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A compute stats command computes the table and column stats for a given table and persists them in the metastore. The table stats consist of the per-partition and per-table row count. The column stats are computed on a per-table basis and consist of the number of distinct values and the number of NULLs per column. This patch introduces a new 'child query' concept that compute stats utilizes. Child queries are cancelled if the parent query is cancelled. A compute stats stmt is executed by the following query hirarchy: parent: compute stats query (DDL) - child: compute table stats query (QUERY) - child: compute column stats query (QUERY) The new child query concept is necessary to decouple child query fetches from parent query fetches, i.e., we could not execute a child query as part of the original compute stats query, because then a client could fetch the results we need for updating the Metastore statistics. The reason why our existing CTAS works without this decoupling is that its insert 'child query' is not fetchable. Change-Id: I560533e3cb09bcbbdb3eea7fcf0b460bc6b36dcd Reviewed-on: http://gerrit.ent.cloudera.com:8080/873 Reviewed-by: Alex Behm <alex.behm@cloudera.com> Tested-by: jenkins
This directory contains Impala test workloads. The directory layout for the workloads should follow: workloads/ <data set name>/<data set name>_dimensions.csv <- The test dimension file <data set name>/<data set name>_core.csv <- A test vector file <data set name>/<data set name>_pairwise.csv <data set name>/<data set name>_exhaustive.csv <data set name>/queries/<query test>.test <- The queries for this workload