[
https://issues.apache.org/jira/browse/FLINK-8790?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16497720#comment-16497720
]
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_r192329562
--- Diff:
flink-state-backends/flink-statebackend-rocksdb/src/main/java/org/apache/flink/contrib/streaming/state/RocksDBKeyedStateBackend.java
---
@@ -795,20 +806,241 @@ private void restoreInstance(
}
/**
- * Recovery from local incremental state.
+ * Recovery from multi incremental states.
+ * In case of rescaling, this method creates a temporary
RocksDB instance for a key-groups shard. All contents
+ * from the temporary instance are copied into the real restore
instance and then the temporary instance is
+ * discarded.
*/
- private void restoreInstance(IncrementalLocalKeyedStateHandle
localKeyedStateHandle) throws Exception {
+ void restoreFromMultiHandles(Collection<KeyedStateHandle>
restoreStateHandles) throws Exception {
+
+ KeyGroupRange targetKeyGroupRange =
stateBackend.keyGroupRange;
+
+ chooseTheBestStateHandleToInit(restoreStateHandles,
targetKeyGroupRange);
+
+ int targetStartKeyGroup =
stateBackend.getKeyGroupRange().getStartKeyGroup();
+ byte[] targetStartKeyGroupPrefixBytes = new
byte[stateBackend.keyGroupPrefixBytes];
--- End diff --
I think this array is not used anymore after we write to it.
> 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.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
