Problem was that the mix of handlers was not consistent between
CREATE and ALTER
changed so that it works like:
- All partitions must use the same engine
AND it must be the same as the table.
- if one does NOT specify an engine on the table level
then one must either NOT specify any engine on any
partition/subpartition OR for ALL partitions/subpartitions
Note: that after a table have been created, the storage engine
is specified for all parts of the table (table/partition/subpartition)
and so when using alter, one does not need to specify it (unless one
wants to change the storage engine, then one have to specify it on the
table level)
When partition pruning resulted in an ordered index scan spanning only
one partition, any descending flag for the scan was wrongly discarded,
turning ORDER BY DESC into ORDER BY ASC, and similar problems.
Fixed by correctly passing descending flag in SCAN_TABREQ signal sent
to data nodes.
