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

From Robert Haas
Subject Re: Surprising dead_tuple_count from pgstattuple
Date
Msg-id AANLkTi=Hq+Xtkm0hqyST32RuwSum-SDuM6DjOy8vmKGQ@mail.gmail.com
Whole thread Raw
In response to Re: Surprising dead_tuple_count from pgstattuple  (Simon Riggs <simon@2ndQuadrant.com>)
Responses Re: Surprising dead_tuple_count from pgstattuple
List pgsql-hackers
On Mon, Aug 9, 2010 at 1:50 PM, Simon Riggs <simon@2ndquadrant.com> wrote:
> 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.

Where does heap_page_prune() get called from in the DELETE path?

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company


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