[GENERAL] Baffled by failure to use index when WHERE uses a function

2006-03-10 Thread Clive Page
I have a table cov3 of about 3 million rows, with a B-tree index on an integer column called hpix. If I do a simple select on this column it works in milliseconds, using the index naturally: select * from cov3 where hpixint = 482787587; hpix| expos | hpixint

Re: [GENERAL] Baffled by failure to use index when WHERE uses a function

2006-03-10 Thread Martijn van Oosterhout
On Fri, Mar 10, 2006 at 09:14:27AM +, Clive Page wrote: I have a table cov3 of about 3 million rows, with a B-tree index on an integer column called hpix. If I do a simple select on this column it works in milliseconds, using the index naturally: snip So I would like to use this

Re: [GENERAL] Baffled by failure to use index when WHERE uses a function

2006-03-10 Thread Michael Fuhr
On Fri, Mar 10, 2006 at 09:14:27AM +, Clive Page wrote: I have a table cov3 of about 3 million rows, with a B-tree index on an integer column called hpix. If I do a simple select on this column it works in milliseconds, using the index naturally: select * from cov3 where hpixint =

Re: [GENERAL] Baffled by failure to use index when WHERE uses a function

2006-03-10 Thread Richard Huxton
Clive Page wrote: I have a table cov3 of about 3 million rows, with a B-tree index on an integer column called hpix. If I do a simple select on this column it works in milliseconds, using the index naturally: select * from cov3 where hpixint = 482787587; hpix| expos | hpixint

Re: [GENERAL] Baffled by failure to use index when WHERE uses a

2006-03-10 Thread Clive Page
On Fri, 10 Mar 2006, Martijn van Oosterhout wrote: You don't describe the exact structure of your table nor the exact declaraion of your function, but is it possible your function is marked VOLATILE rather tha STABLE or IMMUTABLE? Thanks for that hint - my function was not marked in any way,

Re: [GENERAL] Baffled by failure to use index when WHERE uses a function

2006-03-10 Thread Hongxi.Ma
@postgresql.org Sent: Friday, March 10, 2006 5:14 PM Subject: [GENERAL] Baffled by failure to use index when WHERE uses a function I have a table cov3 of about 3 million rows, with a B-tree index on an integer column called hpix. If I do a simple select on this column it works in milliseconds, using