Hi,

I'm using NHibernate, in my application there is a time where I need
to perform an insert on the Database.

This insert carries two images, and some other information, the images are about 25KB each, they are stored as blobs on the Database.

I perform this operation at a rate of 3 per second, during a normal day of operation the table to where this information goes will reach something like 1.2GB.

During 4 hours we will need to maintain this rate, but it might go up to 6 of this operations per second. On the server we have other processes runing that are performing queries, and also deletes from the table. We have a lot of pressure on this table. This is the place on this application where the performance is very critical.

I saw that on average the Insert is taking something like 50ms, but sometimes it takes longer, much longer, sometimes around 100ms.
I need more control about this timming.

Any ideas about how can I improve this?
I know that on this part of my application I need to be very fast.
Thanks for any help.

Regards

Luis

50-100ms is not that much when you are talking about remote call with 50-100Kb to pass.
It is possible that this is simply the network cost.
What happen when you are using raw ADO.Net?

Its may be .NET garbage collection. Maybe you can call GC.Collect at certain points in your code where you can afford that extra 50ms? Otherwise I agree, this is a fixed time and would not cause scaling problems... not sure why this is a problem for you.

Hi.

This is a problem to me because I have some constraints about the timmings.

I have to perform an insert per each document. Each document have two images that are captured by a scanner.

This scanner works at a rate of 3.5 images per second, so I must the information to the database at this rate.
When I have the 100ms I might get in troubles.

Then I measured the time that the insert was taking, and it's not a fixed time, it's always around 50ms. 50 ms is the minimum, sometimes I get 100ms.

This is why I'm asking if this timming is too much for this information, meaning the two images.

The scanner works at a fixed rate and never slow's down, that's why the times are important to me, actually very important.

Thanks for the help.

Luis

p.s. I haven't measured yet with ADO.NET

You need to re-design your solution. Even if I found something that was a consistent 50ms, I would be extremely nervous because you are so vulnerable to problems. What happens when say, Windows Update is running and your inserts start running 10x slower?

You need to architect a 2-stage processing system which uses a queueing system i.e. MSMQ or similiar, where the scanned images are accumulated in a queue and the back end pulls the items from the queue and inserts them in the database.