Re: Questions about connection clean-up and "invalid page header"

Greg Stark wrote:

> On Mon, Jan 25, 2010 at 11:37 AM, Herouth Maoz <herouth(at)unicell(dot)co(dot)il> wrote:
>
>> The tcp_keepalive setting would only come into play if the remote
>> machine crashed or was disconnected from the network.
>>
>>
>> That's the situation I'm having, so it's OK. Crystal, being a Windows
>> application, obviously runs on a different server than the database itself,
>> so the connection between them is TCP/IP, not Unix domain sockets.
>>
>
> The unix socket api is used for both unix domain sockets and internet
> domain sockets. The point is that in the api there's no way to find
> out about a connection the other side has closed except for when you
> write or read from it or when you explicitly check.
>
>
>
>> And
>> furthermore, that was exactly the problem as I described it - the fact that
>> the third party software, instead of somehow instructing Crystal to send a
>> cancel request to PostgreSQL, instead just kills the client process on the
>> Windows side.
>>
>
> Killing the client process doesn't mean the machine has crashed or
> been disconnected from the network. I'm assuming Crystal isn't
> crashing the machine just to stop the report... And even if it did and
> tcp_keepalives kicked in the server *still* wouldn't notice until it
> checked or tried to read or write to that socket.
>
>
Well, I assume by the fact that eventually I get an "Unexpected end of
file" message for those queries, that something does go in and check
them. Do you have any suggestion as to how to cause the postgresql
server to do so earlier?

Herouth