| From: | Jim Nasby <Jim(dot)Nasby(at)BlueTreble(dot)com> |
|---|---|
| To: | Thom Brown <thom(at)linux(dot)com>, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Andres Freund <andres(at)anarazel(dot)de>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Josh Berkus <josh(at)agliodbs(dot)com>, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Michael Paquier <michael(dot)paquier(at)gmail(dot)com>, Petr Jelinek <petr(at)2ndquadrant(dot)com>, Bruce Momjian <bruce(at)momjian(dot)us>, Greg Stark <stark(at)mit(dot)edu>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Jeff Janes <jeff(dot)janes(at)gmail(dot)com> |
| Subject: | Re: Freeze avoidance of very large table. |
| Date: | 2015-11-17 15:43:08 |
| Message-ID: | 564B4B0C.30508@BlueTreble.com |
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| Lists: | pgsql-hackers |
On 11/17/15 4:41 AM, Thom Brown wrote:
> Could someone post a TL;DR summary of what the current plan looks
> like? I can see there is a huge amount of discussion to trawl back
> through. I can see it's something to do with the visibility map. And
> does it avoid freezing very large tables like the title originally
> sought?
Basically, it follows the same pattern that all-visible bits do, except
instead of indicating a page is all-visible, the bit shows that all
tuples on the page are frozen. That allows a scan_all vacuum to skip
those pages.
--
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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