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citus/src/test/regress/expected/multi_mx_router_planner.out

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-- ===================================================================
-- test router planner functionality for single shard select queries
-- ===================================================================
-- run all the router queries from the one of the workers
\c - - - :worker_1_port
-- this table is used in a CTE test
CREATE TABLE authors_hash_mx ( name text, id bigint );
-- create a bunch of test data
INSERT INTO articles_hash_mx VALUES ( 1, 1, 'arsenous', 9572);
INSERT INTO articles_hash_mx VALUES ( 2, 2, 'abducing', 13642);
INSERT INTO articles_hash_mx VALUES ( 3, 3, 'asternal', 10480);
INSERT INTO articles_hash_mx VALUES ( 4, 4, 'altdorfer', 14551);
INSERT INTO articles_hash_mx VALUES ( 5, 5, 'aruru', 11389);
INSERT INTO articles_hash_mx VALUES ( 6, 6, 'atlases', 15459);
INSERT INTO articles_hash_mx VALUES ( 7, 7, 'aseptic', 12298);
INSERT INTO articles_hash_mx VALUES ( 8, 8, 'agatized', 16368);
INSERT INTO articles_hash_mx VALUES ( 9, 9, 'alligate', 438);
INSERT INTO articles_hash_mx VALUES (10, 10, 'aggrandize', 17277);
INSERT INTO articles_hash_mx VALUES (11, 1, 'alamo', 1347);
INSERT INTO articles_hash_mx VALUES (12, 2, 'archiblast', 18185);
INSERT INTO articles_hash_mx VALUES (13, 3, 'aseyev', 2255);
INSERT INTO articles_hash_mx VALUES (14, 4, 'andesite', 19094);
INSERT INTO articles_hash_mx VALUES (15, 5, 'adversa', 3164);
INSERT INTO articles_hash_mx VALUES (16, 6, 'allonym', 2);
INSERT INTO articles_hash_mx VALUES (17, 7, 'auriga', 4073);
INSERT INTO articles_hash_mx VALUES (18, 8, 'assembly', 911);
INSERT INTO articles_hash_mx VALUES (19, 9, 'aubergiste', 4981);
INSERT INTO articles_hash_mx VALUES (20, 10, 'absentness', 1820);
INSERT INTO articles_hash_mx VALUES (21, 1, 'arcading', 5890);
INSERT INTO articles_hash_mx VALUES (22, 2, 'antipope', 2728);
INSERT INTO articles_hash_mx VALUES (23, 3, 'abhorring', 6799);
INSERT INTO articles_hash_mx VALUES (24, 4, 'audacious', 3637);
INSERT INTO articles_hash_mx VALUES (25, 5, 'antehall', 7707);
INSERT INTO articles_hash_mx VALUES (26, 6, 'abington', 4545);
INSERT INTO articles_hash_mx VALUES (27, 7, 'arsenous', 8616);
INSERT INTO articles_hash_mx VALUES (28, 8, 'aerophyte', 5454);
INSERT INTO articles_hash_mx VALUES (29, 9, 'amateur', 9524);
INSERT INTO articles_hash_mx VALUES (30, 10, 'andelee', 6363);
INSERT INTO articles_hash_mx VALUES (31, 1, 'athwartships', 7271);
INSERT INTO articles_hash_mx VALUES (32, 2, 'amazon', 11342);
INSERT INTO articles_hash_mx VALUES (33, 3, 'autochrome', 8180);
INSERT INTO articles_hash_mx VALUES (34, 4, 'amnestied', 12250);
INSERT INTO articles_hash_mx VALUES (35, 5, 'aminate', 9089);
INSERT INTO articles_hash_mx VALUES (36, 6, 'ablation', 13159);
INSERT INTO articles_hash_mx VALUES (37, 7, 'archduchies', 9997);
INSERT INTO articles_hash_mx VALUES (38, 8, 'anatine', 14067);
INSERT INTO articles_hash_mx VALUES (39, 9, 'anchises', 10906);
INSERT INTO articles_hash_mx VALUES (40, 10, 'attemper', 14976);
INSERT INTO articles_hash_mx VALUES (41, 1, 'aznavour', 11814);
INSERT INTO articles_hash_mx VALUES (42, 2, 'ausable', 15885);
INSERT INTO articles_hash_mx VALUES (43, 3, 'affixal', 12723);
INSERT INTO articles_hash_mx VALUES (44, 4, 'anteport', 16793);
INSERT INTO articles_hash_mx VALUES (45, 5, 'afrasia', 864);
INSERT INTO articles_hash_mx VALUES (46, 6, 'atlanta', 17702);
INSERT INTO articles_hash_mx VALUES (47, 7, 'abeyance', 1772);
INSERT INTO articles_hash_mx VALUES (48, 8, 'alkylic', 18610);
INSERT INTO articles_hash_mx VALUES (49, 9, 'anyone', 2681);
INSERT INTO articles_hash_mx VALUES (50, 10, 'anjanette', 19519);
SET citus.task_executor_type TO 'real-time';
SET client_min_messages TO 'DEBUG2';
-- insert a single row for the test
INSERT INTO articles_single_shard_hash_mx VALUES (50, 10, 'anjanette', 19519);
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 10
-- single-shard tests
-- many of the tests in this file is intended for testing non-fast-path
-- router planner, so we're explicitly disabling it in this file.
-- We've bunch of other tests that triggers fast-path-router
SET citus.enable_fast_path_router_planner TO false;
-- test simple select for a single row
SELECT * FROM articles_hash_mx WHERE author_id = 10 AND id = 50;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 10
id | author_id | title | word_count
----+-----------+-----------+------------
50 | 10 | anjanette | 19519
(1 row)
-- get all titles by a single author
SELECT title FROM articles_hash_mx WHERE author_id = 10;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 10
title
------------
aggrandize
absentness
andelee
attemper
anjanette
(5 rows)
-- try ordering them by word count
SELECT title, word_count FROM articles_hash_mx
WHERE author_id = 10
ORDER BY word_count DESC NULLS LAST;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 10
title | word_count
------------+------------
anjanette | 19519
aggrandize | 17277
attemper | 14976
andelee | 6363
absentness | 1820
(5 rows)
-- look at last two articles by an author
SELECT title, id FROM articles_hash_mx
WHERE author_id = 5
ORDER BY id
LIMIT 2;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 5
title | id
---------+----
aruru | 5
adversa | 15
(2 rows)
-- find all articles by two authors in same shard
-- but plan is not router executable due to order by
SELECT title, author_id FROM articles_hash_mx
WHERE author_id = 7 OR author_id = 8
ORDER BY author_id ASC, id;
DEBUG: Creating router plan
DEBUG: Plan is router executable
title | author_id
-------------+-----------
aseptic | 7
auriga | 7
arsenous | 7
archduchies | 7
abeyance | 7
agatized | 8
assembly | 8
aerophyte | 8
anatine | 8
alkylic | 8
(10 rows)
-- same query is router executable with no order by
SELECT title, author_id FROM articles_hash_mx
WHERE author_id = 7 OR author_id = 8;
DEBUG: Creating router plan
DEBUG: Plan is router executable
title | author_id
-------------+-----------
aseptic | 7
agatized | 8
auriga | 7
assembly | 8
arsenous | 7
aerophyte | 8
archduchies | 7
anatine | 8
abeyance | 7
alkylic | 8
(10 rows)
-- add in some grouping expressions, still on same shard
-- having queries unsupported in Citus
SELECT author_id, sum(word_count) AS corpus_size FROM articles_hash_mx
WHERE author_id = 1 OR author_id = 7 OR author_id = 8 OR author_id = 10
GROUP BY author_id
HAVING sum(word_count) > 1000
ORDER BY sum(word_count) DESC;
DEBUG: Creating router plan
DEBUG: Plan is router executable
author_id | corpus_size
-----------+-------------
10 | 59955
8 | 55410
7 | 36756
1 | 35894
(4 rows)
-- however having clause is supported if it goes to a single shard
SELECT author_id, sum(word_count) AS corpus_size FROM articles_hash_mx
WHERE author_id = 1
GROUP BY author_id
HAVING sum(word_count) > 1000
ORDER BY sum(word_count) DESC;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
author_id | corpus_size
-----------+-------------
1 | 35894
(1 row)
-- query is a single shard query but can't do shard pruning,
-- not router-plannable due to <= and IN
SELECT * FROM articles_hash_mx WHERE author_id <= 1;
DEBUG: Router planner cannot handle multi-shard select queries
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
SELECT * FROM articles_hash_mx WHERE author_id IN (1, 3);
DEBUG: Creating router plan
DEBUG: Plan is router executable
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
3 | 3 | asternal | 10480
11 | 1 | alamo | 1347
13 | 3 | aseyev | 2255
21 | 1 | arcading | 5890
23 | 3 | abhorring | 6799
31 | 1 | athwartships | 7271
33 | 3 | autochrome | 8180
41 | 1 | aznavour | 11814
43 | 3 | affixal | 12723
(10 rows)
-- queries with CTEs are supported
WITH first_author AS ( SELECT id FROM articles_hash_mx WHERE author_id = 1)
SELECT * FROM first_author;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id
----
1
11
21
31
41
(5 rows)
-- queries with CTEs are supported even if CTE is not referenced inside query
WITH first_author AS ( SELECT id FROM articles_hash_mx WHERE author_id = 1)
SELECT title FROM articles_hash_mx WHERE author_id = 1;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
title
--------------
arsenous
alamo
arcading
athwartships
aznavour
(5 rows)
-- two CTE joins are supported if they go to the same worker
WITH id_author AS ( SELECT id, author_id FROM articles_hash_mx WHERE author_id = 1),
id_title AS (SELECT id, title from articles_hash_mx WHERE author_id = 1)
SELECT * FROM id_author, id_title WHERE id_author.id = id_title.id;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | id | title
----+-----------+----+--------------
1 | 1 | 1 | arsenous
11 | 1 | 11 | alamo
21 | 1 | 21 | arcading
31 | 1 | 31 | athwartships
41 | 1 | 41 | aznavour
(5 rows)
WITH id_author AS ( SELECT id, author_id FROM articles_hash_mx WHERE author_id = 1),
id_title AS (SELECT id, title from articles_hash_mx WHERE author_id = 3)
SELECT * FROM id_author, id_title WHERE id_author.id = id_title.id;
DEBUG: Creating router plan
DEBUG: Plan is router executable
id | author_id | id | title
----+-----------+----+-------
(0 rows)
-- CTE joins on different workers are supported because they are both planned recursively
WITH id_author AS ( SELECT id, author_id FROM articles_hash_mx WHERE author_id = 1),
id_title AS (SELECT id, title from articles_hash_mx WHERE author_id = 2)
SELECT * FROM id_author, id_title WHERE id_author.id = id_title.id;
DEBUG: cannot run command which targets multiple shards
DEBUG: generating subplan 66_1 for CTE id_author: SELECT id, author_id FROM public.articles_hash_mx WHERE (author_id OPERATOR(pg_catalog.=) 1)
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
DEBUG: generating subplan 66_2 for CTE id_title: SELECT id, title FROM public.articles_hash_mx WHERE (author_id OPERATOR(pg_catalog.=) 2)
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 2
DEBUG: Plan 66 query after replacing subqueries and CTEs: SELECT id_author.id, id_author.author_id, id_title.id, id_title.title FROM (SELECT intermediate_result.id, intermediate_result.author_id FROM read_intermediate_result('66_1'::text, 'binary'::citus_copy_format) intermediate_result(id bigint, author_id bigint)) id_author, (SELECT intermediate_result.id, intermediate_result.title FROM read_intermediate_result('66_2'::text, 'binary'::citus_copy_format) intermediate_result(id bigint, title character varying(20))) id_title WHERE (id_author.id OPERATOR(pg_catalog.=) id_title.id)
DEBUG: Creating router plan
DEBUG: Plan is router executable
id | author_id | id | title
----+-----------+----+-------
(0 rows)
-- recursive CTEs are supported when filtered on partition column
INSERT INTO company_employees_mx values(1, 1, 0);
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
INSERT INTO company_employees_mx values(1, 2, 1);
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
INSERT INTO company_employees_mx values(1, 3, 1);
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
INSERT INTO company_employees_mx values(1, 4, 2);
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
INSERT INTO company_employees_mx values(1, 5, 4);
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
INSERT INTO company_employees_mx values(3, 1, 0);
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 3
INSERT INTO company_employees_mx values(3, 15, 1);
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 3
INSERT INTO company_employees_mx values(3, 3, 1);
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 3
-- find employees at top 2 level within company hierarchy
WITH RECURSIVE hierarchy as (
SELECT *, 1 AS level
FROM company_employees_mx
WHERE company_id = 1 and manager_id = 0
UNION
SELECT ce.*, (h.level+1)
FROM hierarchy h JOIN company_employees_mx ce
ON (h.employee_id = ce.manager_id AND
h.company_id = ce.company_id AND
ce.company_id = 1))
SELECT * FROM hierarchy WHERE LEVEL <= 2;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
company_id | employee_id | manager_id | level
------------+-------------+------------+-------
1 | 1 | 0 | 1
1 | 2 | 1 | 2
1 | 3 | 1 | 2
(3 rows)
-- query becomes not router plannble and gets rejected
-- if filter on company is dropped
WITH RECURSIVE hierarchy as (
SELECT *, 1 AS level
FROM company_employees_mx
WHERE company_id = 1 and manager_id = 0
UNION
SELECT ce.*, (h.level+1)
FROM hierarchy h JOIN company_employees_mx ce
ON (h.employee_id = ce.manager_id AND
h.company_id = ce.company_id))
SELECT * FROM hierarchy WHERE LEVEL <= 2;
DEBUG: Router planner cannot handle multi-shard select queries
ERROR: recursive CTEs are not supported in distributed queries
-- logically wrong query, query involves different shards
-- from the same table, but still router plannable due to
-- shard being placed on the same worker.
WITH RECURSIVE hierarchy as (
SELECT *, 1 AS level
FROM company_employees_mx
WHERE company_id = 3 and manager_id = 0
UNION
SELECT ce.*, (h.level+1)
FROM hierarchy h JOIN company_employees_mx ce
ON (h.employee_id = ce.manager_id AND
h.company_id = ce.company_id AND
ce.company_id = 2))
SELECT * FROM hierarchy WHERE LEVEL <= 2;
DEBUG: cannot run command which targets multiple shards
ERROR: recursive CTEs are not supported in distributed queries
-- grouping sets are supported on single shard
SELECT
id, substring(title, 2, 1) AS subtitle, count(*)
FROM articles_hash_mx
WHERE author_id = 1 or author_id = 3
GROUP BY GROUPING SETS ((id),(subtitle))
ORDER BY id, subtitle;
DEBUG: Creating router plan
DEBUG: Plan is router executable
id | subtitle | count
----+----------+-------
1 | | 1
3 | | 1
11 | | 1
13 | | 1
21 | | 1
23 | | 1
31 | | 1
33 | | 1
41 | | 1
43 | | 1
| b | 1
| f | 1
| l | 1
| r | 2
| s | 2
| t | 1
| u | 1
| z | 1
(18 rows)
-- grouping sets are not supported on multiple shards
SELECT
id, substring(title, 2, 1) AS subtitle, count(*)
FROM articles_hash_mx
WHERE author_id = 1 or author_id = 2
GROUP BY GROUPING SETS ((id),(subtitle))
ORDER BY id, subtitle;
DEBUG: Router planner cannot handle multi-shard select queries
ERROR: could not run distributed query with GROUPING SETS, CUBE, or ROLLUP
HINT: Consider using an equality filter on the distributed table's partition column.
-- queries which involve functions in FROM clause are supported if it goes to a single worker.
SELECT * FROM articles_hash_mx, position('om' in 'Thomas') WHERE author_id = 1;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count | position
----+-----------+--------------+------------+----------
1 | 1 | arsenous | 9572 | 3
11 | 1 | alamo | 1347 | 3
21 | 1 | arcading | 5890 | 3
31 | 1 | athwartships | 7271 | 3
41 | 1 | aznavour | 11814 | 3
(5 rows)
SELECT * FROM articles_hash_mx, position('om' in 'Thomas') WHERE author_id = 1 or author_id = 3;
DEBUG: Creating router plan
DEBUG: Plan is router executable
id | author_id | title | word_count | position
----+-----------+--------------+------------+----------
1 | 1 | arsenous | 9572 | 3
3 | 3 | asternal | 10480 | 3
11 | 1 | alamo | 1347 | 3
13 | 3 | aseyev | 2255 | 3
21 | 1 | arcading | 5890 | 3
23 | 3 | abhorring | 6799 | 3
31 | 1 | athwartships | 7271 | 3
33 | 3 | autochrome | 8180 | 3
41 | 1 | aznavour | 11814 | 3
43 | 3 | affixal | 12723 | 3
(10 rows)
-- they are supported via (sub)query pushdown if multiple workers are involved
SELECT * FROM articles_hash_mx, position('om' in 'Thomas') WHERE author_id = 1 or author_id = 2 ORDER BY 4 DESC, 1 DESC, 2 DESC LIMIT 5;
DEBUG: Router planner cannot handle multi-shard select queries
DEBUG: push down of limit count: 5
id | author_id | title | word_count | position
----+-----------+------------+------------+----------
12 | 2 | archiblast | 18185 | 3
42 | 2 | ausable | 15885 | 3
2 | 2 | abducing | 13642 | 3
41 | 1 | aznavour | 11814 | 3
32 | 2 | amazon | 11342 | 3
(5 rows)
-- subqueries are supported in FROM clause but they are not router plannable
SELECT articles_hash_mx.id,test.word_count
FROM articles_hash_mx, (SELECT id, word_count FROM articles_hash_mx) AS test WHERE test.id = articles_hash_mx.id
ORDER BY test.word_count DESC, articles_hash_mx.id LIMIT 5;
DEBUG: Router planner cannot handle multi-shard select queries
DEBUG: Router planner cannot handle multi-shard select queries
DEBUG: generating subplan 85_1 for subquery SELECT id, word_count FROM public.articles_hash_mx
DEBUG: Plan 85 query after replacing subqueries and CTEs: SELECT articles_hash_mx.id, test.word_count FROM public.articles_hash_mx, (SELECT intermediate_result.id, intermediate_result.word_count FROM read_intermediate_result('85_1'::text, 'binary'::citus_copy_format) intermediate_result(id bigint, word_count integer)) test WHERE (test.id OPERATOR(pg_catalog.=) articles_hash_mx.id) ORDER BY test.word_count DESC, articles_hash_mx.id LIMIT 5
DEBUG: Router planner cannot handle multi-shard select queries
DEBUG: push down of limit count: 5
id | word_count
----+------------
50 | 19519
14 | 19094
48 | 18610
12 | 18185
46 | 17702
(5 rows)
SELECT articles_hash_mx.id,test.word_count
FROM articles_hash_mx, (SELECT id, word_count FROM articles_hash_mx) AS test
WHERE test.id = articles_hash_mx.id and articles_hash_mx.author_id = 1
ORDER BY articles_hash_mx.id;
DEBUG: Router planner cannot handle multi-shard select queries
DEBUG: Router planner cannot handle multi-shard select queries
DEBUG: generating subplan 87_1 for subquery SELECT id, word_count FROM public.articles_hash_mx
DEBUG: Plan 87 query after replacing subqueries and CTEs: SELECT articles_hash_mx.id, test.word_count FROM public.articles_hash_mx, (SELECT intermediate_result.id, intermediate_result.word_count FROM read_intermediate_result('87_1'::text, 'binary'::citus_copy_format) intermediate_result(id bigint, word_count integer)) test WHERE ((test.id OPERATOR(pg_catalog.=) articles_hash_mx.id) AND (articles_hash_mx.author_id OPERATOR(pg_catalog.=) 1)) ORDER BY articles_hash_mx.id
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | word_count
----+------------
1 | 9572
11 | 1347
21 | 5890
31 | 7271
41 | 11814
(5 rows)
-- subqueries are not supported in SELECT clause
SELECT a.title AS name, (SELECT a2.id FROM articles_single_shard_hash_mx a2 WHERE a.id = a2.id LIMIT 1)
AS special_price FROM articles_hash_mx a;
DEBUG: Router planner cannot handle multi-shard select queries
DEBUG: skipping recursive planning for the subquery since it contains references to outer queries
ERROR: could not run distributed query with subquery outside the FROM and WHERE clauses
HINT: Consider using an equality filter on the distributed table's partition column.
-- simple lookup query
SELECT *
FROM articles_hash_mx
WHERE author_id = 1;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
-- below query hits a single shard, router plannable
SELECT *
FROM articles_hash_mx
WHERE author_id = 1 OR author_id = 17;
DEBUG: Creating router plan
DEBUG: Plan is router executable
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
-- below query hits two shards, not router plannable + not router executable
-- handled by real-time executor
SELECT *
FROM articles_hash_mx
WHERE author_id = 1 OR author_id = 18;
DEBUG: Router planner cannot handle multi-shard select queries
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
-- rename the output columns
SELECT id as article_id, word_count * id as random_value
FROM articles_hash_mx
WHERE author_id = 1;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
article_id | random_value
------------+--------------
1 | 9572
11 | 14817
21 | 123690
31 | 225401
41 | 484374
(5 rows)
-- we can push down co-located joins to a single worker
SELECT a.author_id as first_author, b.word_count as second_word_count
FROM articles_hash_mx a, articles_hash_mx b
WHERE a.author_id = 10 and a.author_id = b.author_id
LIMIT 3;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 10
first_author | second_word_count
--------------+-------------------
10 | 17277
10 | 1820
10 | 6363
(3 rows)
-- following join is router plannable since the same worker
-- has both shards
SELECT a.author_id as first_author, b.word_count as second_word_count
FROM articles_hash_mx a, articles_single_shard_hash_mx b
WHERE a.author_id = 10 and a.author_id = b.author_id
LIMIT 3;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 10
first_author | second_word_count
--------------+-------------------
10 | 19519
10 | 19519
10 | 19519
(3 rows)
-- following join is not router plannable since there are no
-- workers containing both shards, but will work through recursive
-- planning
WITH single_shard as (SELECT * FROM articles_single_shard_hash_mx)
SELECT a.author_id as first_author, b.word_count as second_word_count
FROM articles_hash_mx a, single_shard b
WHERE a.author_id = 2 and a.author_id = b.author_id
LIMIT 3;
DEBUG: Found no worker with all shard placements
DEBUG: found no worker with all shard placements
DEBUG: generating subplan 96_1 for CTE single_shard: SELECT id, author_id, title, word_count FROM public.articles_single_shard_hash_mx
DEBUG: Creating router plan
DEBUG: Plan is router executable
DEBUG: Plan 96 query after replacing subqueries and CTEs: SELECT a.author_id AS first_author, b.word_count AS second_word_count FROM public.articles_hash_mx a, (SELECT intermediate_result.id, intermediate_result.author_id, intermediate_result.title, intermediate_result.word_count FROM read_intermediate_result('96_1'::text, 'binary'::citus_copy_format) intermediate_result(id bigint, author_id bigint, title character varying(20), word_count integer)) b WHERE ((a.author_id OPERATOR(pg_catalog.=) 2) AND (a.author_id OPERATOR(pg_catalog.=) b.author_id)) LIMIT 3
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 2
first_author | second_word_count
--------------+-------------------
(0 rows)
-- single shard select with limit is router plannable
SELECT *
FROM articles_hash_mx
WHERE author_id = 1
LIMIT 3;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+----------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
(3 rows)
-- single shard select with limit + offset is router plannable
SELECT *
FROM articles_hash_mx
WHERE author_id = 1
LIMIT 2
OFFSET 1;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+----------+------------
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
(2 rows)
-- single shard select with limit + offset + order by is router plannable
SELECT *
FROM articles_hash_mx
WHERE author_id = 1
ORDER BY id desc
LIMIT 2
OFFSET 1;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+--------------+------------
31 | 1 | athwartships | 7271
21 | 1 | arcading | 5890
(2 rows)
-- single shard select with group by on non-partition column is router plannable
SELECT id
FROM articles_hash_mx
WHERE author_id = 1
GROUP BY id
ORDER BY id;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id
----
1
11
21
31
41
(5 rows)
-- single shard select with distinct is router plannable
SELECT distinct id
FROM articles_hash_mx
WHERE author_id = 1
ORDER BY id;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id
----
1
11
21
31
41
(5 rows)
-- single shard aggregate is router plannable
SELECT avg(word_count)
FROM articles_hash_mx
WHERE author_id = 2;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 2
avg
--------------------
12356.400000000000
(1 row)
-- max, min, sum, count are router plannable on single shard
SELECT max(word_count) as max, min(word_count) as min,
sum(word_count) as sum, count(word_count) as cnt
FROM articles_hash_mx
WHERE author_id = 2;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 2
max | min | sum | cnt
-------+------+-------+-----
18185 | 2728 | 61782 | 5
(1 row)
-- queries with aggregates and group by supported on single shard
SELECT max(word_count)
FROM articles_hash_mx
WHERE author_id = 1
GROUP BY author_id;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
max
-------
11814
(1 row)
-- router plannable union queries are supported
SELECT * FROM (
SELECT * FROM articles_hash_mx WHERE author_id = 1
UNION
SELECT * FROM articles_hash_mx WHERE author_id = 3
) AS combination
ORDER BY id;
DEBUG: Creating router plan
DEBUG: Plan is router executable
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
3 | 3 | asternal | 10480
11 | 1 | alamo | 1347
13 | 3 | aseyev | 2255
21 | 1 | arcading | 5890
23 | 3 | abhorring | 6799
31 | 1 | athwartships | 7271
33 | 3 | autochrome | 8180
41 | 1 | aznavour | 11814
43 | 3 | affixal | 12723
(10 rows)
(SELECT LEFT(title, 1) FROM articles_hash_mx WHERE author_id = 1)
UNION
(SELECT LEFT(title, 1) FROM articles_hash_mx WHERE author_id = 3);
DEBUG: Creating router plan
DEBUG: Plan is router executable
left
------
a
(1 row)
(SELECT LEFT(title, 1) FROM articles_hash_mx WHERE author_id = 1)
INTERSECT
(SELECT LEFT(title, 1) FROM articles_hash_mx WHERE author_id = 3);
DEBUG: Creating router plan
DEBUG: Plan is router executable
left
------
a
(1 row)
SELECT * FROM (
SELECT LEFT(title, 2) FROM articles_hash_mx WHERE author_id = 1
EXCEPT
SELECT LEFT(title, 2) FROM articles_hash_mx WHERE author_id = 3
) AS combination
ORDER BY 1;
DEBUG: Creating router plan
DEBUG: Plan is router executable
left
------
al
ar
at
az
(4 rows)
-- union queries are supported through recursive planning
SET client_min_messages TO DEBUG1;
(SELECT * FROM articles_hash_mx WHERE author_id = 1)
UNION
(SELECT * FROM articles_hash_mx WHERE author_id = 2)
ORDER BY 1,2;
DEBUG: cannot run command which targets multiple shards
DEBUG: generating subplan 110_1 for subquery SELECT id, author_id, title, word_count FROM public.articles_hash_mx WHERE (author_id OPERATOR(pg_catalog.=) 1)
DEBUG: generating subplan 110_2 for subquery SELECT id, author_id, title, word_count FROM public.articles_hash_mx WHERE (author_id OPERATOR(pg_catalog.=) 2)
DEBUG: Plan 110 query after replacing subqueries and CTEs: SELECT intermediate_result.id, intermediate_result.author_id, intermediate_result.title, intermediate_result.word_count FROM read_intermediate_result('110_1'::text, 'binary'::citus_copy_format) intermediate_result(id bigint, author_id bigint, title character varying(20), word_count integer) UNION SELECT intermediate_result.id, intermediate_result.author_id, intermediate_result.title, intermediate_result.word_count FROM read_intermediate_result('110_2'::text, 'binary'::citus_copy_format) intermediate_result(id bigint, author_id bigint, title character varying(20), word_count integer) ORDER BY 1, 2
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
2 | 2 | abducing | 13642
11 | 1 | alamo | 1347
12 | 2 | archiblast | 18185
21 | 1 | arcading | 5890
22 | 2 | antipope | 2728
31 | 1 | athwartships | 7271
32 | 2 | amazon | 11342
41 | 1 | aznavour | 11814
42 | 2 | ausable | 15885
(10 rows)
SELECT * FROM (
(SELECT * FROM articles_hash_mx WHERE author_id = 1)
UNION
(SELECT * FROM articles_hash_mx WHERE author_id = 2)) uu
ORDER BY 1, 2
LIMIT 5;
DEBUG: cannot run command which targets multiple shards
DEBUG: push down of limit count: 5
id | author_id | title | word_count
----+-----------+------------+------------
1 | 1 | arsenous | 9572
2 | 2 | abducing | 13642
11 | 1 | alamo | 1347
12 | 2 | archiblast | 18185
21 | 1 | arcading | 5890
(5 rows)
-- error out for queries with repartition jobs
SELECT *
FROM articles_hash_mx a, articles_hash_mx b
WHERE a.id = b.id AND a.author_id = 1;
DEBUG: Router planner cannot handle multi-shard select queries
ERROR: the query contains a join that requires repartitioning
HINT: Set citus.enable_repartition_joins to on to enable repartitioning
-- queries which hit more than 1 shards are not router plannable or executable
-- handled by real-time executor
SELECT *
FROM articles_hash_mx
WHERE author_id >= 1 AND author_id <= 3
ORDER BY 1,2,3,4;
DEBUG: Router planner cannot handle multi-shard select queries
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
2 | 2 | abducing | 13642
3 | 3 | asternal | 10480
11 | 1 | alamo | 1347
12 | 2 | archiblast | 18185
13 | 3 | aseyev | 2255
21 | 1 | arcading | 5890
22 | 2 | antipope | 2728
23 | 3 | abhorring | 6799
31 | 1 | athwartships | 7271
32 | 2 | amazon | 11342
33 | 3 | autochrome | 8180
41 | 1 | aznavour | 11814
42 | 2 | ausable | 15885
43 | 3 | affixal | 12723
(15 rows)
SET citus.task_executor_type TO 'real-time';
-- Test various filtering options for router plannable check
SET client_min_messages to 'DEBUG2';
-- this is definitely single shard
-- and router plannable
SELECT *
FROM articles_hash_mx
WHERE author_id = 1 and author_id >= 1;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
-- not router plannable due to or
SELECT *
FROM articles_hash_mx
WHERE author_id = 1 or id = 1;
DEBUG: Router planner cannot handle multi-shard select queries
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
-- router plannable
SELECT *
FROM articles_hash_mx
WHERE author_id = 1 and (id = 1 or id = 41);
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+----------+------------
1 | 1 | arsenous | 9572
41 | 1 | aznavour | 11814
(2 rows)
-- router plannable
SELECT *
FROM articles_hash_mx
WHERE author_id = 1 and (id = random()::int * 0);
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+-------+------------
(0 rows)
-- not router plannable due to function call on the right side
SELECT *
FROM articles_hash_mx
WHERE author_id = (random()::int * 0 + 1);
DEBUG: Router planner cannot handle multi-shard select queries
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
-- not router plannable due to or
SELECT *
FROM articles_hash_mx
WHERE author_id = 1 or id = 1;
DEBUG: Router planner cannot handle multi-shard select queries
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
-- router plannable due to abs(-1) getting converted to 1 by postgresql
SELECT *
FROM articles_hash_mx
WHERE author_id = abs(-1);
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
-- not router plannable due to abs() function
SELECT *
FROM articles_hash_mx
WHERE 1 = abs(author_id);
DEBUG: Router planner cannot handle multi-shard select queries
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
-- not router plannable due to abs() function
SELECT *
FROM articles_hash_mx
WHERE author_id = abs(author_id - 2);
DEBUG: Router planner cannot handle multi-shard select queries
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
-- router plannable, function on different field
SELECT *
FROM articles_hash_mx
WHERE author_id = 1 and (id = abs(id - 2));
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+----------+------------
1 | 1 | arsenous | 9572
(1 row)
-- not router plannable due to is true
SELECT *
FROM articles_hash_mx
WHERE (author_id = 1) is true;
DEBUG: Router planner cannot handle multi-shard select queries
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
-- router plannable, (boolean expression) = true is collapsed to (boolean expression)
SELECT *
FROM articles_hash_mx
WHERE (author_id = 1) = true;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
-- router plannable, between operator is on another column
SELECT *
FROM articles_hash_mx
WHERE (author_id = 1) and id between 0 and 20;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+----------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
(2 rows)
-- router plannable, partition column expression is and'ed to rest
SELECT *
FROM articles_hash_mx
WHERE (author_id = 1) and (id = 1 or id = 31) and title like '%s';
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
31 | 1 | athwartships | 7271
(2 rows)
-- router plannable, order is changed
SELECT *
FROM articles_hash_mx
WHERE (id = 1 or id = 31) and title like '%s' and (author_id = 1);
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
31 | 1 | athwartships | 7271
(2 rows)
-- router plannable
SELECT *
FROM articles_hash_mx
WHERE (title like '%s' or title like 'a%') and (author_id = 1);
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
-- router plannable
SELECT *
FROM articles_hash_mx
WHERE (title like '%s' or title like 'a%') and (author_id = 1) and (word_count < 3000 or word_count > 8000);
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+----------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
41 | 1 | aznavour | 11814
(3 rows)
-- window functions are supported if query is router plannable
SELECT LAG(title, 1) over (ORDER BY word_count) prev, title, word_count
FROM articles_hash_mx
WHERE author_id = 5;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 5
prev | title | word_count
----------+----------+------------
| afrasia | 864
afrasia | adversa | 3164
adversa | antehall | 7707
antehall | aminate | 9089
aminate | aruru | 11389
(5 rows)
SELECT LAG(title, 1) over (ORDER BY word_count) prev, title, word_count
FROM articles_hash_mx
WHERE author_id = 5
ORDER BY word_count DESC;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 5
prev | title | word_count
----------+----------+------------
aminate | aruru | 11389
antehall | aminate | 9089
adversa | antehall | 7707
afrasia | adversa | 3164
| afrasia | 864
(5 rows)
SELECT id, MIN(id) over (order by word_count)
FROM articles_hash_mx
WHERE author_id = 1;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | min
----+-----
11 | 11
21 | 11
31 | 11
1 | 1
41 | 1
(5 rows)
SELECT id, word_count, AVG(word_count) over (order by word_count)
FROM articles_hash_mx
WHERE author_id = 1;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | word_count | avg
----+------------+-----------------------
11 | 1347 | 1347.0000000000000000
21 | 5890 | 3618.5000000000000000
31 | 7271 | 4836.0000000000000000
1 | 9572 | 6020.0000000000000000
41 | 11814 | 7178.8000000000000000
(5 rows)
SELECT word_count, rank() OVER (PARTITION BY author_id ORDER BY word_count)
FROM articles_hash_mx
WHERE author_id = 1;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
word_count | rank
------------+------
1347 | 1
5890 | 2
7271 | 3
9572 | 4
11814 | 5
(5 rows)
-- window functions are not supported for not router plannable queries
SELECT id, MIN(id) over (order by word_count)
FROM articles_hash_mx
WHERE author_id = 1 or author_id = 2;
DEBUG: Router planner cannot handle multi-shard select queries
ERROR: could not run distributed query because the window function that is used cannot be pushed down
HINT: Window functions are supported in two ways. Either add an equality filter on the distributed tables' partition column or use the window functions with a PARTITION BY clause containing the distribution column
SELECT LAG(title, 1) over (ORDER BY word_count) prev, title, word_count
FROM articles_hash_mx
WHERE author_id = 5 or author_id = 2;
DEBUG: Router planner cannot handle multi-shard select queries
ERROR: could not run distributed query because the window function that is used cannot be pushed down
HINT: Window functions are supported in two ways. Either add an equality filter on the distributed tables' partition column or use the window functions with a PARTITION BY clause containing the distribution column
-- complex query hitting a single shard
SELECT
count(DISTINCT CASE
WHEN
word_count > 100
THEN
id
ELSE
NULL
END) as c
FROM
articles_hash_mx
WHERE
author_id = 5;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 5
c
---
5
(1 row)
-- same query is not router plannable if hits multiple shards
SELECT
count(DISTINCT CASE
WHEN
word_count > 100
THEN
id
ELSE
NULL
END) as c
FROM
articles_hash_mx
GROUP BY
author_id
ORDER BY c;
DEBUG: Router planner cannot handle multi-shard select queries
c
---
4
5
5
5
5
5
5
5
5
5
(10 rows)
-- queries inside transactions can be router plannable
BEGIN;
SELECT *
FROM articles_hash_mx
WHERE author_id = 1
ORDER BY id;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
END;
-- cursor queries are router plannable
BEGIN;
DECLARE test_cursor CURSOR FOR
SELECT *
FROM articles_hash_mx
WHERE author_id = 1
ORDER BY id;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
FETCH test_cursor;
id | author_id | title | word_count
----+-----------+----------+------------
1 | 1 | arsenous | 9572
(1 row)
FETCH test_cursor;
id | author_id | title | word_count
----+-----------+-------+------------
11 | 1 | alamo | 1347
(1 row)
FETCH BACKWARD test_cursor;
id | author_id | title | word_count
----+-----------+----------+------------
1 | 1 | arsenous | 9572
(1 row)
END;
-- queries inside copy can be router plannable
COPY (
SELECT *
FROM articles_hash_mx
WHERE author_id = 1
ORDER BY id) TO STDOUT;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
1 1 arsenous 9572
11 1 alamo 1347
21 1 arcading 5890
31 1 athwartships 7271
41 1 aznavour 11814
-- table creation queries inside can be router plannable
CREATE TEMP TABLE temp_articles_hash_mx as
SELECT *
FROM articles_hash_mx
WHERE author_id = 1
ORDER BY id;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
-- router plannable queries may include filter for aggragates
SELECT count(*), count(*) FILTER (WHERE id < 3)
FROM articles_hash_mx
WHERE author_id = 1;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
count | count
-------+-------
5 | 1
(1 row)
-- non-router plannable queries support filters as well
SELECT count(*), count(*) FILTER (WHERE id < 3)
FROM articles_hash_mx
WHERE author_id = 1 or author_id = 2;
DEBUG: Router planner cannot handle multi-shard select queries
count | count
-------+-------
10 | 2
(1 row)
-- prepare queries can be router plannable
PREPARE author_1_articles as
SELECT *
FROM articles_hash_mx
WHERE author_id = 1;
EXECUTE author_1_articles;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
-- parametric prepare queries can be router plannable
PREPARE author_articles(int) as
SELECT *
FROM articles_hash_mx
WHERE author_id = $1;
EXECUTE author_articles(1);
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
-- queries inside plpgsql functions could be router plannable
CREATE OR REPLACE FUNCTION author_articles_max_id() RETURNS int AS $$
DECLARE
max_id integer;
BEGIN
SELECT MAX(id) FROM articles_hash_mx ah
WHERE author_id = 1
into max_id;
return max_id;
END;
$$ LANGUAGE plpgsql;
SELECT author_articles_max_id();
DEBUG: Creating router plan
CONTEXT: SQL statement "SELECT MAX(id) FROM articles_hash_mx ah
WHERE author_id = 1"
PL/pgSQL function author_articles_max_id() line 5 at SQL statement
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
CONTEXT: SQL statement "SELECT MAX(id) FROM articles_hash_mx ah
WHERE author_id = 1"
PL/pgSQL function author_articles_max_id() line 5 at SQL statement
author_articles_max_id
------------------------
41
(1 row)
-- plpgsql function that return query results are not router plannable
CREATE OR REPLACE FUNCTION author_articles_id_word_count() RETURNS TABLE(id bigint, word_count int) AS $$
DECLARE
BEGIN
RETURN QUERY
SELECT ah.id, ah.word_count
FROM articles_hash_mx ah
WHERE author_id = 1;
END;
$$ LANGUAGE plpgsql;
SELECT * FROM author_articles_id_word_count();
DEBUG: Creating router plan
CONTEXT: SQL statement "SELECT ah.id, ah.word_count
FROM articles_hash_mx ah
WHERE author_id = 1"
PL/pgSQL function author_articles_id_word_count() line 4 at RETURN QUERY
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
CONTEXT: SQL statement "SELECT ah.id, ah.word_count
FROM articles_hash_mx ah
WHERE author_id = 1"
PL/pgSQL function author_articles_id_word_count() line 4 at RETURN QUERY
id | word_count
----+------------
1 | 9572
11 | 1347
21 | 5890
31 | 7271
41 | 11814
(5 rows)
-- materialized views can be created for router plannable queries
CREATE MATERIALIZED VIEW mv_articles_hash_mx AS
SELECT * FROM articles_hash_mx WHERE author_id = 1;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
SELECT * FROM mv_articles_hash_mx;
id | author_id | title | word_count
----+-----------+--------------+------------
1 | 1 | arsenous | 9572
11 | 1 | alamo | 1347
21 | 1 | arcading | 5890
31 | 1 | athwartships | 7271
41 | 1 | aznavour | 11814
(5 rows)
SET client_min_messages to 'INFO';
DROP MATERIALIZED VIEW mv_articles_hash_mx;
SET client_min_messages to 'DEBUG2';
CREATE MATERIALIZED VIEW mv_articles_hash_mx_error AS
SELECT * FROM articles_hash_mx WHERE author_id in (1,2);
DEBUG: Router planner cannot handle multi-shard select queries
-- router planner/executor is disabled for task-tracker executor
-- following query is router plannable, but router planner is disabled
-- TODO: Uncomment once we fix task-tracker issue
--SET citus.task_executor_type to 'task-tracker';
--SELECT id
-- FROM articles_hash_mx
-- WHERE author_id = 1;
-- insert query is router plannable even under task-tracker
INSERT INTO articles_hash_mx VALUES (51, 1, 'amateus', 1814);
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
-- verify insert is successfull (not router plannable and executable)
SELECT id
FROM articles_hash_mx
WHERE author_id = 1;
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
id
----
1
11
21
31
41
51
(6 rows)
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