|
Name
|
Default Value
|
Notes
|
|---|---|---|
|
Initial Connection Pool Size
|
5
|
Number of connections a pool will try to acquire upon startup
|
|
Connection Acquire Increment
|
5
|
Determines how many connections will be acquired when the pool is exhausted
|
|
Max Connection Pool Size
|
100
|
Maximum number of connections a pool maintains at any given time
|
|
Min Connection Pool Size
|
5
|
Minimum number of connections a pool maintains at any given time
|
|
Max Cached Statements
|
100
|
Size of global PreparedStatement cache
|
|
Acquire Retry Attempts
|
3
|
Defines how many times the connection pool will try to acquire a new connection
|
|
Acquire Retry Delay
|
10000
|
Time in milliseconds in which the connection pool will wait between acquire attempts
|
|
Checkout Retry Timeout
|
1000000
|
Number of milliseconds a client calling getConnection will wait for a connection to be checked in or acquired when the pool is exhausted
|
|
Max Idle Time
|
0
|
Seconds a connection can remain pooled but unused before being discarded. Zero means idle connections never expire.
|
|
Max Connection Age
|
0
|
Connections older than this time, in seconds, will be destroyed and purged from the pool. Zero means no maximum age is enforced.
|
|
Number of Helper Threads
|
8
|
Slow JDBC operations are generally performed by helper threads that do not hold contended locks. Spreading these operations over multiple threads can significantly improve performance by allowing multiple operations to be performed simultaneously.
|
|
Unreturned Connection Timeout
|
0
|
If the application acquires a connection but failed to close it within the specified period of time, in seconds, the pool will destroy the connection. Zero means no timeout, and the applications are expected to close their own connections.
|
|
Max Idle Time for Excess Connections
|
300
|
Number of seconds that connections in excess of minPoolSize should be permitted to remain idle in the pool before being destroyed. Zero means no enforcement and excess connections are not destroyed.
|
|
Max Cached Statements Per Connection
|
50
|
You should not change this value since it is tuned to the number of frequently-used statements in the code. It is the number of prepared statements that c3p0 will cache for a single-pooled connection. If both maxStatements and maxStatementsPerConnection are zero, statement caching will not be enabled. If maxStatementsPerConnection is zero but maxStatements is a non-zero value, statement caching will be enabled, and a global limit will be enforced. Otherwise, no limit will be set on the number of cached statements for a single connection.
If set, maxStatementsPerConnection should be set to the number of distinct prepared statements that are used frequently in your application, plus two or three extra so infrequent statements do not force the common cached statements to be called.
Although maxStatements is the JDBC standard parameter for controlling statement caching, users may find maxStatementsPerConnection more intuitive to use.
|
|
Table Lock Timeout
|
10000
|
The number of seconds until a lock timeout exception is thrown.
|