zhijiangW commented on a change in pull request #11515: [FLINK-16744][task]
implement channel state persistence for unaligned checkpoints
URL: https://github.com/apache/flink/pull/11515#discussion_r405303703
##########
File path:
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/tasks/SubtaskCheckpointCoordinatorImpl.java
##########
@@ -130,95 +130,108 @@ public void checkpointState(
// Step (1): Prepare the checkpoint, allow operators to do some
pre-barrier work.
// The pre-barrier work should be nothing or minimal
in the common case.
- operatorChain.prepareSnapshotPreBarrier(checkpointId);
+
operatorChain.prepareSnapshotPreBarrier(metadata.getCheckpointId());
// Step (2): Send the checkpoint barrier downstream
- operatorChain.broadcastCheckpointBarrier(
- checkpointId,
- checkpointMetaData.getTimestamp(),
- checkpointOptions);
+
operatorChain.broadcastCheckpointBarrier(metadata.getCheckpointId(),
metadata.getTimestamp(), options);
- // Step (3): Take the state snapshot. This should be largely
asynchronous, to not
- // impact progress of the streaming topology
+ // Step (3): Take the state snapshot. This should be largely
asynchronous, to not impact progress of the streaming topology
- long startSyncPartNano = System.nanoTime();
-
- HashMap<OperatorID, OperatorSnapshotFutures>
operatorSnapshotsInProgress = new
HashMap<>(operatorChain.getNumberOfOperators());
- ChannelStateWriteResult channelStateWriteResult =
- checkpointOptions.getCheckpointType() == CHECKPOINT ?
channelStateWriter.getWriteResult(checkpointMetaData.getCheckpointId()) :
- ChannelStateWriteResult.EMPTY;
+ Map<OperatorID, OperatorSnapshotFutures> snapshotFutures = new
HashMap<>(operatorChain.getNumberOfOperators());
try {
- for (StreamOperatorWrapper<?, ?> operatorWrapper :
operatorChain.getAllOperators(true)) {
- operatorSnapshotsInProgress.put(
-
operatorWrapper.getStreamOperator().getOperatorID(),
- buildOperatorSnapshotFutures(
- checkpointMetaData,
- checkpointOptions,
- operatorChain,
-
operatorWrapper.getStreamOperator(),
- isCanceled,
- channelStateWriteResult)
- );
- }
-
checkpointStorage.clearCacheFor(checkpointMetaData.getCheckpointId());
+ takeSnapshotSync(snapshotFutures, metadata, metrics,
options, operatorChain, isCanceled);
+ finishAndReportAsync(snapshotFutures, metadata,
metrics);
+ } catch (Exception ex) {
+ cleanup(snapshotFutures, metadata, metrics, options,
ex);
+ }
+ }
- if (LOG.isDebugEnabled()) {
- LOG.debug("Finished synchronous checkpoints for
checkpoint {} on task {}",
- checkpointMetaData.getCheckpointId(),
taskName);
- }
+ private void cleanup(
+ Map<OperatorID, OperatorSnapshotFutures>
operatorSnapshotsInProgress,
+ CheckpointMetaData metadata,
+ CheckpointMetrics metrics, CheckpointOptions options,
+ Exception ex) throws Exception {
- long startAsyncPartNano = System.nanoTime();
-
-
checkpointMetrics.setSyncDurationMillis((startAsyncPartNano -
startSyncPartNano) / 1_000_000);
-
- // we are transferring ownership over
snapshotInProgressList for cleanup to the thread, active on submit
- executorService.execute(new AsyncCheckpointRunnable(
- operatorSnapshotsInProgress,
- checkpointMetaData,
- checkpointMetrics,
- startAsyncPartNano,
- taskName,
- closeableRegistry,
- env,
- asyncExceptionHandler));
-
- if (LOG.isDebugEnabled()) {
- LOG.debug(
- "{} - finished synchronous part of
checkpoint {}. Alignment duration: {} ms, snapshot duration {} ms",
- taskName,
checkpointMetaData.getCheckpointId(),
-
checkpointMetrics.getAlignmentDurationNanos() / 1_000_000,
-
checkpointMetrics.getSyncDurationMillis());
- }
- } catch (Exception ex) {
- // Cleanup to release resources
- for (OperatorSnapshotFutures operatorSnapshotResult :
operatorSnapshotsInProgress.values()) {
- if (null != operatorSnapshotResult) {
- try {
- operatorSnapshotResult.cancel();
- } catch (Exception e) {
- LOG.warn("Could not properly
cancel an operator snapshot result.", e);
- }
+ for (OperatorSnapshotFutures operatorSnapshotResult :
operatorSnapshotsInProgress.values()) {
+ if (operatorSnapshotResult != null) {
+ try {
+ operatorSnapshotResult.cancel();
+ } catch (Exception e) {
+ LOG.warn("Could not properly cancel an
operator snapshot result.", e);
}
}
+ }
- if (LOG.isDebugEnabled()) {
- LOG.debug(
- "{} - did NOT finish synchronous part
of checkpoint {}. Alignment duration: {} ms, snapshot duration {} ms",
- taskName,
checkpointMetaData.getCheckpointId(),
-
checkpointMetrics.getAlignmentDurationNanos() / 1_000_000,
-
checkpointMetrics.getSyncDurationMillis());
- }
+ if (LOG.isDebugEnabled()) {
+ LOG.debug(
+ "{} - did NOT finish synchronous part of
checkpoint {}. Alignment duration: {} ms, snapshot duration {} ms",
+ taskName, metadata.getCheckpointId(),
+ metrics.getAlignmentDurationNanos() / 1_000_000,
+ metrics.getSyncDurationMillis());
+ }
- if
(checkpointOptions.getCheckpointType().isSynchronous()) {
- // in the case of a synchronous checkpoint, we
always rethrow the exception,
- // so that the task fails.
- // this is because the intention is always to
stop the job after this checkpointing
- // operation, and without the failure, the task
would go back to normal execution.
- throw ex;
- } else {
-
env.declineCheckpoint(checkpointMetaData.getCheckpointId(), ex);
- }
+ if (options.getCheckpointType().isSynchronous()) {
+ // in the case of a synchronous checkpoint, we always
rethrow the exception,
+ // so that the task fails.
+ // this is because the intention is always to stop the
job after this checkpointing
+ // operation, and without the failure, the task would
go back to normal execution.
+ throw ex;
+ } else {
+ env.declineCheckpoint(metadata.getCheckpointId(), ex);
+ }
+ }
+
+ private void finishAndReportAsync(Map<OperatorID,
OperatorSnapshotFutures> snapshotFutures, CheckpointMetaData metadata,
CheckpointMetrics metrics) {
+ // we are transferring ownership over snapshotInProgressList
for cleanup to the thread, active on submit
+ executorService.execute(new AsyncCheckpointRunnable(
+ snapshotFutures,
+ metadata,
+ metrics,
+ System.nanoTime(),
+ taskName,
+ closeableRegistry,
+ env,
+ asyncExceptionHandler));
+ }
+
+ private void takeSnapshotSync(
+ Map<OperatorID, OperatorSnapshotFutures>
operatorSnapshotsInProgress, CheckpointMetaData checkpointMetaData,
Review comment:
it is not suggested putting multiple arguments in one line. split line for
every argument
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