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| https://news.ycombinator.com/reply?id=13613909&goto=item%3Fid%3D13610146%2313613909 | |
| --- | |
| smc=# explain SELECT * FROM file_use WHERE project_id = any(select project_id from projects where users ? '25e2cae4-05c7-4c28-ae22-1e6d3d2e8bb3') ORDER | |
| BY last_edited DESC limit 100; | |
| QUERY PLAN | |
| --------------------------------------------------------------------------------------------------------------------------- | |
| Limit (cost=0.85..8198.07 rows=100 width=242) | |
| -> Nested Loop Semi Join (cost=0.85..1736663.69 rows=21186 width=242) | |
| -> Index Scan Backward using file_use_last_edited_idx on file_use (cost=0.43..462869.27 rows=2214686 width=242) | |
| -> Index Scan using projects_pkey on projects (cost=0.42..0.58 rows=1 width=16) | |
| Index Cond: (project_id = file_use.project_id) | |
| Filter: (users ? '25e2cae4-05c7-4c28-ae22-1e6d3d2e8bb3'::text) | |
| (6 rows) | |
| smc=# \timing | |
| Timing is on. | |
| smc=# SELECT * FROM file_use WHERE project_id = any(select project_id from projects where users ? '25e2cae4-05c7-4c28-ae22-1e6d3d2e8bb4') ORDER BY last | |
| _edited DESC limit 100; | |
| id | project_id | path | users | last_edited | |
| ----+------------+------+-------+------------- | |
| (0 rows) | |
| Time: 11695.095 ms | |
| smc=# BEGIN; | |
| BEGIN | |
| Time: 0.124 ms | |
| smc=# SET LOCAL enable_nestloop = off; | |
| SET | |
| Time: 0.172 ms | |
| smc=# SELECT * FROM file_use WHERE project_id = any(select project_id from projects where users ? '25e2cae4-05c7-4c28-ae22-1e6d3d2e8bb4') ORDER BY last | |
| _edited DESC limit 100; | |
| id | project_id | path | users | last_edited | |
| ----+------------+------+-------+------------- | |
| (0 rows) | |
| Time: 1.479 ms | |
| smc=# commit; | |
| COMMIT | |
| Time: 0.166 ms | |
| smc=# \d file_use | |
| Table "public.file_use" | |
| Column | Type | Modifiers | |
| -------------+-----------------------------+----------- | |
| id | character(40) | not null | |
| project_id | uuid | | |
| path | text | | |
| users | jsonb | | |
| last_edited | timestamp without time zone | | |
| Indexes: | |
| "file_use_pkey" PRIMARY KEY, btree (id) | |
| "file_use_last_edited_idx" btree (last_edited) | |
| "file_use_project_id_idx" btree (project_id) | |
| Triggers: | |
| change_12294c1fc89b482b AFTER INSERT OR DELETE OR UPDATE OF project_id, path, users, last_edited, id ON file_use FOR EACH ROW EXECUTE PROCEDURE change_12294c1fc89b482b() | |
| smc=# \d projects | |
| Table "public.projects" | |
| Column | Type | Modifiers | |
| -----------------+-----------------------------+----------- | |
| project_id | uuid | not null | |
| title | text | | |
| description | text | | |
| users | jsonb | | |
| invite | jsonb | | |
| invite_requests | jsonb | | |
| deleted | boolean | | |
| host | jsonb | | |
| settings | jsonb | | |
| status | jsonb | | |
| state | jsonb | | |
| last_edited | timestamp without time zone | | |
| last_active | jsonb | | |
| created | timestamp without time zone | | |
| action_request | jsonb | | |
| storage | jsonb | | |
| last_backup | timestamp without time zone | | |
| storage_request | jsonb | | |
| course | jsonb | | |
| run | boolean | | |
| storage_server | integer | | |
| storage_ready | boolean | | |
| disk_size | integer | | |
| resources | jsonb | | |
| preemptible | boolean | | |
| idle_timeout | integer | | |
| Indexes: | |
| "projects_pkey" PRIMARY KEY, btree (project_id) |
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Interesting. Can you maybe also (i) show the
EXPLAINfor theenable_nestloop = offcase, and (ii)EXPLAIN (ANALYZE, BUFFERS)for both queries?