Re: Visibility map, partial vacuums - Mailing list pgsql-hackers

From Decibel!
Subject Re: Visibility map, partial vacuums
Date
Msg-id 294448DB-AD20-4E4B-BDC6-6937D9E01039@decibel.org
Whole thread Raw
In response to Re: Visibility map, partial vacuums  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Nov 23, 2008, at 3:18 PM, Tom Lane wrote:
> So it seems like we do indeed want to rejigger autovac's rules a bit
> to account for the possibility of wanting to apply vacuum to get
> visibility bits set.


That makes the idea of not writing out hint bit updates unless the  
page is already dirty a lot easier to swallow, because now we'd have  
a mechanism in place to ensure that they were set in a reasonable  
timeframe by autovacuum. That actually wouldn't incur much extra  
overhead at all, except in the case of a table that's effectively  
write-only. Actually, that's not even true; you still have to  
eventually freeze a write-mostly table.
-- 
Decibel!, aka Jim C. Nasby, Database Architect  decibel@decibel.org
Give your computer some brain candy! www.distributed.net Team #1828




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