Re: Avoiding second heap scan in VACUUM - Mailing list pgsql-hackers

From Gregory Stark
Subject Re: Avoiding second heap scan in VACUUM
Date
Msg-id 874p8ip2rd.fsf@oxford.xeocode.com
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In response to Re: Avoiding second heap scan in VACUUM  (Simon Riggs <simon@2ndquadrant.com>)
Responses Re: Avoiding second heap scan in VACUUM  (Simon Riggs <simon@2ndquadrant.com>)
List pgsql-hackers
"Simon Riggs" <simon@2ndquadrant.com> writes:

> So the idea is to have one pass per VACUUM, but make that one pass do
> the first pass of *this* VACUUM and the second pass of the *last*
> VACUUM.

I think that's exactly the same as the original suggestion of having HOT
pruning do the second pass of the last vacuum. The trick is to know whether
the last vacuum committed or not. If it didn't commit then it's not safe to
remove those line pointers yet.

--  Gregory Stark EnterpriseDB          http://www.enterprisedb.com Ask me about EnterpriseDB's On-Demand Production
Tuning


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