Hi Paul,

We have been experiencing exactly the same problem, with some 23 million
rows in both BB_BB60.ACTIVITY_ACCUMULATOR
and BB_BB60_STATS.ACTIVITY_ACCUMULATOR.  We have discussed this with
Blackboard Support, and have managed to resolve the problem.

My understanding of the system is that all activity is recorded in
BB_BB60.ACTIVITY_ACCUMULATOR, but this is synchronised with
BB_BB60_STATS.ACTIVITY_ACCUMULATOR on a daily basis.  This process also
purges old data from BB_BB60.ACTIVITY_ACCUMULATOR, by default, anything
older than 180 days.  However, if you have a particularly large amount
of data, the purge can fail, leading to this situation.

The synchronisation process calls the script blackboard\tools\admin
\PurgeAccumulator.bat.  This will synchronise the two databases, and
perform the purge.  You can run PurgeAccumulator.bat from a command
line, specifying the number of days of data to keep - instructions on
this are on pages 266-267 of the Administrator's Manual (Release 7.3).
However, this may not work if you try to delete a very large amount of
data at once.

The settings for the automatic process are stored in
blackboard\config\bb-tasks.xml - there is a section which starts:

  <task-entry key="bb.stats.purging" version="60">

This includes the time of day which the process is executed and the
number of day's worth of data to keep in BB_BB60.ACTIVITY_ACCUMULATOR.

However, the first thing we did to solve the problem was to manually
reduce the amount of data in BB_BB60.ACTIVITY_ACCUMULATOR.  We deleted
data based on the timestamp, so we could get to a stage where the
automatic process could cope with the daily purge.  To avoid locking the
database for a long time, we performed a series of small deletes, each
removing a few weeks worth of data.  The script was along the lines of:

Delete from dbo.ACTIVITY_ACCUMULATOR where TIMESTAMP < '15/02/2008'

You may need to confirm the data is in the correct format.

Once this was complete, the automatic process continued to work
successfully.

Obviously I would advise caution with all of this as it involves
deleting data, and a potentially large volume of data, but I hope this
points you in the right direction to solving the problem.

Kind regards

Chris Boon
Senior ILT Support Analyst
City College Norwich

-----Original Message-----
From: Blackboard/Courseinfo userslist
[mailto:[log in to unmask]] On Behalf Of Beckett Paul
Mr (ITCS)
Sent: 14 February 2008 17:48
To: [log in to unmask]
Subject: ACTIVITY_ACCUMULTOR table : excessive logging

We're are experiencing performance problems with the course stats & the
activity accumulator because of the rate our activity accumulator table
is growing: 40 million rows from the last six months. Over 75% of the
growth relates to logging of displaying 'tabs' and 'modules' in the
community system, which we are not interested in.

Has anyone selectively deleted logging from BB_BB60.ACTIVITY_ACCUMULATOR
or BB_BB60_STATS.ACTIVITY_ACCUMULATOR based upon EVENT_TYPE? If so, did
you encounter any problems as a result? Do you mind sharing the SQL
command you used? Was this action supported by your TSM?

Is course statistics reporting done from BB_BB60.ACTIVITY_ACCUMULATOR,
BB_BB60_STATS.ACTIVITY_ACCUMULATOR or both?

To compound the problem we effectively have two copies (of the 40
million rows) in both: BB_BB60_STATS.ACTIVITY_ACCUMULATOR and
BB_BB60.ACTIVITY_ACCUMULATOR. The later contains everything the former
one does, plus a few extra days beyond the 180 days logged in BB_BB60
and minus the most recent day.

Is there a way to have days 0 - 180 in BB_BB60 , and days - 181 -
onward, in BB_BB60_STATS?

Otherwise is it possible to have days 0 - 180 in BB_BB60 and nothing in
BB_BB60_STATS?

Sorry about the huge list of questions. Any help / guidance / info would
be very gratefully received.

Thanks,
Paul

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