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Posted to commits@flume.apache.org by hs...@apache.org on 2015/04/16 07:55:15 UTC
flume git commit: FLUME-2652. Documented transaction handling
semantics incorrect in developer guide.
Repository: flume
Updated Branches:
refs/heads/trunk b92fbdcf0 -> e1740c056
FLUME-2652. Documented transaction handling semantics incorrect in developer guide.
(Graham Gear via Hari)
Project: http://git-wip-us.apache.org/repos/asf/flume/repo
Commit: http://git-wip-us.apache.org/repos/asf/flume/commit/e1740c05
Tree: http://git-wip-us.apache.org/repos/asf/flume/tree/e1740c05
Diff: http://git-wip-us.apache.org/repos/asf/flume/diff/e1740c05
Branch: refs/heads/trunk
Commit: e1740c0568024570611fd42175f1c782e8093067
Parents: b92fbdc
Author: Hari Shreedharan <hs...@apache.org>
Authored: Wed Apr 15 22:54:05 2015 -0700
Committer: Hari Shreedharan <hs...@apache.org>
Committed: Wed Apr 15 22:54:05 2015 -0700
----------------------------------------------------------------------
flume-ng-doc/sphinx/FlumeDeveloperGuide.rst | 33 +++++++++---------------
1 file changed, 12 insertions(+), 21 deletions(-)
----------------------------------------------------------------------
http://git-wip-us.apache.org/repos/asf/flume/blob/e1740c05/flume-ng-doc/sphinx/FlumeDeveloperGuide.rst
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diff --git a/flume-ng-doc/sphinx/FlumeDeveloperGuide.rst b/flume-ng-doc/sphinx/FlumeDeveloperGuide.rst
index 52a0cf2..b848c0d 100644
--- a/flume-ng-doc/sphinx/FlumeDeveloperGuide.rst
+++ b/flume-ng-doc/sphinx/FlumeDeveloperGuide.rst
@@ -644,9 +644,10 @@ Flume ``Transaction``.
:alt: Transaction sequence diagram
A ``Transaction`` is implemented within a ``Channel`` implementation. Each
-``Source`` and ``Sink`` that is connected to ``Channel`` must obtain a
-``Transaction`` object. The ``Source``\ s actually use a ``ChannelSelector``
-interface to encapsulate the ``Transaction``. The operation to stage an
+``Source`` and ``Sink`` that is connected to a ``Channel`` must obtain a
+``Transaction`` object. The ``Source``\ s use a ``ChannelProcessor``
+to manage the ``Transaction``\ s, the ``Sink``\ s manage them explicitly via
+their configured ``Channel``. The operation to stage an
``Event`` (put it into a ``Channel``) or extract an ``Event`` (take it out of a
``Channel``) is done inside an active ``Transaction``. For example:
@@ -759,8 +760,6 @@ processing its own configuration settings. For example:
if (t instanceof Error) {
throw (Error)t;
}
- } finally {
- txn.close();
}
return status;
}
@@ -770,13 +769,12 @@ Source
~~~~~~
The purpose of a ``Source`` is to receive data from an external client and store
-it into the ``Channel``. A ``Source`` can get an instance of its own
-``ChannelProcessor`` to process an ``Event``. The ``ChannelProcessor`` in turn
-can get an instance of its own ``ChannelSelector`` that's used to get the
-``Channel``\ s associated with the ``Source``, as configured in the Flume
-properties file. A ``Transaction`` can then be retrieved from each associated
-``Channel`` so that the ``Source`` can place ``Event``\ s into the ``Channel``
-reliably, within a ``Transaction``.
+it into the configured ``Channel``\ s. A ``Source`` can get an instance of its own
+``ChannelProcessor`` to process an ``Event``, commited within a ``Channel``
+local transaction, in serial. In the case of an exception, required
+``Channel``\ s will propagate the exception, all ``Channel``\ s will rollback their
+transaction, but events processed previously on other ``Channel``\ s will remain
+committed.
Similar to the ``SinkRunner.PollingRunner`` ``Runnable``, there’s
a ``PollingRunner`` ``Runnable`` that executes on a thread created when the
@@ -826,24 +824,17 @@ mechanism that captures the new data and stores it into the ``Channel``. The
public Status process() throws EventDeliveryException {
Status status = null;
- // Start transaction
- Channel ch = getChannel();
- Transaction txn = ch.getTransaction();
- txn.begin();
try {
- // This try clause includes whatever Channel operations you want to do
+ // This try clause includes whatever Channel/Event operations you want to do
// Receive new data
Event e = getSomeData();
// Store the Event into this Source's associated Channel(s)
- getChannelProcessor().processEvent(e)
+ getChannelProcessor().processEvent(e);
- txn.commit();
status = Status.READY;
} catch (Throwable t) {
- txn.rollback();
-
// Log exception, handle individual exceptions as needed
status = Status.BACKOFF;