Re: read() returns ERANGE in Mac OS X

Excerpts from Florian Pflug's message of jue may 17 09:08:26 -0400 2012:
> On May16, 2012, at 15:51 , Tom Lane wrote:

> > It is by design, in that the only contemplated case was truncated-away
> > pages. I'm pretty hesitant to consider allowing arbitrary kernel errors
> > to be ignored here …
>
> Maybe we should have zero_missing_pages which would only zero on short reads,
> and zero_damaged_pages which would zero on all IO errors?
>
> Or we could have zero_damaged_pages zero only if reports EIO, and then add
> any platform-specific additional error codes as we learn about them. ERANGE
> on darwin would be the first such addition.

Seems to me that we could make zero_damaged_pages an enum. The default
value of "on" would only catch truncated-away pages; another value would
also capture kernel-level error conditions.

The thing is, once you start getting kernel-level errors you're pretty
much screwed and there's no way to just recover whatever data is
recoverable.

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Álvaro Herrera <alvherre(at)commandprompt(dot)com>
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