Log-based or trigger-based database capture?

This topic contains 0 replies, has 1 voice, and was last updated by  Mark Van de Wiel 1 week, 1 day ago.

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    Mark Van de Wiel

    Why would I still use trigger-based database capture when HVR supports log-based capture on all platforms?

    The general rule is to use log-based capture, unless you have a good reason not to.

    Log-based capture is beneficial over trigger-based capture because:

    • Log reading takes place asynchronously, so transaction processing is not directly affected by log-based change data capture.
    • The transaction log has a history of changes, so it is possible to go back in time and re-capture changes should that be necessary.
    • Generally log-based capture uses less system resources than trigger-based capture, and does this more in a continuous mode rather than in bursts.

    However there are uncommon exceptions when trigger-based capture may be used as an alternative.

    • The database you want to capture from does not provide sufficient required functionality for HVR to perform log-based capture. A good example is SQL Server Express Edition which does not allow HVR to add supplemental logging to tables and hence log-based capture cannot be used.
    • The database does not provide required access to the logs. This may be the case in some cloud environments like Azure SQL.
    • The database runs on an old and unsupported OS but is still in use. For example there are still Ingres databases out there running on VMS…
    • Additional logic is required upon capture, e.g. to support capture out of views as documented in the User Manual.

    Please note that HVR does not support trigger-based capture on all supported source platforms. It is supported on Oracle, SQL Server and Ingres.

    • This topic was modified 1 week, 1 day ago by  hvr_admin.
    • This topic was modified 1 week, 1 day ago by  hvr_admin.
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