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Subject: Re: MultiXact\SLRU buffers configuration
From: Andrey Borodin <x4mmm@yandex-team.ru>
In-Reply-To: <B7D61584-6CAC-4CF9-B3D4-7CC52D6C4C5C@yandex-team.ru>
Date: Wed, 7 Apr 2021 15:13:26 +0300
Cc: Gilles Darold <gilles@darold.net>,
 Tomas Vondra <tomas.vondra@enterprisedb.com>,
 Tomas Vondra <tomas.vondra@2ndquadrant.com>,
 Alexander Korotkov <aekorotkov@gmail.com>,
 Anastasia Lubennikova <a.lubennikova@postgrespro.ru>,
 Daniel Gustafsson <daniel@yesql.se>,
 Kyotaro Horiguchi <horikyota.ntt@gmail.com>,
 pgsql-hackers <pgsql-hackers@postgresql.org>
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References: <a7f1c4e1-1015-92a4-2bd4-6736bd13d03e@postgrespro.ru>
 <20201028013651.de5cj2xadgmba5nf@development>
 <13D8FD63-559A-4737-B7FD-05288D1CEF8B@yandex-team.ru>
 <20201028233243.ygm6yqlynkqpzekr@development>
 <43F3DE92-F236-4EA5-B4D6-39BEF6BD849D@yandex-team.ru>
 <20201029134933.xd4mh2cofuf6tdfz@development>
 <65C1B4BA-D16F-4939-978B-AC8F370F5A5E@yandex-team.ru>
 <9b4d17df-b811-8323-16be-3cab913216d1@enterprisedb.com>
 <A64B924A-B08E-417D-BD3D-D396D722053B@yandex-team.ru>
 <35862787-8b4d-a290-789e-6e12dc6527e8@enterprisedb.com>
 <13F86913-C01B-4983-AE2E-493F5A028280@yandex-team.ru>
 <6ba7eae2-8b0c-0690-11a5-e921e6586180@darold.net>
 <3F5E23A3-6250-486E-9CCA-E2A5B6A28B4F@yandex-team.ru>
 <636f694a-4d69-d6d9-78d1-c88714f3e2e0@darold.net>
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 <1E3DD5BF-A54E-4203-86C5-94C9EFA0E095@yandex-team.ru>
 <04ae150b-6442-148a-bb23-77082f6fca1d@darold.net>
 <3768803E-4794-409D-88D2-C3EF7CA1B7FC@yandex-team.ru>
 <CA+hUKGJ4TwipnMDmKdORu4zUo_rofsuu5FQsgV=UHJ3bY38ERw@mail.gmail.com>
 <CA+hUKGK2bkx91=CWRuPqWdXAu2JSS0mDPBh8DNuSeKhy8eOLgg@mail.gmail.com>
 <CA+hUKGL0g+Nmf=2XePaXtw82BkW9CRzoxxXB4gqZOk7tHxNJXg@mail.gmail.com>
 <D330C01E-789A-4DDD-B2B1-4561B8B7F41D@yandex-team.ru>
 <75B95FDD-2BE0-4525-8BDD-FC67C8BCBD53@yandex-team.ru>
 <CA+hUKGKVqrxOp82zER1=XN=yPwV_-OCGAg=ez=1iz9rG+A7Smw@mail.gmail.com>
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 <018EF641-FC9D-4BA9-A458-6842E27E91C2@yandex-team.ru>
 <B8AC2998-942F-40F0-ADDD-7846C6AE7705@yandex-team.ru>
 <CA+hUKGKEdeVKpOqBxzRF+Z4=j0T+CA7ERrXni5De71Mm6-dBWA@mail.gmail.com>
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To: Thomas Munro <thomas.munro@gmail.com>
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> 7 =D0=B0=D0=BF=D1=80. 2021 =D0=B3., =D0=B2 14:44, Andrey Borodin =
<x4mmm@yandex-team.ru> =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0=D0=BB(=D0=B0):=

>=20
> Maybe instead of fully associative cache with random replacement we =
could use 1-associative cache?
> i.e. each page can reside only in one spcific buffer slot. If there's =
something else - evict it.
> I think this would be as efficient as RR cache. And it's soooo fast.

I thought a bit more and understood that RR is protected from two =
competing pages in working set, while 1-associative cache is not. So, =
discard that idea.

Best regards, Andrey Borodin.