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Slow query selecting 1 row


Slow query selecting 1 row

New Contributor



I have setup a POC with Cloudera Enterprise and GoGrid (1 manager and 3 data nodes).

I have created a database, row fromat parquet, with 575M rows and 26 columns.

Most queries are running very fast, but there is 1 query which performs very slow.


select distinct(msisdn) from cdrmainparquet where msisdn=2255763xxxx: 6 seconds : OK

select msisdn from cdrmainparquet where msisdn=225576xxxx: 2.77 seconds: OK

select msisdn,imsi from cdrmainparquet where msisdn=2255763xxxx: 4.58 seconds: ?

select msisdn,imsi,eventtype,eventduration from cdrmainparquet where msisdn=2255763xxxx: 175 seconds : ??

select * (26 columns) takes 5minutes!


Why does this happen? Can I do something to let this single query running faster?




Re: Slow query selecting 1 row

Master Collaborator

Would you be able to post the runtime profiles of the slow queries? The runtime profiles contain detailed performance counters that may help us identify the problem.

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