Re: Permission denied on fsync / Win32 (was right

Here's the evidence from this morning. I have to admit I'm not really
sure what to make of it though.

Pete

The fsync / Permission denied errors occurred on 2 of 3 active servers
for the 7 am CLUSTER cycle.

Server #1 (with fsync errors):
- Both old and new relfilenodes are still visible with a 'dir':
04/19/2006 07:00 AM 16,384 1532868
04/19/2006 07:06 AM 8,192 1536650

- postgres.exe processes have handles to both old and new
relfilenodes

#1:
F64: File G:\pgsql\data\base\16385\1532868
F84: Event \BaseNamedObjects\pgident: postgres: bigbird
bigbird 127.0.0.1(1745) idle

#2:
F80: File G:\pgsql\data\base\16385\1536650
AB4: Event \BaseNamedObjects\pgident: postgres: writer
process

#3:
F0C: File G:\pgsql\data\base\16385\1536650
F48: Event \BaseNamedObjects\pgident: postgres: bigbird
bigbird 127.0.0.1(1732) idle

(plus a few more like this)

Server #2 (with fsync errors):
- Same pattern as Server #1. bgwriter has a handle to the new
relfilenode. Other backends have a handle to either old or new.

Server #3 (w/o fsync errors):
- Only the new relfilenode is visible with a 'dir':
04/19/2006 07:34 AM 16,384 1550915

- postgres.exe processes have handles to both old and new
relfilenodes

#1:
F60: File G:\pgsql\data\base\16385\1547888
F84: Event \BaseNamedObjects\pgident: postgres: bigbird
bigbird 127.0.0.1(4060) idle

(plus two more like this)

#2:
F78: File G:\pgsql\data\base\16385\1550915
F84: Event \BaseNamedObjects\pgident: postgres: bigbird
bigbird 127.0.0.1(2925) idle

(plus two more like this)

>>> "Magnus Hagander" <mha(at)sollentuna(dot)net> 04/18/06 9:00 pm >>>
> It happens often enough and the episodes last long enough
> that grabbing a handle dump while this is going on should be
> easily done.
>
> Regarding the Win32 error code, backend/storage/file/fd.c
> calls _commit().
> http://msdn2.microsoft.com/en-us/library/17618685(VS.80).aspx
> It looks
> like it is already using errno to report errors. Will
> GetLastError() return something useful there?

Good point.
Ran a quick test. If I open the file read-only and then fsync, I get
errno=9 (EBADF) and GetLastError()=5. Which explains the fact that we
got the wrong error-code. The *underlying API call* to _commit()
returns
access denied...

Looking at the source to _commit(), if the call to FlushFileBuffers()
returns an error, it will set _doserrno to that value,and then return
with errno=EBADF.

So, this basicalliyu means that FlushFileBuffers() returns ACCESS
DENIED.

//Magnus

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