The bug allow multiple executing transactions working with non-transactional
to interfere with each others by interleaving the events of different trans-
actions.
Bug is fixed by writing non-transactional events to the transaction cache and
flushing the cache to the binary log at statement commit. To mimic the behavior
of normal statement-based replication, we flush the transaction cache in row-
based mode when there is no committed statements in the transaction cache,
which means we are committing the first one. This means that it will be written
to the binary log as a "mini-transaction" with just the rows for the statement.
Note that the changes here does not take effect when building the server with
HAVE_TRANSACTIONS set to false, but it is not clear if this was possible before
this patch either.
For row-based logging, we also have that when AUTOCOMMIT=1, the code now always
generates a BEGIN/COMMIT pair for single statements, or BEGIN/ROLLBACK pair in the
case of non-transactional changes in a statement that was rolled back. Note that
for the case where changes to a non-transactional table causes a rollback due
to error, the statement will now be logged with a BEGIN/ROLLBACK pair, even
though some changes has been committed to the non-transactional table.
Refactoring code to add parameter to pack() and unpack() functions with
purpose of indicating if data should be packed in little-endian or
native order. Using new functions to always pack data for binary log
in little-endian order. The purpose of this refactoring is to allow
proper implementation of endian-agnostic pack() and unpack() functions.
Eliminating several versions of virtual pack() and unpack() functions
in favor for one single virtual function which is overridden in
subclasses.
Implementing pack() and unpack() functions for some field types that
packed data in native format regardless of the value of the
st_table_share::db_low_byte_first flag.
The field types that were packed in native format regardless are:
Field_real, Field_decimal, Field_tiny, Field_short, Field_medium,
Field_long, Field_longlong, and Field_blob.
Before the patch, row-based logging wrote the rows incorrectly on
big-endian machines where the storage engine defined its own
low_byte_first() to be FALSE on big-endian machines (the default
is TRUE), while little-endian machines wrote the fields in correct
order. The only known storage engine that does this is NDB. In effect,
this means that row-based replication from or to a big-endian
machine where the table was using NDB as storage engine failed if the
other engine was either non-NDB or on a little-endian machine.
With this patch, row-based logging is now always done in little-endian
order, while ORDER BY uses the native order if the storage engine
defines low_byte_first() to return FALSE for big-endian machines.
In addition, the max_data_length() function available in Field_blob
was generalized to the entire Field hierarchy to give the maximum
number of bytes that Field::pack() will write.
