Support Questions
Find answers, ask questions, and share your expertise
Announcements
Alert: Welcome to the Unified Cloudera Community. Former HCC members be sure to read and learn how to activate your account here.

what exactly column and row stats implies in a running impala query?

what exactly column and row stats implies in a running impala query?

Explorer

Hi Team,

 

i see coulmn stats and row stats is unavaialble in impala query. can i know what exactly this means?

partitions=1/1 files=200 size=8.77GB
   stats-rows=unavailable extrapolated-rows=disabled
   table stats: rows=unavailable size=8.77GB
   column stats: unavailable

 thanks.

1 REPLY 1

Re: what exactly column and row stats implies in a running impala query?

Master Collaborator

Impala requires statistics about the data in your table so that it can optimise query plans for most efficient execution.

 

 

You should generally run "compute stats" on your tables after loading data into them or after the data has changed significantly. For more details I'd recommend our docs, which have more information than I could fit in this reply

https://www.cloudera.com/documentation/enterprise/latest/topics/impala_compute_stats.html

Don't have an account?
Coming from Hortonworks? Activate your account here