Skip site navigation (1) Skip section navigation (2)

Re: FSM search modes

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Alvaro Herrera <alvherre(at)commandprompt(dot)com>, decibel <decibel(at)decibel(dot)org>, Itagaki Takahiro <itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: FSM search modes
Date: 2009-10-01 21:08:12
Message-ID: 4274.1254431292@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-hackers
Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> The elephant in the room here is that if the relation is a million
> pages of which 1-100,000 and 1,000,000 are in use, no amount of bias
> is going to help us truncate the relation unless every tuple on page
> 1,000,000 gets updated or deleted.

Well, there is no way to move a tuple across pages in a user-invisible,
non-blocking fashion, so our ability to do something automatic about the
above scenario is limited.  The discussion at the moment is about ways
of reducing the probability of getting into that situation in the first
place.  That doesn't preclude also providing some more-invasive tools
that people can use when they do get into that situation; but let's
not let I-want-a-magic-pony syndrome prevent us from doing anything
at all.

			regards, tom lane

In response to

Responses

pgsql-hackers by date

Next:From: Robert HaasDate: 2009-10-01 21:09:33
Subject: Re: FSM search modes
Previous:From: Bernd HelmleDate: 2009-10-01 21:07:32
Subject: Re: TODO item: Allow more complex user/database default GUC settings

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group