Results 1 to 7 of 7
  1. #1
    New Lounger
    Join Date
    Feb 2001
    Location
    Central Islip, New York, USA
    Posts
    9
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Replication Losing Records when Synching (Access 2000)

    I have 7 replicas on 7 servers being directly synchronized with a Hub Replica via VB code daily. Design Master sits in a separate folder and is not part of this schedule. Three days ago, I learned that not all of the new and updated records from the replicas were synchronizing, in fact they were gone! The day this started happening was after one of the replicas received the "record was deleted" error message. I had to create make tables of the data and import them into a new replica. I tested the new replica by adding new records and synching it with the hub and had no problems. Synchronization has occured 3 times since the error happened! Therefore, my backups are now useless to retrieve the information because of this !!!

    Has this happened to anyone else? I need some guidance here.....first it was network issues and now this! I am at my wit's end with this replication.....

    Thank you for any information you can provide....

  2. #2
    New Lounger
    Join Date
    Feb 2001
    Location
    Central Islip, New York, USA
    Posts
    9
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Re: Replication Losing Records when Synching (Access 2000)

    Wendell,

    I think I have read every FAQ, MS KB article and quite a few books regarding replication that are out there! I read your article (well-written, by the way!) right before I posted this message ... I just haven't come across any that mention losing (or deleting somehow) records that have already been saved to the database before synchronizing.

    You mention synchronizing to a backup replica, I read about this at trigeminal.com....a replica farm? Your article made it so much clearer to me! So the users will be entering their data into their replica, which I then synchronize one way with a "backup replica", which in turn is the one that synchronizes to my hub, which then synchronizes in turn with the other replicas. This makes more sense to me now.

    Thank you for the reply, I appreciate it !

  3. #3
    Plutonium Lounger
    Join Date
    Dec 2000
    Location
    Sacramento, California, USA
    Posts
    16,775
    Thanks
    0
    Thanked 1 Time in 1 Post

    Re: Replication Losing Records when Synching (Access 2000)

    I suspect that if you dig deeply enough, you'll find that those records were deleted somewhere. Deletions also get synchronized. Design changes can throw a monkey wrench into replication as well, since design changes are replicated first, then data changes. So if you make a change to table structures, by deleting or renaming a field for instance, and sync the replicas, you may wind up with data conflicts because the table structure in the child replicas where data has been entered doesn't match the structure in the master.
    Charlotte

  4. #4
    Super Moderator
    Join Date
    Aug 2001
    Location
    Evergreen, CO, USA
    Posts
    6,624
    Thanks
    3
    Thanked 60 Times in 60 Posts

    Re: Replication Losing Records when Synching (Access 2000)

    <P ID="edit" class=small>(Edited by WendellB on 04-Feb-04 06:35. To fix a typo that made my comments sort of unintelligible[blush])</P>
    <hr>I am at my wit's end with this replication.....<hr>
    Most of us who have worked with replication feel this way frequently. It is one of the most complicated situations you are likely to encounter in database land. (That's why I don't have my userpic normally showing <img src=/S/hairout.gif border=0 alt=hairout width=31 height=23> <img src=/S/gramps.gif border=0 alt=gramps width=20 height=20>) As far as replication is concerned, backups are pretty much worthless with replication because the backup is almost never synchronized with all the copies out there. The typical strategy that people use (in my experience anyhow) is to replicate to a backup replica after each round of synchronizing with all the working replicas. That copy which is never updated in any other way is effectively the backup. But the real challenge usually revolves around conflict resolution - which from your description is probably what caused your problem. There are a number of reference documents available on replication - you might start at our tutorial in the "Where do I get more information?" section.
    Wendell

  5. #5
    Super Moderator
    Join Date
    Aug 2001
    Location
    Evergreen, CO, USA
    Posts
    6,624
    Thanks
    3
    Thanked 60 Times in 60 Posts

    Re: Replication Losing Records when Synching (Access 2000)

    I agree with Charlotte - the most likely scenario is that someone somewhere deleted the three records in question - possibly unintentionally. One thing we typically do is to never allow the deletion of a record - instead we put a logical delete, and we only allow forms to change records for any user other than the database administrator. That way the conflict resolution gets a bit simpler - but that is still the biggest challenge with replication. It takes lots of analysis and a very logical mind to figure out which changes should be kept and which should be dropped when a conflict occurs. BTW, if you haven't read the stuff on replication in the Access Developers Handbook, it's well worth it. Alison Balter's book volume 2 for 2002 also has some pragmatic and useful info. Another question - are you using replication manager from the Developer version of Access 2K? If you are, there is some good information about replication configurations in a readme doc with that package.

    Best of luck with your situation - if you have further questions we'll be happy to try to help.
    Wendell

  6. #6
    New Lounger
    Join Date
    Feb 2001
    Location
    Central Islip, New York, USA
    Posts
    9
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Re: Replication Losing Records when Synching (Access 2000)

    <P ID="edit" class=small>(Edited by WendellB on 16-Feb-04 14:21. To activate website link)</P>Thank you, Charlotte and Wendell, for taking time to address my dilemma.

    Unfortunately the loss of records is occuring at several of the replicas in various tables. The users do not have capability to delete records, this can only be done by an administrator. There have been no design changes done since the replicas were created.

    I am using the Sychronizer code from http://www.Trigeminal.com to accomplish the synchronization. First I synchronize all replicas one by one with the hub....and then I do it all over again....so all replicas have same info. Conflicts I can deal with, it is the replication errors which are corrupting the replicas and the losing of records that has been the most aggravating.

    We had hoped this would be a solution for our users, instead it has been a nightmare.....as of this week we will no longer use replication and synchronization. Too unreliable and the administrative costs too high!

  7. #7
    Super Moderator
    Join Date
    Aug 2001
    Location
    Evergreen, CO, USA
    Posts
    6,624
    Thanks
    3
    Thanked 60 Times in 60 Posts

    Re: Replication Losing Records when Synching (Access 2000)

    Hi Rosanne,
    Sorry to hear you've had major problems with replication - we've used it successfully if it is carefully engineered and found it to be a useful tool when people travel. One thing that could well be contributing to your problems is that the Syncronizer code you referenced was written for Access 97 and there were a number of modifications made in Access 2000 to the replication feature and in particular to the default conflict resolution process. I don't understand your network topology, but I noted that you had experienced some network problems a few years ago. Does that mean that all of your replicas are on a LAN? Unfortunately, if you have issues with the reliability of your network, Access won't like it, and you get corruption and replication errors. In your situation, I would most certainly be using the Replication Manager that comes as a part of the Office Developer Suite - among other things it will support text to text replication over dial-up connections, and is much more robust than a direct synchronization. Another thing yo might look at is SQL Server as an ODBC back-end - it is much more immune to network problems, and has such things as two-phase commits which pretty much ensure that things get properly saved.

    Again, sorry you've had troubles with your application. If you want to describe your environment in more detail, we can try to make suggestions as to what would improve the situation.
    Wendell

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •