KUDU-861 Support changing default, storage attributes
This patch adds support for adding, changing, or removing column defaults
and changing the storage attributes of a column. Changes to a column are
encoded as a ColumnSchemaDelta, which can be merged with a ColumnSchema
to change it.
Changing type and nullability of a column is still unsupported.
No failures in 100+ iterations of alter_table-randomized-test.
I also ran into an issue with altering RLE columns:
1. Add an RLE-encoded column to a table
2. Alter the column
3. Scan the column
3 will cause a check failure on scanning to pos 0 of an empty RLE
block. Test and fix included.
Reviewed-on: http:Tested-by: Kudu Jenkins
Reviewed-by: Dan Burkert <firstname.lastname@example.org>