From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
---|---|
To: | Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> |
Cc: | Arthur Zakirov <a(dot)zakirov(at)postgrespro(dot)ru>, Andres Freund <andres(at)anarazel(dot)de>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: [PROPOSAL] Shared Ispell dictionaries |
Date: | 2019-02-01 14:40:44 |
Message-ID: | CA+TgmobejQCE7GEX5Nx6ZDwT1ifdjtK+q5dWZV9QXXe_CjQkHw@mail.gmail.com |
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On Tue, Jan 22, 2019 at 2:17 PM Tomas Vondra
<tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
> I think there are essentially two ways:
>
> (a) Define max amount of memory available for shared dictionarires, and
> come up with an eviction algorithm. This will be tricky, because when
> the frequently-used dictionaries need a bit more memory than the limit,
> this will result in trashing (evict+load over and over).
>
> (b) Define what "unused" means for dictionaries, and unload dictionaries
> that become unused. For example, we could track timestamp of the last
> time each dict was used, and decide that dictionaries unused for 5 or
> more minutes are unused. And evict those.
>
> The advantage of (b) is that it adopts automatically, more or less. When
> you have a bunch of frequently used dictionaries, the amount of shared
> memory increases. If you stop using them, it decreases after a while.
> And rarely used dicts won't force eviction of the frequently used ones.
+1 for (b).
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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