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From François Méthot <fmetho...@gmail.com>
Subject Re: Simple query on 150 billion records
Date Tue, 05 Apr 2016 18:27:03 GMT
What I ended up doing is restart our Drill cluster.

The same query ran in 19 minutes, scanning the same amount of rows (~79
Billions)

So it looks like that after long period of up time and heavy usage, our
Drill cluster got into a certain state and become difficult to work with.

Until we find a better solution, we might just have to restart drill every
morning and whenever we encounter certain type of query error or
performance degradation.

Any else noticed something similar?
Is there specific query error that could lead to performance and stability
issue and that would inevitably require a restart?


Thanks for help











On Tue, Apr 5, 2016 at 9:18 AM, Darshan Singh <darshan.meel@gmail.com>
wrote:

> Hi,
>
> How much data  you got from this query
>
> create table ANALYSIS_RESULT as (
> select Int32Field1 as SECONDS from hdfs.`/data/` where Int32Field2=123456
> or Int32Field2=4567898);
>
> As per your email you said single record.Also, in this query you used
> Int32Field1 as Seconds whereas in the first query it was just seconds.Are
> these same fields or do you have some sort for conversion for these fields
> in first query.
>
> A plan would be grateful as well.
>
> Thanks
>
> On Mon, Apr 4, 2016 at 3:09 PM, François Méthot <fmethot78@gmail.com>
> wrote:
>
> > Hi,
> >
> >   Querying 150 Billion records spread over ~21 000 parquets stored in
> hdfs
> > on 13 nodes (6 cores each, Max Dir. Mem: 32GB, Max Heap 8 GB).
> >
> > Is their a known issue or drill limitation that would explain why the
> first
> > query below can't return the expected single row and aggregation ?
> >
> > create table ANALYSIS_RESULT as (
> > select to_date(to_timestamp((SECONDS)), count(1)
> > from hdfs.`/data/
> > where Int32Field2=123456 or Int32Field2=4567898
> > group by to_date(to_timestamp((SECONDS)));
> >
> > After *20 hours*, SYSTEM ERROR: Foreman Exception: One more more nodes
> lost
> > connectivity during query.
> >
> >
> > If we do the query in 2 steps:
> > create table ANALYSIS_RESULT as (
> > select Int32Field1 as SECONDS from hdfs.`/data/` where Int32Field2=123456
> > or Int32Field2=4567898);
> >
> > result was returned in *43 minutes* ( a single record ).
> >
> > select to_date(to_timestamp((SECONDS)), count(1)
> > from ANALYSIS_RESULT
> > group by to_date(to_timestamp((SECONDS));
> >
> > Aggregation of that single record is of course done in  < 1 second.
> >    2016-04-04          1
> >
> >
> >
> > I also tried
> > select to_date(to_timestamp((SECONDS)), count(1)  from (
> > select Int32Field1 as SECONDS
> > from hdfs.`/data/`
> > where Int32Field2=123456 or Int32Field2=4567898)
> > group by o_date(to_timestamp((SECONDS))
> >
> > Same thing: After *21 hours*, SYSTEM ERROR: Foreman Exception: One more
> > more nodes lost connectivity during query.
> >
> >
> > Thanks for your help
> > Francois
> >
>

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