On 9/14/2007 3:10 PM, Dmitry Koterov wrote:
> MySQL has the "binary log" to which all data is appended before it is 
> committed to the real table. All MySQL replicas are simply replaying 
> this binary log from a specified position, so it is quite close to what 
> Slony does (but Slony uses its own event log, not built-in as in MySQL). 
> Seems an asynchronous statement-based replication does not exists in the 
> world at all.

According to the MySQL 5.1 manual

     http://dev.mysql.com/doc/refman/5.1/en/binary-log.html

it contains statements. Seems people aren't exactly sure what a 
statement is in MySQL land.

Then again:

"The format of the events recorded in the binary log is dependent on the 
binary logging format. Three format types are supported, row-based 
logging, statement-based logging and mixed-base logging. The binry 
logging format used deoends on the MySQL version. For more information 
on logging formats, see Section 5.11.4.1, “Binary Logging Formats”."

Which is as best confusing. So different versions support different 
logging formats, and they are not all available at the same time? And 
what the heck is mixed-based? Have MySQL (which is known to make pretty 
bad judgments when it comes the integrity and consistency of YOUR data) 
chose when to aim for row based and when statement based might be "faster"?

Further down it explains that writes to the log are handled like MyISAM 
writes. Which doesn't really mean much to me, but maybe someone can tell 
if that means that a transaction, done and committed against InnoDB 
tables, could be recovered in a server crash situation but lost from the 
"binary log"? Or is that something 100% guaranteed impossible? The 
manual isn't quite clear about that.


Jan

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