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  • 1.  IPL commit (tx:

    Posted Tue February 24, 2026 06:52 PM

    Hi Y'all.

    There a message that occasionally pops up in the message log; here's one from December of last year:

    12/29/25 21:56:19  Warning: IPL commit (tx:396465e28) is suspended, waiting for an open
              transaction from the oldest logical log (<some seq num>) to complete.

    When I googled the above it sent me to an HCL page with a similar message but gave advice useless to my situation.  Here's how I understand the message but I believe my understanding is flawed.

    • Suppose I have 1000 log files and the log sequence number of the oldest log file is 100001.
    • I am currently at log sequence number 100123.
    • There is a still a transaction open whose BEGIN  record sits in log[100001].
    • It is still within the bounds of LTXHWM (or we would have gotten an LTX rollback message).

    But somehow, something triggered this IPL warning.

    There is obviously a difference between this IPL warning and the LTX rollback.  We have procedures to seek out and kill the culprit session and certainly don't need to add a log (as per that aforementioned useless advice). So, after an uncharacteristically short explanation, here are my questions:

    1. What triggers this IPL warning, since it's not LTX? By my understanding, if the current log were 100002 - just in the next sequence number, there are likely MANY transactions with their BEGIN in log[100001].  Yet thatdid not trigger the IPL warning.  What log sequence # would we have to be at to trigger this?
    2. I also understand that IPL is a TLA for Index Page Logging.  What in blazes does this situation with log files have to do with logging of index pages?

    Will someone please fill the gap between my ears on this issue?🤦‍♀️

    Thanks much!



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    +-----------------------------------------------------------+
    | I am pleased to report that I had no problems today. |
    | I had only issues, opportunities, challenges and valuable |
    | learning experiences. |
    +------------------------------------------ Jacob S --------+
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  • 2.  RE: IPL commit (tx:

    Posted Tue February 24, 2026 07:04 PM
    Jacob:

    You are in luck as I just explained this one to another client:

    OK, this turns out to be what I suspected it is. Those messages indicate that a change to an index page needed to be logged, however, there was an open transaction (as noted in the message) in the oldest logical log file and the logs as a whole were approaching the point where the LTXHWM setting would kick in and declare that oldest transaction to be a "long transaction" such that it would be rolled back to free up logical log space. To prevent that from happening due to an index page change (which is essentially recoverable without the corresponding logical log entry), the index transaction was paused and retried a little later. If you see the same transaction number (tx:700020076f808e0 in this case), several times that just means that the transaction that was updating the index (a background task) had to be paused for a longer time until that very old transaction was finally committed or rolled back. No harm was done. This is ultimately caused by having enabled LOG_INDEX_BUILDS which is a required parameter setting when you have any RSS secondary servers, as you do.

    As I explained to that client, the proximate cause is usually not having enough logical logs and applications that are holding transactions open for a relatively long time.

    Art

    Art S. Kagel, President and Principal Consultant
    ASK Database Management


    Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference.  Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves.







    Original Message


  • 3.  RE: IPL commit (tx:

    Posted Wed February 25, 2026 11:06 AM

    Well, it's not a "change to an index page" that's being logged here, but rather an entire new index:  with LOG_INDEX_BUILDS on, a new index, once fully built, is being copied to the logical log, page by page, so a secondary server would save building the index on its own while having a guaranteed binary copy of the primary's index.

    Depending on the size of such index, a large amount of logical log space can be consumed which in turn could compromise other parts of the system, esp. legitimate larger/longer other transactions suddenly running a risk of becoming LTX.  To reduce this risk, IPL periodically checks for older transactions and temporarily suspends itself until such old guy is done.



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    Andreas Legner
    Informix Dev
    HCL Software
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    Original Message


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