Re: Unused indexes - PostgreSQL 9.2 - Mailing list pgsql-general
| From | Lucas Possamai |
|---|---|
| Subject | Re: Unused indexes - PostgreSQL 9.2 |
| Date | |
| Msg-id | CAE_gQfUYk4GxFyLxA_nB-jdJVVPceqiKKMfvQyp4EMA_sCRfvw@mail.gmail.com Whole thread Raw |
| In response to | Re: Unused indexes - PostgreSQL 9.2 (Melvin Davidson <melvin6925@gmail.com>) |
| Responses |
Re: Unused indexes - PostgreSQL 9.2
|
| List | pgsql-general |
Hello Melvin, how are you doing?
And what happens if you run this query?
SELECT idstat.schemaname AS schema,
idstat.relname AS table_name,
indexrelname AS index_name,
idstat.idx_scan AS times_used,
pg_size_pretty(pg_relation_size(quote_ident(idstat.schemaname) || '.' || quote_ident(idstat.relname))) AS table_size,
pg_size_pretty(pg_relation_size(quote_ident(idstat.schemaname) || '.' || quote_ident(indexrelname))) AS index_size,
n_tup_upd + n_tup_ins + n_tup_del as num_writes,
indexdef AS definition
FROM pg_stat_user_indexes AS idstat
JOIN pg_indexes ON indexrelname = indexname
JOIN pg_stat_user_tables AS tabstat ON idstat.relname = tabstat.relname
WHERE indexrelname = ' {YOUR QUERY NAME } ';
I've added some new indexes this week into my prod environment, and I used your query to see if they're being used or not.
Query:
SELECT idstat.schemaname AS schema,
idstat.relname AS table_name,
indexrelname AS index_name,
idstat.idx_scan AS times_used,
pg_size_pretty(pg_relation_size(quote_ident(idstat.schemaname) || '.' || quote_ident(idstat.relname))) AS table_size,
pg_size_pretty(pg_relation_size(quote_ident(idstat.schemaname) || '.' || quote_ident(indexrelname))) AS index_size,
n_tup_upd + n_tup_ins + n_tup_del as num_writes,
indexdef AS definition
FROM pg_stat_user_indexes AS idstat
JOIN pg_indexes ON indexrelname = indexname
JOIN pg_stat_user_tables AS tabstat ON idstat.relname = tabstat.relname
WHERE indexrelname = 'ix_ja_jobs_clientid_title_time_job';
Returns:
schema table_name index_name times_used table_size index_size num_writes definition
------ ---------- ---------------------------------- ---------- ---------- ---------- ---------- -------------------------------------------------------------------------------------------------------------------------------------------------------
public ja_jobs ix_ja_jobs_clientid_title_time_job 41536 3526 MB 484 MB 38266927 CREATE INDEX "ix_ja_jobs_clientid_title_time_job" ON "ja_jobs" USING "btree" ("clientid", "lower"(("title")::"text") "varchar_pattern_ops", "time_job")
That index has been added just 3 hours ago, and you can see that the times_used goes over 41000.... How is that possible??
Don't think the query is right.
Can you please check ?
Thank you.
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