Allow kPointInTimeRecovery to recover until corrupted write batch #12840
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@jowlyzhang I think the call to HandleWriteBatchTimestampSizeDifference() above probably needs similar handling since it could iterate through a write batch.
Thanks for the fix and thanks for this note. A quick question, my understanding is kPointInTimeRecovery tries to recover a prefix of the wal records. With this type of handling, if the mal formatted WriteBatch is at the tail of the wal records, I think it's helpful to proceed like this to allow open and still be at point in time. But if the mal formatted WriteBatch is in the middle of the wal records, if we continue like this to recover the latter good WriteBatches, would it contradict what point in time means? |
reporter.Corruption() will set the status and the while loop checks status.ok() and should exit after a corruption is set. |
| status = WriteBatchInternal::UpdateProtectionInfo(batch_to_use, | ||
| /*bytes_per_key=*/8); | ||
| TEST_SYNC_POINT_CALLBACK( | ||
| "DBImpl::RecoverLogFiles:UpdateProtectionInfo::status", &status); | ||
| if (!status.ok()) { | ||
| if (status.IsCorruption()) { | ||
| reporter.Corruption(record.size(), status); | ||
| continue; | ||
| } else { | ||
| // Fail DB open for non-corruption failure. | ||
| return status; | ||
| } | ||
| } |
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I stared at this for a while without understanding it. Maybe some comment will help: "UpdateProtectionInfo() examines the contents of the WriteBatch to calculate KV checksums. Any corruptions in the WriteBatch will be surfaced during this processing. Corruptions here indicate the WriteBatch we read was corrupted, so we follow the usual convention for reporting a Corruption in the input data. For cases where KV checksum detects a corruption introduced by the recovery process, see VerifyChecksum() below"
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I don't know if this is too complicated, but you might want to VerifyChecksum() even after detecting a corruption here to check whether the write batch became ill-formed by recovery corruption (and in that case do not use reporter.Corruption()).
Summary: instead of failing DB open, when we see a corrupted write batch, we should follow the convention to report corruption and decide on what to do based on wal recovery mode.
Test plan: added a new unit test.