Allow isc_tpb_read_consistency to imply read committed #8746
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…t more robust to improper set of flags
hvlad
reviewed
Sep 21, 2025
…fied without isc_tpb_read_committed
hvlad
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Sep 21, 2025
dyemanov
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Sep 29, 2025
* Allow isc_tpb_read_consistency used alone to imply Read Committed Read Consistency * Sync the trace logic with MON$ tables regarding txn isolation, make it more robust to improper set of flags * Restore the original error for isc_tpb_[no_]rec_version version specified without isc_tpb_read_committed
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We allow to specify
isc_tpb_read_consistencyalone and at least one driver currently specifies ReadCommitted ReadConsistency mode this way. However, in fact the transaction isolation becomes Snapshot withTRA_read_consistencyflag being set too. This causes asserts in the code and I'm not really sure the chase/restart logic works properly in all cases.Given that such a usage seems quite logical and handy, I suggest to not raise an error but rather imply ReadCommitted instead of Snapshot in this case.
Also, the transaction isolation detection in the trace was changed to be more resistant to weird flag combinations like the one described above and not raise unexpected asserts. It's now also in sync with the value of
MON$ISOLATION_MODE.