Re: [PATCH] Custom code int(32|64) => text conversions out of performance reasons

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

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, pgsql-hackers@postgresql.org
Date: 2010-11-20T17:34:04Z
Lists: pgsql-hackers
BTW, while we're thinking about marginal improvements: instead of
constructing the string backwards and then reversing it in-place,
what about building it working backwards from the end of the buffer
and then memmove'ing it down to the start of the buffer?

I haven't tested this but it seems likely to be roughly a wash
speed-wise.  The reason I find the idea attractive is that it will
immediately expose any caller that is providing a buffer shorter
than the required length, whereas now such callers will appear to
work fine if they're only tested on small values.

A small downside is that pg_itoa would then need its own implementation
instead of just punting to pg_ltoa.

			regards, tom lane