ha_partition stores records in array of m_ordered_rec_buffer and uses
it for prio queue in ordered index scan. When the records are restored
from the array the blob buffers may be already freed or rewritten.
The solution is to take temporary ownership of cached blob buffers via
String::swap(). When the record is restored from m_ordered_rec_buffer
the ownership is returned to table fields.
Cleanups:
init_record_priority_queue(): removed needless !m_ordered_rec_buffer
check as there is same assertion few lines before.
dbug_print_row() for arbitrary row pointer
table.cc:
virtual columns must be computed for INSERT, if they're part
of the partitioning expression.
this change broke gcol.gcol_partition_innodb.
fix CHECK TABLE for partitioned tables and vcols.
sql_partition.cc:
mark prerequisite base columns in full_part_field_set
ha_partition.cc
initialize vcol_set accordingly
