DISABLE_ROW_RUNTIME_FILTERING Query Option (Impala 2.5 or higher only)
DISABLE_ROW_RUNTIME_FILTERING query option
reduces the scope of the runtime filtering feature. Queries still dynamically prune
partitions, but do not apply the filtering logic to individual rows within partitions.
Only applies to queries against Parquet tables. For other file formats, Impala only prunes at the level of partitions, not individual rows.
Type: Boolean; recognized values are 1 and 0, or
any other value interpreted as
Added in: Impala 2.5.0
Impala automatically evaluates whether the per-row filters are being effective at reducing the amount of intermediate data. Therefore, this option is typically only needed for the rare case where Impala cannot accurately determine how effective the per-row filtering is for a query.
Because the runtime filtering feature applies mainly to resource-intensive and long-running queries, only adjust this query option when tuning long-running queries involving some combination of large partitioned tables and joins involving large tables.
Because this setting only improves query performance in very specific circumstances, depending on the query characteristics and data distribution, only use it when you determine through benchmarking that it improves performance of specific expensive queries. Consider setting this query option immediately before the expensive query and unsetting it immediately afterward.
File format considerations:
This query option only applies to queries against HDFS-based tables using the Parquet file format.
When applied to a query involving a Kudu table, this option turns off all runtime filtering for the Kudu table.