Re: [GENERAL] Interpreting statistics collector output

2007-08-18 Thread Ron Mayer
Decibel! wrote: > On Aug 15, 2007, at 2:11 PM, Gregory Stark wrote: >> "Decibel!" <[EMAIL PROTECTED]> writes: >>> On Wed, Aug 15, 2007 at 01:26:02PM -0400, Steve Madsen wrote: On Aug 15, 2007, at 11:52 AM, Decibel! wrote: > I can't really think of a case where a seqscan wouldn't return all

Re: [GENERAL] Interpreting statistics collector output

2007-08-15 Thread Decibel!
On Aug 15, 2007, at 2:11 PM, Gregory Stark wrote: "Decibel!" <[EMAIL PROTECTED]> writes: On Wed, Aug 15, 2007 at 01:26:02PM -0400, Steve Madsen wrote: On Aug 15, 2007, at 11:52 AM, Decibel! wrote: I can't really think of a case where a seqscan wouldn't return all the rows in the table... tha

Re: [GENERAL] Interpreting statistics collector output

2007-08-15 Thread Gregory Stark
"Decibel!" <[EMAIL PROTECTED]> writes: > On Wed, Aug 15, 2007 at 01:26:02PM -0400, Steve Madsen wrote: >> On Aug 15, 2007, at 11:52 AM, Decibel! wrote: >> >I can't really think of a case where a seqscan wouldn't return all the >> >rows in the table... that's what it's meant to do. LIMIT -- Gr

Re: [GENERAL] Interpreting statistics collector output

2007-08-15 Thread Decibel!
On Wed, Aug 15, 2007 at 01:26:02PM -0400, Steve Madsen wrote: > On Aug 15, 2007, at 11:52 AM, Decibel! wrote: > >I can't really think of a case where a seqscan wouldn't return all the > >rows in the table... that's what it's meant to do. > > Isn't a sequential scan the only option if an appropriat

Re: [GENERAL] Interpreting statistics collector output

2007-08-15 Thread Steve Madsen
On Aug 15, 2007, at 11:52 AM, Decibel! wrote: I can't really think of a case where a seqscan wouldn't return all the rows in the table... that's what it's meant to do. Isn't a sequential scan the only option if an appropriate index does not exist? E.g., for a query with a WHERE clause, but n

Re: [GENERAL] Interpreting statistics collector output

2007-08-15 Thread Decibel!
On Thu, Aug 09, 2007 at 09:14:55PM -0400, Steve Madsen wrote: > On Aug 8, 2007, at 6:08 PM, Decibel! wrote: > >Something else I like to look at is pg_stat_all_tables seq_scan and > >seq_tup_read. If seq_scan is a large number and seq_tup_read/ > >seq_scan is > >also large, that indicates that you

Re: [GENERAL] Interpreting statistics collector output

2007-08-09 Thread Steve Madsen
On Aug 8, 2007, at 6:08 PM, Decibel! wrote: Something else I like to look at is pg_stat_all_tables seq_scan and seq_tup_read. If seq_scan is a large number and seq_tup_read/ seq_scan is also large, that indicates that you could use an index on that table. If seq_tup_read / seq_scan is large r

Re: [GENERAL] Interpreting statistics collector output

2007-08-08 Thread Decibel!
On Wed, Aug 08, 2007 at 11:01:13AM -0400, Steve Madsen wrote: > Can anyone provide a brief overview of how to go about interpreting > the information generated by the statistics collector? I've looked > around and can't find old mailing list messages or anything in the > manual beyond the ba