Lets say I have two columns, A and B. They are each indexed seperately. If I do a query like:
SELECT * FROM table WHERE A = 1 AND B = 2;
postgres can only use one index.

I assume that postgres uses the index data to narrow down pages in the table to visit when doing its search. Then it goes through and filters on the second condition.

My question: why can't it go through the first index, get a list of pages in the table, then go through the second index, union the result with the results from first index, and then go into the table?

---------------------------(end of broadcast)---------------------------
TIP 2: you can get off all lists at once with the unregister command
   (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])

Reply via email to