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Re: Surprising dead_tuple_count from pgstattuple - Mailing list pgsql-hackers

From Simon Riggs
Subject Re: Surprising dead_tuple_count from pgstattuple
Date
Msg-id 1281376228.2142.1232.camel@ebony
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In response to Re: Surprising dead_tuple_count from pgstattuple  (Gordon Shannon <gordo169@gmail.com>)
Responses Re: Surprising dead_tuple_count from pgstattuple  (Robert Haas <robertmhaas@gmail.com>)
Re: Surprising dead_tuple_count from pgstattuple  (Itagaki Takahiro <itagaki.takahiro@gmail.com>)
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On Sat, 2010-08-07 at 16:11 -0700, Gordon Shannon wrote:

> So, I guess my real question here is, what happened to the "missing"
> 100 items?  If it was HOT prune, can anyone summarize what that does?

Itagaki already explained that the second DELETE would have removed the
100 dead rows you consider to be missing.

Any SQL statement that reads a block can do HOT pruning, if the block is
otherwise unlocked.

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Development, 24x7 Support, Training and Services

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