fix(UserMountCache): Set transaction isolation level to REPEATABLE_READ before executing insertIfNotExist without unique index#56929
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…olation Signed-off-by: provokateurin <[email protected]>
…AD before executing insertIfNotExist without unique index Signed-off-by: provokateurin <[email protected]>
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Tested it locally like this:
Without this PR With this PR |
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This can be used as a patch to mitigate the issue, but the real fix is still under development. |
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Closing in favor of #56933 |
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oc_mountsno longer has a unique index since #32877, so theinsertIfNotExistdoes not work properly and depends on consistent reads always getting the same data, which is not possible withREAD_COMMITTED(https://dev.mysql.com/doc/refman/9.2/en/innodb-transaction-isolation-levels.html).The proper fix is to add back the unique index, but with a hash of the mountpoint column (which was too long for the index and was the reason the unique index was removed). This type of workaround is already used for the
share_externaltable.All other
insertIfNotExistin server are fine, because they operate on tables with a unique index.