Zakelly commented on a change in pull request #16153:
URL: https://github.com/apache/flink/pull/16153#discussion_r654810546
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File path:
flink-streaming-java/src/main/java/org/apache/flink/streaming/api/environment/StreamExecutionEnvironment.java
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@@ -607,6 +612,53 @@ public StateBackend getStateBackend() {
return defaultStateBackend;
}
+ /**
+ * Enable the change log for current state backend. this changelog allows
operators to persist
+ * state changes in a very fine-grained manner, as described below:
+ *
+ * <p>Stateful operators write the state changes to that log (logging the
state), in addition to
+ * applying them to the state tables in RocksDB or the in-mem Hashtable.
+ *
+ * <p>An operator can acknowledge a checkpoint as soon as the changes in
the log have reached
+ * the durable checkpoint storage.
+ *
+ * <p>The state tables are persisted periodically, independent of the
checkpoints. We call this
+ * the materialization of the state on the checkpoint storage.
+ *
+ * <p>Once the state is materialized on checkpoint storage, the state
changelog can be truncated
+ * to the corresponding point.
+ *
+ * <p>It establish a way to drastically reduce the checkpoint interval for
streaming
+ * applications across state backends. For more details please check the
FLIP-158.
+ *
+ * <p>If this method is not called explicitly, it means no preference for
enabling the change
+ * log. Configs for change log enabling will override in different config
levels
+ * (job/local/cluster).
+ *
+ * @param enabled true if enable the change log for state backend
explicitly, otherwise disable
+ * the change log.
+ * @return This StreamExecutionEnvironment itself, to allow chaining of
function calls.
+ * @see #isChangelogStateBackendEnabled()
+ */
+ @PublicEvolving
+ public StreamExecutionEnvironment enableChangelogStateBackend(boolean
enabled) {
Review comment:
Yes, I added some description. 🙂
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