Re: fd.c: flush data problems on osx

Andres Freund <andres@anarazel.de> writes:
> I'm not entirely sure what

> +   /*
> +    * Caution: do not call pg_flush_data with amount = 0, it could trash the
> +    * file's seek position.
> +    */
> +   if (amount <= 0)
> +       return;
> +

> is about?

fd.c tracks seek position for open files.  I'm not sure that that
function can get called with amount == 0, but if it did, the caller
would certainly not be expecting the file position to change.
        regards, tom lane