Re: PsqlODBC slow on UNION queries

Ludek Finstrle írta:

>>>If I set only Declare/Fetch or both to ON, opening the VIEW in Access
>>>comes close to what I experinced in psql, e.g. it appears almost instantly
>>>when using UNION ALL, and just under 7 seconds when using UNION.
>>>
>>>I don't remember which ODBC settings I used for the Windows2000 client
>>>and PowerBuilder, I am not near that machine. I will recheck it when
>>>I get back to my workplace next monday.
>>>
>>>
>>There is another thing. psqlODBC driver simulate SQLColAttributes (I wrote
>>it on the fly so it could be different ODBC API) throught call
>>the query and then get the columns information before query is already
>>open. So it could be the time bottleneck.
>>I try describe it better:
>>SQLPrepare, SQLColAttributes (this call the statement for getting columns
>>information), SQLExecute (this call the statement for result).
>>
>>If you want trace it down the good start point is turn mylog output on
>>and read the result in C:\mylog_XXXX.log (or txt extension?).
>>
>>
>
>I forgot. Feel free to send the mylog output here to list. We can
>help you to decode it ;-)
>
>

I will, when I am back to my workplace.

In the meantime, I have set MyLog on in WinXP under VMWare here,
but Access produced some 120+ MB log and it wasn't even finished
reading the records... I didn't feel like I have to send it to the list. ;-)
Anyway, it turned out it used DECLARE CURSOR and it fetched
100 records at a time.

Best regards,
Zoltán Böszörményi