Performance of a Query : which one is giving good performace

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Performance of a Query : which one is giving good performace

Raghu.K

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Points: 286
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December 28, 2012 at 3:45 am

#286731

Hi Please help me...
I want join 4 tables in the Oracle.Table 1 is having 4 different where conditions.
Which one is better (Performance wise)
1.Join all 4 tables and write table1 where conditions globally (After Joining 4 tables)
2.Make Table1 as Derived Table with all where conditions and joining with 3 tables.
Please help me

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Gail Shaw SSC Guru Points: 1004504 More actions · Answer 1

Test them and see?

Alternately, maybe ask on an Oracle forum where you're more likely to get an answer.

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
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Jo Pattyn SSC-Dedicated Points: 32070 More actions · Answer 2

Can't tell much without actually seeing it. I had success using orafaq[/url], just be sure you read the forum guide. Do you have a testcase (create table, insert data, select query,query plan)?

nick.mcdermaid Hall of Fame Points: 3809 More actions · Answer 3

Generally speaking (as this is a general question), probably Option 1 as it lets Oracle pick the best way of applying predicates. Under limited circumstances, option 2 will limit the way in which it applies predicates.

Ask a general question get a general answer.

PaulB-TheOneAndOnly SSC Guru Points: 66772 More actions · Answer 4

Raghu.K (12/28/2012)
I want join 4 tables in the Oracle.Table 1 is having 4 different where conditions.
Which one is better (Performance wise)
1.Join all 4 tables and write table1 where conditions globally (After Joining 4 tables)
2.Make Table1 as Derived Table with all where conditions and joining with 3 tables.

Not much to work with.

Assuming you have the right indexes on place, test both cases. Since this is an Oracle question I would suggest to trace/tkprof both solutions then look at buffer_gets on both of them, usually the solution with the less buffer_gets would be the one that would perform the better.

Hope this helps.

_____________________________________
Pablo (Paul) Berzukov

Author of Understanding Database Administration available at Amazon and other bookstores.

Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.