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 1281394845.2142.1268.camel@ebony
Whole thread Raw
In response to Re: Surprising dead_tuple_count from pgstattuple  (Itagaki Takahiro <itagaki.takahiro@gmail.com>)
Responses Re: Surprising dead_tuple_count from pgstattuple
List pgsql-hackers
On Tue, 2010-08-10 at 07:43 +0900, Itagaki Takahiro wrote:
> 2010/8/10 Simon Riggs <simon@2ndquadrant.com>:
> > Any SQL statement that reads a block can do HOT pruning, if the block is
> > otherwise unlocked.
> 
> We use the term "HOT" for two features:
>   1. HOT updates: Avoiding index updates when keys are not modified.
>   2. HOT pruning: Removing tuple bodies, that works even for indexed tuples.
> 
> 2 is the point of the case, but ambiguous "HOT" might confuse some people.

Good point. We should say "HOT updates" and "pruning" as separate
techniques. Itagaki invented the pruning technique and deserves much
credit for that.

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



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