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To: pgsql-performance@postgresql.org, "Willy-Bas Loos" <willybas@gmail.com>
Subject: Re: turn off caching for performance test
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> The bitmap heap scan is 3% faster,

3% isn't really significant. Especially if the new setting makes one query  
100 times slower... Like a query which will, by bad luck, get turned into  
a nested loop index scan for a lot of rows, on a huge table which isn't in  
cache...