On 7 June 2018 at 06:01, David Rowley <david.rowley@2ndquadrant.com> wrote: > On 7 June 2018 at 16:13, Andres Freund <andres@anarazel.de> wrote: >> in PortalRun(). That's actually fairly trivial to optimize - we don't >> need the full blown snprintf machinery here. A quick benchmark >> replacing it with: >> >> memcpy(completionTag, "SELECT ", sizeof("SELECT ")); >> pg_lltoa(nprocessed, completionTag + 7); > > I'd also noticed something similar with some recent benchmarks I was > doing for INSERTs into partitioned tables. In my case I saw as high as > 0.7% of the time spent building the INSERT tag. So I think it's worth > fixing this. > > I think it would be better to invent a function that accepts a > CmdType, int64 and Oid that copies the tag into the supplied buffer, > then make a more generic change that also replaces the code in > ProcessQuery() which builds the tag. I'm sure there must be some way > to get the CmdType down to the place you've patched so we can get rid > of the if (strcmp(portal->commandTag, "SELECT") == 0) line too.
Sounds better
Do we actually need the completion tag at all? In most cases??
affected rows is taken from this value on protocol level
Regards
Pavel
Perhaps we should add a parameter to make it optional and turn it off by default, except for psql. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
