Hi, On 2023-03-25 11:56:22 +0900, Michael Paquier wrote: > On Thu, Mar 16, 2023 at 02:13:45PM +0100, Drouvot, Bertrand wrote: > > On 3/16/23 12:46 PM, Michael Paquier wrote: > >>> I don't think we should pay any particular attention to those 2 ones > >>> as anyway nothing prevent the 7 others to be called outside of the > >>> pg_stat_xact_all_tables view. > >> > >> I am not quite sure, TBH. Did you look at the difference with a long > >> chain of subtrans, like savepoints? The ODBC driver "loves" producing > >> a lot of savepoints, for example. > > > > No, I did not measure the impact. > > I have been thinking again about this particular point, and I would be > fine with an additional boolean flag to compute the subtrans data in > the global counter when only necessary. This would not make the > macros for the stat functions that much more complicated, while being > sure that we don't do unnecessary computations when we know that we > don't need them..
I don't understand what we're optimizing for here. These functions are very very very far from being a hot path. The xact functions are barely ever used. Compared to the cost of query evaluation the cost of iterating throught he subxacts is neglegible. Greetings, Andres Freund
