Thread

1. DB Connections in TIME_WAIT state

   John Gateley <gateley@jriver.com> — 2008-05-13T13:22:15Z

   Hi, I'm using the Pg perl module to connect to Postgresql 8.1
   via localhost (127.0.0.1) from webscripts. I'm noticing a lot
   of TIME_WAIT socket connections:
   
   tcp        0      0 127.0.0.1:39291         127.0.0.1:5432          TIME_WAIT  
   tcp        0      0 127.0.0.1:60720         127.0.0.1:5432          TIME_WAIT  
   tcp        0      0 127.0.0.1:60735         127.0.0.1:5432          TIME_WAIT  
   tcp        0      0 127.0.0.1:60769         127.0.0.1:5432          TIME_WAIT  
   tcp        0      0 127.0.0.1:39281         127.0.0.1:5432          TIME_WAIT  
   ...
   
   I think the number is high enough (200~250) that sometime the
   server runs out of sockets.
   
   What's the proper way to close the postgresql connection so that
   it doesn't go into a TIME_WAIT state?
   
   I tried:
   
   use Pg;
   my $Connection = Pg::connectdb($ConnectString);
   ... do some stuff
   $Connection = 0;
   
   That doesn't seem to close the connection.
   
   Any ideas?
   
   Thanks,
   
   j
   -- 
   John Gateley <gateley@jriver.com>
   
   

2. Re: DB Connections in TIME_WAIT state

   Tom Lane <tgl@sss.pgh.pa.us> — 2008-05-13T14:23:48Z

   John Gateley <gateley@jriver.com> writes:
   > Hi, I'm using the Pg perl module to connect to Postgresql 8.1
   > via localhost (127.0.0.1) from webscripts. I'm noticing a lot
   > of TIME_WAIT socket connections:
   
   > tcp        0      0 127.0.0.1:39291         127.0.0.1:5432          TIME_WAIT  
   > tcp        0      0 127.0.0.1:60720         127.0.0.1:5432          TIME_WAIT  
   > tcp        0      0 127.0.0.1:60735         127.0.0.1:5432          TIME_WAIT  
   > tcp        0      0 127.0.0.1:60769         127.0.0.1:5432          TIME_WAIT  
   > tcp        0      0 127.0.0.1:39281         127.0.0.1:5432          TIME_WAIT  
   > ...
   
   This seems like a kernel bug to me.  The TCP stack ought to know it
   doesn't need any shutdown delay on a local connection.
   
   > I think the number is high enough (200~250) that sometime the
   > server runs out of sockets.
   
   Maybe you need to stop using so many connections --- quite aside
   from any kernel issues, a database session isn't exactly cheap
   to launch.  Consider some form of connection pooling.
   
   			regards, tom lane