Program is slower with Oracle 12c compared to Oracle 11G

Discussion of open issues, suggestions and bugs regarding ODAC (Oracle Data Access Components) for Delphi, C++Builder, Lazarus (and FPC)
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lior
Posts: 34
Joined: Mon 01 Aug 2011 07:11

Program is slower with Oracle 12c compared to Oracle 11G

Post by lior » Tue 12 Jan 2021 18:57

Hello,
I have a Delphi program that runs fine with Oracle 11G. When I run it with Oracle 12C it is much slower.
I found that the slowness is mainly where TOraTables are opened.
Similar result with ODAC Version 8.0.2 for Delphi 7 and with ODAC Version 11.3.2 For RAD Studio 10.3.
Can you advise me of recommended changes in ODAC configuration, Delphi code or maybe in ORACLE 12C setup?
Thanks in advance

lior
Posts: 34
Joined: Mon 01 Aug 2011 07:11

Re: Program is slower with Oracle 12c compared to Oracle 11G

Post by lior » Wed 13 Jan 2021 12:10

I think found the problem. Some TOraTables had an empty KeyField.
I don't understand why this speed problem happens with Oracle 12C and not with Oracle 11G ?

MaximG
Devart Team
Posts: 1551
Joined: Mon 06 Jul 2015 11:34

Re: Program is slower with Oracle 12c compared to Oracle 11G

Post by MaximG » Wed 13 Jan 2021 12:49

Do Oracle 12c tables open slowly when you don't use our components? For example, when you run the query SELECT * FROM table_name using standard tool Oracle SQL*Plus. Please make sure the table has identical data in different versions of Oracle Database and let us know whether the execution times of the query differ across databases.

lior
Posts: 34
Joined: Mon 01 Aug 2011 07:11

Re: Program is slower with Oracle 12c compared to Oracle 11G

Post by lior » Wed 13 Jan 2021 14:26

I have further improvement by setting the Oracle parameter OPTIMIZER_ADAPTIVE_FEATURES to FALSE.
I think this is the main problem.

MaximG
Devart Team
Posts: 1551
Joined: Mon 06 Jul 2015 11:34

Re: Program is slower with Oracle 12c compared to Oracle 11G

Post by MaximG » Fri 15 Jan 2021 06:56

We are glad that you found a necessary solution. Please don't hesitate to contact us with questions concerning ODAC usage.

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