[Bucardo-general] Bucardo design question

[Michelle Sullivan]

Greg Sabino Mullane wrote:
>> I'm really running into problems getting this to catch up - the time to
>> gather the data for the sync is increasing to unworkable levels.  The
>> problems are not due to Bucardo but my knowledge about the cleanup crons
>> , and a couple of hardware issues.  These have been solved and I need
>> for this to catchup really quick.  Can you explain (very quickly) how
>> Bucardo knows about transactions....
>>     
>
> How big are the tables? At some point it becomes easier to simply 
> do a onetimecopy (unless this is a swap sync)
>   

swap_sync... 146G across 58 tables.... between australia and the US
>   
>> Specifically I have writers in my app that will 'BEGIN' then insert or
>> update several tables before 'COMMIT'ing...  Does Bucardo see the update
>> of all the tables as a single transaction?
>>     
>
> Yes.
>
>   
>> Does Bucardo know about the foreign keys so that it only inserts rows in
>> the correct order?
>>     
>
> As long as all the tables linked by foreign keys are in the same sync, there 
> is no problem and no need to worry about the correct order.
>   

They are.
>   
>> How does Bucardo choose what to sync from each table, point in time (ie
>> now) or to the last transaction?
>>     
>
> Neither: it simply gathers a list of all rows that have changed since the 
> last time it synced, and applied those. The time and the transaction do 
> not enter into it.
>
>   
Is it possible to grab them by transactions?

Michelle