RE: Mysterious 5 second delay on sybase_connect()

["Tom Lloyd" <TomLloyd@xxxxxxxxxxxxxxxxxx>]

nsswitch seems to be OK, but it wasn't aliased to localhost for ipv6.  I've fixed that now (and knocked back the ipv6 precedence in /etc/gai.conf) and it seems to be behaving... 

Still doesn't explain to me why it was looking itself up in the first place...  Weird :/

-- Tom

-----Original Message-----
From: charlesmorris@xxxxxxxxx [mailto:charlesmorris@xxxxxxxxx] On Behalf Of Charles Morris
Sent: 24 May 2012 17:40
To: Tom Lloyd
Cc: Matijn Woudt; php-db@xxxxxxxxxxxxx
Subject: Re:  Mysterious 5 second delay on sybase_connect()

Is it's own host name in the hosts file and nsswitch.conf set up correctly?

Alternatively disable all the ipv6 adapters if you aren't using them.

On Thu, May 24, 2012 at 12:23 PM, Tom Lloyd <TomLloyd@xxxxxxxxxxxxxxxxxx> wrote:
> Say the webserver is called foo, on the domain company.local.  No ipv6 is enabled in the network.  A network trace tells me that when the HTTP request comes in, the webserver sends out a DNS request for "AAAA foo.company.local".  Nothing replies, and after 5 seconds it times out and carries on doing what it was doing.
>
> Why would it be doing a DNS lookup for the IPv6 address of its own hostname?  And more urgently, how can I stop it?
>
> -----Original Message-----
> From: Tom Lloyd
> Sent: 24 May 2012 16:26
> To: 'Matijn Woudt'
> Cc: php-db@xxxxxxxxxxxxx
> Subject: RE:  Mysterious 5 second delay on sybase_connect()
>
> I'm getting increasingly suspicious that DNS is to blame.  If I was to do something like:
>
> $conn = sybase_connect( "10.0.0.11\SQLMAIN", $user, $pass )
>
> Would that trigger a lookup of some variety?
>
> -----Original Message-----
> From: Matijn Woudt [mailto:tijnema@xxxxxxxxx]
> Sent: 24 May 2012 13:00
> To: Tom Lloyd
> Cc: php-db@xxxxxxxxxxxxx
> Subject: Re:  Mysterious 5 second delay on sybase_connect()
>
> On Thu, May 24, 2012 at 10:51 AM, Tom Lloyd <TomLloyd@xxxxxxxxxxxxxxxxxx> wrote:
>> Hi there.  I'm working on a PHP-driven project on Debian Squeeze that 
>> connects to an instance of Microsoft SQL Server on Windows Server 2008.
>> I'm using the sybase extensions to PHP.
>>
>> Since I rebooted the webserver on the weekend, both the
>> sybase_connect() and sybase_pconnect() commands will sometimes take 
>> exactly 5 seconds to execute.  It seems to be random whether they do 
>> this or not.  I can't think of anything that could have been changed 
>> by the reboot, unless a package was updated but its associated process never got restarted...
>>
>> Does anyone know what might cause this behaviour?
>>
>> Cheers,
>> Tom Lloyd
>>
>
> It most likely has nothing to do with PHP, but is rather a routing issue. 5 seconds is the default connection time out for TCP/IP, so it probably makes sense that the connection is failing at a lower level.
>
> - Matijn

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