Hi Sudheesh,

  If I add selection filter so that no row are returned, the same problem
occur. I also simplified the query to include only few integer columns.

That particular data repo is ~200+ Billions records spread over ~50 000
parquet files.

We have other CSV data repo that are 100x smaller that does not trigger
this issue.


+ Is atsqa4-133.qa.lab [1] the Foreman node for the query in this case?
There is also a bizarre case where the node that is reported as lost is the
node itself.
Yes, the stack trace is from the ticket, It did occurred once or twice (in
the many many attempts) that it was the node itself.

+ Is there a spike in memory usage of the Drillbit this is the Foreman for
the query (process memory, not just heap)?
We don't notice any unusual spike, each nodes gets busy in the same range
when query is running.

I tried running with 8GB/20GB and 4GB/24GB heap/off-heap, did not see any
improvement.


We will update from 1.7 to 1.8 before going ahead with more investigation.

Thanks a lot.










On Mon, Sep 19, 2016 at 1:19 PM, Sudheesh Katkam <skat...@maprtech.com>
wrote:

> Hi Francois,
>
> A simple query with only projections is not an “ideal” use case, since
> Drill is bound by how fast the client can consume records. There are 1000
> scanners sending data to 1 client (vs far fewer scanners sending data in
> the 12 node case).
>
> This might increase the load on the Drillbit that is the Foreman for the
> query. In the query profile, the scanners should be spending a lot more
> time “waiting” to send records to the client (via root fragment).
> + Is atsqa4-133.qa.lab [1] the Foreman node for the query in this case?
> There is also a bizarre case where the node that is reported as lost is the
> node itself.
> + Is there a spike in memory usage of the Drillbit this is the Foreman for
> the query (process memory, not just heap)?
>
> Regarding the warnings ...
>
> > 2016-09-19 13:31:56,866 [BitServer-7] WARN
> > o.a.d.exec.rpc.control.ControlServer - Message of mode REQUEST of rpc
> type
> > 6 took longer than 500 ms. Actual Duration was 16053ms.
>
>
> RPC type 6 is a cancellation request; DRILL-4766 [2] should help in this
> case, which is resolved in the latest version of Drill. So as Chun
> suggested, upgrade the cluster to the latest version of Drill.
>
> > 2016-09-19 14:15:33,357 [BitServer-4] WARN
> > o.a.d.exec.rpc.control.ControlClient - Message of mode RESPONSE of rpc
> type
> > 1 took longer than 500 ms. Actual Duration was 981ms.
>
> I am surprised that responses are taking that long to handle.
> + Are both messages on the same Drillbit?
>
> The other warnings can be ignored.
>
> Thank you,
> Sudheesh
>
> [1] I just realized that atsqa4-133.qa.lab is in one of our test
> environments :)
> [2] https://issues.apache.org/jira/browse/DRILL-4766 <
> https://issues.apache.org/jira/browse/DRILL-4766>
>
> > On Sep 19, 2016, at 9:15 AM, François Méthot <fmetho...@gmail.com>
> wrote:
> >
> > Hi Sudheesh,
> >
> >
> > + Does the query involve any aggregations or filters? Or is this a select
> > query with only projections?
> > Simple query with only projections
> >
> > + Any suspicious timings in the query profile?
> > Nothing specially different than our working query on our small cluster.
> >
> > + Any suspicious warning messages in the logs around the time of failure
> on
> > any of the drillbits? Specially on atsqa4-133.qa.lab? Specially this one
> > (“..” are place holders):
> >  Message of mode .. of rpc type .. took longer than ..ms.  Actual
> duration
> > was ..ms.
> >
> > Well we do see this warning on the failing node (on my last test), I
> found
> > this WARNING in our log for the past month for pretty much every node I
> > checked.
> > 2016-09-19 13:31:56,866 [BitServer-7] WARN
> > o.a.d.exec.rpc.control.ControlServer - Message of mode REQUEST of rpc
> type
> > 6 took longer than 500 ms. Actual Duration was 16053ms.
> > 2016-09-19 14:15:33,357 [BitServer-4] WARN
> > o.a.d.exec.rpc.control.ControlClient - Message of mode RESPONSE of rpc
> type
> > 1 took longer than 500 ms. Actual Duration was 981ms.
> >
> > We really appreciate your help. I will dig in the source code for when
> and
> > why this error happen.
> >
> >
> > Francois
> >
> > P.S.:
> > We do see this also:
> > 2016-09-19 14:48:23,444 [drill-executor-9] WARN
> > o.a.d.exec.rpc.control.WorkEventBus - Fragment ......:1:2 not found in
> the
> > work bus.
> > 2016-09-19 14:48:23,444 [drill-executor-11] WARN
> > o.a.d.exec.rpc.control.WorkEventBus - Fragment ....:1:222 not found in
> the
> > work bus.
> > 2016-09-19 14:48:23,444 [drill-executor-12] WARN
> > o.a.d.exec.rpc.control.WorkEventBus - Fragment ....:1:442 not found in
> the
> > work bus.
> > 2016-09-19 14:48:23,444 [drill-executor-10] WARN
> > o.a.d.exec.rpc.control.WorkEventBus - Fragment ....:1:662 not found in
> the
> > work bus.
> >
> >
> >
> >
> > On Sun, Sep 18, 2016 at 2:57 PM, Sudheesh Katkam <skat...@maprtech.com>
> > wrote:
> >
> >> Hi Francois,
> >>
> >> More questions..
> >>
> >>> + Can you share the query profile?
> >>>  I will sum it up:
> >>> It is a select on 18 columns: 9 string, 9 integers.
> >>> Scan is done on 13862 parquet files spread  on 1000 fragments.
> >>> Fragments are spread accross 215 nodes.
> >>
> >> So ~5 leaf fragments (or scanners) per Drillbit seems fine.
> >>
> >> + Does the query involve any aggregations or filters? Or is this a
> select
> >> query with only projections?
> >> + Any suspicious timings in the query profile?
> >> + Any suspicious warning messages in the logs around the time of failure
> >> on any of the drillbits? Specially on atsqa4-133.qa.lab? Specially this
> one
> >> (“..” are place holders):
> >>  Message of mode .. of rpc type .. took longer than ..ms.  Actual
> >> duration was ..ms.
> >>
> >> Thank you,
> >> Sudheesh
> >>
> >>> On Sep 15, 2016, at 11:27 AM, François Méthot <fmetho...@gmail.com>
> >> wrote:
> >>>
> >>> Hi Sudheesh,
> >>>
> >>> + How many zookeeper servers in the quorum?
> >>> The quorum has 3 servers, everything looks healthy
> >>>
> >>> + What is the load on atsqa4-133.qa.lab when this happens? Any other
> >>> applications running on that node? How many threads is the Drill
> process
> >>> using?
> >>> The load on the failing node(8 cores) is 14, when Drill is running.
> Which
> >>> is nothing out of the ordinary according to our admin.
> >>> HBase is also running.
> >>> planner.width.max_per_node is set to 8
> >>>
> >>> + When running the same query on 12 nodes, is the data size same?
> >>> Yes
> >>>
> >>> + Can you share the query profile?
> >>>  I will sum it up:
> >>> It is a select on 18 columns: 9 string, 9 integers.
> >>> Scan is done on 13862 parquet files spread  on 1000 fragments.
> >>> Fragments are spread accross 215 nodes.
> >>>
> >>>
> >>> We are in process of increasing our Zookeeper session timeout config to
> >> see
> >>> if it helps.
> >>>
> >>> thanks
> >>>
> >>> Francois
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>> On Wed, Sep 14, 2016 at 4:40 PM, Sudheesh Katkam <skat...@maprtech.com
> >
> >>> wrote:
> >>>
> >>>> Hi Francois,
> >>>>
> >>>> Few questions:
> >>>> + How many zookeeper servers in the quorum?
> >>>> + What is the load on atsqa4-133.qa.lab when this happens? Any other
> >>>> applications running on that node? How many threads is the Drill
> process
> >>>> using?
> >>>> + When running the same query on 12 nodes, is the data size same?
> >>>> + Can you share the query profile?
> >>>>
> >>>> This may not be the right thing to do, but for now, If the cluster is
> >>>> heavily loaded, increase the zk timeout.
> >>>>
> >>>> Thank you,
> >>>> Sudheesh
> >>>>
> >>>>> On Sep 14, 2016, at 11:53 AM, François Méthot <fmetho...@gmail.com>
> >>>> wrote:
> >>>>>
> >>>>> We are running 1.7.
> >>>>> The log were taken from the jira tickets.
> >>>>>
> >>>>> We will try out 1.8 soon.
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> On Wed, Sep 14, 2016 at 2:52 PM, Chun Chang <cch...@maprtech.com>
> >> wrote:
> >>>>>
> >>>>>> Looks like you are running 1.5. I believe there are some work done
> in
> >>>> that
> >>>>>> area and the newer release should behave better.
> >>>>>>
> >>>>>> On Wed, Sep 14, 2016 at 11:43 AM, François Méthot <
> >> fmetho...@gmail.com>
> >>>>>> wrote:
> >>>>>>
> >>>>>>> Hi,
> >>>>>>>
> >>>>>>> We are trying to find a solution/workaround to issue:
> >>>>>>>
> >>>>>>> 2016-01-28 16:36:14,367 [Curator-ServiceCache-0] ERROR
> >>>>>>> o.a.drill.exec.work.foreman.Foreman - SYSTEM ERROR:
> >> ForemanException:
> >>>>>>> One more more nodes lost connectivity during query.  Identified
> nodes
> >>>>>>> were [atsqa4-133.qa.lab:31010].
> >>>>>>> org.apache.drill.common.exceptions.UserException: SYSTEM ERROR:
> >>>>>>> ForemanException: One more more nodes lost connectivity during
> query.
> >>>>>>> Identified nodes were [atsqa4-133.qa.lab:31010].
> >>>>>>>      at org.apache.drill.exec.work.foreman.Foreman$ForemanResult.
> >>>>>>> close(Foreman.java:746)
> >>>>>>> [drill-java-exec-1.5.0-SNAPSHOT.jar:1.5.0-SNAPSHOT]
> >>>>>>>      at org.apache.drill.exec.work.foreman.Foreman$StateSwitch.
> >>>>>>> processEvent(Foreman.java:858)
> >>>>>>> [drill-java-exec-1.5.0-SNAPSHOT.jar:1.5.0-SNAPSHOT]
> >>>>>>>      at org.apache.drill.exec.work.foreman.Foreman$StateSwitch.
> >>>>>>> processEvent(Foreman.java:790)
> >>>>>>> [drill-java-exec-1.5.0-SNAPSHOT.jar:1.5.0-SNAPSHOT]
> >>>>>>>      at org.apache.drill.exec.work.foreman.Foreman$StateSwitch.
> >>>>>>> moveToState(Foreman.java:792)
> >>>>>>> [drill-java-exec-1.5.0-SNAPSHOT.jar:1.5.0-SNAPSHOT]
> >>>>>>>      at org.apache.drill.exec.work.foreman.Foreman.moveToState(
> >>>>>>> Foreman.java:909)
> >>>>>>> [drill-java-exec-1.5.0-SNAPSHOT.jar:1.5.0-SNAPSHOT]
> >>>>>>>      at org.apache.drill.exec.work.foreman.Foreman.access$2700(
> >>>>>>> Foreman.java:110)
> >>>>>>> [drill-java-exec-1.5.0-SNAPSHOT.jar:1.5.0-SNAPSHOT]
> >>>>>>>      at org.apache.drill.exec.work.foreman.Foreman$StateListener.
> >>>>>>> moveToState(Foreman.java:1183)
> >>>>>>> [drill-java-exec-1.5.0-SNAPSHOT.jar:1.5.0-SNAPSHOT]
> >>>>>>>
> >>>>>>>
> >>>>>>> DRILL-4325  <https://issues.apache.org/jira/browse/DRILL-4325>
> >>>>>>> ForemanException:
> >>>>>>> One or more nodes lost connectivity during query
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> Any one experienced this issue ?
> >>>>>>>
> >>>>>>> It happens when running query involving many parquet files on a
> >> cluster
> >>>>>> of
> >>>>>>> 200 nodes. Same query on a smaller cluster of 12 nodes runs fine.
> >>>>>>>
> >>>>>>> It is not caused by garbage collection, (checked on both ZK node
> and
> >>>> the
> >>>>>>> involved drill bit).
> >>>>>>>
> >>>>>>> Negotiated max session timeout is 40 seconds.
> >>>>>>>
> >>>>>>> The sequence seems:
> >>>>>>> - Drill Query begins, using an existing ZK session.
> >>>>>>> - Drill Zk session timeouts
> >>>>>>>    - perhaps it was writing something that took too long
> >>>>>>> - Drill attempts to renew session
> >>>>>>>     - drill believes that the write operation failed, so it
> attempts
> >>>>>> to
> >>>>>>> re-create the zk node, which trigger another exception.
> >>>>>>>
> >>>>>>> We are open to any suggestion. We will report any finding.
> >>>>>>>
> >>>>>>> Thanks
> >>>>>>> Francois
> >>>>>>>
> >>>>>>
> >>>>
> >>>>
> >>
> >>
>
>

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