Monitoring/src/V3/Aggregation.php
public function setGroupByFields($var)
    {
        $arr = GPBUtil::checkRepeatedField($var, \Google\Protobuf\Internal\GPBType::STRING);
        $this->group_by_fields = $arr;

        return $this;
    }
public function setGroupByFields($var)
    {
        $arr = GPBUtil::checkRepeatedField($var, \Google\Protobuf\Internal\GPBType::STRING);
        $this->group_by_fields = $arr;

        return $this;
    }
public function setGroupByFields ( $ var ) { $ arr = GPBUtil :: checkRepeatedField ( $ var , \ Google \ Protobuf \ Internal \ GPBType :: STRING ) ; $ this -> group_by_fields = $ arr ; return $ this ; }
The set of fields to preserve when `crossSeriesReducer` is
specified. The `groupByFields` determine how the time series are
partitioned into subsets prior to applying the aggregation
function. Each subset contains time series that have the same
value for each of the grouping fields. Each individual time
series is a member of exactly one subset. The
`crossSeriesReducer` is applied to each subset of time series.
It is not possible to reduce across different resource types, so
this field implicitly contains `resource.type`.  Fields not
specified in `groupByFields` are aggregated away.  If
`groupByFields` is not specified and all the time series have
the same resource type, then the time series are aggregated into
a single output time series. If `crossSeriesReducer` is not
defined, this field is ignored.

Generated from protobuf field <code>repeated string group_by_fields = 5;</code>
@param string[]|\Google\Protobuf\Internal\RepeatedField $var
@return $this
The set of fields to preserve when crossSeriesReducer is specified . The groupByFields determine how the time series are partitioned into subsets prior to applying the aggregation function . Each subset contains time series that have the same value for each of the grouping fields . Each individual time series is a member of exactly one subset . The crossSeriesReducer is applied to each subset of time series . It is not possible to reduce across different resource types so this field implicitly contains resource . type . Fields not specified in groupByFields are aggregated away . If groupByFields is not specified and all the time series have the same resource type then the time series are aggregated into a single output time series . If crossSeriesReducer is not defined this field is ignored .