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Possible interesting extra information for explain analyze?

From: Jeff <threshar(at)torgo(dot)978(dot)org>
To: performance pgsql <pgsql-performance(at)postgresql(dot)org>
Subject: Possible interesting extra information for explain analyze?
Date: 2005-02-25 13:49:23
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Lists: pgsql-performance
Given some recent posts / irc issues with dead tuple bloat..

And given that a lot of these people have at least been smart enough to 
explain analyze would it be A. possible B. useful C. None of the above 
to have various "scan" nodes of explain analyze also report how many 
invisible / dead tuples they had to disqualify (Just to clarify, they 
matched the search criteria, but were invisible due to MVCC rules).  
Some thing like:

  Seq Scan on boards  (cost=0.00..686.30 rows=25430 width=0) (actual 
time=8.866..5407.693 rows=18636 loops=1 invisiblerows=8934983098294)

This may help us to point out tuple bloat issues quicker... or it may 
give the developer enough of a clue to search around and find out he 
needs to vacuum... hmm.. but once we have an integrated autovacuum it 
will be a moot point.....

Also another thing I started working on back in the day and hope to 
finish when I get time (that is a funny idea) is having explain analyze 
report when a step required the use of temp files.
Jeff Trout <jeff(at)jefftrout(dot)com>


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