Re: Exposing the Xact commit order to the user

On 6/3/2010 7:11 PM, Alvaro Herrera wrote:
> Excerpts from Chris Browne's message of jue jun 03 16:21:35 -0400 2010:
> 
>> What this offers is *SOME* idea of how much updating work a particular
>> transaction did.  It's a bit worse than you suggest:
>> 
>>  - If replication triggers have captured tuples, those would get
>>    counted.
>> 
>>  - TOAST updates might lead to extra updates being counted.
>> 
>> But back to where you started, I'd anticipate 7 inserts, 7 deletes,
>> and 7 updates being counted as something around 21 updates.
>> 
>> And if that included 5 TOAST changes, it might bump up to 26.
>> 
>> If there were replication triggers in place, that might bump the count
>> up to 45 (which I chose arbitrarily).
> 
> Why not send separate numbers of tuple inserts/updates/deletes, which we
> already have from pgstats?
> 

We only have them for the entire database. The purpose of this is just a 
guesstimate about what data volume to expect if I were to select all log 
from a particular transaction.

This datum isn't critical, just handy for the overall feature to be useful.


Jan

-- 
Anyone who trades liberty for security deserves neither
liberty nor security. -- Benjamin Franklin