Re: HOT is applied - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: HOT is applied
Date
Msg-id 46F3E09E.6060603@enterprisedb.com
Whole thread Raw
In response to Re: HOT is applied  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Tom Lane wrote:
> I don't much like the idea of adding an xid to the page header --- for
> one thing, *which* xid would you put there, and what would you test it
> against?

I was thinking that you would put the smallest in-progress xmax on the
page there, and you would test it against OldestXmin. If all
transactions commit, there surely isn't anything to prune until that xid
falls beyond the OldestXmin horizon. If an inserting transaction aborts,
we could prune the aborted tuple earlier, but optimizing for aborts
doesn't seem that important.

--  Heikki Linnakangas EnterpriseDB   http://www.enterprisedb.com


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