Reply To: F_JT044C: Warning: HVR encountered change to table ‘mytable’ in transaction id 0xXX but it did not see the corresponding ‘begin transaction’ record

#8810
Simon Faas
Keymaster

HVR capture has the concept of expiring transactions.

This can happen for 2 reasons

1) the transaction is open for more than 3 hours and it has no changes to replicated tables inside, it will be silently expired

2) the transaction is open for more than 3 days it will be expired even it if it has replicated transactions inside. But in this case a warning will be issued.

This “expiring of transaction” has been implemented to avoid capture going back too far after a restart ( HVR’s capture will go back to the oldest open transaction after a restart, which may cause high latency).

The most likely reason for the warning that you got is that we had a transaction that was expiring due to reason 1 and then a change to a replicated table came in. HVR had already expired the begin transaction record and will give a warning. But it will replicate the change nevertheless.

Note: The timeouts for 1 and 2 can be modified using environment variables. But I would recommend against that. I think the default values are fine.

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