[dancer-users] Dancer::Plugin::Database Hangs Randomly on check_connection

[Hugues]

Hello James
if you app works well on localnetwork, the problem come from your vpn  
connection.
Please check MTU and fragmantion packet of your vpn ( depend of vpn 
type, ipsec, ssl , other )
see 
http://codeidol.com/telecommunications/vpn/Scaling-and-Optimizing-IPsec-VPNs/MTU-and-Fragmentation-Considerations-in-an-IPsec-VPN/
bye
Hugues.


Le 21/04/2014 18:55, James Baer a écrit :
> Hello - I'm having an issue with Dancer::Plugin::Database that has 
> been hard to reproduce and track down.
>
> I have a new app that I just moved to its production environment. It 
> connects to a database that is in a remote data center over a vpn 
> tunnel. Everything functions normally as expected 98% of the time, 
> however occasionally I will hit a worker thread (deployed via Starman) 
> that just hangs trying to get a database handle. It hangs in the 
> _check_connection subroutine until it reaches some timeout. Then will 
> reconnect just fine with a new connection.
>
> I'm using plugin version 1.82 and I have traced it down to this line 
> in the plugin:
> if ($dbh->{Active} && (my $result = $dbh->ping)) {
>
> Right at this if statement is where it hangs, i assume while calling 
> the ping function. It seems there is some confusion as to whether the 
> dbh is still active, it then calls ping which hangs for a number of 
> minutes (not sure how many exactly yet, b/t 3-5). This renders this 
> worker thread unresponsive until it times out. It will eventuall fall 
> into the else block and just return false, which then a new connection 
> is established just fine.
>
> I have successfully deployed a number of apps using this same plugin 
> with no problems this only difference here is the physical location so 
> there maybe something network related, just not sure where.
>
> I have dug into DBI, etc and the ping functions works fine on all my 
> test scripts. Again, this only happens once in a while so I cannot 
> reproduce on command, which makes it difficult to debug.
>
>
> Here is the output of my debug statements, showing the one thread that 
> hangs:
>
> [27037] debug @0.005053> [hit #4]Database connection_check_threshold 
> [30] in /usr/local/share/perl5/Dancer/Plugin/Database.pm l. 69
> [27037] debug @0.005189> [hit #4]Database handle last check 
> [1398093938] in /usr/local/share/perl5/Dancer/Plugin/Database.pm l. 70
> [27037] debug @0.005345> [hit #4]Database calling check_connection in 
> /usr/local/share/perl5/Dancer/Plugin/Database.pm l. 83
> [27037] debug @0.005481> [hit #4]Database.pm in check_connection 
> before if active and ping in 
> /usr/local/share/perl5/Dancer/Plugin/Database.pm l. 265
> ... other threads working ...
> [27037] debug @962.134467> [hit #4]Database in check_connectiion false 
> return  in /usr/local/share/perl5/Dancer/Plugin/Database.pm l. 285
> [27037] debug @962.134667> [hit #4]Database connection went away, 
> reconnecting in /usr/local/share/perl5/Dancer/Plugin/Database.pm l. 90
> [27037] debug @962.134894> [hit #4]Database calling get_connection in 
> /usr/local/share/perl5/Dancer/Plugin/Database.pm l. 97
> [27037] debug @962.135059> [hit #4]Adding mysql_enable_utf8 to DBI 
> connection params to enable UTF-8 support in /usr/local/share/perl5/Dance
>
>
>
> Any help or suggestions on where to look next is appreciated.
>
> Thank you.
>
>
>
>
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