Re: Selectivity estimation for intarray

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Stephen Frost <sfrost(at)snowman(dot)net>
Cc: Alexander Korotkov <aekorotkov(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Selectivity estimation for intarray
Date: 2015-04-29 16:05:26
Message-ID: 35337.1430323526@sss.pgh.pa.us
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Stephen Frost <sfrost(at)snowman(dot)net> writes:
> * Tom Lane (tgl(at)sss(dot)pgh(dot)pa(dot)us) wrote:
>> For the specific cases you mention, perhaps it would be all right if we
>> taught plancache.c to blow away *all* cached plans upon seeing any change
>> in pg_operator; but that seems like a brute-force solution.

> Agreed that it is- but is that really a problem...?

Perhaps it isn't; we certainly have assumptions that pg_amop, for
instance, changes seldom enough that it's not worth tracking individual
changes. The same might be true of pg_operator. I'm not sure though.

The core point I'm trying to make is that making pg_operator entries
mutable is something that's going to require very careful review.

regards, tom lane

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