| From: | "Tsunakawa, Takayuki" <tsunakawa(dot)takay(at)jp(dot)fujitsu(dot)com> |
|---|---|
| To: | "Ideriha, Takeshi" <ideriha(dot)takeshi(at)jp(dot)fujitsu(dot)com>, 'Kyotaro HORIGUCHI' <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp> |
| Cc: | "alvherre(at)2ndquadrant(dot)com" <alvherre(at)2ndquadrant(dot)com>, "tomas(dot)vondra(at)2ndquadrant(dot)com" <tomas(dot)vondra(at)2ndquadrant(dot)com>, "bruce(at)momjian(dot)us" <bruce(at)momjian(dot)us>, "andres(at)anarazel(dot)de" <andres(at)anarazel(dot)de>, "robertmhaas(at)gmail(dot)com" <robertmhaas(at)gmail(dot)com>, "tgl(at)sss(dot)pgh(dot)pa(dot)us" <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "pgsql-hackers(at)lists(dot)postgresql(dot)org" <pgsql-hackers(at)lists(dot)postgresql(dot)org>, "michael(dot)paquier(at)gmail(dot)com" <michael(dot)paquier(at)gmail(dot)com>, "david(at)pgmasters(dot)net" <david(at)pgmasters(dot)net>, "craig(at)2ndquadrant(dot)com" <craig(at)2ndquadrant(dot)com> |
| Subject: | RE: Protect syscache from bloating with negative cache entries |
| Date: | 2019-02-21 06:11:51 |
| Message-ID: | 0A3221C70F24FB45833433255569204D1FB9EC1D@G01JPEXMBYT05 |
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| Lists: | pgsql-hackers |
From: Ideriha, Takeshi/出利葉 健
> I checked it with perf record -avg and perf report.
> The following shows top 20 symbols during benchmark including kernel space.
> The main difference between master (unpatched) and patched one seems that
> patched one consumes cpu catcache-evict-and-refill functions including
> SearchCatCacheMiss(), CatalogCacheCreateEntry(),
> CatCacheCleanupOldEntries().
> So it seems to me that these functions needs further inspection
> to suppress the performace decline as much as possible
Thank you. It's good to see the expected functions, rather than strange behavior. The performance drop is natural just like the database cache's hit ratio is low. The remedy for performance by the user is also the same as the database cache -- increase the catalog cache.
Regards
Takayuki Tsunakawa
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