Re: Replication Syatem - Mailing list pgsql-performance

From Tom Lane
Subject Re: Replication Syatem
Date
Msg-id 18684.1209566788@sss.pgh.pa.us
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In response to Re: Replication Syatem  ("Pavan Deolasee" <pavan.deolasee@gmail.com>)
Responses Re: Replication Syatem  ("Pavan Deolasee" <pavan.deolasee@gmail.com>)
List pgsql-performance
"Pavan Deolasee" <pavan.deolasee@gmail.com> writes:
> That's weird. With that fillfactor, you should have a very high
> percentage of HOT update ratio. It could be a very special case that
> we might be looking at.

He's testing

>> update table1 set delta1 = 100 where code/1000000 =999;

so all the rows being updated fall into a contiguous range of "code"
values.  If the table was loaded in such a way that those rows were
also physically contiguous, then the updates would be localized and
would very soon run out of freespace on those pages.

            regards, tom lane

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