ANALYZE INDEX ...

From: Jenda Krynicky <Jenda_at_Krynicky.cz>
Date: Mon, 22 Nov 1999 11:06:03 GMT
Message-ID: <1103_943268763@prague_main>

I think I should better RTFM but there's tooooo much of it so ...

Thanks for any help.

I've noticed something strange.

I have run "EXPLAIN PLAN" on a SELECT STATEMENT like this :

SELECT whatever, including(some,functions,like,SUBSTR) from Table WHERE Field1 = 'const1' AND Field2 = 'const2' AND Field3 = 'const3';

I have created separate indexes for all these three fields, but the EXPLAIN PLAN returned
"TABLE ACCESS FULL ..."
So I thought maybe Oracle is not able to use the indexes (I think it should, but ...) so I created one index for all three fields.

And EXPLAIN PLAN said the SELECT will use the index.

Then I "ANALYZED" the index (whatever that means) and voila ... EXPLAIN PLAN once again returns
"TABLE ACCESS FULL ...".
What's going on in here ? What am I doing wrong?

FYI, the table has about one million rows, all the fields in question are CHAR(something).

Jenda
http://Jenda.Krynicky.cz Received on Mon Nov 22 1999 - 05:06:03 CST