Использую PGSQL, есть простой запрос,
| Код |
EXPLAIN (ANALYZE,BUFFERS)
WITH data_to_cte AS (
SELECT
unnest[1]::integer account
, unnest[2]::text user_id
, unnest[3]::integer target_id
FROM
(
SELECT
unnest('{ "{ 7267996,4,96394594 }" }'::text[])::text[]
) f
)
SELECT
"DocumentsId",
data_to_cte.*
FROM
data_to_cte
JOIN
"Documents"
on "Account" = account AND
"Target" = target_id and
"User" = user_id AND
"User" IS NOT NULL
|
план такой
| Код |
Nested Loop (cost=0.58..8.68 rows=1 width=48) (actual time=23.352..23.353 rows=0 loops=1)
Buffers: shared hit=16730
-> Result (cost=0.00..0.04 rows=1 width=32) (actual time=0.008..0.012 rows=1 loops=1)
-> ProjectSet (cost=0.00..0.02 rows=1 width=32) (actual time=0.004..0.007 rows=1 loops=1)
-> Result (cost=0.00..0.01 rows=1 width=0) (actual time=0.002..0.002 rows=1 loops=1)
-> Index Scan using "iDocuments-AccountUser" on "Documents" (cost=0.58..8.61 rows=1 width=28) (actual time=23.334..23.334 rows=0 loops=1)
Index Cond: (("Account" = (((((unnest('{"{ 7267996,4,96394594 }"}'::text[])))::text[]))[1])::integer) AND ("User" = ((((unnest('{"{ 7267996,4,96394594 }"}'::text[])))::text[]))[2]))
Filter: ((((((unnest('{"{ 7267996,4,96394594 }"}'::text[])))::text[]))[3])::integer = "Target")
Rows Removed by Filter: 19163
Buffers: shared hit=16730
Planning Time: 0.318 ms
Execution Time: 23.397 ms
|
Хочется чтобы использовался такой индекс
| Код |
CREATE INDEX "iDocuments-AccountTarget"
ON "Documents" USING btree
("Account" NULLS LAST, "Target" NULLS LAST, "User" NULLS LAST)
WHERE ("User" IS NOT NULL);
|
Что нужно сделать, возможно переписать запрос?
Например, если указать напрямую Target, то используется нужный индекс
| Код |
EXPLAIN (ANALYZE,BUFFERS)
WITH data_to_cte AS (
SELECT
unnest[1]::integer account
, unnest[2]::text user_id
, unnest[3]::integer target_id
FROM
(
SELECT
unnest('{ "{ 7267996,4,96394594 }" }'::text[])::text[]
) f
)
SELECT
"DocumentsId",
data_to_cte.*
FROM
data_to_cte
JOIN
"Documents"
on "Account" = account AND
"Target" = 4 and
"User" = user_id AND
"User" IS NOT NULL
|
|