (SELECT t31_1.a, t31_1.b FROM (SELECT intermediate_result.a, intermediate_result.b FROM read_intermediate_result('XXX_16'::text, 'binary'::citus_copy_format) intermediate_result(a integer, b integer)) t31_1) t31 USING (a, b)) LEFT JOIN (SELECT t34_1.a, t34_1.b FROM (SELECT intermediate_result.a, intermediate_result.b FROM read_intermediate_result('XXX_17'::text, 'binary'::citus_copy_format) intermediate_result(a integer, b integer)) t34_1) t34 USING (a, b)) LEFT JOIN (SELECT intermediate_result.a, intermediate_result.b FROM read_intermediate_result('XXX_4'::text, 'binary'::citus_copy_format) intermediate_result(a integer, b integer)) cte_1 USING (a, b)) LEFT JOIN (SELECT intermediate_result.a FROM read_intermediate_result('XXX_15'::text, 'binary'::citus_copy_format) intermediate_result(a bigint)) t30 ON ((t30.a OPERATOR(pg_catalog.=) cte_1.a))) ORDER BY t31.b, (SELECT max(t32.b) AS max FROM (recurring_outer_join.ref_1 t32 LEFT JOIN (SELECT t33_1.a, t33_1.b FROM (SELECT intermediate_result.a, intermediate_result.b FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(a integer, b integer)) t33_1) t33 USING (a, b)) WHERE (t31.a OPERATOR(pg_catalog.=) t32.a)), (SELECT t34.a)
DEBUG: recursively planning right side of the left join since the outer side is a recurring rel
DEBUG: recursively planning distributed relation "dist_1" "t3" since it is part of a distributed join node that is outer joined with a recurring rel
DEBUG: Wrapping relation "dist_1" "t3" to a subquery
DEBUG: generating subplan XXX_19 for subquery SELECT a, b FROM recurring_outer_join.dist_1 t3 WHERE true
DEBUG: generating subplan XXX_18 for subquery SELECT DISTINCT t31.b, (SELECT max(t32.b) AS max FROM (recurring_outer_join.ref_1 t32 LEFT JOIN (SELECT NULL::integer AS a, t33_1.b FROM (SELECT intermediate_result.b FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(b integer)) t33_1) t33 USING (b)) WHERE (t31.a OPERATOR(pg_catalog.=) t32.a)) AS max, (SELECT t34.a) AS a FROM ((((recurring_outer_join.ref_1 t35 LEFT JOIN (SELECT t31_1.a, t31_1.b FROM (SELECT intermediate_result.a, intermediate_result.b FROM read_intermediate_result('XXX_16'::text, 'binary'::citus_copy_format) intermediate_result(a integer, b integer)) t31_1) t31 USING (a, b)) LEFT JOIN (SELECT t34_1.a, t34_1.b FROM (SELECT intermediate_result.a, intermediate_result.b FROM read_intermediate_result('XXX_17'::text, 'binary'::citus_copy_format) intermediate_result(a integer, b integer)) t34_1) t34 USING (a, b)) LEFT JOIN (SELECT intermediate_result.a, intermediate_result.b FROM read_intermediate_result('XXX_4'::text, 'binary'::citus_copy_format) intermediate_result(a integer, b integer)) cte_1 USING (a, b)) LEFT JOIN (SELECT intermediate_result.a FROM read_intermediate_result('XXX_15'::text, 'binary'::citus_copy_format) intermediate_result(a bigint)) t30 ON ((t30.a OPERATOR(pg_catalog.=) cte_1.a))) ORDER BY t31.b, (SELECT max(t32.b) AS max FROM (recurring_outer_join.ref_1 t32 LEFT JOIN (SELECT NULL::integer AS a, t33_1.b FROM (SELECT intermediate_result.b FROM read_intermediate_result('XXX_1'::text, 'binary'::citus_copy_format) intermediate_result(b integer)) t33_1) t33 USING (b)) WHERE (t31.a OPERATOR(pg_catalog.=) t32.a)), (SELECT t34.a)
DEBUG: push down of limit count: 10
DEBUG: generating subplan XXX_20 for subquery SELECT b, (SELECT t2.a FROM (recurring_outer_join.ref_1 t2 LEFT JOIN (SELECT t3_1.a, t3_1.b FROM (SELECT intermediate_result.a, intermediate_result.b FROM read_intermediate_result('XXX_19'::text, 'binary'::citus_copy_format) intermediate_result(a integer, b integer)) t3_1) t3 USING (a, b)) WHERE (t2.a OPERATOR(pg_catalog.=) t1.a) ORDER BY t2.a LIMIT 1) AS a FROM recurring_outer_join.dist_1 t1 ORDER BY b, (SELECT t2.a FROM (recurring_outer_join.ref_1 t2 LEFT JOIN (SELECT t3_1.a, t3_1.b FROM (SELECT intermediate_result.a, intermediate_result.b FROM read_intermediate_result('XXX_19'::text, 'binary'::citus_copy_format) intermediate_result(a integer, b integer)) t3_1) t3 USING (a, b)) WHERE (t2.a OPERATOR(pg_catalog.=) t1.a) ORDER BY t2.a LIMIT 1) LIMIT 10
DEBUG: recursively planning right side of the left join since the outer side is a recurring rel
DEBUG: recursively planning distributed relation "dist_1" "t5" since it is part of a distributed join node that is outer joined with a recurring rel
DEBUG: Wrapping relation "dist_1" "t5" to a subquery
DEBUG: generating subplan XXX_21 for subquery SELECT a, b FROM recurring_outer_join.dist_1 t5 WHERE true
DEBUG: generating subplan XXX_22 for subquery SELECT a, b FROM (SELECT t8.a, t8.b FROM (SELECT t7.a, t7.b FROM (SELECT t6.a, t6.b FROM (SELECT t4.a, t4.b FROM (recurring_outer_join.ref_1 t4 LEFT JOIN (SELECT t5_1.a, t5_1.b FROM (SELECT intermediate_result.a, intermediate_result.b FROM read_intermediate_result('XXX_21'::text, 'binary'::citus_copy_format) intermediate_result(a integer, b integer)) t5_1) t5 USING (a, b))) t6) t7) t8) t9 OFFSET 0
DEBUG: generating subplan XXX_19 for subquery SELECT b, (SELECT t2.a FROM (recurring_outer_join.ref_1 t2 LEFT JOIN recurring_outer_join.dist_1 t3 USING (a, b)) WHERE (t2.a OPERATOR(pg_catalog.=) t1.a) ORDER BY t2.a LIMIT 1) AS a FROM recurring_outer_join.dist_1 t1 ORDER BY b, (SELECT t2.a FROM (recurring_outer_join.ref_1 t2 LEFT JOIN recurring_outer_join.dist_1 t3 USING (a, b)) WHERE (t2.a OPERATOR(pg_catalog.=) t1.a) ORDER BY t2.a LIMIT 1) LIMIT 10
DEBUG: generating subplan XXX_20 for subquery SELECT a, b FROM (SELECT t8.a, t8.b FROM (SELECT t7.a, t7.b FROM (SELECT t6.a, t6.b FROM (SELECT t4.a, t4.b FROM (recurring_outer_join.ref_1 t4 LEFT JOIN recurring_outer_join.dist_1 t5 USING (a, b))) t6) t7) t8) t9 OFFSET 0
DEBUG: recursively planning right side of the left join since the outer side is a recurring rel
DEBUG: recursively planning distributed relation "dist_1" "t11" since it is part of a distributed join node that is outer joined with a recurring rel
DEBUG: Wrapping relation "dist_1" "t11" to a subquery
DEBUG: generating subplan XXX_23 for subquery SELECT b FROM recurring_outer_join.dist_1 t11 WHERE true
DEBUG: Plan XXX query after replacing subqueries and CTEs: SELECT a, b FROM recurring_outer_join.ref_1 t36 WHERE (((b, 100, a) OPERATOR(pg_catalog.=) ANY (SELECT intermediate_result.b, intermediate_result.max, intermediate_result.a FROM read_intermediate_result('XXX_18'::text, 'binary'::citus_copy_format) intermediate_result(b integer, max integer, a integer))) AND (NOT (a OPERATOR(pg_catalog.=) ANY (SELECT outer_cte_1.b FROM ((SELECT intermediate_result.b, intermediate_result.a FROM read_intermediate_result('XXX_20'::text, 'binary'::citus_copy_format) intermediate_result(b integer, a integer)) outer_cte_1 LEFT JOIN (SELECT t10.b, t10.a, t11.a FROM ((SELECT intermediate_result.a, intermediate_result.b FROM read_intermediate_result('XXX_22'::text, 'binary'::citus_copy_format) intermediate_result(a integer, b integer)) t10 LEFT JOIN (SELECT NULL::integer AS a, t11_1.b FROM (SELECT intermediate_result.b FROM read_intermediate_result('XXX_23'::text, 'binary'::citus_copy_format) intermediate_result(b integer)) t11_1) t11 USING (b))) outer_cte_2(b, a, a_1) USING (b))))))
DEBUG: generating subplan XXX_21 for subquery SELECT b FROM recurring_outer_join.dist_1 t11 WHERE true
DEBUG: Plan XXX query after replacing subqueries and CTEs: SELECT a, b FROM recurring_outer_join.ref_1 t36 WHERE (((b, 100, a) OPERATOR(pg_catalog.=) ANY (SELECT intermediate_result.b, intermediate_result.max, intermediate_result.a FROM read_intermediate_result('XXX_18'::text, 'binary'::citus_copy_format) intermediate_result(b integer, max integer, a integer))) AND (NOT (a OPERATOR(pg_catalog.=) ANY (SELECT outer_cte_1.b FROM ((SELECT intermediate_result.b, intermediate_result.a FROM read_intermediate_result('XXX_19'::text, 'binary'::citus_copy_format) intermediate_result(b integer, a integer)) outer_cte_1 LEFT JOIN (SELECT t10.b, t10.a, t11.a FROM ((SELECT intermediate_result.a, intermediate_result.b FROM read_intermediate_result('XXX_20'::text, 'binary'::citus_copy_format) intermediate_result(a integer, b integer)) t10 LEFT JOIN (SELECT NULL::integer AS a, t11_1.b FROM (SELECT intermediate_result.b FROM read_intermediate_result('XXX_21'::text, 'binary'::citus_copy_format) intermediate_result(b integer)) t11_1) t11 USING (b))) outer_cte_2(b, a, a_1) USING (b))))))
a | b
---------------------------------------------------------------------
1 | 11

40
src/test/regress/sql/recurring_outer_join.sql
View File

@ -292,8 +292,11 @@ LATERAL
WHERE r1.a > dist_1.b
) as foo;
-- Qual is the same but top-level join is an anti-join. Right join
-- is pushed down.
-- Qual is the same but top-level join is an anti-join.
-- The right join between t2 and t3 is pushed down.
-- Citus determines that the whole query can be pushed down
-- due to the equality constraint between two distributed
-- tables t1 and t2.
SELECT COUNT(*) FROM dist_1 t1
WHERE NOT EXISTS (
SELECT * FROM dist_1 t2
@ -301,11 +304,17 @@ WHERE NOT EXISTS (
WHERE t2.a = t1.a
);
SET client_min_messages TO DEBUG3;
-- This time the semi-join qual is <t3.a = t1.a> (not <<t2.a = t1.a>)
-- where t3 is the outer rel of the right join. Hence Postgres can't
-- replace right join with an inner join and so we recursively plan
-- inner side of the right join since the outer side is a recurring
-- rel.
-- replace right join with an inner join.
-- Citus pushes down the right join between t2 and t3 with constraints on
-- the recurring outer part (t3). However, it cannnot push down the whole
-- query as it can not establish an equivalence between the distribution
-- tables t1 and t2. Hence, Citus tries to recursively plan the subquery.
-- This attempt fails since the subquery has a reference to outer query.
-- See #8113
SELECT COUNT(*) FROM dist_1 t1
WHERE EXISTS (
SELECT * FROM dist_1 t2
@ -320,6 +329,25 @@ WHERE NOT EXISTS (
WHERE t3.a = t1.a
);
SET client_min_messages TO DEBUG1;
-- Force recursive planning of the right join with offset
SELECT COUNT(*) FROM dist_1 t1
WHERE EXISTS (
SELECT * FROM dist_1 t2
RIGHT JOIN ref_1 t3 USING (a)
WHERE t3.a = t1.a
OFFSET 0
);
SELECT COUNT(*) FROM dist_1 t1
WHERE NOT EXISTS (
SELECT * FROM dist_1 t2
RIGHT JOIN ref_1 t3 USING (a)
WHERE t3.a = t1.a
OFFSET 0
);
--
-- more complex cases
--
@ -840,7 +868,7 @@ SELECT * FROM ref_1 t36 WHERE (b,100,a) IN (
DISTINCT t31.b,
-- 1) we first search for such joins in the target list and recursively plan t33
-- because t32 is recurring
(SELECT max(b) FROM ref_1 t32 LEFT JOIN dist_1 t33 USING(a,b) WHERE t31.a = t32.a),
(SELECT max(b) FROM ref_1 t32 LEFT JOIN dist_1 t33 USING(b) WHERE t31.a = t32.a),
(SELECT t34.a)
FROM ref_1 t35
LEFT JOIN dist_1 t31 USING (a,b)