fix(db): Do not log transacted reads as dirty read #42929
Merged
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Summary
Starting a transaction makes
\Doctrine\DBAL\Connections\PrimaryReadReplicaConnection::beginTransaction
switch over to the primary. That means reading implicitly becomes safe because we are not connected to an outdated replica.Reads are only dirty if data has been written to the primary within the same request and we are now reading from a replica.
How to test
tail -f nextcloud.log
master: lots of logs for dirty reads. On closer inspection the majority is written as dirty not because there was a preceding write but because there is an ongoing transaction.
here: only a few logs when we indeed write+read without a transaction within the same request.
Checklist