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Thread Recompiling DBSRVR
Thu, Feb 23 2006 3:02 PMPermanent Link

Jose Eduardo Helminsky
I have been playing with some little adjusts in the project DBSRVR.

I would like some comments about someone that have changed some of these settings. My intention is increase the performance and avoid some "freeze" problems during transactions. I am
investigating the real cause of the problem. I've changed the server timeout to 60 seconds (the minimum) but users are complaining that app freezes until around 5 minutes waiting for a
session with troubles inside the transaction. All the errors are trapped inside a generic routine assigned to Application.OnException where has a call to Database.RollBack.

MaxTableBlobBufferCount * 2
MaxTableBlobBufferSize * 2
MaxTableDataBufferCount * 2
MaxTableDataBufferSize * 2
MaxTableIndexBufferCount * 2
MaxTableIndexBufferSize * 2

TableMaxReadLockCount := 10

TableTransLockRetryCount := 2000;
// With this setting the app will have around 30 seconds to get transaction lock and after that it will raise #10229 error and a message like "Database is busy right now, try this operation
later" will be displayed.  
Fri, Feb 24 2006 1:14 PMPermanent Link

Tim Young [Elevate Software]

Elevate Software, Inc.

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Email timyoung@elevatesoft.com

Eduardo,

<< I would like some comments about someone that have changed some of these
settings. My intention is increase the performance and avoid some "freeze"
problems during transactions. I am investigating the real cause of the
problem. I've changed the server timeout to 60 seconds (the minimum) but
users are complaining that app freezes until around 5 minutes waiting for a
session with troubles inside the transaction.

TableTransLockRetryCount := 2000;
// With this setting the app will have around 30 seconds to get transaction
lock and after that it will raise #10229 error and a message like "Database
is busy right now, try this operation later" will be displayed. >>

Do the users receive this error message and then still wait an additional
few minutes ?  Are you retrying the transaction inadvertently, perhaps ?

--
Tim Young
Elevate Software
www.elevatesoft.com

Fri, Feb 24 2006 4:38 PMPermanent Link

"Jose Eduardo Helminsky"
Tim

> Do the users receive this error message and then still wait an additional
> few minutes ?  Are you retrying the transaction inadvertently, perhaps ?
No, I was not clear. Users are complaining about some "locks". They told me
the app freeze around 5 minutes. I know the problem start with one user (I
don't know who) and then other users were waiting for the first user call a
COMMIT or ROLLBACK but even when timeout setting is 60 seconds the app
freezes around 5 minutes or more. I am trying to replicate the problem here
in my office taking out TP cable while a transaction is running and see what
happen. I've installed the changes this morning and log all erros received
and I've checked some #10229 erros just after a #11279 error at server side.
I will investigate more details about it.

Eduardo

Mon, Feb 27 2006 6:45 AMPermanent Link

Tim Young [Elevate Software]

Elevate Software, Inc.

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Email timyoung@elevatesoft.com

Eduardo,

<< No, I was not clear. Users are complaining about some "locks". They told
me the app freeze around 5 minutes. I know the problem start with one user
(I don't know who) and then other users were waiting for the first user call
a COMMIT or ROLLBACK but even when timeout setting is 60 seconds the app
freezes around 5 minutes or more. I am trying to replicate the problem here
in my office taking out TP cable while a transaction is running and see what
happen. I've installed the changes this morning and log all erros received
and I've checked some #10229 erros just after a #11279 error at server side.
I will investigate more details about it. >>

The worst-case scenario in terms of wait time for an outstanding transaction
whose client has terminated improperly is:

Connection timeout (server) + Dead session expiration (server)

BTW, what were the #11279 error messages ?

--
Tim Young
Elevate Software
www.elevatesoft.com

Mon, Feb 27 2006 11:08 AMPermanent Link

"Jose Eduardo Helminsky"
Tim

Connection timeout (server) + Dead session expiration (server)
60 + 0

Max number of dead sessions = 0

About the error #11279, I don't know exactly what is producing this error.
Users don't help me in this way but I suspect the "lock" happen after that.

Eduardo

Tue, Feb 28 2006 8:13 AMPermanent Link

Tim Young [Elevate Software]

Elevate Software, Inc.

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Email timyoung@elevatesoft.com

Eduardo,

<< Connection timeout (server) + Dead session expiration (server) 60 + 0 >>

In that case, the longest they should wait is 60 seconds before the session
is removed.  Were you able to verify whether there were any dead sessions
"hanging around" on the database server when this occurred ?

--
Tim Young
Elevate Software
www.elevatesoft.com

Wed, Mar 1 2006 4:47 AMPermanent Link

"Jose Eduardo Helminsky"
Tim

I am trying to catch this situation but it happens sometimes and users can't
explain when and even what they were doing. I will prepare a small app only
to administrator of the network "see" the connections and check dead
sessions.

Eduardo

Wed, Mar 1 2006 10:32 AMPermanent Link

Tim Young [Elevate Software]

Elevate Software, Inc.

Avatar

Email timyoung@elevatesoft.com

Eduardo,

<< I am trying to catch this situation but it happens sometimes and users
can't explain when and even what they were doing. I will prepare a small app
only to administrator of the network "see" the connections and check dead
sessions. >>

I understand, it's very difficult to expect users to decipher what's going
on.  The administrator app sounds like a good idea and should reveal some
more information.

--
Tim Young
Elevate Software
www.elevatesoft.com

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