>
> I looking for information on the Transaction Manager and how it deals with
> logical transactions in Image.
>
> I'm running on a 997/800 MPE iX 5.5 pp 6 with 3.8 GB of memory.
>
> What is the limit of the logging buffer?  How do I determine how many of my
> logical transactions the buffer can handle before it becomes a "stalled
> transaction".
>
> Thank you.

First off, as far as I know there is no reliable way to determine how many
transactions will fit into an XM user log file. The sizes of 'activity'
records written to the file will vary. A log activity record can be as
little as 1 byte or quite alot more than that.

The XM user log file is typically built to be ~16MB. It can be half that
if the master volume of the set is < 350MB. Each volume set will have
its own set of XM log files.

The XM user log (and system log) are managed in a circular fashion (but
are not CIRcular files!). Each file has 2 halves, the middle and end.
When we reach the end of file we wrap around to the beginning. If a
transaction was begun in a log half that is about to become the current
half to be written to we must move or copy that transaction forward.
A userlog transaction can be copied forward up to 100 times after which
is is deemed to be 'stalled' and is rolled back. On 6.0 we will do
copy-forwards on 'system transaction' which is handy if you have large
directories! More details on XM on 6.0 can be found at

http://docs.hp.com/dynaweb/smpe/b1015/b975/@Generic__BookTextView/15894

XM will save off some statistical information and I -believe- this is
available via the measurement interface which would mean that HP or
other performance monitoring utilities could be of assistance in
understanding the dynamics of XM on your system.

I hope this is of some assistance.

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+---------------------------------------------------------------------+
|Bill Cadier                         | Is computer science?           |
|Hewlett-Packard Co.                 |            -author unknown     |
|Commercial Systems Division         |                                |
|Albuquerque, New Mexico             |                                |
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