Hi,

I have a table containing columns:

  "END_DATE" timestamptz NOT NULL
  "REO_ID" int4 NOT NULL

and i am indexed "REO_ID" coulumn.
I have a query:

select "REO_ID", "END_DATE" from "PRIORITY_STATISTICS" where "REO_ID" IN
('112851'  ,'112859'  ,'112871'  ,'112883'  ,'112891'  ,'112904'  ,'112915'
,'112924'  ,'112939'  ,'112947'  ,'112960'  ,'112984'  ,'112999'  ,'113013'
,'113032'  ,'113059'  ,'113067'  ,'113084'  ,'113096'  ,'113103'  ,'113110'
,'113117'  ,'113125'  ,'113132'  ,'113139'  ,'113146'  ,'113153'  ,'113160'
,'113167'  ,'113174'  ,'113181'  ,'113188'  ,'113195'  ,'113204'  ,'113268'
,'113279'  ,'113294'  ,'113302'  ,'113317'  ,'113340'  ,'113358'  ,'113385'
,'113404'  ,'113412'  ,'113419'  ,'113429'  ,'113436'  ,'113443'  ,'113571'
,'113636'  ,'113649'  ,'113689'  ,'113705'  ,'113744'  ,'113755'  ,'113724'
,'113737' ,'113812'  ,'113828'  ,'113762'  ,'113842'  ,'113869'  ,'113925'
,'113976'  ,'114035'  ,'114044'  ,'114057'  ,'114070'  ,'114084'  ,'114094'
,'114119' )

and it is _not_ using that index

But following query (notice there are less id-s in WHERE clause, but rest is
same)

select "REO_ID", "END_DATE" from "PRIORITY_STATISTICS" where  "REO_ID" IN
('112851'  ,'112859'  ,'112871'  ,'112883'  ,'112891'  ,'112904'  ,'112915'
,'112924'  ,'112939'  ,'112947'  ,'112960'  ,'112984'  ,'112999'  ,'113013'
,'113032'  ,'113059'  ,'113067'  ,'113084'  ,'113096'  ,'113103'  ,'113110'
,'113117'  ,'113125'  ,'113132'  ,'113139'  ,'113146'  ,'113153'  ,'113160'
,'113167'  ,'113174'  ,'113181'  ,'113188'  ,'113195'  ,'113204'  ,'113268'
,'113279'  ,'113294'  ,'113302'  ,'113317'  ,'113340'  ,'113358'  ,'113385'
,'113404'  ,'113412'  ,'113419'  ,'113429'  ,'113436'  ,'113443'  ,'113571'
,'113636'  ,'113649'  ,'113689'  ,'113705'  ,'113744'  ,'113755'  ,'113724'
,'113737' )

will _is_ using index:

Why not. It's just because the second query is more selective. Probably you don't have too many rows in your table and Postgres thinks it's better (faster) to use sequential scan than index one.


Regards,
Tomasz Myrta


---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]

Reply via email to