[Bucardo-general] Questions regarding synchronization and sequences

[Greg Sabino Mullane]

> Is it possible to configure Bucardo in such a way that a sync will not occur during a given timeframe?
> 
> Perhaps the best way to go about it is to write a cronjob that will 
> "bucardo_ctl stop" on Friday night, and "bucardo_ctl start" on Monday morning. 
> Is this advisable?  What would other people recommend?

Yes, that should be fine. Or maybe wrap that into the script that actually 
shuts down and restores the instance, if you can. Keep in mind there will 
be a slight spinup cost as Bucardo processes all the changes while things 
were down. So ideally you might keep the application away from the database 
until things are caught up. This could take seconds or minutes: you will have 
to measure.

> Also, I have one other question.  Do table sequences need to be explicitly 
> added to Bucardo?  I ran a basic example consisting of two source tables, 
> each with a sequence.  I did not explicitly add the sequences, and everything 
> seems to be OK.  In what situation would you want to explicitly add them?  The 
> reason that I am asking is because the sequences in my database are controlled 
> by Hibernate.  There is a hibernate_sequence that is used to generate the 
> sequence ID's for every table in the database.  The default Hibernate sequence 
> generator uses a Hi/Lo algorithm, so the numbers can jump around quite a bit.  
> I just want to make sure that this wouldn't cause any problems with Bucardo.

Hard to tell - is this hibernate_sequence an actual Postgres sequence that 
lives on each database? In which case, yes, that would cause lots of problems 
as both masters will start inserting records with identical pks (assuming 
that hibernate_sequence is used indirectly to generate the PKs). The best 
solution is probably the same as non-hibernate Bucardos: do not add them to 
Bucardo, and simply have them alternate even and odds so that the same numbers 
are never produced on each one. If that doesn't fit your situation or sounds 
wrong please let us know.


-- 
Greg Sabino Mullane greg at endpoint.com
End Point Corporation
PGP Key: 0x14964AC8
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