The building of command completion tags could often be seen showing up in
profiles when running high tps workloads.
The query completion tags were being built with snprintf, which is slow at
the best of times when compared with more manual ways of formatting
strings. Here we introduce BuildQueryCompletionString() to do this job
for us. We also now store the completion tag's strlen in the
CommandTagBehavior struct so that we can quickly memcpy this number of
bytes into the completion tag string. Appending the rows affected is done
via pg_ulltoa_n. BuildQueryCompletionString returns the length of the
built string. This saves us having to call strlen to figure out how many
bytes to pass to pq_putmessage().
Author: David Rowley, Andres Freund
Reviewed-by: Andres Freund
Discussion: https://postgr.es/m/CAHoyFK-Xwqc-iY52shj0G+8K9FJpse+FuZ36XBKy78wDVnd=Qg@mail.gmail.com
Make sure that function declarations use names that exactly match the
corresponding names from function definitions in optimizer, parser,
utility, libpq, and "commands" code, as well as in remaining library
code. Do the same for all code related to frontend programs (with the
exception of pg_dump/pg_dumpall related code).
Like other recent commits that cleaned up function parameter names, this
commit was written with help from clang-tidy. Later commits will handle
ecpg and pg_dump/pg_dumpall.
Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: David Rowley <dgrowleyml@gmail.com>
Discussion: https://postgr.es/m/CAH2-WznJt9CMM9KJTMjJh_zbL5hD9oX44qdJ4aqZtjFi-zA3Tg@mail.gmail.com
The backend was using strings to represent command tags and doing string
comparisons in multiple places, but that's slow and unhelpful. Create a
new command list with a supporting structure to use instead; this is
stored in a tag-list-file that can be tailored to specific purposes with
a caller-definable C macro, similar to what we do for WAL resource
managers. The first first such uses are a new CommandTag enum and a
CommandTagBehavior struct.
Replace numerous occurrences of char *completionTag with a
QueryCompletion struct so that the code no longer stores information
about completed queries in a cstring. Only at the last moment, in
EndCommand(), does this get converted to a string.
EventTriggerCacheItem no longer holds an array of palloc’d tag strings
in sorted order, but rather just a Bitmapset over the CommandTags.
Author: Mark Dilger, with unsolicited help from Álvaro Herrera
Reviewed-by: John Naylor, Tom Lane
Discussion: https://postgr.es/m/981A9DB4-3F0C-4DA5-88AD-CB9CFF4D6CAD@enterprisedb.com
Bruce Momjian
David Rowley
Peter Geoghegan
Alvaro Herrera