Re: Question about explain of index scan - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: Question about explain of index scan
Date
Msg-id 20050904223714.GB14515@surnet.cl
Whole thread Raw
In response to Re: Question about explain of index scan  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Question about explain of index scan
List pgsql-hackers
On Sun, Sep 04, 2005 at 06:21:51PM -0400, Tom Lane wrote:

> XID comparison works OK as long as you make sure that all the XIDs
> extant in the system at any one time are within +/- 2 billion of each
> other, and so transitivity does hold within that subset.  The problem
> with a btree is that upper-level tree nodes are likely to contain page
> boundary keys copied from data that vanished some time ago from the
> underlying table.

So there would be no problem if a REINDEX was forced every two billion
transactions, right?  (A bit less, I think.)

-- 
Alvaro Herrera -- Valdivia, Chile         Architect, www.EnterpriseDB.com
"Oh, great altar of passive entertainment, bestow upon me thy discordant images
at such speed as to render linear thought impossible" (Calvin a la TV)


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