Re: HOT latest patch - version 8 - Mailing list pgsql-patches

From Tom Lane
Subject Re: HOT latest patch - version 8
Date
Msg-id 22798.1184343058@sss.pgh.pa.us
Whole thread Raw
In response to Re: HOT latest patch - version 8  (Heikki Linnakangas <heikki@enterprisedb.com>)
Responses Re: HOT latest patch - version 8  (Heikki Linnakangas <heikki@enterprisedb.com>)
List pgsql-patches
Heikki Linnakangas <heikki@enterprisedb.com> writes:
> Tom Lane wrote:
>> Heikki Linnakangas <heikki@enterprisedb.com> writes:
>>> A much simpler approach would be to try to acquire the vacuum lock, and
>>> compact the page the usual way, and fall back to a cold update if we
>>> can't get the lock immediately.
>>
>> Seems like that could work.

> I just realized that there's a big problem with that. The process doing
> the update surely holds a pin on the buffer itself. Needs more thought..

So does VACUUM when it's trying to lock a page, no?  In any case we
could surely make an extra parameter to LockBufferForCleanup if it
really needs to distinguish the cases.

            regards, tom lane

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