UniQuery open very slow with order by syntax on oracle

[wbjsoft]

Delphi XE2 - RemObjects - Unidac8 - Oracle10g

TUniQuery.Open procedure takes about 4000 ms when SQL contains order by syntax.
but it taks only 100ms when SQL contains no order-by syntax.

same data in MariaDB5.5 TUniQuery.Open takes same period

Is there any option about ordering?

thank you in advance

[MaximG]

Does the ordering work fast in Oracle 10g and MariaDB when you use any other tool, e.g., the command-line tools SQL *Plus and mysql sql shell?

[wbjsoft]

Yes. It is.
other tool works fast.
It is slow on TUniQuery.Open procedure

[MaximG]

Please create and send us a sample project with source code where the issue can be reproduced. Also we need the DDL script that creates the tables that you use in the sample project. For your convenience, please use the e-support form https://www.devart.com/company/contactform.html

[wbjsoft]

I found reason.
SpecificOptions.Values['OptimizerMode'] := 'omFirstRows';
I changed option to
SpecificOptions.Values['OptimizerMode'] := 'omDefault';

issue is solved.

does the option can make performance slow?

[MaximG]

The 'OptimizerMode' option affects the query performance as it defines the Oracle optimizer settings. See the Oracle documentation for more information: https://docs.oracle.com/cd/B19306_01/se ... REFRN10145