Re: NetBase Shadowing Slowness

Hi, James. One thing that can cause shadowing to lag behind is that the
shadow posting is single-threaded. On the master machine you can have a
multitude of processes updating several databases concurrently, but on
the shadow machine the transactions are posted one at a time in the
order they are encountered in the queue file. One extreme example of
the impact that can have is a database we have (designed by someone who
must have been very ignorant of Image internals) that has very long
sorted chains. When that database is being updated, it can be extremely
slow. It's not very noticeable on the master machine, because not many
processes use that database, but on the shadow machine the slowness of
those updates slows down everything else.

One trick I have used on occasion is to defer posting on the offending
database for awhile. This will cause any transactions for that database
to be written to a PQ file. When you "undefer" the database, a separate
posting process is launched to post the transactions in the PQ files.
This allows greater parallelism and keeps the slow transactions from
affecting others. Until the PQ files are drained, the primary posting
process will continue to write the transactions to the PQ files, so the
second posting process can stay alive for quite a long time, even if you
undefer after only a short time.

Of course, using this trick will not preserve the sequence of
transactions to the deferred database relative to the others, so some
logical inconsistency could exist temporarily.

John Clogg

-----Original Message-----
From: HP-3000 Systems Discussion [mailto:HP3000-L@xxxxxxxxxxxxx] On
Behalf Of Reynolds, James
Sent: Wednesday, January 04, 2006 7:18 AM
To: HP3000-L@xxxxxxxxxxxxx
Subject: NetBase Shadowing Slowness

Greeting all,

This past weekend, I had to resync my databases on my 997. I
started out with about 80 Qfiles to post and now I have 143 to post, and
it's still growing... anyone have any idea why the shadow system's
posting could be so slow?

Thanks



James R. Reynolds
HP 3000 System Engineer
Time-Life Customer Service,Inc
2600 International Pkwy
Virginia Beach, VA, 23452
Phone: 757-427-7784
Cell: 757-651-8735
Email: James.Reynolds@xxxxxxxxxxxx
I am careful not to confuse Excellence with Perfection. Excellence I
can reach for. Perfection is God's Business. Michael J. Fox





* To join/leave the list, search archives, change list settings, *
* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *

* To join/leave the list, search archives, change list settings, *
* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *

.

Relevant Pages

  • Re: My Book is Incomplete Regarding SQL Commands ;-(
    ... Thanks for posting it. ... Hitchhiker's Guide to Visual Studio and SQL Server ... manage the database table you reference. ...
    (microsoft.public.dotnet.framework.adonet)
  • Re: Event 1000 Windows SharePoint Services 2.0 Error
    ... And these patches don't barf on everyone, so this isn't widespread. ... Volume Shadow Copy for D ... I'm using Small Business Server 2003. ... "Cannot connect to the configuration database." ...
    (microsoft.public.windows.server.sbs)
  • Re: Event 1000 Windows SharePoint Services 2.0 Error
    ... BTW I do differentiate between the DIYer and the VAR/VAP but you can call into MS support, explain the situation and it will be a free call. ... Volume Shadow Copy for D Drive is enabled. ... At 3 am this morning, my MSSQL$Sharepoint service stopped running and the server restarts by itself, most probably due to an update. ... And this morning when I came to work, I discovered that when I try to access http://companyweb/, I receive the "Cannot connect to the configuration database." ...
    (microsoft.public.windows.server.sbs)
  • Re: Problem with email attachment, 1 becomes 10
    ... My CV should be attached as a pdf-file. ... posting guidelines for this group is, before posting, to always try to ... stuff involving reading lines from the database, ... attachment, which might be where the bug happened, although I think it's ...
    (comp.lang.perl.misc)
  • RE: 1202 Errors, Article 278316, "ESENT event IDs 1000, 1202, 412
    ... This posting is provided "AS IS" with no warranties,and confers no rights. ... 1202 Errors, Article 278316, "ESENT event IDs 1000, 1202, 412 ... services Database recovery/restore failed with unexpected error ... attempting to open the local security policy results in the error ...
    (microsoft.public.win2000.group_policy)