When a table has 8 columns that could be NULL and a NOT NULL column
after the NULLable columns the check to see if we have gone over the
NULL bitmap byte limit is run prematurely trigging an error.
This patch moves the check to only run when we are looking at NULLable
columns.
This changes the warning for truncation to the correct MariaDB error
code (1264).
In addition it passes the strict mode up into the DML class to roll back
correctly.
It also sets the abort_on_warning flag for updates as this isn't set on
the rnd_init phase but is needed for strict mode to work.
When infinidb_use_import_for_batchinsert is enabled the NULL handling
for the batch insert was incorrect. This is due to an off-by-one on the
NULL bitmap. This also affects INSERT...SELECT.
NULL is now pushed through the MariaDB storage engine plugin down to the
insert processing. A '0000-00-00' date is now a separate value to NULL.
This is more in-line with MariaDB's handling.
