Yuan Wang wrote:
> Hi Mats
>
> Thank you for your kind reply. But how to handle binlog in the engine?
> Could you be so kind to give me some hints?
Hi Yuan,
The only self-logging engine that MySQL has is NDB. It keeps a separate injector
thread which receives events from the NDB cluster and inject them into the
binlog using the injector interface.
If you take a look at ha_ndbcluster_binlog.cc, you can see how it works.
Best wishes,
Mats Kindahl
>
> On Fri, Nov 20, 2009 at 4:06 PM, Mats Kindahl <mats@stripped> wrote:
>> Hi Yuan,
>>
>> No, you are understanding it correctly, each statement is a transactional unit
>> and all rows are cached until the statement completes.
>>
>> You might be able to use the "self-logging" flag to indicate that the storage
>> engine is going to handle the logging itself.
>>
>> Best wishes,
>> Mats Kindahl
>>
>> Yuan Wang wrote:
>>> We are developed a storage engine using row based replication. This
>>> engine is non-transactional and will use row level locking. The row
>>> locks will only be holded for a very short time, just to protect a
>>> single row from concurrent update. If a statement updates multiple
>>> rows, the engine will lock the first row, update it, unlock it, and
>>> lock the second row, update it, unlock it, etc. So the following
>>> senario is possible:
>>>
>>> statement 1: update row1;
>>> statement 2: update row2;
>>> statement 1: update row2;
>>> statement 2: update row1;
>>>
>>> That is. The final state of row1 is statement 2's, and the final state
>>> of row2 is statement 1's. For proper replication, the binlog events
>>> should be written is the following order:
>>>
>>> statement 1's update of row1;
>>> statement 2's update of row2;
>>> statement 1's update of row2;
>>> statement 2's update of row1;
>>>
>>> However based on the manual, it seems that multiple binlog events of
>>> the same statement will be cached and be written as a whole unit when
>>> the statement finished.
>>>
>>> This will lead to improper replication. So I'm curious to know is this
>>> the case or I misunderstanded.
>>>
>> --
>> Mats Kindahl
>> Senior Software Engineer
>> Database Technology Group
>> Sun Microsystems
>>
--
Mats Kindahl
Senior Software Engineer
Database Technology Group
Sun Microsystems
