In need of material and Tuning Tips

Tuning de Banco, Tuning de SQL, Ferramentas de tuning
  

Poston Thu, 09 Jul 2009 10:58 am

Personnel, was in need of a material of tuning to improve the performance of some hundreds of query in Oracle here at my job. Does anyone have any interesting stuff about it, or so, some tips for me?

I'vê heard q the position in which the tables are declared in the FROM clause can influence the performance of the query (at least in Oracle).


Vlw,
rodcapella
Location: Rio de Janeiro - RJ

Poston Wed, 22 Jul 2009 9:20 am

Good day, First a very good tip is to use the capabilities of oracle 10 g and 9i tuning solutions and graphics he has to assist in the creation of indices.
Second tip is to observe whether the SQLs in are bringing only what you need in the SELECT clause.
About SQLs in, despite not be oracle's standard, I use very INNER JOIN to relate the tables because it facilitates the visualization of relationships (this tip would be to better the \"layout\" of your SQL and is easier to understand in a future maintenance what SQL does).
toferraz
Location: Uberaba - MG

Poston Wed, 22 Jul 2009 9:37 am

[quote = " rodcapella "]I'vê heard q the position in which the tables are declared in the FROM clause can influence the performance of the query (at least in Oracle). [/quote]

It is only when you're using the RULE-based optimizer. Hence the order influences. But normal is that the optimizer's COST, based on collected statistics and histograms of the tables. Hence no matter the order.
dr_gori
Location: Seattle, WA, USA

Thomas F. G
https://www.patreon.com/glufke

Poston Wed, 22 Jul 2009 9:53 am

Dr_Gori, When you say RULE-based optimizer, you are indicating something of type: SELECT/* + RULE */CODPROD FROM COMMODITY você force Oracle to use the Rule-based optimizer and not on Cost. Is this?
rodcapella
Location: Rio de Janeiro - RJ

_________________
Rodrigo Póvoa
Analista de Sistemas Júnior
Oracle Developer

Poston Wed, 22 Jul 2009 10:01 am

That's right. When com + force RULE, give the order influences.
dr_gori
Location: Seattle, WA, USA

Thomas F. G
https://www.patreon.com/glufke

Poston Wed, 22 Jul 2009 10:37 am

Dr_Gori, and the choice to make a query by rule or by cost will just depend on the environment? May have queries that are more efficient with the use of the/* + RULE */with regard to cost, isn't it?

Would you happen to have some material on this subject? Recommend some reading?

Vlw,
rodcapella
Location: Rio de Janeiro - RJ

_________________
Rodrigo Póvoa
Analista de Sistemas Júnior
Oracle Developer


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