On Wed, Nov 8, 2017 at 8:46 AM, Robert Haas <robertmh...@gmail.com> wrote:
> On Tue, Nov 7, 2017 at 4:31 AM, Haribabu Kommi <kommi.harib...@gmail.com> > wrote: > >> Updated patch attached. > > Patch rebased. > > I think the earlier concerns about the performance impact of this are > probably very valid concerns, and I don't see how the new version of > the patch gets us much closer to solving them. > I will check the performance with the changes of removing the stats collector usage and provide the details. > I am also not sure I understand how the backend_write_blocks column is > intended to work. The only call to pgstat_send_walwrites() is in > WalWriterMain, so where do the other backends report anything? > With the current patch, All the backends update the stats in shared memory structure and only WAL writer process gathers the stats and share with the stats collector. > Also, if there's only ever one global set of counters (as opposed to > one per table, say) then why use the stats collector machinery for > this at all, vs. having a structure in shared memory that can be > updated directly? It seems like adding a lot of overhead for no > functional benefit. > Yes, I agree that using stats collector for these stats is an overhead. I change the patch to use just the shared memory structure and gather the performance results and post it to the next commitfest. Currently I marked the patch as "returned with feedback" in the ongoing commitfest. Regards, Hari Babu Fujitsu Australia
