Hi all,
I would like to introduce a topic for discussion, regarding DB connection pools used in CloudStack, currently Apache Commons DBCP 1.4 (http://commons.apache.org/) is used. I've been investigating this topic as we are having complains of random issues on MySQL connection pool on large environments. Please let me know if this topic has already been discussed before. First of all, DBCP 1.4 has been released on 2010 (https://commons.apache.org/proper/commons-dbcp/changes-report.html), and no minor/patch version has been released since then. It seems to work in high performance with relatively low traffic and low load applications. However, it is single threaded, and in order to be thread-safe, the entire pool needs to be locked. It is also reported that an CPU and concurrent threads increases, the performance gets affected. This is a serious issue on highly concurrent systems, such as CloudStack. I've been investigating some options to replace it: - The first option can be upgrading to version 2.x. Issues on performance and concurrency could be solved using this version. - Tomcat JDBC Connection Pool. Please check: https://tomcat.apache.org/tomcat-7.0-doc/jdbc-pool.html. - Other replacement options found: BoneCP, C3P0, HikariCP Given these options, I've been looking for benchmarks to compare them (*). Looks like HikariCP (http://brettwooldridge.github.io/HikariCP/) could be the best replacement, improving performance and stability. Another good replacement option could be Tomcat. I've been also examining the codebase, data source initialization is done on TransactionLegacy class under the cloud-framework-db project. Replacement work should be done on this class. Instead of pure replacement, a global setting can be introduced to make the admins able to select which connection pool to use. What do you think? Any possitive/negative feedback is welcome as well as new ideas. As mentioned before, I don't know if it has been discussed before, sorry in advance if it has. Kind regards, Nicolas (*) Links to benchmarks and comparissons: https://www.wix.engineering/single-post/how-many-threads-does-it-take-to-fill-a-pool https://www.wix.engineering/single-post/how-does-hikaricp-compare-to-other-connection-pools <https://www.wix.engineering/single-post/how-does-hikaricp-compare-to-other-connection-pools>https://beansroasted.wordpress.com/2017/07/29/connection-pool-analysis/ https://beansroasted.wordpress.com/tag/connection-pool-comparison/ <https://beansroasted.wordpress.com/tag/connection-pool-comparison/>https://github.com/brettwooldridge/HikariCP/wiki/%22My-benchmark-doesn't-show-a-difference.%22 http://www.trustiv.co.uk/2014/06/battle-connection-pools nicolas.vazq...@shapeblue.com www.shapeblue.com , @shapeblue
