Re: [HACKERS] Checksums by default? - Mailing list pgsql-hackers

From Tom Lane
Subject Re: [HACKERS] Checksums by default?
Date
Msg-id 28454.1485016517@sss.pgh.pa.us
Whole thread Raw
In response to [HACKERS] Checksums by default?  (Magnus Hagander <magnus@hagander.net>)
Responses Re: [HACKERS] Checksums by default?  (Tomas Vondra <tomas.vondra@2ndquadrant.com>)
List pgsql-hackers
Stephen Frost <sfrost@snowman.net> writes:
> * Tom Lane (tgl@sss.pgh.pa.us) wrote:
>> Have we seen *even one* report of checksums catching problems in a useful
>> way?

> This isn't the right question.

I disagree.  If they aren't doing something useful for people who have
turned them on, what's the reason to think they'd do something useful
for the rest?

> The right question is "have we seen reports of corruption which
> checksums *would* have caught?"

Sure, that's also a useful question, one which hasn't been answered.

A third useful question is "have we seen any reports of false-positive
checksum failures?".  Even one false positive, IMO, would have costs that
likely outweigh any benefits for typical installations with reasonably
reliable storage hardware.

I really do not believe that there's a case for turning on checksums by
default, and I *certainly* won't go along with turning them on without
somebody actually making that case.  "Is it time yet" is not an argument.
        regards, tom lane



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