kylin-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From ShaoFeng Shi <shaofeng...@apache.org>
Subject Re: Empty Cube
Date Wed, 28 Sep 2016 09:41:55 GMT
I also encountered the "empty cube" issue in an environment yesterday; By
checking Hive I found one of the sample table
"DEFAULT.KYLIN_CATEGORY_GROUPINGS" has no record. Since the "kylin_sales"
cube uses "inner" joins for all tables, causing the cube no data.

After some troubleshoting I identify it is an issue of the "beeline" client
(my env configures beeline as hive cli in kylin), when it executes the
sample_cube/create_sample_tables.sql, the last line wasn't executed, which
caused the csv file wasn't uploaded.

By adding a blank line in the end of this sql file, it runs successfully. I
will checkin this change in kylin soon. If you faced the same issue, please
take a try.

2016-09-09 13:47 GMT+08:00 ShaoFeng Shi <shaofengshi@apache.org>:

> Hi Niasari,
>
> During the query time, Kylin will not touch Hive, all queries will go to
> HBase, so you still get results on kylin_cal_dt; If you also want to remove
> that also in Kylin, please disable and then drop the cube.
>
> For the empty cube, it is possible and allowed in Kylin; Thinking that an
> user uses incremental build, and for a time period there is no source data,
> so empty cube is expected. Of course you can configure Kylin to let it
> report error when there is no source record, see: https://issues.apache.
> org/jira/browse/KYLIN-1752
>
> For the empty cube issue, I guess there is some thing wrong, making no
> data be built into cube. If you want to get remote debug or support, please
> contact me offline.
>
>
>
> 2016-09-07 5:17 GMT+08:00 Niasari, Mehrdad <mehrdad.niasari@rbc.com>:
>
>> The range is up to 2015 and that’s not the problem.
>>
>>
>>
>> The only query that doesn’t return zero/empty result is from table
>> kylin_cal_dt. When I delete this table from hive, still the result is not
>> empty and Kylin doesn’t complain! Where does Kylin bring the data of this
>> table even when it’s not on hive?
>>
>> Also I checked the cube itself on Hbase and it’s empty. Any other
>> suggestion? Can it be because of some wrong configuration in connecting
>> Kylin to Hive/Hbase? If that’s the case why it can create the cube
>> successfully?
>>
>>
>>
>> Also I have a question regarding uuid. What is this for?
>>
>> I’m asking this cause I cannot fully understand that why you have used a
>> fixed value in sample cube json files (for example for kylin_sales_cube
>> uuid is: “2fbca32a-a33e-4b69-83dd-0bb8b1f8c53b”). How come it doesn’t
>> conflict if you run the sample cube multiple times?
>>
>>
>>
>> Thanks,
>>
>> Mehrdad
>>
>>
>>
>> *From:* ShaoFeng Shi [mailto:shaofengshi@apache.org]
>> *Sent:* 2016, September, 01 9:01 PM
>>
>> *To:* user
>> *Subject:* Re: Empty Cube
>>
>>
>>
>> ok; The table "kylin_sales" contains data for 2012 and 2013, so need make
>> sure the build range covers these years; please have a check and I guess it
>> is some minor mistake; BTW, empty cube will return zero since it doesn't
>> have data.
>>
>>
>>
>> 2016-09-02 1:34 GMT+08:00 Niasari, Mehrdad <mehrdad.niasari@rbc.com>:
>>
>> Thanks for the reply.
>>
>>
>>
>> There is no error in the log. Also I checked the hive tables and they are
>> not empty; I can run any query on them using Hue and work well.
>>
>>
>>
>> Also the size of cube in the cubes section in 0.00KB! But even with an
>> empty cube the result of queries on the tables should not be empty/zero,
>> right?
>>
>> Any other suggestion how to debug it?
>>
>>
>>
>> Thanks,
>>
>> Mehrdad
>>
>>
>>
>> *From:* ShaoFeng Shi [mailto:shaofengshi@apache.org]
>> *Sent:* 2016, August, 31 9:04 PM
>> *To:* user
>> *Subject:* Re: Empty Cube
>>
>>
>>
>> Hi Mehrdad,
>>
>>
>>
>> When you run the query, is there any error reported in the logs/kylin.log?
>>
>>
>>
>> If no error, please check whether the source hive table has data, you can
>> do this easily in hive, by running HQL "select * from default.kylin_sales
>> limit 100"; it is very likely that the "sample.sh" failed to upload the
>> file; if it is this case, you may need manually import the data files
>>  (sample_cube/data) to hive;
>>
>>
>>
>> 2016-09-01 4:06 GMT+08:00 Niasari, Mehrdad <mehrdad.niasari@rbc.com>:
>>
>> Hi All,
>>
>>
>>
>> When I run the sample cube of Kylin the result is empty, i.e. the cube is
>> computed successfully, the status is ready but nothing is in the cube and
>> every query gets zero.
>>
>> Do you have any suggestion what can cause the problem?
>>
>> How should I debug it?
>>
>>
>>
>> Thanks,
>>
>> Mehrdad
>>
>>
>>
>>
>>
>> _______________________________________________________________________
>>
>> If you received this email in error, please advise the sender (by return
>> email or otherwise) immediately. You have consented to receive the attached
>> electronically at the above-noted email address; please retain a copy of
>> this confirmation for future reference.
>>
>> Si vous recevez ce courriel par erreur, veuillez en aviser l'expéditeur
>> immédiatement, par retour de courriel ou par un autre moyen. Vous avez
>> accepté de recevoir le(s) document(s) ci-joint(s) par voie électronique à
>> l'adresse courriel indiquée ci-dessus; veuillez conserver une copie de
>> cette confirmation pour les fins de reference future.
>>
>>
>>
>>
>>
>> --
>>
>> Best regards,
>>
>>
>>
>> Shaofeng Shi
>>
>>
>>
>> _______________________________________________________________________
>>
>> If you received this email in error, please advise the sender (by return
>> email or otherwise) immediately. You have consented to receive the attached
>> electronically at the above-noted email address; please retain a copy of
>> this confirmation for future reference.
>>
>> Si vous recevez ce courriel par erreur, veuillez en aviser l'expéditeur
>> immédiatement, par retour de courriel ou par un autre moyen. Vous avez
>> accepté de recevoir le(s) document(s) ci-joint(s) par voie électronique à
>> l'adresse courriel indiquée ci-dessus; veuillez conserver une copie de
>> cette confirmation pour les fins de reference future.
>>
>>
>>
>>
>>
>> --
>>
>> Best regards,
>>
>>
>>
>> Shaofeng Shi
>>
>>
>>
>> _______________________________________________________________________
>>
>> If you received this email in error, please advise the sender (by return
>> email or otherwise) immediately. You have consented to receive the attached
>> electronically at the above-noted email address; please retain a copy of
>> this confirmation for future reference.
>>
>> Si vous recevez ce courriel par erreur, veuillez en aviser l'expéditeur
>> immédiatement, par retour de courriel ou par un autre moyen. Vous avez
>> accepté de recevoir le(s) document(s) ci-joint(s) par voie électronique à
>> l'adresse courriel indiquée ci-dessus; veuillez conserver une copie de
>> cette confirmation pour les fins de reference future.
>>
>>
>
>
> --
> Best regards,
>
> Shaofeng Shi
>
>


-- 
Best regards,

Shaofeng Shi 史少锋

Mime
View raw message