Re: Why long transaction cannot rollback?????
Posted in 1997
I am not sure whether this applies to your version of Informix; however, I was told in a performance and tuning class that the system will examine the logical logs after passing the high water mark and examine the processes active in the current logical log. If one has five logical logs and there happens to be one unfinished transaction in the first logical log and the mark is passed in the third logical log, the transactions in the third logcal log are targeted for rollback. The transaction in the first logical log will continue to remain active without being rolled back. This condition will fill your logical logs if the transaction of the first logical log continues to produce modifications. The only way around this is to be alerted when LTXHWM is crossed and closley examine the logical logs to see if a process must be terminated. If I am in error please email me. I would not want to plod on erroneously in this area. Sincerely, William J. Mitlyng Database Administrator ABN-AMRO Bank NV