RE: Protect syscache from bloating with negative cache entries - Mailing list pgsql-hackers

From Ideriha, Takeshi
Subject RE: Protect syscache from bloating with negative cache entries
Date
Msg-id 4E72940DA2BF16479384A86D54D0988A6F448206@G01JPEXMBKW04
Whole thread Raw
In response to Re: Protect syscache from bloating with negative cache entries  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: Protect syscache from bloating with negative cache entries
List pgsql-hackers
>From: Robert Haas [mailto:robertmhaas@gmail.com]
>On Thu, Mar 7, 2019 at 9:49 AM Tomas Vondra <tomas.vondra@2ndquadrant.com>
>wrote:
>> I don't think this shows any regression, but perhaps we should do a
>> microbenchmark isolating the syscache entirely?
>
>Well, if we need the LRU list, then yeah I think a microbenchmark would be a good idea
>to make sure we really understand what the impact of that is going to be.  But if we
>don't need it and can just remove it then we don't.

Just to be sure, we introduced the LRU list in this thread to find the entries less than threshold time
without scanning the whole hash table. If hash table becomes large without LRU list, scanning time becomes slow.

Regards,
Takeshi Ideriha

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