markap14 commented on a change in pull request #5042:
URL: https://github.com/apache/nifi/pull/5042#discussion_r625953729
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File path: nifi-api/src/main/java/org/apache/nifi/processor/ProcessSession.java
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@@ -101,6 +102,105 @@
*/
void commit();
+ /**
+ * <p>
+ * Commits the current session ensuring all operations against FlowFiles
+ * within this session are atomically persisted. All FlowFiles operated on
+ * within this session must be accounted for by transfer or removal or the
+ * commit will fail.
+ * </p>
+ *
+ * <p>
+ * Unlike the {@link #commit()} method, the persistence of data to the
repositories is not
+ * guaranteed to have occurred by the time that this method returns.
Therefore, if any follow-on actions
+ * are necessary after the data has been persisted to the repository (for
example, acknowledging receipt from
+ * a source system, removing a source file, etc.) that logic should be
performed only by invoking {@link #commitAsync(Runnable, Consumer)}
+ * and implementing that action in the provided callback.
+ * </p>
+ *
+ * <p>
+ * If the session cannot be committed, an error will be logged and the
session will be rolled back instead.
+ * </p>
+ *
+ * @throws IllegalStateException if called from within a read or write
callback (See {@link #write(FlowFile, StreamCallback)}, {@link #write(FlowFile,
OutputStreamCallback)},
+ * {@link #read(FlowFile, InputStreamCallback)}).
+ *
+ * @throws FlowFileHandlingException if any FlowFile is not appropriately
accounted for by transferring it to a Relationship (see {@link
#transfer(FlowFile, Relationship)})
+ * or removed (see {@link #remove(FlowFile)}.
+ */
+ void commitAsync();
+
+ /**
+ * <p>
+ * Commits the current session ensuring all operations against FlowFiles
+ * within this session are atomically persisted. All FlowFiles operated on
+ * within this session must be accounted for by transfer or removal or the
+ * commit will fail.
+ * </p>
+ *
+ * <p>
+ * Unlike the {@link #commit()} method, the persistence of data to the
repositories is not
Review comment:
So the session can be reused after calling `commitAsync`. What this is
meant to convey is that with `commit()` we typically see something like:
```
getMessageFromSource();
session.commit();
acknowledgeMessageFromSource();
```
And that CANNOT change to:
```
getMessageFromSource();
session.commitAsync();
acknowledgeMessage();
```
Because when `commitAsync()` returns, the data hasn't necessarily been
stored to the repositories and as a result acknowledging the message could
result in data loss.
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