Hello Prakash,

What kind of drive is it? My experience is that SATA drives hate being
banged on from multiple threads. They just can't handle multiple
simultaneous work loads without slowing down drastically. They're fine
with heavy duty single threaded IO. In my application, I serialize
most heavy duty disk IO for this reason. If the drive is hanging off a
USB interface, it's much worse.

In your case, I might consider a "server" application that answers
requests from the clients so, only one process is banging on the disk
at a time.


Thursday, November 18, 2010, 4:21:04 PM, you wrote:

PRB> Hi,

PRB> I have a database placed on a shared drive.
PRB> Two processes (from different hosts) do a bunch of select commands.

PRB> I have a busy handler that sleeps of 1 second in each attempt
PRB> and bails out after 10 attempts.

PRB> The observation is that, if only one process is running (on any
PRB> host) the results are returned pretty fast. However, if both
PRB> processes are doing the selects concurrently the performance is dead slow.
PRB> Note that each process is doing somewhere around 5000 selects.
PRB> My understanding is that when only selects are happening there is no 
locking involved.

PRB> I am using 3.7.2.

PRB> Regards,

PRB> Prakash Bande
PRB> Altair Engg. Inc.
PRB> Troy MI
PRB> Ph: 248-614-2400 ext 489
PRB> Cell: 248-404-0292

PRB> _______________________________________________
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Best regards,
 Teg                            mailto:t...@djii.com

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