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From Paul Brannan <paul.bran...@thesystech.com>
Subject Re: mixing range and hash partitioning
Date Tue, 07 Mar 2017 02:09:11 GMT
I think you're right; I'm on 1.2 now, and can't reproduce the behavior I as
seeing.

On Mon, Mar 6, 2017 at 7:57 PM, Dan Burkert <danburkert@apache.org> wrote:

> Hi Paul,
>
> Sorry for the slow followup, been pulled a few different ways with the
> upcoming 1.3 release.  The issue you run into is KUDU-1792
> <https://issues.apache.org/jira/browse/KUDU-1792>, which was fixed in
> Kudu 1.2.  KUDU-1792 only comes into play when adding a range partition
> where either the upper or lower bound is unbounded, but this is actually
> the case in your repro example due to a copy/paste error where the lower
> limit is being set twice and the upper limit is not being set.  I think the
> fix is to upgrade to Kudu 1.2 and recreate the table if it still has the
> buggy partitions.  Thanks again for the report!
>
> - Dan
>
> On Tue, Feb 28, 2017 at 1:03 PM, Dan Burkert <danburkert@apache.org>
> wrote:
>
>> Yep: https://issues.apache.org/jira/browse/KUDU-1903
>>
>> - Dan
>>
>> On Tue, Feb 28, 2017 at 12:51 PM, Todd Lipcon <todd@cloudera.com> wrote:
>>
>>> Hey Dan,
>>>
>>> Mind filing a critical or blocker JIRA against 1.3 so we can track
>>> remaining things that should go into the branch before release?
>>>
>>> -Todd
>>>
>>> On Tue, Feb 28, 2017 at 10:05 AM, Dan Burkert <danburkert@apache.org>
>>> wrote:
>>>
>>>> Hey Paul,
>>>>
>>>> Thanks for checking that out and following up.  I'm going to try and
>>>> root cause this today so that we have plenty of time to get a fix in to 1.3
>>>> if it requires one.   Thanks again for the report. In the meantime, let me
>>>> know if the alter table workaround is not enough for you to make progress
>>>> with Kudu.
>>>>
>>>> -Dan
>>>>
>>>>
>>>> On Mon, Feb 27, 2017 at 3:02 PM Paul Brannan <
>>>> paul.brannan@thesystech.com> wrote:
>>>>
>>>> One side-effect of neglecting to drop the unbounded range partition: I
>>>> get a stack trace when I try to scan:
>>>>
>>>> F0227 15:00:12.696625 76369 map-util.h:112] Check failed: it !=
>>>> collection.end() Map key not found: ▒3
>>>> *** Check failure stack trace: ***
>>>>     @     0x7fca2a5506ad  (unknown)
>>>>     @     0x7fca2a55271c  (unknown)
>>>>     @     0x7fca2a550209  (unknown)
>>>>     @     0x7fca2a5530af  (unknown)
>>>>     @     0x7fca2a3de482  (unknown)
>>>>     @     0x7fca2a3dae70  (unknown)
>>>>     @     0x7fca2a3dc100  (unknown)
>>>>     @     0x7fca2a429a44  (unknown)
>>>>     @     0x7fca2a42ab47  (unknown)
>>>>     @     0x7fca2a42e94c  (unknown)
>>>>     @     0x7fca2a43081c  (unknown)
>>>>     @     0x7fca2a5a9a56  (unknown)
>>>>     @     0x7fca2a5aa948  (unknown)
>>>>     @     0x7fca2a41ac8b  (unknown)
>>>>     @     0x7fca2a4dcfc8  (unknown)
>>>>     @     0x7fca290d6182  start_thread
>>>>     @     0x7fca2980947d  clone
>>>>     @              (nil)  (unknown)
>>>>
>>>>
>>>> On Sun, Feb 26, 2017 at 6:53 PM, Paul Brannan <
>>>> paul.brannan@thesystech.com> wrote:
>>>>
>>>> Is that 4TB per tablet server, regardless of how many tablets it has?
>>>>
>>>> If I have 128GB of data per day, then each tablet server hits the
>>>> recommended limit after about a month.  To store 10 years of data, I would
>>>> need 120 tablet servers to avoid going over the limit.  Is that the best
>>>> solution or is there another alternative?
>>>>
>>>> How many cores are recommended per tablet server?  If I typically only
>>>> scan one day of data at time, could a single core service multiple tablet
>>>> servers?
>>>>
>>>>
>>>> On Fri, Feb 24, 2017 at 11:22 PM, Paul Brannan <
>>>> paul.brannan@thesystech.com> wrote:
>>>>
>>>> The test doesn't exactly reproduce what I did in my sample program.
>>>>
>>>> I'm able to successfully drop the unbounded partition in both cases
>>>> (calling set_range_partition_columns only vs calling
>>>> set_range_partition_columns+add_hash_partitions).  However, if I omit
>>>> the call to DropRangePartition, then AddRangePartition succeeds in the
>>>> first case and fails in the second case.  I expect it to succeed in both
>>>> cases or fail in both cases.
>>>>
>>>> I've attached a simple program which demonstrates.
>>>>
>>>>
>>>> On Fri, Feb 24, 2017 at 7:09 PM, Dan Burkert <danburkert@apache.org>
>>>> wrote:
>>>>
>>>> Hi Paul,
>>>>
>>>> I can't reproduce the behavior you are describing, I always get a
>>>> single unbounded range partition when creating the table without specifying
>>>> range bounds or splits (regardless of hash partitioning). I searched and
>>>> couldn't find a unit test for this behavior, so I wrote one - you might
>>>> compare your code against my test. https://gerrit.cloudera.
>>>> org/#/c/6153/
>>>>
>>>> Thanks,
>>>> Dan
>>>>
>>>> On Fri, Feb 24, 2017 at 2:41 PM, Paul Brannan <
>>>> paul.brannan@thesystech.com> wrote:
>>>>
>>>> I can verify that dropping the unbounded range partition allows me to
>>>> later add bounded partitions.
>>>>
>>>> If I only have range partitioning (by commenting out the call to
>>>> add_hash_partitions), adding a bounded partition succeeds, regardless of
>>>> whether I first drop the unbounded partition.  This seems surprising; why
>>>> the difference?
>>>>
>>>> On Fri, Feb 24, 2017 at 4:20 PM, Dan Burkert <danburkert@apache.org>
>>>> wrote:
>>>>
>>>> Hi Paul,
>>>>
>>>> I think the issue you are running into is that if you don't add a range
>>>> partition explicitly during table creation (by calling add_range_partition
>>>> or inserting a split with add_range_partition_split), Kudu will default to
>>>> creating 1 unbounded range partition.  So your two options are to add the
>>>> range partition during table creation time, or if you only know that
>>>> partition you want at a later time, you can drop the existing partition
>>>> (alterer->DropRangePartition with two empty rows), then add the range
>>>> partition.  Note that dropping the range partition will effectively
>>>> truncate the table.  This can be done with the same alterer in a single
>>>> transaction.  If you want to see a bunch of examples, you can check out
>>>> this unit test: https://github.com/apache/kudu/blob/master/src/kudu/in
>>>> tegration-tests/alter_table-test.cc#L1106.
>>>>
>>>> - Dan
>>>>
>>>> On Fri, Feb 24, 2017 at 10:53 AM, Paul Brannan <
>>>> paul.brannan@thesystech.com> wrote:
>>>>
>>>> I'm trying to create a table with one-column range-partitioned and
>>>> another column hash-partitioned.  Documentation for add_hash_partitions and
>>>> set_range_partition_columns suggest this should be possible ("Tables must
>>>> be created with either range, hash, or range and hash partitioning").
>>>>
>>>> I have a schema with three INT64 columns ("time", "key", and "value").
>>>> When I create the table, I set up the partitioning:
>>>>
>>>> (*table_creator)
>>>>   .table_name("test_table")
>>>>   .schema(&schema)
>>>>   .add_hash_partitions({"key"}, 2)
>>>>   .set_range_partition_columns({"time"})
>>>>   .num_replicas(1)
>>>>   .Create()
>>>>
>>>> I later try to add a partition:
>>>>
>>>> auto timesplit(KuduSchema & schema, std::int64_t t) {
>>>>   auto split = schema.NewRow();
>>>>   check_ok(split->SetInt64("time", t));
>>>>   return split;
>>>> }
>>>>
>>>> alterer->AddRangePartition(
>>>>   timesplit(schema, date_start),
>>>>   timesplit(schema, next_date_start));
>>>>
>>>> check_ok(alterer->Alter());
>>>>
>>>> But I get an error "Invalid argument: New range partition conflicts
>>>> with existing range partition".
>>>>
>>>> How are hash and range partitioning intended to be mixed?
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> Todd Lipcon
>>> Software Engineer, Cloudera
>>>
>>
>>
>

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