Home » RDBMS Server » Performance Tuning » Program is slower with Oracle12C compared to Oracle 11G (Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production)
Program is slower with Oracle12C compared to Oracle 11G [message #683428] Wed, 13 January 2021 04:06 Go to next message
LiorI
Messages: 9
Registered: December 2019
Junior Member
Hello,

Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
Windows Server 2012R2

I have a program written in Delphi that runs much faster with Oracle 11G then it does with Oracle 12C.
I found that the slowness problem is mainly when a table component is opened inside the program.
Are there Oracle 12C parameters or configuration that have different default values then those that are in Oracle 11G?
What differences can cause this slowness? Oracle 12C should be faster than 11G.
I know it’s not a specific question, but any advice where to look is welcomed.
Thanks in advance

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Re: Program is slower with Oracle12C compared to Oracle 11G [message #683431 is a reply to message #683428] Wed, 13 January 2021 06:10 Go to previous messageGo to next message
John Watson
Messages: 8960
Registered: January 2010
Location: Global Village
Senior Member
Quote:
Oracle 12C should be faster than 11G.
Why do you say this?

However, one not uncommon reason for performance issues when upgrading to 12.1 is the use of adaptive features. They are all enabled by default in 12.1, they are not in 12.2 and later. Perhaps you could try disabling them.

Incidentally, are you aware that your target release, 12.1.0.2, went out of Premier Support in 2018?

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Re: Program is slower with Oracle12C compared to Oracle 11G [message #683433 is a reply to message #683431] Wed, 13 January 2021 06:30 Go to previous messageGo to next message
LiorI
Messages: 9
Registered: December 2019
Junior Member
Do you refer to the optimizer_adaptive_features parameter?
As to the "Oracle 12C should be faster than 11G" Oracle published that 12C is up to 30% faster.

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Re: Program is slower with Oracle12C compared to Oracle 11G [message #683675 is a reply to message #683433] Fri, 12 February 2021 06:15 Go to previous message
Andrey_R
Messages: 441
Registered: January 2012
Location: Israel
Senior Member
LiorI wrote on Wed, 13 January 2021 14:30
Do you refer to the optimizer_adaptive_features parameter?
As to the "Oracle 12C should be faster than 11G" Oracle published that 12C is up to 30% faster.
That's marketing. Like when they advertise a new car's gas consumption. They provide figures based on optimally tuned lab-condition tests.

Try to run your program with
alter system set optimizer_features_enable='11.2.0.4' on the 12c database, the run your Delphi code, and compare to the same on the 11g database.

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