DataSnap Application : First connection is really slow, subsequent connections much faster

2007-05-02 04:48:43 PM
I hope someone can help here. BDS 2006, dbExpress SQL2000
I have an application that consists of a TSQLDataset and a Dataset
provider along with a TROBPDXHTTPServer and some other RemObjects
stuff. I have asked this question on RO news group but they think it
might be a DataSnap issue so I am asking here.
This application is constructed as a Service and has been working fine.
I built a client to connect to the service and it passes a commandText
from the TClientDataSet to the Service and retrieves information from
the database. I use a windows message handler to post the results back
to a memo for observation. This is all running on one machine at the
My next step was to re-create the client application as another
service. I have removed all non thread safe types ie. Memo etc. The
problem is now that the first time an application connects to this
service there is a delay of 20 seconds until data is returned,
subsequent connections return with lots more data almost instantly
usually 1000 records in 0.05 seconds.
This is slightly puzzling, and I find it difficult to debug, due to the
fact that to replicate this I have to restart all the services that are
part of this application.
Are there any known issues with Datasnap services taking time to
execute first time round? Or can anyone think of something else that
might be causing this delay?
thanks for your time.