[Qt-interest] qsqlquery anyone with any experience at all?

[Scott Aron Bloom]

The .value( 0 ) is what of course converts the data to the qvariant...

What kind of server are you connected too.. That just seems awfully
slow, and I haven't seen that before...

Is it possible that the server, or your query, is returning raw strings,
and you are converting them to other types??

Your datetimes can be very slow because of the string to date parsing
that goes on...


-----Original Message-----
From: Roland Tollenaar [mailto:rwatollenaar at gmail.com] 
Sent: Wednesday, September 01, 2010 12:15 AM
To: Scott Aron Bloom
Cc: Qt-interest
Subject: Re: [Qt-interest] qsqlquery anyone with any experience at all?

Hi Scott,

exec and the (empty) while(query.next()) loop takes < 2 seconds to
execute.

adding only this line:

query.value(0);

in the while(query.next()) loop takes the time up to 40 seconds.

This is on my local  database, to the serverr over the network takes a 
bit longer.

There are about 15000 records.

Datatype is varchar, text and datetime. No BLOBS.

any ideas?

Kind regards,

Roland



On 01-09-2010 8:52 AM, Scott Aron Bloom wrote:
> Message received...
>
> Some pointers, the Qt overhead, is really quite minimal..
>
> First, does your SQL backend, have a "preferred client" how quickly
does
> it send back large record sets...
>
> What data is being sent back?? Large BLOBs get read into QByteArrays,
> meaning they take up ram... is it possible your just dealing with a
ton
> of data..
>
> For me, I tend to find the majority of the delay in the exec, not in
the
> query.next()...
>
> Scott
>
> -----Original Message-----
> From: qt-interest-bounces at trolltech.com
> [mailto:qt-interest-bounces at trolltech.com] On Behalf Of Roland
Tollenaar
> Sent: Tuesday, August 31, 2010 11:27 PM
> To: Qt-interest
> Subject: [Qt-interest] qsqlquery anyone with any experience at all?
>
> Hi,
>
> I posted below but am not sure whether my posts are arriving on the
> list.
>
> Is there anyone who has _any_ experience with qsqlquery at all?
>
> Regards,
>
> Roland
>
> Hi,
>
> we have found that using query.next() in combination with qodbc is
very
> very slow in qt 4.5.2.
>
> Is there a faster manner to process large recordsets or has the
> qsqlquery (or qodbc) class been improved dramatically in 4.6 that
anyone
>
> knows of?
>
> thanks in advance for any advice,
>
> Roland
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