Author: Matthew Jacobs <firstname.lastname@example.org>
Date: Fri Aug 19 08:49:25 2016 -0700
IMPALA-3481: Use Kudu ScanToken API for scan ranges
Switches the planner and KuduScanNode to use Kudu's new
ScanToken API instead of explicitly constructing scan ranges
for all tablets of a table, regardless of whether they were
needed. The ScanToken API allows Impala to specify the
projected columns and predicates during planning, and Kudu
returns a set of 'scan tokens' that represent a scanner for
each tablet that needs to be scanned. The scan tokens can
be serialized and distributed to the scan nodes, which can
then deserialize them into Kudu scanner objects. Upon
deserialization, the scan token has all scan parameters
already, including the 'pushed down' predicates. Impala no
longer needs to send the Kudu predicates to the BE and
convert them at the scan node.
This change also fixes:
IMPALA-4016: Avoid materializing slots only referenced
by Kudu conjuncts
IMPALA-3874: Predicates are not always pushed to Kudu
TODO: Consider additional planning improvements.
Testing: Updated the existing tests, verified everything
works as expected. Some BE tests no longer make sense and
they were removed.
KUDU-1065 is resolved, add tests that demonstrate pruning.
Reviewed-by: Matthew Jacobs <email@example.com>
Tested-by: Internal Jenkins