Author: Alex Behm <firstname.lastname@example.org>
Date: Mon May 23 11:01:39 2016 -0700
IMPALA-3369: Add ALTER TABLE SET COLUMN STATS statement.
Adds a new command to manually set the table-level column stats.
ALTER TABLE [<db_name>.]<tbl_name> SET COLUMN STATS <col_name>
Valid values for 'statsKey': numDVs, numNulls, avgSize, maxSize
The 'val' portion needs to be a number appropriate for the given stats
key (e.g., a long for numDVs, a float for avgSize).
The special value of '-1' is allowed to reset stats to 'unknown'.
The keys as well as the values are specified as string literals to be
consistent with the existing DDL for setting TBLPROPERTIES/SERDEPROPERTIES,
in particular, setting the 'numRows' table/partition property.
Testing: Ran the tests locally on exhaustive. Did private runs
on core/hdfs and core/S3.
Reviewed-by: Alex Behm <email@example.com>
Tested-by: Internal Jenkins