| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Andres Freund <andres(at)anarazel(dot)de> |
| Cc: | Mathieu Fenniak <mathieu(dot)fenniak(at)replicon(dot)com>, pgsql-general(at)postgresql(dot)org |
| Subject: | Re: Logical decoding CPU-bound w/ large number of tables |
| Date: | 2017-05-06 01:32:27 |
| Message-ID: | 19256.1494034347@sss.pgh.pa.us |
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| Lists: | pgsql-general |
Andres Freund <andres(at)anarazel(dot)de> writes:
> On 2017-05-05 14:24:07 -0600, Mathieu Fenniak wrote:
>> It appears that most of the time is spent in the
>> RelfilenodeMapInvalidateCallback and CatalogCacheIdInvalidate cache
>> invalidation callbacks, both of which appear to be invalidating caches
>> based upon the cache value.
> I think optimizing those has some value (and I see Tom is looking at
> that aspect, but the bigger thing would probably be to do fewer lookups.
I'm confused --- the lookup side of things is down in the noise in
Mathieu's trace. Further reducing the number of lookups doesn't seem
like it helps this scenario at all. It might matter once we've whacked
down the cost of invalidations ...
regards, tom lane
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