storage: mvccExportToWriter should always return buffered range keys #98289
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In cockroachdb#96691, we changed the return type of mvccExportToWriter such that it now indicates when a CPU limit has been reached. As part of that change, when the CPU limit was reached, we would immedately `return` rather than `break`ing out of the loop. This introduced a bug, since the code after the loop that the `break` was taking us to is important. Namely, we may have previously buffered range keys that we need to write into our response still. By replacing the break with a return, these range keys were lost. The end-user impact of this is that a BACKUP that _ought_ to have included range keys (such as a backup of a table with a rolled back IMPORT) would not include those range keys and thus would end up resurecting deleted keys upon restore. This PR brings back the `break` and adds a test that covers exporting with range keys under CPU exhaustion. This bug only ever existed on master. Informs cockroachdb#97694 Epic: none Release note: None
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stevendanna
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In #96691, we changed the return type of mvccExportToWriter such that it now indicates when a CPU limit has been reached. As part of that change, when the CPU limit was reached, we would immedately
returnrather thanbreaking out of the loop. This introduced a bug, since the code after the loop that thebreakwas taking us to is important. Namely, we may have previously buffered range keys that we need to write into our response still. By replacing the break with a return, these range keys were lost.The end-user impact of this is that a BACKUP that ought to have included range keys (such as a backup of a table with a rolled back IMPORT) would not include those range keys and thus would end up resurecting deleted keys upon restore.
This PR brings back the
breakand adds a test that covers exporting with range keys under CPU exhaustion.This bug only ever existed on master.
Informs #97694
Epic: none
Release note: None