Re: [PERFORM] Linux machine aggressively clearing cache

2012-03-28 Thread Joshua Berkus
> This may just be a typo, but if you really did create write (dirty) > block device cache by writing the pg_dump file somewhere, then that > is what it's supposed to do ;) The pgdump was across the network. So the only caching on the machine was read caching. > Read cache of course does not

Re: [PERFORM] Distinct + Limit

2012-03-28 Thread Merlin Moncure
On Wed, Mar 28, 2012 at 9:13 AM, Tom Lane wrote: > Francois Deliege writes: >> I have the following table with millions of rows: > >> CREATE TABLE table1 >> ( >>   col1 text, >>   col2 text, >>   col3 text, >>   col4 text, >>   col5 text, >>   col6 text >> ) > >> select col1 from table1 group by

Re: [PERFORM] Distinct + Limit

2012-03-28 Thread Tom Lane
Francois Deliege writes: > I have the following table with millions of rows: > CREATE TABLE table1 > ( > col1 text, > col2 text, > col3 text, > col4 text, > col5 text, > col6 text > ) > select col1 from table1 group by col1 limit 1; > select distinct on (col1) col1 from table1 limit