Slow release of files

[Lawrence Fox 0]

I'm not sure how to phrase the topic, but here's what's happening.

 

My client has a Win2K server and Win2K workstations, 100 Mbps network, switched at the server and a RAID (mirrored) in the server.

 

When I put a copy of their database on a local hard drive and query it, it takes about 10 seconds to go through 400,000+ records and return the recordset.

 

When I put the database on the server, it takes 5 minutes.

 

A colleague with a simiilar setup ran the tests--and got response times of around 10-15 seconds, so I'm sure it some kind of setup issue on either the server or the workstations, but I'm darned if I can figure it out.

 

We have turned off virus checking (McAfee) on the data folders and there's no compression being used on the server. No change in the timing was noted.

 

Op locks are turned off on the server as well.

 

As a related issue (and I don't know if this is a red herring or if it'll ring some bells), I used Explorer to open a folder on the server, highlighted all 640 files (totalling 330meg) in the folder and the pressed DEL. There was a significant delay until the "deleting" animation showed up.

 

All suggestions gratefully accepted....thanks

[DS3Circuit 0]

What kind of DB ... Access .... SQL ??

[Bursar 0]

Are you running QoS or any uneeded protocols on the affected workstation?

 

Does the affected workstation have the same version of the ODBC drivers as the speedy workstation (if you're using them)?

 

Any other patch/version differences to Windows and the database software between the quick and slow machines?

 

How are they connected to the server? Are both machines plugged into the same switch, or different switches? Can you get them both onto the same switch to see if it's network hardware at fault?

[clutch 1]

OK, there's a couple of things you need to know about how a system behaves with a file when it's local and when it's on a network. First, when accessing a file, you are *probably* getting around 4-5MB/s in access speed over a decently switched network over an SMB (network neighborhood/NetBIOS share) connection. Now, compare that to a local access of maybe 30MB/s or greater and you can see why accessing the file locally is going to be faster. Now, couple that with a high incidence of acknowledgment frames (a return frame that's around every 4th or 5th frame that says "hey, I got the other frames, send me some more") PLUS file locking mechanisms that have to interact between the client and the server, and you can now see why your access is so slow. This is why you want to use a "real" client/server DB setup (MS SQL, MSDE, Oracle, Progress, PostgreSQL, MySQL, DB2, etc) where the DB is a "living" system that can handle requests and return records on straight IP via data connectors (like ADO, ODBC, JDBC, etc.) which is much faster. Also, the system can be setup to handle queries locally, rather than having the client scour the DB itself of the needed information.

 

As for the deleting question, Explorer is in effect "downloading" all the files in question, and then gives you the prompt asking if you want to delete them. Then, it repeats the process to delete them. This is why it takes so long, and can sometimes time out or have other errors. While it isn't really downloading them, it is itemizing them and during this process it takes about as long as copying it over to the local system. And remember, downloading/deleting a single 300MB file is a LOT faster than downloading/deleting 300MB worth of 1MB files.

[Lawrence Fox 0]

Database is DataEase.

 

It doesn't use ODBC.

 

The tests were done on the SAME PC, not different ones. IOW, "Dave's PC" when searching on DAVE's hard drive is fast, but Dave's PC's when searching on the server is slow.

 

(Same behaviour noted on several other machines).

 

Why do I get no noticeable speed degradation on a different network at a different location?

[clutch 1]

That was what I was talking about. When searching locally (i.e. the DB copied onto the local harddrive) you are limited to the I/O speed of the HDD interface, whereas searching the files across the network limits you the the I/O speed of the NICs and hubs/switches between the machines.

[DS3Circuit 0]

Quote:

OK, there's a couple of things you need to know about how a system behaves with a file when it's local and when it's on a network. First, when accessing a file, you are *probably* getting around 4-5MB/s in access speed over a decently switched network over an SMB (network neighborhood/NetBIOS share) connection. Now, compare that to a local access of maybe 30MB/s or greater and you can see why accessing the file locally is going to be faster. Now, couple that with a high incidence of acknowledgment frames (a return frame that's around every 4th or 5th frame that says "hey, I got the other frames, send me some more") PLUS file locking mechanisms that have to interact between the client and the server, and you can now see why your access is so slow. This is why you want to use a "real" client/server DB setup (MS SQL, MSDE, Oracle, Progress, PostgreSQL, MySQL, DB2, etc) where the DB is a "living" system that can handle requests and return records on straight IP via data connectors (like ADO, ODBC, JDBC, etc.) which is much faster. Also, the system can be setup to handle queries locally, rather than having the client scour the DB itself of the needed information.

As for the deleting question, Explorer is in effect "downloading" all the files in question, and then gives you the prompt asking if you want to delete them. Then, it repeats the process to delete them. This is why it takes so long, and can sometimes time out or have other errors. While it isn't really downloading them, it is itemizing them and during this process it takes about as long as copying it over to the local system. And remember, downloading/deleting a single 300MB file is a LOT faster than downloading/deleting 300MB worth of 1MB files.

If thats not hitting the idea home ..... what is ....

[DS3Circuit 0]

Quote:

If thats not hitting the idea home ..... what is ....

And APK gives it a 2 run shot deep into center field