| Re: Slow Sql that access Large Data [message #372584] |
Mon, 26 February 2001 09:57 |
Bala
Messages: 205
Registered: November 1999
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Senior Member |
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Hi,
Effective coding is the best performance booster than any thing else..
other things you may have to look are...
1. indexes...... again it depends whether your have select only database or insert/update/delete database. More Indexs on the former is good but its not good on the later.....
2. parallel processing, you can give a hint in your query to run the query parallel.
The level of parallel you can go depends on the no of processors you have in your server...
roughly...
no. of parallel = 4 * no. of processors
for inst if you have 4 processors(CPUs)
your query would be
SQL> select /* parallel(tablename, 16) */ ........;
3. Other hints like hash join, star join , use index....
4. function based indexes, bitmap indexes are usefull on some cases...
5. memory sort is better if you can afford then disk sort...
(getting the query plan will be helpful for tuning.)
Good luck.
Bala
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