DB Connection Limit

[Sammich]

Does anyone know if there is a maximum number of db connections that the Java Bridge Server can support? I know in the java.conf file you can set the pool.maxActive to specify the maximum number of active database connections, but is there a limit to this?

[ziegfried · Accepted solution]

The limit highly depends on the environment. Both the type operating system and especially the limit on max. open file descriptors and hardware such as available memory will be a limiting factor. The database server might limit the number of connections per host or user as well.

In general pool.maxActive count being higher than the number of available threads will not have any effect since DB Connect will only use/open 1 connection per thread. There are 2 thread-pools for DB Connect:

• bridge: 10 threads for commands (ie. dbquery, dbinfo, dboutput)
• dbmon: 5 threads for database inputs

These thread-pool sizes can be configured in java.conf. For example:

[bridge]
threads = 20

[dbmon]
threads = 50

[dbx]
pool.maxActive = 70

This would give a total of 70 available threads, so setting the max. size of the connection pool to 70 is a reasonable choice.