Increase the performence of the query how

Question

SELECT * from load_log
where
filetype = 'O/C'
AND EXISTS (SELECT '1' FROM view_orders
     WHERE O_ftype = ftype
AND o_loadno = loadno -- << this line
          AND o_cocode = 1)
HOW TO INCREASE THIS QUERY PERFORMENCE.
THE view_orders IS THE VIEW THAT CREATED FROM 4 TABLES WHICH HAVE SAME COLUMSN EXCEPT FTYPE
if i remove this line the query execute very fast
AND o_loadno = loadno --<<
PLEASE GIVE ME SOME IDEAS/SUGGESTIONS.
THANKS
HARDSTONE

Answer 1

hard_stone wrote:
hello,
any budy there..plzzz
its urgentIf you mark your question as answered it's quite likely that you won't get any attention any longer.
As already mentioned in the thread, start with an EXPLAIN PLAN to get the execution plan of your statement. Fiddling around with indexes without proper information at hand is like trial-and-error, therefore try to use a systematic approach.
The optimizer might estimate that all your indexes are not selective enough and/or the clustering factor is too high so that the cost accessing the corresponding tables by random access is too high and therefore decides to use a full table scan.
But this can only be checked if you post a proper explain plan output.
Generic instructions how to do so and post the results in proper mono-space formatting here follow:
Could you please post an properly formatted explain plan output using DBMS_XPLAN.DISPLAY including the "Predicate Information" section below the plan to provide more details regarding your statement. Please use the {noformat}[{noformat}code{noformat}]{noformat} tag before and {noformat}[{noformat}/code{noformat}]{noformat} tag after or the {noformat}{{noformat}code{noformat}}{noformat} tag before and after to enhance readability of the output provided:
In SQL*Plus:
SET LINESIZE 130
EXPLAIN PLAN FOR <your statement>;
SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY);Note that the package DBMS_XPLAN.DISPLAY is only available from 9i on.
In 9i and above, if the "Predicate Information" section is missing from the DBMS_XPLAN.DISPLAY output but you get instead the message "Plan table is old version" then you need to re-create your plan table using the server side script "$ORACLE_HOME/rdbms/admin/utlxplan.sql".
In previous versions you could run the following in SQL*Plus (on the server) instead:
@?/rdbms/admin/utlxplsA different approach in SQL*Plus:
SET AUTOTRACE ON EXPLAIN
<run your statement>;will also show the execution plan.
In order to get a better understanding where your statement spends the time you might want to turn on SQL trace as described here:
When your query takes too long ...
and post the "tkprof" output here, too.
Regards,
Randolf
Oracle related stuff blog:
http://oracle-randolf.blogspot.com/
SQLTools++ for Oracle (Open source Oracle GUI for Windows):
http://www.sqltools-plusplus.org:7676/
http://sourceforge.net/projects/sqlt-pp/