Flume
  1. Flume
  2. FLUME-1030

Retry logic for failover sink processor to handle downstream exceptions in a predictable manner.

    Details

    • Type: Improvement Improvement
    • Status: Resolved
    • Priority: Major Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: v1.2.0
    • Component/s: Sinks+Sources
    • Labels:
      None

      Description

      One may want to refer to FLUME-984 for some history of this.

      As it stands, a sink can have several outcomes:

      • OK - succesfully transferred some data
      • TRY_LATER - no data to transfer
      • throw EventDeliveryException - Give the sink a short breather to recover, then try again
      • throw anything else - get logged and more or less ignored

      I don't think the last choice in particular is a good idea as it encourages throwing Sink specific exceptions. Further, there is no distinction between temporary disconnectivity(e.g. HBase timed out because of a compaction or something), and more permanent problems(e.g. cannot write to a file).

      One solution to this is to add a second type of exception that delivery mechanisms can throw, ConnectivityException/FatalException or something similar. For the purposes of any failover/load balancing mechanism this would signal that a component is out of order for a more significant amount of time and thus constant polling should be stopped(perhaps retry it every 5 minutes instead, or have an exponentially increasing retry time).

      If adding another exception is not deemed acceptable, there is always the possibility of expecting SinkProcessors to figure out if a sink is dead... E.g. counting sequential failures, though I do not think this is ideal. I would prefer to see a clear contract defined by SinkRunner that well behaved sinks could adhere to and get the benefits of graceful temporary/longterm failure from.

      If someone has other suggestions for distinguishing between temporary and longer term failure please let me know. As it stands, components that are unresponsive can and do get called constantly, and some components trigger retries and can actually block a SinkRunner thread for a fair while.

      1. FLUME-1030.4.patch
        9 kB
        Juhani Connolly
      2. FLUME-1030.3.patch
        7 kB
        Juhani Connolly
      3. FLUME-1030.2.patch
        7 kB
        Juhani Connolly

        Activity

        Hide
        Hudson added a comment -

        Integrated in flume-trunk #141 (See https://builds.apache.org/job/flume-trunk/141/)
        FLUME-1030. Retry mechanism for failover sink processor.

        (Juhani Connolly via Arvind Prabhakar) (Revision 1304474)

        Result = SUCCESS
        arvind : http://svn.apache.org/viewvc/?view=rev&rev=1304474
        Files :

        • /incubator/flume/trunk/flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java
        • /incubator/flume/trunk/flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java
        Show
        Hudson added a comment - Integrated in flume-trunk #141 (See https://builds.apache.org/job/flume-trunk/141/ ) FLUME-1030 . Retry mechanism for failover sink processor. (Juhani Connolly via Arvind Prabhakar) (Revision 1304474) Result = SUCCESS arvind : http://svn.apache.org/viewvc/?view=rev&rev=1304474 Files : /incubator/flume/trunk/flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java /incubator/flume/trunk/flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java
        Arvind Prabhakar made changes -
        Status Patch Available [ 10002 ] Resolved [ 5 ]
        Resolution Fixed [ 1 ]
        Hide
        Arvind Prabhakar added a comment -

        Patch committed. Thanks Juhani!

        Show
        Arvind Prabhakar added a comment - Patch committed. Thanks Juhani!
        Arvind Prabhakar made changes -
        Summary Distinguish between temporary and longterm failure to avoid repeated beating on dead components Retry logic for failover sink processor to handle downstream exceptions in a predictable manner.
        Hide
        Arvind Prabhakar added a comment -

        Updating the title of the issue to match what has been checked in.

        Show
        Arvind Prabhakar added a comment - Updating the title of the issue to match what has been checked in.
        Hide
        jiraposter@reviews.apache.org added a comment -

        -----------------------------------------------------------
        This is an automatically generated e-mail. To reply, visit:
        https://reviews.apache.org/r/4445/#review6289
        -----------------------------------------------------------

        Ship it!

        +1

        • Arvind

        On 2012-03-23 05:28:45, Juhani Connolly wrote:

        -----------------------------------------------------------

        This is an automatically generated e-mail. To reply, visit:

        https://reviews.apache.org/r/4445/

        -----------------------------------------------------------

        (Updated 2012-03-23 05:28:45)

        Review request for Flume.

        Summary

        -------

        As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions.

        Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?)

        This addresses bug FLUME-1030.

        https://issues.apache.org/jira/browse/FLUME-1030

        Diffs

        -----

        flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121

        flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57

        Diff: https://reviews.apache.org/r/4445/diff

        Testing

        -------

        Modified the test for the new functionality, new test passes

        No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow

        Thanks,

        Juhani

        Show
        jiraposter@reviews.apache.org added a comment - ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/4445/#review6289 ----------------------------------------------------------- Ship it! +1 Arvind On 2012-03-23 05:28:45, Juhani Connolly wrote: ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/4445/ ----------------------------------------------------------- (Updated 2012-03-23 05:28:45) Review request for Flume. Summary ------- As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions. Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?) This addresses bug FLUME-1030 . https://issues.apache.org/jira/browse/FLUME-1030 Diffs ----- flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121 flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57 Diff: https://reviews.apache.org/r/4445/diff Testing ------- Modified the test for the new functionality, new test passes No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow Thanks, Juhani
        Juhani Connolly made changes -
        Attachment FLUME-1030.4.patch [ 12519588 ]
        Hide
        jiraposter@reviews.apache.org added a comment -

        -----------------------------------------------------------
        This is an automatically generated e-mail. To reply, visit:
        https://reviews.apache.org/r/4445/
        -----------------------------------------------------------

        (Updated 2012-03-23 05:28:45.159536)

        Review request for Flume.

        Changes
        -------

        Fixed suggested changes and also added some javadoc describing functioning and new config setting.

        Summary
        -------

        As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions.
        Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?)

        This addresses bug FLUME-1030.
        https://issues.apache.org/jira/browse/FLUME-1030

        Diffs (updated)


        flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121
        flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57

        Diff: https://reviews.apache.org/r/4445/diff

        Testing
        -------

        Modified the test for the new functionality, new test passes

        No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow

        Thanks,

        Juhani

        Show
        jiraposter@reviews.apache.org added a comment - ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/4445/ ----------------------------------------------------------- (Updated 2012-03-23 05:28:45.159536) Review request for Flume. Changes ------- Fixed suggested changes and also added some javadoc describing functioning and new config setting. Summary ------- As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions. Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?) This addresses bug FLUME-1030 . https://issues.apache.org/jira/browse/FLUME-1030 Diffs (updated) flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121 flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57 Diff: https://reviews.apache.org/r/4445/diff Testing ------- Modified the test for the new functionality, new test passes No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow Thanks, Juhani
        Hide
        jiraposter@reviews.apache.org added a comment -

        On 2012-03-23 03:48:14, Arvind Prabhakar wrote:

        > flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java, line 193

        > <https://reviews.apache.org/r/4445/diff/2/?file=94789#file94789line193>

        >

        > Log the exception.

        Did this, changed EventDeliveryException->Exception

        On 2012-03-23 03:48:14, Arvind Prabhakar wrote:

        > flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java, line 182

        > <https://reviews.apache.org/r/4445/diff/2/?file=94789#file94789line182>

        >

        > It will be good to log this exception so we have a trace of the failures that are happening.

        Was just using it to guard against null and number exceptions at the same time. Separated it out and checked for null. Logging the Number exception because it's probably a typo in config

        On 2012-03-23 03:48:14, Arvind Prabhakar wrote:

        > flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java, line 138

        > <https://reviews.apache.org/r/4445/diff/2/?file=94789#file94789line138>

        >

        > This seems like a typo. Perhaps you want to do something like

        >

        > maxPenalty = context.getInteger(CONF_KEY_MAX_PENALTY, DEFAULT_MAX_PENALTY);

        >

        >

        Yes. Probably not enough sleep. I checked in the debugger that things were getting correctly set/read now

        On 2012-03-23 03:48:14, Arvind Prabhakar wrote:

        > flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java, lines 94-95

        > <https://reviews.apache.org/r/4445/diff/2/?file=94789#file94789line94>

        >

        > The max penalty calculated during configure of the sink processor should be applied here to enforce the ceiling.

        Done

        On 2012-03-23 03:48:14, Juhani Connolly wrote:

        > Rest of the changes look good to me.

        Wow, what a mess. Must've been tired or something.

        The name of the max limit also had a period on its end that I removed.

        • Juhani

        -----------------------------------------------------------
        This is an automatically generated e-mail. To reply, visit:
        https://reviews.apache.org/r/4445/#review6265
        -----------------------------------------------------------

        On 2012-03-23 02:41:03, Juhani Connolly wrote:

        -----------------------------------------------------------

        This is an automatically generated e-mail. To reply, visit:

        https://reviews.apache.org/r/4445/

        -----------------------------------------------------------

        (Updated 2012-03-23 02:41:03)

        Review request for Flume.

        Summary

        -------

        As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions.

        Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?)

        This addresses bug FLUME-1030.

        https://issues.apache.org/jira/browse/FLUME-1030

        Diffs

        -----

        flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121

        flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57

        Diff: https://reviews.apache.org/r/4445/diff

        Testing

        -------

        Modified the test for the new functionality, new test passes

        No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow

        Thanks,

        Juhani

        Show
        jiraposter@reviews.apache.org added a comment - On 2012-03-23 03:48:14, Arvind Prabhakar wrote: > flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java, line 193 > < https://reviews.apache.org/r/4445/diff/2/?file=94789#file94789line193 > > > Log the exception. Did this, changed EventDeliveryException->Exception On 2012-03-23 03:48:14, Arvind Prabhakar wrote: > flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java, line 182 > < https://reviews.apache.org/r/4445/diff/2/?file=94789#file94789line182 > > > It will be good to log this exception so we have a trace of the failures that are happening. Was just using it to guard against null and number exceptions at the same time. Separated it out and checked for null. Logging the Number exception because it's probably a typo in config On 2012-03-23 03:48:14, Arvind Prabhakar wrote: > flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java, line 138 > < https://reviews.apache.org/r/4445/diff/2/?file=94789#file94789line138 > > > This seems like a typo. Perhaps you want to do something like > > maxPenalty = context.getInteger(CONF_KEY_MAX_PENALTY, DEFAULT_MAX_PENALTY); > > Yes. Probably not enough sleep. I checked in the debugger that things were getting correctly set/read now On 2012-03-23 03:48:14, Arvind Prabhakar wrote: > flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java, lines 94-95 > < https://reviews.apache.org/r/4445/diff/2/?file=94789#file94789line94 > > > The max penalty calculated during configure of the sink processor should be applied here to enforce the ceiling. Done On 2012-03-23 03:48:14, Juhani Connolly wrote: > Rest of the changes look good to me. Wow, what a mess. Must've been tired or something. The name of the max limit also had a period on its end that I removed. Juhani ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/4445/#review6265 ----------------------------------------------------------- On 2012-03-23 02:41:03, Juhani Connolly wrote: ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/4445/ ----------------------------------------------------------- (Updated 2012-03-23 02:41:03) Review request for Flume. Summary ------- As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions. Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?) This addresses bug FLUME-1030 . https://issues.apache.org/jira/browse/FLUME-1030 Diffs ----- flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121 flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57 Diff: https://reviews.apache.org/r/4445/diff Testing ------- Modified the test for the new functionality, new test passes No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow Thanks, Juhani
        Hide
        jiraposter@reviews.apache.org added a comment -

        -----------------------------------------------------------
        This is an automatically generated e-mail. To reply, visit:
        https://reviews.apache.org/r/4445/#review6265
        -----------------------------------------------------------

        Thanks for making the changes Juhani. Some feedback follows.

        flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java
        <https://reviews.apache.org/r/4445/#comment13571>

        The max penalty calculated during configure of the sink processor should be applied here to enforce the ceiling.

        flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java
        <https://reviews.apache.org/r/4445/#comment13570>

        This seems like a typo. Perhaps you want to do something like

        maxPenalty = context.getInteger(CONF_KEY_MAX_PENALTY, DEFAULT_MAX_PENALTY);

        flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java
        <https://reviews.apache.org/r/4445/#comment13568>

        It will be good to log this exception so we have a trace of the failures that are happening.

        flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java
        <https://reviews.apache.org/r/4445/#comment13569>

        Log the exception.

        Rest of the changes look good to me.

        • Arvind

        On 2012-03-23 02:41:03, Juhani Connolly wrote:

        -----------------------------------------------------------

        This is an automatically generated e-mail. To reply, visit:

        https://reviews.apache.org/r/4445/

        -----------------------------------------------------------

        (Updated 2012-03-23 02:41:03)

        Review request for Flume.

        Summary

        -------

        As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions.

        Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?)

        This addresses bug FLUME-1030.

        https://issues.apache.org/jira/browse/FLUME-1030

        Diffs

        -----

        flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121

        flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57

        Diff: https://reviews.apache.org/r/4445/diff

        Testing

        -------

        Modified the test for the new functionality, new test passes

        No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow

        Thanks,

        Juhani

        Show
        jiraposter@reviews.apache.org added a comment - ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/4445/#review6265 ----------------------------------------------------------- Thanks for making the changes Juhani. Some feedback follows. flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java < https://reviews.apache.org/r/4445/#comment13571 > The max penalty calculated during configure of the sink processor should be applied here to enforce the ceiling. flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java < https://reviews.apache.org/r/4445/#comment13570 > This seems like a typo. Perhaps you want to do something like maxPenalty = context.getInteger(CONF_KEY_MAX_PENALTY, DEFAULT_MAX_PENALTY); flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java < https://reviews.apache.org/r/4445/#comment13568 > It will be good to log this exception so we have a trace of the failures that are happening. flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java < https://reviews.apache.org/r/4445/#comment13569 > Log the exception. Rest of the changes look good to me. Arvind On 2012-03-23 02:41:03, Juhani Connolly wrote: ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/4445/ ----------------------------------------------------------- (Updated 2012-03-23 02:41:03) Review request for Flume. Summary ------- As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions. Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?) This addresses bug FLUME-1030 . https://issues.apache.org/jira/browse/FLUME-1030 Diffs ----- flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121 flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57 Diff: https://reviews.apache.org/r/4445/diff Testing ------- Modified the test for the new functionality, new test passes No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow Thanks, Juhani
        Juhani Connolly made changes -
        Attachment FLUME-1030.3.patch [ 12519574 ]
        Juhani Connolly made changes -
        Attachment FLUME-1030.3.patch [ 12519575 ]
        Juhani Connolly made changes -
        Attachment FLUME-1030.3.patch [ 12519574 ]
        Hide
        jiraposter@reviews.apache.org added a comment -

        -----------------------------------------------------------
        This is an automatically generated e-mail. To reply, visit:
        https://reviews.apache.org/r/4445/
        -----------------------------------------------------------

        (Updated 2012-03-23 02:41:03.472482)

        Review request for Flume.

        Changes
        -------

        Wasn't applying the penalty limit, fixed now

        Summary
        -------

        As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions.
        Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?)

        This addresses bug FLUME-1030.
        https://issues.apache.org/jira/browse/FLUME-1030

        Diffs (updated)


        flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121
        flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57

        Diff: https://reviews.apache.org/r/4445/diff

        Testing
        -------

        Modified the test for the new functionality, new test passes

        No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow

        Thanks,

        Juhani

        Show
        jiraposter@reviews.apache.org added a comment - ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/4445/ ----------------------------------------------------------- (Updated 2012-03-23 02:41:03.472482) Review request for Flume. Changes ------- Wasn't applying the penalty limit, fixed now Summary ------- As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions. Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?) This addresses bug FLUME-1030 . https://issues.apache.org/jira/browse/FLUME-1030 Diffs (updated) flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121 flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57 Diff: https://reviews.apache.org/r/4445/diff Testing ------- Modified the test for the new functionality, new test passes No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow Thanks, Juhani
        Juhani Connolly made changes -
        Status Open [ 1 ] Patch Available [ 10002 ]
        Juhani Connolly made changes -
        Attachment FLUME-1030.2.patch [ 12519572 ]
        Hide
        Juhani Connolly added a comment -

        Adding the updated patch from review

        Show
        Juhani Connolly added a comment - Adding the updated patch from review
        Hide
        jiraposter@reviews.apache.org added a comment -

        -----------------------------------------------------------
        This is an automatically generated e-mail. To reply, visit:
        https://reviews.apache.org/r/4445/
        -----------------------------------------------------------

        (Updated 2012-03-23 01:48:59.198037)

        Review request for Flume.

        Changes
        -------

        Updated with the suggested changes.

        All tests pass

        Summary
        -------

        As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions.
        Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?)

        This addresses bug FLUME-1030.
        https://issues.apache.org/jira/browse/FLUME-1030

        Diffs (updated)


        flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121
        flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57

        Diff: https://reviews.apache.org/r/4445/diff

        Testing
        -------

        Modified the test for the new functionality, new test passes

        No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow

        Thanks,

        Juhani

        Show
        jiraposter@reviews.apache.org added a comment - ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/4445/ ----------------------------------------------------------- (Updated 2012-03-23 01:48:59.198037) Review request for Flume. Changes ------- Updated with the suggested changes. All tests pass Summary ------- As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions. Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?) This addresses bug FLUME-1030 . https://issues.apache.org/jira/browse/FLUME-1030 Diffs (updated) flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121 flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57 Diff: https://reviews.apache.org/r/4445/diff Testing ------- Modified the test for the new functionality, new test passes No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow Thanks, Juhani
        Hide
        jiraposter@reviews.apache.org added a comment -

        On 2012-03-22 17:07:01, Arvind Prabhakar wrote:

        > Thanks for the patch Juhani. I was able to run the tests successfully. I have some minor feedback below for your consideration.

        thanks for running the tests. back to normal on my end too

        On 2012-03-22 17:07:01, Arvind Prabhakar wrote:

        > flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java, line 90

        > <https://reviews.apache.org/r/4445/diff/1/?file=94575#file94575line90>

        >

        > It will be good to cap this penalty amount to a predefined/configured ceiling value.

        Added a config variable

        On 2012-03-22 17:07:01, Arvind Prabhakar wrote:

        > flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java, lines 120-121

        > <https://reviews.apache.org/r/4445/diff/1/?file=94575#file94575line120>

        >

        > There is one slight issue here though - which is if the channel is empty, the sink being attempted to recover will likely return BACKOFF, implying that the sink is normal and has recovered.

        >

        > A minor nit: it will be nice if the process invocation on the failed sink was from within the process() that calls the active Sink. That way the logic stays in one place.

        I got rid of the queue subclass and put the code in process... Though I'm not sure if that is the easiest way for the human brain to parse it...

        I also changed things so that a backoff results in being returned to the failed list without a penalty

        • Juhani

        -----------------------------------------------------------
        This is an automatically generated e-mail. To reply, visit:
        https://reviews.apache.org/r/4445/#review6231
        -----------------------------------------------------------

        On 2012-03-22 08:23:00, Juhani Connolly wrote:

        -----------------------------------------------------------

        This is an automatically generated e-mail. To reply, visit:

        https://reviews.apache.org/r/4445/

        -----------------------------------------------------------

        (Updated 2012-03-22 08:23:00)

        Review request for Flume.

        Summary

        -------

        As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions.

        Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?)

        This addresses bug FLUME-1030.

        https://issues.apache.org/jira/browse/FLUME-1030

        Diffs

        -----

        flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121

        flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57

        Diff: https://reviews.apache.org/r/4445/diff

        Testing

        -------

        Modified the test for the new functionality, new test passes

        No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow

        Thanks,

        Juhani

        Show
        jiraposter@reviews.apache.org added a comment - On 2012-03-22 17:07:01, Arvind Prabhakar wrote: > Thanks for the patch Juhani. I was able to run the tests successfully. I have some minor feedback below for your consideration. thanks for running the tests. back to normal on my end too On 2012-03-22 17:07:01, Arvind Prabhakar wrote: > flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java, line 90 > < https://reviews.apache.org/r/4445/diff/1/?file=94575#file94575line90 > > > It will be good to cap this penalty amount to a predefined/configured ceiling value. Added a config variable On 2012-03-22 17:07:01, Arvind Prabhakar wrote: > flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java, lines 120-121 > < https://reviews.apache.org/r/4445/diff/1/?file=94575#file94575line120 > > > There is one slight issue here though - which is if the channel is empty, the sink being attempted to recover will likely return BACKOFF, implying that the sink is normal and has recovered. > > A minor nit: it will be nice if the process invocation on the failed sink was from within the process() that calls the active Sink. That way the logic stays in one place. I got rid of the queue subclass and put the code in process... Though I'm not sure if that is the easiest way for the human brain to parse it... I also changed things so that a backoff results in being returned to the failed list without a penalty Juhani ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/4445/#review6231 ----------------------------------------------------------- On 2012-03-22 08:23:00, Juhani Connolly wrote: ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/4445/ ----------------------------------------------------------- (Updated 2012-03-22 08:23:00) Review request for Flume. Summary ------- As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions. Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?) This addresses bug FLUME-1030 . https://issues.apache.org/jira/browse/FLUME-1030 Diffs ----- flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121 flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57 Diff: https://reviews.apache.org/r/4445/diff Testing ------- Modified the test for the new functionality, new test passes No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow Thanks, Juhani
        Hide
        jiraposter@reviews.apache.org added a comment -

        -----------------------------------------------------------
        This is an automatically generated e-mail. To reply, visit:
        https://reviews.apache.org/r/4445/#review6231
        -----------------------------------------------------------

        Thanks for the patch Juhani. I was able to run the tests successfully. I have some minor feedback below for your consideration.

        flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java
        <https://reviews.apache.org/r/4445/#comment13432>

        It will be good to cap this penalty amount to a predefined/configured ceiling value.

        flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java
        <https://reviews.apache.org/r/4445/#comment13438>

        There is one slight issue here though - which is if the channel is empty, the sink being attempted to recover will likely return BACKOFF, implying that the sink is normal and has recovered.

        A minor nit: it will be nice if the process invocation on the failed sink was from within the process() that calls the active Sink. That way the logic stays in one place.

        • Arvind

        On 2012-03-22 08:23:00, Juhani Connolly wrote:

        -----------------------------------------------------------

        This is an automatically generated e-mail. To reply, visit:

        https://reviews.apache.org/r/4445/

        -----------------------------------------------------------

        (Updated 2012-03-22 08:23:00)

        Review request for Flume.

        Summary

        -------

        As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions.

        Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?)

        This addresses bug FLUME-1030.

        https://issues.apache.org/jira/browse/FLUME-1030

        Diffs

        -----

        flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121

        flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57

        Diff: https://reviews.apache.org/r/4445/diff

        Testing

        -------

        Modified the test for the new functionality, new test passes

        No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow

        Thanks,

        Juhani

        Show
        jiraposter@reviews.apache.org added a comment - ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/4445/#review6231 ----------------------------------------------------------- Thanks for the patch Juhani. I was able to run the tests successfully. I have some minor feedback below for your consideration. flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java < https://reviews.apache.org/r/4445/#comment13432 > It will be good to cap this penalty amount to a predefined/configured ceiling value. flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java < https://reviews.apache.org/r/4445/#comment13438 > There is one slight issue here though - which is if the channel is empty, the sink being attempted to recover will likely return BACKOFF, implying that the sink is normal and has recovered. A minor nit: it will be nice if the process invocation on the failed sink was from within the process() that calls the active Sink. That way the logic stays in one place. Arvind On 2012-03-22 08:23:00, Juhani Connolly wrote: ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/4445/ ----------------------------------------------------------- (Updated 2012-03-22 08:23:00) Review request for Flume. Summary ------- As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions. Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?) This addresses bug FLUME-1030 . https://issues.apache.org/jira/browse/FLUME-1030 Diffs ----- flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121 flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57 Diff: https://reviews.apache.org/r/4445/diff Testing ------- Modified the test for the new functionality, new test passes No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow Thanks, Juhani
        Hide
        jiraposter@reviews.apache.org added a comment -

        -----------------------------------------------------------
        This is an automatically generated e-mail. To reply, visit:
        https://reviews.apache.org/r/4445/
        -----------------------------------------------------------

        Review request for Flume.

        Summary
        -------

        As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions.
        Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?)

        This addresses bug FLUME-1030.
        https://issues.apache.org/jira/browse/FLUME-1030

        Diffs


        flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121
        flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57

        Diff: https://reviews.apache.org/r/4445/diff

        Testing
        -------

        Modified the test for the new functionality, new test passes

        No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow

        Thanks,

        Juhani

        Show
        jiraposter@reviews.apache.org added a comment - ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/4445/ ----------------------------------------------------------- Review request for Flume. Summary ------- As discussed in the JIRA item, I modified FailoverSink to deal with all exceptions. Now a sink that fails will be put onto a failed links queue, from which a recovery will be attempted after a timeout. Each sequential failure the timeout will increase. I am open to other methods of increasing the timeout(maybe add on a ceiling?) This addresses bug FLUME-1030 . https://issues.apache.org/jira/browse/FLUME-1030 Diffs flume-ng-core/src/test/java/org/apache/flume/sink/TestFailoverSinkProcessor.java 195c121 flume-ng-core/src/main/java/org/apache/flume/sink/FailoverSinkProcessor.java 7eada57 Diff: https://reviews.apache.org/r/4445/diff Testing ------- Modified the test for the new functionality, new test passes No other tests should be affected, but my environment was having some weird problems. I'll look into them tomorrow, just leaving this up so people can have a browse and will confirm tests passing tomorrow Thanks, Juhani
        Hide
        Arvind Prabhakar added a comment -

        One way of dealing with this with multiple sinks is to just put sinks that had exceptions on a priority list with the time to reactivate them, passing events to other sinks until "recovery". Since balancing/failover processors have other alternatives, they can just get another sink to deal with it, using longer timeouts than would be applied by backoff. Would this be a better way to deal with balancing/failover?

        Yes - that makes sense to me and will be a deterministic solution regardless of the underlying problem.

        This has made me curious of exactly what the intended use of EventDeliveryException is now. The distinction between it and other Exceptions is pretty blurred now that we just elect to log everything

        As the name suggests - it indicates a failure to relay the event to it's next hop destination. Ideally it should have the causal exception buried within itself that gives more of a clue as to what may have gone wrong. Eventually, if we see a pattern of failures emerging out of this, we should modify the component that is responsible to deal with it rather than adding that logic to the exception handling code.

        Show
        Arvind Prabhakar added a comment - One way of dealing with this with multiple sinks is to just put sinks that had exceptions on a priority list with the time to reactivate them, passing events to other sinks until "recovery". Since balancing/failover processors have other alternatives, they can just get another sink to deal with it, using longer timeouts than would be applied by backoff. Would this be a better way to deal with balancing/failover? Yes - that makes sense to me and will be a deterministic solution regardless of the underlying problem. This has made me curious of exactly what the intended use of EventDeliveryException is now. The distinction between it and other Exceptions is pretty blurred now that we just elect to log everything As the name suggests - it indicates a failure to relay the event to it's next hop destination. Ideally it should have the causal exception buried within itself that gives more of a clue as to what may have gone wrong. Eventually, if we see a pattern of failures emerging out of this, we should modify the component that is responsible to deal with it rather than adding that logic to the exception handling code.
        Arvind Prabhakar made changes -
        Field Original Value New Value
        Fix Version/s v1.2.0 [ 12320243 ]
        Fix Version/s v1.1.0 [ 12319284 ]
        Hide
        Juhani Connolly added a comment -

        The method you describe is fine for a processor dealing with a single sink but seems a bit vague for multiple sinks that are being balanced or being used for failover.

        One way of dealing with this with multiple sinks is to just put sinks that had exceptions on a priority list with the time to reactivate them, passing events to other sinks until "recovery". Since balancing/failover processors have other alternatives, they can just get another sink to deal with it, using longer timeouts than would be applied by backoff. Would this be a better way to deal with balancing/failover?

        This has made me curious of exactly what the intended use of EventDeliveryException is now. The distinction between it and other Exceptions is pretty blurred now that we just elect to log everything

        Show
        Juhani Connolly added a comment - The method you describe is fine for a processor dealing with a single sink but seems a bit vague for multiple sinks that are being balanced or being used for failover. One way of dealing with this with multiple sinks is to just put sinks that had exceptions on a priority list with the time to reactivate them, passing events to other sinks until "recovery". Since balancing/failover processors have other alternatives, they can just get another sink to deal with it, using longer timeouts than would be applied by backoff. Would this be a better way to deal with balancing/failover? This has made me curious of exactly what the intended use of EventDeliveryException is now. The distinction between it and other Exceptions is pretty blurred now that we just elect to log everything
        Hide
        Arvind Prabhakar added a comment -

        Thanks Juhani for filing this issue. Here are my thoughts on the issue:

        Any exception including EventDeliveryException can likely be due to a relatively permanent failure. Therefore it is non-trivial for the sink implementation to detect and throw the appropriate exception type as expected by any upstream contract. Failure to throw the correct exception will cause the system to enter an inconsistent state.

        I therefore suggest we stick to simple exception handling mechanism - where the processor catches all exceptions and backs off from retries for a predictable amount of time. If the problem is permanent, it will eventually be resolved by human intervention, and the backoff mechanism will ensure that it does not tax the system too much.

        Having sophisticated exceptions will lead to unpredictable behavior and will still require manual intervention for recovery, only the state will be more complex than the other implementation.

        Show
        Arvind Prabhakar added a comment - Thanks Juhani for filing this issue. Here are my thoughts on the issue: Any exception including EventDeliveryException can likely be due to a relatively permanent failure. Therefore it is non-trivial for the sink implementation to detect and throw the appropriate exception type as expected by any upstream contract. Failure to throw the correct exception will cause the system to enter an inconsistent state. I therefore suggest we stick to simple exception handling mechanism - where the processor catches all exceptions and backs off from retries for a predictable amount of time. If the problem is permanent, it will eventually be resolved by human intervention, and the backoff mechanism will ensure that it does not tax the system too much. Having sophisticated exceptions will lead to unpredictable behavior and will still require manual intervention for recovery, only the state will be more complex than the other implementation.
        Juhani Connolly created issue -

          People

          • Assignee:
            Juhani Connolly
            Reporter:
            Juhani Connolly
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              Updated:
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