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https://issues.apache.org/jira/browse/FLINK-8790?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16497757#comment-16497757
]
ASF GitHub Bot commented on FLINK-8790:
---------------------------------------
Github user StefanRRichter commented on a diff in the pull request:
https://github.com/apache/flink/pull/5582#discussion_r192337341
--- Diff:
flink-state-backends/flink-statebackend-rocksdb/src/test/java/org/apache/flink/contrib/streaming/state/RocksDBStateBackendTest.java
---
@@ -547,4 +549,30 @@ public boolean accept(File file, String s) {
return true;
}
}
+
+ private static class TestRocksDBStateBackend extends
RocksDBStateBackend {
+
+ public TestRocksDBStateBackend(AbstractStateBackend
checkpointStreamBackend, boolean enableIncrementalCheckpointing) {
+ super(checkpointStreamBackend,
enableIncrementalCheckpointing);
+ }
+
+ @Override
+ public <K> AbstractKeyedStateBackend<K> createKeyedStateBackend(
+ Environment env,
+ JobID jobID,
+ String operatorIdentifier,
+ TypeSerializer<K> keySerializer,
+ int numberOfKeyGroups,
+ KeyGroupRange keyGroupRange,
+ TaskKvStateRegistry kvStateRegistry) throws IOException
{
+
+ AbstractKeyedStateBackend<K> keyedStateBackend =
super.createKeyedStateBackend(
+ env, jobID, operatorIdentifier, keySerializer,
numberOfKeyGroups, keyGroupRange, kvStateRegistry);
+
+ // We ignore the range deletions on production, but
when we are running the tests we shouldn't ignore it.
--- End diff --
As I see, this is only happening in the case where there is only one handle
and we are only interested in a subset of the key-groups. Unfortunately, that
should be the common case of scaling out. I am wondering if we should not
prefer to apply normal deletes over range delete, because what will happen if
we take again a snapshot from a database that was using range deletes? Will the
keys all be gone in cases of full and incremental snapshots? If the performance
of normal deletes is not terrible, that might be cleaner for as long as range
deletes are not working properly or have potential negative side-effects. What
is your opinion about this?
> Improve performance for recovery from incremental checkpoint
> ------------------------------------------------------------
>
> Key: FLINK-8790
> URL: https://issues.apache.org/jira/browse/FLINK-8790
> Project: Flink
> Issue Type: Improvement
> Components: State Backends, Checkpointing
> Affects Versions: 1.5.0
> Reporter: Sihua Zhou
> Assignee: Sihua Zhou
> Priority: Major
> Fix For: 1.6.0
>
>
> When there are multi state handle to be restored, we can improve the
> performance as follow:
> 1. Choose the best state handle to init the target db
> 2. Use the other state handles to create temp db, and clip the db according
> to the target key group range (via rocksdb.deleteRange()), this can help use
> get rid of the `key group check` in
> `data insertion loop` and also help us get rid of traversing the useless
> record.
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