Re: Too much blocks read - Mailing list pgsql-performance

From Craig James
Subject Re: Too much blocks read
Date
Msg-id 4B042101.5090500@emolecules.com
Whole thread Raw
In response to Too much blocks read  (Waldomiro <waldomiro@shx.com.br>)
List pgsql-performance
Waldomiro wrote:
> ...
> I´m thinking It hapens because in the 7 millions tables, the same 8k
> block has diferent records with different keys, so only a few records
> with 'my_key' is retrieved when I read a 8k block.
> In the part_table, all records stored in a 8k block have 'my_key', so
> It´s much optimized.
>
> My doubt, there is a way to defrag my 7 millions table to put all
> records with the same key in the same 8k block?

Read about the "CLUSTER ON index-name" SQL command.  It does exactly what you're asking.

Craig

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