| From: | Andres Freund <andres(at)anarazel(dot)de> |
|---|---|
| To: | Tomas Vondra <tomas(dot)vondra(at)enterprisedb(dot)com> |
| Cc: | Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>, Michael Paquier <michael(at)paquier(dot)xyz>, Bharath Rupireddy <bharath(dot)rupireddyforpostgres(at)gmail(dot)com>, Kyotaro Horiguchi <horikyota(dot)ntt(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Pavan Deolasee <pavan(dot)deolasee(at)gmail(dot)com>, Anastasia Lubennikova <a(dot)lubennikova(at)postgrespro(dot)ru>, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, Paul Guo <guopa(at)vmware(dot)com> |
| Subject: | Re: Performance degradation of REFRESH MATERIALIZED VIEW |
| Date: | 2021-05-21 16:43:44 |
| Message-ID: | 20210521164344.ortxzvuw2p5lvf4w@alap3.anarazel.de |
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| Lists: | pgsql-hackers |
Hi,
On 2021-05-21 18:17:01 +0200, Tomas Vondra wrote:
> OK, so here are the flamegraphs, for all three cases - current master,
> 0c7d3bb99 (i.e. before heap_insert changes) and with the pinning patch
> applied. I did this using the same test case as before (50M table), but with
> -fno-omit-frame-pointer to get better profiles. It may add some overhead,
> but hopefully that applies to all cases equally.
>
> The first 10 runs for each case look like this:
>
> old master patched
> ----------------------
> 55045 74284 58246
> 53927 74283 57273
> 54090 74114 57336
> 54194 74059 57223
> 54189 74186 57287
> 54090 74113 57278
> 54095 74036 57176
> 53896 74215 57303
> 54101 74060 57524
> 54062 74021 57278
> ----------------------
> 54168 74137 57392
> 1.36x 1.05x
>
> which is mostly in line with previous findings (the master overhead is a bit
> worse, possibly due to the frame pointers).
>
> Attached are the flame graphs for all three cases. The change in master is
> pretty clearly visible, but I don't see any clear difference between old and
> patched code :-(
I'm pretty sure it's the additional WAL records?
Greetings,
Andres Freund
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