SELECT FROM DUAL slow

[IncredibleMrT]

Hi,
I was debugging some speed issues against some meaty SQL I have, and it seems to come down to selecting from dual but only in a SQL window.

So, I did a quick test and found that doing it through PLSQL Dev's SQL window was very slow, whilst PLSQL Dev's command window, SQLPlus and Oracle SQL Developer was lightning.

Consider the following from SQLPlus.

SQL> select 1 from dual;

         1
----------
         1

Executed in 0.019 seconds

The same in SQL Window executes in around 0.5s consistently.

I've tried the same on other machines at my disposal and it seems consistent.

Is this a known issue or is it something to do with our setup?

Thanks
Matt.

 

[Worker]

Maybe this is related to Preferences->Oracle->Options->Automatic statistics ?

 

[IncredibleMrT]

I don't have that enabled.
However, I have just enabled every option in that setting and re-tested - it's running in the same ball park.
Thanks though.

Maybe this is related to Preferences->Oracle->Options->Automatic statistics ?

 

[Marco Kalter]

To obtain some more diagnostic information, can you modify the shortcut and add the DebugSQL parameter? For example:

"C:\Program Files\PLSQL Developer 12\plsqldev.exe" DebugSQL

Reproduce the problem and send me the debug.txt file that is generated in the %APPDATA%\PLSQL Developer 12 directory (e.g. C:\Users\\AppData\Roaming\PLSQL Developer 12).