Re: is necessary to recheck cached data in fn_extra?

From: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: is necessary to recheck cached data in fn_extra?
Date: 2019-08-07 16:18:40
Message-ID: CAFj8pRAPpT29i3W-pXv4P-1sTMqGZtkubqKhiAey80+0pqu2mA@mail.gmail.com
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st 7. 8. 2019 v 17:39 odesílatel Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> napsal:

> Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> writes:
> > I should to use a cache accessed via fn_extra. There will be stored data
> > about function parameters (types). If I understand correctly, these data
> > should be stable in query, and then recheck is not necessary. Is it true?
>
> I wouldn't trust that. You don't really know what the lifespan of
> a fn_extra cache is.
>

fn_extra cache cannot be longer than query. And if I understand well, then
is not possible to change parameter types inside query?

Pavel

> regards, tom lane
>

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