Re: Current int & float overflow checking is slow.
Robert Haas <robertmhaas@gmail.com>
From: Robert Haas <robertmhaas@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andres Freund <andres@anarazel.de>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2017-10-25T05:33:46Z
Lists: pgsql-hackers
On Tue, Oct 24, 2017 at 9:28 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote: > I don't like changing well-defined, user-visible query behavior for > no other reason than a performance gain (of a size that hasn't even > been shown to be interesting, btw). Will we change it back in another > ten years if the performance tradeoff changes? > > Also, if I recall the old discussion properly, one concern was getting > uniform behavior across different platforms. I'm worried that if we do > what Andres suggests, we'll get behavior that is not only different but > platform-specific. Now, to the extent that you believe that every modern > platform implements edge-case IEEE float behavior the same way, that worry > may be obsolete. But I don't think I believe that. Yeah, those are reasonable concerns. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
Commits
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Provide overflow safe integer math inline functions.
- 4d6ad31257ad 11.0 landed
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Use new overflow aware integer operations.
- 101c7ee3ee84 11.0 landed