For reasons, I'm trying to work out just how much undo any single query generates.
I know how to get this in Oracle DB, but don't know if it's possible in MariaDB/MySQL.
Is it possible, and how?
MariaDB 10.6.
1 Answer
Your Question is rather general., So here is a rather general Answer: A copy of each modified row is saved for Undo.
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It's general yes, but it is a general question. Given any query that I can run, is it possible to identify the volume of undo that it has generated? Commented Jan 5 at 10:44
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@PhilSumner - I don't think there is any metric, at least not any reliable metric. For example, watching disk space is unreliable because each extra row copy will usually fill in free space; only occasionally will it do a block split, thereby consuming 16KB. Commented Jan 6 at 1:50