Needing Material and Tuning Tips

[rodcapella]

Personal,

I needed a tuning stuff to improve the performance of a few hundred query in Oracle here in my work. Does anyone have some interesting material about it, or else, some tips to give me?

I have heard that the position in which the tables are declared in the FROM clause can influence Query's performance (at least in Oracle).


vlw,

[toferraz]

Good morning,

First a very good tip is to use the Oracle 10G and 9i features of graphics and tuning solutions that he owns to assist you in creating indices.
Second tip is to observe if SQLs are bringing only what you need in the Select clause.
About SQLS, although not Oracle's standard, I use a lot of Inner Join to relate the tables because it facilitates in the viewing of the relationships performed (this tip would be more for the "layout" of your SQL and it is easier to understand a future maintenance what SQL does).

[dr_gori]

I'vê heard that the position in which the tables are declared in the From Clause can influence Query's performance (at least in Oracle).

This applies only when you are using rule-based optimizer. Hence the order influences. But normal is that the optimizer is cost, based on statistics and histograms collected from the tables. Hence no matter the order.

[rodcapella]

Dr_gori,

When you say rule-based optimizer, you are indicating something like:

Select all

SELECT /* +RULE */ CODPROD 
FROM PRODUCTO

You force the Oracle to use rule-based optimizer and not cost. That's it ?

[dr_gori]

That's right. When force with + rule, it hurts the order influences.

[rodcapella]

Dr_gori,

and the choice of making a query per rule or cost will just depend on the environment? You may have any more efficient with the use of / * + rule * / relative to cost, is not it?

Do you happen to have any material on this subject? Do you recommend any reading?

vlw,