Horton

Re: SendRowDescriptionMessage() is slow for queries with a lot of columns

Tom Lane <tgl@sss.pgh.pa.us>

View thread View on postgr.es
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: pgsql-hackers@postgresql.org
Date: 2017-09-28T04:01:53Z
Lists: pgsql-hackers 
Andres Freund <andres@anarazel.de> writes:
> Attached is an extension of the already existing pg_bswap.h that
> a) adds 16 bit support
> b) moves everything to inline functions, removing multiple evaluation
>    hazards that were present everywhere.
> c) adds pg_nto{s,l,ll} and pg_hton{s,l,ll} wrappers that only do work
>    if necessary.

Could we please not perpetuate the brain-dead "s" and "l" suffixes
on these names?  Given the lack of standardization as to how long
"long" is, that's entirely unhelpful.  I'd be fine with names like
pg_ntoh16/32/64 and pg_hton16/32/64.

			regards, tom lane

Commits

  1. Replace remaining uses of pq_sendint with pq_sendint{8,16,32}.

  2. Improve performance of SendRowDescriptionMessage.

  3. Use one stringbuffer for all rows printed in printtup.c.

  4. Add configure infrastructure to detect support for C99's restrict.

  5. Add more efficient functions to pqformat API.

  6. Allow to avoid NUL-byte management for stringinfos and use in format.c.

  7. Replace most usages of ntoh[ls] and hton[sl] with pg_bswap.h.

  8. Extend & revamp pg_bswap.h infrastructure.