This is the documentation for Cloudera Impala 2.1.x.
Documentation for other versions is available at

V_CPU_CORES (CDH 5 only)

The number of per-host virtual CPU cores to request from YARN. If set, the query option overrides the automatic estimate from Impala. Used in conjunction with the Impala resource management feature in Impala 1.2 and higher and CDH 5.

Default: 0 (use automatic estimates)