KAFKA-15048: Improve handling of unexpected quorum controller errors #13799
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When the active quorum controller encounters an "unexpected" error, such as a NullPointerException, it currently resigns its leadership. This PR fixes it so that in addition to doing that, it also increments the metadata error count metric. This will allow us to better track down these errors. This PR also fixes a minor bug where performing read operations on a standby controller would result in an unexpected RuntimeException. The bug happened because the standby controller does not take in-memory snapshots, and read operations were attempting to read from the epoch of the latest committed offset. The fix is for the standby controller to simply read the latest value of each data structure. This is always safe, because standby controllers don't contain uncommitted data. Also, fix a bug where listPartitionReassignments was reading the latest data, rather than data from the last committed offset.
dengziming
approved these changes
Jun 2, 2023
| // Standby controllers never have uncommitted data in memory. Therefore, we return | ||
| // Long.MAX_VALUE, a special value which means "always read the latest from every | ||
| // data structure." | ||
| return Long.MAX_VALUE; |
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How about using SnapshotRegistry.LATEST_EPOCH
3 tasks
mumrah
reviewed
Jun 2, 2023
| * @param latestController The current controller. | ||
| * @return The new NotControllerException. | ||
| */ | ||
| public static NotControllerException newPreMigrationException(OptionalInt latestController) { |
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I'm guessing the argument here is the controller ID? Can you rename it to reflect that? (same for other methods in this class)
| @@ -2024,13 +2029,8 @@ public CompletableFuture<ElectLeadersResponseData> electLeaders( | |||
| public CompletableFuture<FinalizedControllerFeatures> finalizedFeatures( | |||
| ControllerRequestContext context | |||
| ) { | |||
| // It's possible that we call ApiVersionRequest before consuming the log since ApiVersionRequest is sent when | |||
| // initialize NetworkClient, we should not return an error since it would stop the NetworkClient from working correctly. | |||
| if (lastCommittedOffset == -1) { | |||
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Was this a bug previously? If another node sent an ApiVersionRequest prior to loading the log, we would have not returned any MetadataVersion (whereas with this patch, we would).
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yes, this was previously a bug.
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When the active quorum controller encounters an "unexpected" error, such as a NullPointerException, it currently resigns its leadership. This PR fixes it so that in addition to doing that, it also increments the metadata error count metric. This will allow us to better track down these errors.
This PR also fixes a minor bug where performing read operations on a standby controller would result in an unexpected RuntimeException. The bug happened because the standby controller does not take in-memory snapshots, and read operations were attempting to read from the epoch of the latest committed offset. The fix is for the standby controller to simply read the latest value of each data structure. This is always safe, because standby controllers don't contain uncommitted data.
Also, fix a bug where listPartitionReassignments was reading the latest data, rather than data from the last committed offset.