From: | Jim Nasby <Jim(dot)Nasby(at)BlueTreble(dot)com> |
---|---|
To: | Andres Freund <andres(at)anarazel(dot)de> |
Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>, Stephen Frost <sfrost(at)snowman(dot)net>, Michael Paquier <michael(dot)paquier(at)gmail(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Reviewing freeze map code |
Date: | 2016-07-01 20:49:04 |
Message-ID: | b24fecf9-6dfb-89b7-904c-bef387025614@BlueTreble.com |
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Lists: | pgsql-hackers |
On 7/1/16 3:43 PM, Andres Freund wrote:
> On 2016-07-01 15:42:22 -0500, Jim Nasby wrote:
>> On 7/1/16 2:23 PM, Andres Freund wrote:
>>>>> The only
>>>>> cost of that is that vacuum will come along and mark the page
>>>>> all-visible again instead of skipping it, but that's probably not an
>>>>> enormous expense in most cases.
>>> I think the main cost is not having the page marked as all-visible for
>>> index-only purposes. If it's an insert mostly table, it can be a long
>>> while till vacuum comes around.
>>
>> ISTM that's something that should be addressed anyway (and separately), no?
>
> Huh? That's the current behaviour in heap_lock_tuple.
Oh, I was referring to autovac not being aggressive enough on
insert-mostly tables. Certainly if there's a reasonable way to avoid
invalidating the VM when locking a tuple that'd be good.
--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com
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