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Thread Dbisam 3->4 big slowdown on fileserver
Wed, Apr 12 2006 6:04 PMPermanent Link

Ian
Hi,

I have recently upgraded my app from DBISAM 3 to 4 and using D2006. Most of my users seem
very happy but at one site, accessing the DBISAM files on a server there has been a
maasive slowdown even withonly a sngle user accessing the files e.g. Startup time from 3-4
seconds to 20+ seconds. The bulk of the startup is opening various tables, all in direct
mode i.e. not SQL. The only real change I have made while upgrading was to tidy up some of
the tables reads to be read-only which (as expected) seemed to speed things up (for me at
least)

I have tried various tweaks as suggested, the temp dir is local,  I have bumped up the
memory buffers * 3, all without any benefit.

The network reponse seems ok with other apps and straight file copies.

I appreciate these things are a bit of a black art but was there any significant
underlying Db architecture change between DBISAM 3 and 4 that could account for such a
massive slowdown?

Cheers,
Ian

Wed, Apr 12 2006 6:40 PMPermanent Link

"Jose Eduardo Helminsky"
Ian

Check opportunistic locking at file server (NT, Windows 2000, Windows 2003)

Eduardo

Wed, Apr 12 2006 7:37 PMPermanent Link

Ian
"Check opportunistic locking at file server (NT, Windows 2000, Windows 2003)"

Thanks Eduardo. I will check it out. Has this become more significant between DBISAM 3 -> 4?

Ian

Thu, Apr 13 2006 7:39 AMPermanent Link

Tim Young [Elevate Software]

Elevate Software, Inc.

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Email timyoung@elevatesoft.com

Ian,

<< I have recently upgraded my app from DBISAM 3 to 4 and using D2006. Most
of my users seem very happy but at one site, accessing the DBISAM files on a
server there has been a maasive slowdown even withonly a sngle user
accessing the files e.g. Startup time from 3-4
seconds to 20+ seconds. The bulk of the startup is opening various tables,
all in direct mode i.e. not SQL. The only real change I have made while
upgrading was to tidy up some of the tables reads to be read-only which (as
expected) seemed to speed things up (for me at
least) >>

How many tables are being opened up during the 20+ seconds ?  If anything
DBISAM 4.x should be faster than 3.x in terms of file-sharing on a Windows
file server that is using opportunistic locking.  The reason for this is
reduced locking in 4.x in the .dat, .idx, and .blb files.

<< I have tried various tweaks as suggested, the temp dir is local,  I have
bumped up the memory buffers * 3, all without any benefit. >>

The memory buffers won't have any bearing on this type of issue.

<< The network reponse seems ok with other apps and straight file copies. >>

That pretty much rules out a hardware or configuration issue.  However, just
to be sure, what type of configuration are we talking about in terms of
client OS, network speed, file server OS, etc. ?

--
Tim Young
Elevate Software
www.elevatesoft.com

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