Re: (was: similar problem) Connection Pool Dies
This is a follow-up message, for the record. Following Antonio Fiol's kind prompting, I added the following Commons-DBCP elements to the DataSource resource parameters specified in my application's context fragment: validationQuery -- select 'x' from dual testWhileIdle -- true timeBetweenEvictionRunsMillis -- 60 numTestsPerEvictionRun -- 10 minEvictableIdleTimeMillis -- 60 And I'm glad to say that my web application has maintained its connection(s) despite being idle for several hours, overnight. I logged in immediately this morning. It seems easy enough once you know how, but I suppose trying to wear both developer and administrator hats is a bit of a tall order: there is just so much stuff! Good stuff, I hasten to add. Really good stuff :-) Thanks again to Antonio, and the others who responded. Kind regards Harry Mantheakis London, UK Hi Harry, I'm going to try and hijack this thread if I may (!) because, as you say... Welcome! ;-) [...] The other Tomcat server runs on a Red Hat 9 machine at my home. It connects to the above Oracle DB box - far away - using the same static IP address. [...] The problem is with the the DB connections on my own RH9 server - they just *die* after a period of inactivity :-( That period of inactivity can be as little as half and hour. [...] Very typical behaviour... at least in our scenario. BTW - the 'first' login attempt (which reactivates the connection pooling) never gets a response - it just times out. Very true. Do you think you can shed any light on this? I'll try. I have read just about every single forum discussion - from Tomcat-User to Commons DBCP to you-name-it, and I just cannot find the answer. I have a very strict firewall policy on my Linux box - using iptables. Only port 80 packets get through. Nothing else. Does that have something to do with my problem? Is there an ICMP port that I need to open up? Nope. No ICMP is needed for keepalives. The reason of your headaches may be in /proc/sys/net/ipv4/netfilter There, you have several timeout values. Check ip_conntrack_tcp_timeout_established. Anyway, however high you set the values in there, there will be an upper limit. So, I think you need to avoid your connection being idle, so that your firewall does not drop it, even with low timeout values. To do that, I suggest to use the mechanism provided by DBCP to test idle connections every now and then. testWhileIdle -- true validationQuery -- select 'x' from dual timeBetweenEvictionRunsMillis -- 30 (five minutes. Or longer, as far as it works...) On Monday, I may send you out production values. Now I don't have them, so I worked out some ;-) I am not sure whether you will need to set some more parameters. The authoritative source of information is: http://jakarta.apache.org/commons/dbcp/configuration.html Other sources (link below) say that you also have to set numTestsPerEvictionRun. I'd suggest a value equal to maxIdle. http://www.mail-archive.com/[EMAIL PROTECTED]/msg05339.html And he also proposes another solution (which I have not tested): --- You can prevent that your firewall from dropping the connection using a oracle technique. SQL*Net has a parameter which defines time interval to send a probe message to identify if the client process is still alive - SQLNET.EXPIRE_TIME, sqlnet.ora file on the server side. SQLNET.EXPIRE_TIME = your_value Set it to something like 30 when your firewall drops connection after 60 minutes. --- I hope that helped. Antonio Fiol - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: (was: similar problem) Connection Pool Dies
Hi Harry, I'm going to try and hijack this thread if I may (!) because, as you say... Welcome! ;-) [...] The other Tomcat server runs on a Red Hat 9 machine at my home. It connects to the above Oracle DB box - far away - using the same static IP address. [...] The problem is with the the DB connections on my own RH9 server - they just *die* after a period of inactivity :-( That period of inactivity can be as little as half and hour. [...] Very typical behaviour... at least in our scenario. BTW - the 'first' login attempt (which reactivates the connection pooling) never gets a response - it just times out. Very true. Do you think you can shed any light on this? I'll try. I have read just about every single forum discussion - from Tomcat-User to Commons DBCP to you-name-it, and I just cannot find the answer. I have a very strict firewall policy on my Linux box - using iptables. Only port 80 packets get through. Nothing else. Does that have something to do with my problem? Is there an ICMP port that I need to open up? Nope. No ICMP is needed for keepalives. The reason of your headaches may be in /proc/sys/net/ipv4/netfilter There, you have several timeout values. Check ip_conntrack_tcp_timeout_established. Anyway, however high you set the values in there, there will be an upper limit. So, I think you need to avoid your connection being idle, so that your firewall does not drop it, even with low timeout values. To do that, I suggest to use the mechanism provided by DBCP to test idle connections every now and then. testWhileIdle -- true validationQuery -- select 'x' from dual timeBetweenEvictionRunsMillis -- 30 (five minutes. Or longer, as far as it works...) On Monday, I may send you out production values. Now I don't have them, so I worked out some ;-) I am not sure whether you will need to set some more parameters. The authoritative source of information is: http://jakarta.apache.org/commons/dbcp/configuration.html Other sources (link below) say that you also have to set numTestsPerEvictionRun. I'd suggest a value equal to maxIdle. http://www.mail-archive.com/[EMAIL PROTECTED]/msg05339.html And he also proposes another solution (which I have not tested): --- You can prevent that your firewall from dropping the connection using a oracle technique. SQL*Net has a parameter which defines time interval to send a probe message to identify if the client process is still alive - SQLNET.EXPIRE_TIME, sqlnet.ora file on the server side. SQLNET.EXPIRE_TIME = your_value Set it to something like 30 when your firewall drops connection after 60 minutes. --- I hope that helped. Antonio Fiol smime.p7s Description: S/MIME Cryptographic Signature
Re: (was: similar problem) Connection Pool Dies
Thank you Antonio (!) Your suggestions sound very plausible - I shall look into them and I promise to post a follow up (for the record) in due course, though it might take me a couple of days. Many thanks indeed, and kind regards Harry Mantheakis London, UK Hi Harry, I'm going to try and hijack this thread if I may (!) because, as you say... Welcome! ;-) [...] The other Tomcat server runs on a Red Hat 9 machine at my home. It connects to the above Oracle DB box - far away - using the same static IP address. [...] The problem is with the the DB connections on my own RH9 server - they just *die* after a period of inactivity :-( That period of inactivity can be as little as half and hour. [...] Very typical behaviour... at least in our scenario. BTW - the 'first' login attempt (which reactivates the connection pooling) never gets a response - it just times out. Very true. Do you think you can shed any light on this? I'll try. I have read just about every single forum discussion - from Tomcat-User to Commons DBCP to you-name-it, and I just cannot find the answer. I have a very strict firewall policy on my Linux box - using iptables. Only port 80 packets get through. Nothing else. Does that have something to do with my problem? Is there an ICMP port that I need to open up? Nope. No ICMP is needed for keepalives. The reason of your headaches may be in /proc/sys/net/ipv4/netfilter There, you have several timeout values. Check ip_conntrack_tcp_timeout_established. Anyway, however high you set the values in there, there will be an upper limit. So, I think you need to avoid your connection being idle, so that your firewall does not drop it, even with low timeout values. To do that, I suggest to use the mechanism provided by DBCP to test idle connections every now and then. testWhileIdle -- true validationQuery -- select 'x' from dual timeBetweenEvictionRunsMillis -- 30 (five minutes. Or longer, as far as it works...) On Monday, I may send you out production values. Now I don't have them, so I worked out some ;-) I am not sure whether you will need to set some more parameters. The authoritative source of information is: http://jakarta.apache.org/commons/dbcp/configuration.html Other sources (link below) say that you also have to set numTestsPerEvictionRun. I'd suggest a value equal to maxIdle. http://www.mail-archive.com/[EMAIL PROTECTED]/msg05339.html And he also proposes another solution (which I have not tested): --- You can prevent that your firewall from dropping the connection using a oracle technique. SQL*Net has a parameter which defines time interval to send a probe message to identify if the client process is still alive - SQLNET.EXPIRE_TIME, sqlnet.ora file on the server side. SQLNET.EXPIRE_TIME = your_value Set it to something like 30 when your firewall drops connection after 60 minutes. --- I hope that helped. Antonio Fiol - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
