| From: | Simen Andreas Andreassen Lønsethagen <simen(dot)lonsethagen(at)fremtind(dot)no> |
|---|---|
| To: | Justin Pryzby <pryzby(at)telsasoft(dot)com> |
| Cc: | "pgsql-performance(at)lists(dot)postgresql(dot)org" <pgsql-performance(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Performance of lateral join |
| Date: | 2021-07-27 09:08:49 |
| Message-ID: | 58EEA217-E918-49C0-987A-E634AD6BB1B2@fremtind.no |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
> Easy first question: is the temp table analyzed before being used in a join ?
No, I haven't done that. Today, I tried to run
ANALYZE records_to_filter_on;
on the same sample data set (3.75 million rows) before the join, and it did not seem to make much of a difference in terms of time (new output of EXPLAIN ANALYZE at https://explain.dalibo.com/plan/YZu - it seems very similar to me).
Not sure if it is relevant, but I did some experimentation with smaller samples, and for those, there was a significant speedup. Could there be some size threshold on the temp table after which running ANALYZE does not yield any speedup?
> I think the attachment is missing.
Added now.
Simen
| Attachment | Content-Type | Size |
|---|---|---|
| explain_analyze.json | application/json | 5.2 KB |
| pg_settings.conf | application/octet-stream | 53.9 KB |
| From | Date | Subject | |
|---|---|---|---|
| Next Message | kenny a | 2021-07-27 17:14:03 | Query performance ! |
| Previous Message | kenny a | 2021-07-26 23:59:19 | Query performance ! |