Re: Losing records when server hang

lec wrote:

> Scott Marlowe wrote:
>
>>On Sun, 2004-08-08 at 19:43, lec wrote:
>>
>>
>>>Hi,
>>>
>>>I'm observing the following:
>>>If I commit the following records 1,2,3,4,5,6,7,8,9,10 to the database
>>>and the server hangs, I could lose records 5,6,7,8,9 but record 10 is
>>>there.  How is this possible and do anyone know how Postgresql
>>>physically writes the records?
>>>
>>>
>>
>>Assuming a properly function storage subsystem and a kernel that does
>>not lie about fsync, this is not possible.
>>
>>Are you running on top of IDE drives with the write cache enabled?
>>Most, if not all, IDE drives lie about FSYNC and can lose data if power
>>is disconnected abrubtly.
>>
>>
> SCSI
>
>>Or if you are running with fsync=false in postgresql.conf the same thing
>>can happen.  Otherwise, not, it should not happen.  More info perhaps?
>>
>>
>>
>>
> I didn't change the default fsync, which I believe is fsync=true.

Could your SCSI controller be misbehaving?  Could this be leading to a
system hang (say when swap space is being called back into memory)?

Best Wishes,
Chris Travers
Metatron Technology Consulting