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Re: Review of patch for MDEV-4820
On 08/13/2013 09:49 AM, Kristian Nielsen wrote:
You can always use the contents of the binlogs to know this. You can
search the binlogs for your GTID and determine if it was a) logged in
an earlier binlog that was purged, b) found in the binlog, c) a "hole"
due to filtering or whatever, or d) not yet existing at all in the
binlog (not yet received from the master or completely alternate future).
There is a big assumption here, that you have that binlog file
available. If it is c) and d) look very similar if this binlog is the
only one available currently.
What exactly is it that the implementation does not allow, or which is
hard to implement?
Let's assume we do not have master up and running. But there are several
slaves to choose. If every slave have different last GTID as executed,
what automatic rule you could come up to choose the correct up the date
slave as master ? The fact that some slave has largest GTID does not
mean that it has executed all the same GTIDs as the former master (now
dead and might have lost its binlog). If all slaves are in different
alternate futures, not sure which one to select or maybe we should
select superposition of all of those ;-)