Hi, On Tue, Feb 25, 2014 at 1:26 AM, Christopher Schultz < ch...@christopherschultz.net> wrote:
> -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA256 > > Charles, > > On 2/24/14, 10:15 AM, Charles Richard wrote: > > Sorry if this is not the right forum for this kind of inquiry. I > > figure the best candidates would be in this forum from personal > > experience. > > > > Our company is having production issues which I believe are either > > due to application inefficiencies or a bug somewhere in our > > software stack. > > > > We are having production issues with our Tomcat connection pool > > using c3p0 and while my knowledge in this area has improved, I lack > > the Java developer background that might help in this area and we > > are at a point where we need this solved quickly. > > I've never gotten the sense that c3p0 was production-ready. What made > you deploy with c2p0 instead of either of the two connection pools > that ship with Tomcat? (Note that c3p0 has nothing to do with Tomcat, > other than that Tomcat can be configured to use c3p0 as its > connection-pool). > > That is good to know that c3p0 might not be commonly used in production by companies using tomcats. I was under the impression it was the most commonly used. > The problems could be related to leaked connections which I'm quite > > sure we have. I have turned on c3p0 debugging and identified this > > in the past and the ideal consultant could identify in our code > > where those are happening and fix them. > > Both pools Tomcat provides can help you track-down so-called > "abandoned" connections by providing stack traces that point to the > line of code that obtained the connection (or even Statement or > ResultSet). > > C3P0 also allows you to track down abandoned connections and my gut feeling tells me how problem is not tied down exclusively to this as our Tomcat connection pools go from 1 used connection to 150 in a minute and I know we are not losing that many leaked connections in a minute. Regardless, I will check with the manager here to see if this has been tried in the past before I started this job and potentially try this as unfortunately, the problem is not happening in our staging environment. > I would highly recommend that you read this blog post I wrote several > years ago that can help you look for obvious errors by providing > examples for what JDBC code should look like -- if you are managing > your own JDBC calls of course: > > http://blog.christopherschultz.net/index.php/2009/03/16/properly-handling-pooled-jdbc-connections/ > > > We are looking to hire a consultant that would come to Fredericton, > > NB, Canada to work with us on this problem. Serious inquiries only. > > I will be looking for proof that you have extensive experience with > > Tomcat, Java Spring and c3p0. > > > > If you are interested, send me your resume (through your company > > or individually) and send me as much proof as possible of your > > experience with the specific technologies mentioned. > > While there is certainly no prohibition against doing so, this isn't > really a "help wanted" message board. We are happy to help you -- for > free! -- via email to solve your own problems. If you find this free > forum helpful, please consider staying to be a part of the community. > You may help others or learn things yourself. > > I find this forum for the most part helpful and I've posted a few times before. In general though, I haven't felt that comfortable to post here. Before you hire anyone, you might want to try the following: > > 1. Swap c3p0 for something more reliable such as Tomcat's default pool > (based upon commons-dbcp) or the newer, higher-performance > tomcat-pool. You can find documentation for both of those online in > the Users' Guide. If the pool is performing okay, this may not be > necessary, but it's nearly free to try so it may be a good first-step. > I might have to wait a month to try this so our peak traffic subsides as I could test the config on our staging environment but since the problem is only happening on production, I would be nervous of not having the optimal configuration and make things worse. > > 2. Check your own code for resource-handling errors. Take some time to > read my blog post, or have your engineers do it (better yet, have > everyone read it). > > Will do. > 3. Run a static-analysis tool such as FindBugs (which is free) against > your code. It can detect resource leaks you may not have known you > had. Running the tool takes almost no setup and/or skill, and you can > read the report entirely for free. If you have a million errors, it > might take you a lot of staff to identify and fix the problems, but > it's likely to point-out some problem areas -- and point you to the > exact line numbers where problems are likely to be. > > Thanks for the recommendation, I've never heard of this tool. > You might get a lot of mileage (kilometerage?) out of the above > without having to hire anyone. > > Thanks for taking the time to write this and trying to help! > - -chris > Cheers! Charles > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1 > Comment: GPGTools - http://gpgtools.org > Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ > > iQIcBAEBCAAGBQJTDCmHAAoJEBzwKT+lPKRYUTAP/iNhYjUQqaYIXCEn7WrKEpVW > PCn4+ZLmzlmm1r7GSVbSc0+632JKA+YSOz+c8LplGnMAmUa6eU7sz2KgrunsnCCm > y5UiNySJ3nQEtKcHn0c7TpNmfGUGn61Y0GoK9A+JID8jubxBNMmt4nvH7FBfRrGA > GjB93hwIsJ0pK0InmejXmcoBxRYIzaVavV7nW7I/63SURv+TnXmuriHtrC5KBB39 > /o5V9VNaDZqsm7zsi3qqEYoxY2/yEMt+W9++bYajXFhhhUevWdRw2NFgihyewRuL > xc4GWV+5OIvSlsr0JtKXlJha8ooz1BVPigRd6vRQDaw2DFNzXy0Jl30kGK5ECuwI > SmldUzYjZZGEJBhN2RGNsJgDi0zpvOIBmAciUCWZFNy7xzhubx+DTK1AHUYjW15j > H1ujwZAkXfSsfY9h+vP9ATntn2YBQ3R3L7pKtjd+d7T5C9ULDIglH4o3+2kK4TEg > zV+bUhyLXM/sf9IXMOTUZa9TsF8EovbaT5sRx2gXWqbMKOgyy3lJuzMaOg3110Cd > P5tOfypeevWE0NY5+nUXDtmgKz+GHAkaOkdhlvDBjQ0UwNL/yV9WU5ui1pev2KLi > Ct7DHj92K//ROM6RerkMjHPCcLPX5c6bbBzXl5R/unfprkPoRZ0RwgxQK/2ARAst > ZDSf1VD+AUL82qVQy1rf > =VgOW > -----END PGP SIGNATURE----- > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > >
