Re: Deleting takes days, should I add some index?

Hi

čt 25. 2. 2021 v 19:39 odesílatel Alexander Farber <
alexander(dot)farber(at)gmail(dot)com> napsal:

> Pavel, thank you for asking!
>
> I have put the anonymized dump of my database at:
>
> http://wordsbyfarber.com/words_dev.sql.gz (beware, it is a 1.3 GB
> download)
>
> The question is why does the command take days (when I tried last time):
>
> delete from words_games where created < now() - interval '12 month';
>
>
I tried to remove just only one row

postgres=# explain analyze delete from words_games where gid = 44877;
┌────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ QUERY PLAN
│
╞════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════════╡
│ Delete on words_games (cost=0.42..8.44 rows=0 width=0) (actual
time=0.268..0.270 rows=0 loops=1) │
│ -> Index Scan using words_games_pkey on words_games (cost=0.42..8.44
rows=1 width=6) (actual time=0.205..0.209 rows=1 loops=1) │
│ Index Cond: (gid = 44877)
│
│ Planning Time: 0.328 ms
│
│ Trigger for constraint words_chat_gid_fkey on words_games: time=0.215
calls=1 │
│ Trigger for constraint words_moves_gid_fkey on words_games: time=0.240
calls=1 │
│ Trigger for constraint words_scores_gid_fkey on words_games: time=0.103
calls=1 │
│ Trigger for constraint words_puzzles_mid_fkey on words_moves: time=56.099
calls=4 │
│ Trigger for constraint words_scores_mid_fkey on words_moves:
time=22536.280 calls=4 │
│ Execution Time: 22593.293 ms
│
└────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
(10 rows)

looks so you miss index

create index on words_scores(mid);

Regards

Pavel