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  1. #1
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    Default [SOLVED] Prevent Database Problems - Avoid Feature Update 2020 & These Updates

    [EDIT June 16, 2020 - In our testing here, we found that the KB4560960 prerequisite for the Windows 10 Feature Update 2004 also has the bad Jet Database engine. We're trying to find a way to have the 2004 Feature Update installed without having any of the KBs with the bad Jet Database engine. For now if you have Scheduler avoid this KB and the 2004 update.]

    [EDIT June 11, 2020 - Two customer report having received KB4549951 and removing that also "fixed" the Jet Database problem]

    [EDIT June 19, 2020] - One of our customers describes how to replace the broken DLLs with the earlier ones that work. You may need to do this if you cannot remove the Window Update that broke it.

    [EDIT Aug 13, 2020) Here is the workaround discussion thread for this, in case you are interested. William added some info today.


    June 16 - We just did a second mass mailing to all customers on this. If you haven't seen it, please have a look now.

    ALERT UPDATE: ACP Scheduler and Windows 10 Updates (June 16)

    It affects Windows 10 1903 and 1909. This "just started happening" in mid May, when the KB4556799 Windows Update was released. We haqve discovered two other variants of this, one which is a pre-requisite to the new Feature Update to Windows 10 version 2204. If you encounter an error saying the Scheduler database is not in a recognized format e.g. Cannot open database. It may not be a database that your application recognizes or the file may be corrupt, and you see that the file SchedulerData.mdb (in Program Files (x86)\ACP Scheduler) is like 2Gb, here's how to recover:

    How to Recover:

    Run the
    JETCOMP utility located in the Scheduler (8.3) install folder under Program Files (also attached if you are on an older Scheduler version, it has been confirmed to be happening with earlier versions). Details are in the Scheduler 8.3 Help under Advanced Features (sorry about the giant font in the warning). Be patient it may take many minutes:

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    How to Prevent Future Problems: See the instructions in the mass mailing we just sent (June 16)

    If you cannot remove the update or if you got the Feature Update for Windows 10 Version 2004: See the instructions in this post (Windows skills needed)

    Attached Files Attached Files
    Last edited by Bob Denny; Aug 13, 2020 at 23:25. Reason: Updated info from the last couple of weeks
    -- Bob

  2. #2
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    We just submitted another report to the Microsoft Feedback Hub including BOTH KB updates (and both contain "security fixes" to Jet database). Let's keep our fingers crossed.
    -- Bob

  3. #3
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    We just discovered here that the KB4560960 update, which is a pre-requisite to the big Windows 10 Feature Update 2004, also includes the broken Jet Database engine. We filed yet another Feedback Hub ticket (see below) and we'll be sending out a mass mailing to Schedler customers soon. If you got the Feature Update 2004 installed already you will have no option other than to repeatedly compress the Scheduler database until Microsoft comes out with a fix for the broken Jet Database engine.

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    -- Bob

  4. #4
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    Default Replace new broken DLLs with older working ones (last resort)

    [EDIT: This was copied from the premium ACP Expert Scheduler thread]

    I have researched the various KB's associated with the changed behaviour of the scheduler, have found eight KB.s so far, but there are probably more.

    The relevant DLL modules in Windows 10 builds 1903 through 2004 that introduced the problem scheduler growth are limited to just two:

    msjet40.dll and msrd3x40.dll

    The above reside in C:\Windows\SysWOW64 and are both JET Database components.

    These two components are a matched pair and any build versions later than: msjet40.dll v4.00.9801.20 and msrd3x40.dll v4.00.9801.19​ will cause the scheduler database growth problem.
    (mouse-right-click the files and read the current versions in the properties tab)

    Replacing later versions of these two .dll's with the last known-to-be-good versions in test VM's of builds 1903, 1909 and 2004 fixes the database growth problem without appearing to cause issues elsewhere.

    I am not a Microsoft expert and not able to test every possibly combination of Windows 10 build and application software package for compatibility issues so I can't stick my head above the parapet to say this is a cure for everyone and I don't have the programming skills necessary to create an installer that a user can run that would automatically replace these dll's with ones that work.

    However, if you are really stuck and Microsoft is slow to issue a fix you can replace the above files with the ones attached to this post and it should cure the problem until you next install a quality update.

    (Note: each Windows quality update is a cumulative roll-up and so each successive quality KBxxxxxx will bring all files up to the latest build version, even if the specific changes for the JET database are not listed in that KB's release notes, therefore after each "Patch Tuesday's" (second Tuesday of every month), quality KBxxxxxx, is installed then the two .dll's listed above will be replaced again with the problematic ones)

    Install notes:
    The existing .dll's in the SysWOW64 folder are currently owned by "Trusted Installer" and you have to change permissions for the two existing .dll's to be controlled by you, the administrator, see the webpage here if you don't know how to do this (not for Bob, he already knows this stuff):

    https://www.windowscentral.com/how-t...ers-windows-10

    After you change ownership of the two .dll's to give you control, rename the existing .dll's to OLD_msjet40.dll and OLD_msrd3x40.dll.
    Do not delete the existing .dll's, if this fix does not work you can delete the substituted versions and rename the old files back again to restore original state.

    Unzip and copy the two .dll's from the attachment into folder C:\Windows\SysWOW64.
    You should find:

    msjet40.dll version: v4.00.9801.20
    msrd3x40.dll version: v4.00.9801.19

    I have already changed permissions for the attached.dll's to "Everyone" but you may need to add permissions for your system/user if Windows 10 blocks you from copying them to the SysWOW64 folder and running them on your system.

    Reboot Windows 10, run the JET Database compression tool on your existing scheduler database and then test to see if the growth issue is resolved.

    Until Microsoft fix the problem, after each monthly quality update is installed you will have to go through the above procedure and replace the current .dll's noted above, with the older ones provided.

    To recap after a long post, you can install the latest KBxxxxxx quality updates, even update to build 2004, and then replace the two .dlls' listed above with the ones I have attached and the scheduler database growth issue should be fixed.

    As I only have access to a limited range of Windows builds and application software I can't promise that replacing the above .dll's won't cause system instability, or problems elsewhere, and I can only test up until todays date, I can't even be sure that this will work with every build of Windows 10 in use, and it is quite possible that the next quality update will not be compatible with the older .dll's provided and you will be back to square one.

    Hopefully the above may provide another option to deal with the JET Database growth issue until Microsoft come up with a permanent fix.

    William.
    Attached Files Attached Files
    Last edited by Bob Denny; Jun 19, 2020 at 19:04.

  5. #5
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    Additional news. I talked with a Microsoft Insider and it seems that the Jet Relational Database Engine used by Scheduler is alive and well in Microsoft! It is being used in the support infrastructure for the Microsoft HoloLens 2 project, other areas such as Azure, and of course within "billions and billions" of Microsoft Access based applications. It's reassuring to know it is highly regarded and in widespread use outside of Microsoft Office.

    Since we haven't seen a fix come out, it's possible that I am using some combination of features that, taken together, were broken by Microsoft for database size stability in the last update of Jet, and thus not affecting everyone. I naively thought "oh we'll just diff our code and knowing what the problem is, we should be able to see where we screwed up". It appears that may not happen (still holding out for a fix from them), so I am going to put together the simplest possible repro scenario I can. It could be a big job because there are so many moving parts in the database, the stored procedures, the SQL statements and the logic in my scheduling object model wrapper layer on top of the database API.

    Stay tuned, I'm on it.
    -- Bob

  6. #6
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    Well in the process of working on the "repro kit" for Microsoft, I stumbled on what looked like a way to work around the problem: create and dispose database objects, opening and closing connections, in a granular way. I modified all of the components of the Web Schedule browser, removed the shared Database connection from ACP.exe and other things (leaving myself open to subtle bugs). Well 3+ days later it turns out to be a bust. Although eventually I got the web UI completely free of DB expansions, once I started the scheduler itself or tried to use the desktop schedule browser, and especially while ACP is running a Scheduler Observation (AcquireScheduler), back to expanding database. Furthermore, by repeatedly opening and closing the database (creating and disposing database wrapper objects) the responsiveness of the web UI suffered badly. There is something really wrong with having multiple connections all right.

    SCHEDULER-1785 - Database grows in large jumps until 2Gb then Scheduler N/G
    ACP-1786 - Eliminate shared/cached database access object

    I need to get this repro kit into the hands of MS and it is a time-consuming process. A lot of trial and error. I'm not going to make the mistake of going for a "sucker hack" again though. The DB really has changed its behavior in a bad way after all these years.
    -- Bob

  7. #7
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    I have filed a help request on the Microsoft Tech Community for Access (which also uses the Jet database engine). I was unaware of this service of MS, and I got there doing Google searches for clues and ideas. Here's the post:

    Problem with MSJET40 Started in May 2020 - Rapidly Inflating database until 2Gb then stops working

    You might not be able to see this without being a member. I have attached a PDF capture of my post.
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    -- Bob

  8. #8
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    My goal this week is to create a little app that will replace the two Jet database DLLs with the older ones that work. I will make it so you can go back and forth between old and new at a minimum and maybe also provide an easy UI to JETCOMP (thanks to Dick Berg's research). Once I get that into your hands to mitigate the problem, I'll go back to working with Microsoft. I think that one is going to be painfully long process. Neither the failed workaround week before last nor my efforts to precisely characterize the problem last week bore fruit.
    -- Bob

  9. #9
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    One of our customers, George Silvis of AAVSO, has written a Windows Script that helps automate the process of using JETCOMP to compress the database. Please remember that both Scheduler and ACP must be shut down for JETCOMP to have access to the database for compressing.

    Coping with the Scheduler Database Expansion issue
    -- Bob

  10. #10
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    WooHoo!! I received a reply on the Microsoft Tech Community post I made:

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    I also got a back channel note that indicated that it's possible that this fix will be in the September rollup (Sept 6). With this on the horizon, I'm suspending my workaround activities since there are (klunky) ways to work around it already, including replacing the broken DLLs with good ones. I had just started building an Admin level command line app to do this and also compress the database, but the best of all would be for the problem to go away.
    -- Bob

 

 

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