Re: win32 _dosmaperr()

Qingqing wrote:
> There were several reports of "unable to read/write" on Pg8.0.x win32
> port:
>
> http://archives.postgresql.org/pgsql-bugs/2005-02/msg00181.php
>
> I encounter this several times and finally I catch the GetLastError()
> number. It is
>
>     32, ERROR_SHARING_VIOLATION
>     The process cannot access the file because it is being used by
another
> process.
>
> But PG server error message is "invalid parameter" which makes this
error
> difficult to understand and track. After examing win32 CRT's
_dosmaperr()
> implementation, I found they failed to transalte
ERROR_SHARING_VIOLATION,
> so
> the default errno is set to EINVAL. To solve it, we can do our own
> _dosmaperr(GetLastError()) again if read/write failed. Unfortunately
our
> _dosmaperr() failed to do so either, so here is a patch of error.c.
Also,
> I
> raised the error level to NOTICE for better bug report. If this is
> acceptable, I will patch FileRead()/FileWrite() etc.
>
> However, I am very sure why this could happen. That is, who uses the
data
> file in a non-sharing mode? There are many possibilities, a common
> concensus
> is [Anti-]virus software. Yes, I do have one installed. If we can
confirm
> this, then we could at least print a hint message.

I had similar problems since the early days of the win32 port, random
restarts of the stats collector and other unexplainable things.  This
only ever happened under heavy loads (1000+/sec sustained query
processing) with statement level stats on.  This played havoc with my
user diagnostic tools because it randomly restarted the stats collector
so I've had to keep row level stats off.

Merlin