- In ha_innobase::prepare_inplace_alter_table(), InnoDB should
check whether the table is empty. If the table is empty then
server should avoid downgrading the MDL after prepare phase.
It is more like instant alter, does change only in dicationary
and metadata.
- Changed few debug test case to make non-empty DDL table
When logging ROW_T_INSERT or ROW_T_UPDATE records, we did not normalize
the DB_TRX_ID of the current transaction into 0 if the current transaction
had started (modifying other tables) before the ALTER TABLE started.
MDEV-13654 introduced this normalization for ROW_T_DELETE
and for all operations with ADD PRIMARY KEY, in row_log_table_get_pk().
