-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Neven,
On 3/5/14, 8:25 PM, Neven Cvetkovic wrote: > On Wed, Mar 5, 2014 at 3:15 PM, S Ahmed <sahmed1...@gmail.com> > wrote: > >> Hi, >> >> With jdbc pool, is each socket connection in the pool handled by >> a separate thread? >> >> > Ahmed, thanks for asking this question - it is sometimes very > confusing with all different kind of pools: connection pools, > threadpools, etc... > > Chris pointed out already - the connection pool does not have any > threads... It is not a process that runs in the background, these > are just connection objects that are sitting in memory. The connection pool does not "run in the background". The code executes when a request-processing thread requests a connection. Threads execute code. Code doesn't execute or "run" itself. > Threads are created by the Tomcat container (executor) once the > connection is received by the Connector. The created thread is then > going to be handled by the container and it will go through the > stack call, through Valves, Filters, Servlets, your middleware > layer, DAOs, JDBC/JPA calls and then finally through your > datasource object, connection, PreparedStatement, ResultSet, etc... > and back all the way to the socket that browser initiated, > returning the thread to the threadpool (e.g. http-bio-8080). > > Now, I am not sure about the connection pool implementation > details, how connection pool keeps connections open, if there are > any background threads that are handling connection management > (closing abandoned connections, opening new connections as the > demand rises, etc...) > > Maybe someone can comment on that. There are such threads, if you configure them. >> Say you have 20 connections set to be open at minimum, does that >> mean there will be 20 threads? If not, then there is a degree of >> serialization then right? >> > > > Well, there will be no serialization, but rather "synchronization" > as there are at most XXXX available connections, if the connection > pool (datasource) reaches maximum allowed connections, depending on > the implementation - it would be a blocking call, until the pool > has available connection to provide... In the threading world, "synchronization" and "serialization" essentially mean the same thing: protected and exclusive access to a particular resource. Presumably, the OP wanted to know whether it was safe to use a connection pool in a multi-threaded setting, but it wasn't clear if he meant the connection pool itself, or an individual connection obtained from the pool. That's why I asked. - -chris -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: GPGTools - http://gpgtools.org Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBCAAGBQJTGfIPAAoJEBzwKT+lPKRYRuIP/2/Dd4dZtUy4/NUomnxsTQB3 PnTiq4wPcun8+iF4pIF6QAmyQImhVcfqhp/PhpenR3LrH/B0nPooV5XO5zBsgzQB r6TY81895MHCU6ICLsSDItAwvESRrtlj3k2cHfNXwankhePjAHgpfbS7pyn7FFiL 15ItenAG1zQDXpfPEEcHq/q1oF42s+GRRwVqN+LNCG9WP6eI5+nnMTvRhyE3aprc g98EdfI852svQK+dAE4S3kN3HxE5nfjEk0m0paDZLl4nWCbAs6PfgIjsRe+YV/hO MEaONNIGFtHk/wvmAzB12xXLm0y/XH9QF8uv/JNr/ZdPbFq1OOPaRY+7IPZEZkxa itYe5lEKpyH+xZFSStAD6UPmdzenYpDbrsUEZgMbVVhnSnrrS/VkcRDk+P3lsPui j1MW5Lt1YyJnweNio3w8NQN5VX8CZm1CjqLMqcVX05qSj+pysX+siKTxAXOUydzG Qg1Yu3XL598O+9aETCybYbFf9bM6UuYsbVG879sDyt3EJVxu6TKwEYi5JH9fKME3 Sl/kdFCY4+6XwQ5yhlwVhAgPV6BF1GP9LGPtKkwvrUxtv75o+WtXLzTEYf/WAOA/ Mk+kXXuYFA2sfrUl096G06Y3mipwfxwmKG9WX55TtIDDgd9zzzVNFm4T0V+1QQHV nXQ6lCWO4nUKTZLOKdQD =yFSO -----END PGP SIGNATURE----- --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
