Connection pool advanced settings
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Resources | JDBC | JDBC providers | JDBC_provider | Data sources | data_source | Connection pool | Advanced connection pool properties
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Resources | JMS | JMS providers | Default messaging | Queue connection factory | JMS_queue_connection_factory | Connection pools | Advanced connection pool properties
The number of shared partitions, the number of free pool partitions, and the free pool distribution table size are properties related to reducing the time a thread needs to wait for a synchronization lock. On systems with a single processor, these values make no difference. On systems with multiple processors, these settings can reduce the performance cost associated with managing multiple threads.
Configuration tab
- Number of shared partitions
- Number of partitions that are created in each of the shared pools.
Partition support is always enabled. The default values of 0 should be used to enable the connection pool to pick the best values for performance. In some cases where large multiprocessor systems are used, adjusting the partition support properties might help performance.
Data type integer Default value 0 Range 0 to max int - Number of free pool partitions
- Number of partitions that are created in each of the free pools.
Data type integer Default value 0 Range 0 to max int - Free pool distribution table size
- Determines the distribution of Subject and CRI hash values in the table that indexes connection usage data.
These hash values are used to match connection request credentials with the connections. A free pool distribution table size larger than 1 can yield more efficient distribution of hash values, to help minimize search collisions within the table. Fewer collisions can result in faster retrieval of a connection that matches a request. Use a larger value for free pool distribution table size if your resource receives many incoming requests with varying credentials. Smaller values (1) should be used if the same credentials apply to all incoming requests for the resource. The value of 0 means random distribution.
Data type integer Default value 0 Range 0 to max int - Surge threshold
- Number of connections created before surge protection is activated.
Surge protection is designed to prevent overloading of a data source when too many connections are created at the same time. Surge protection is controlled by two properties, surge threshold and surge creation interval.
The surge threshold property specifies the number of connections created before surge protection is activated. After you reach the specified number of connections, you enter surge mode.
The surge creation interval property specifies the amount of time, in seconds, between the creation of connections when in surge mode.
For example, assume the follow settings:
- maxConnections = 50
- surgeThreshold = 10
- surgeCreationInterval = 30 seconds
If the connection pool receives 15 connection requests, 10 connections are created at about the same time. The 11th connection is created 30 seconds after the first 10 connections. The 12th connection is created 30 seconds after the 11th connection. Connections continue to be created every 30 seconds until there are no more new connections needed or you reach the maxConnections value.
Surge connection support starts if the surge threshold is > -1 and the surge creation interval is > 0. The surge threshold property has a default value of -1, which indicates that it is turned off.
wsadmin examples
$AdminControl getAttribute $objectname surgeCreationInterval $AdminControl setAttribute $objectname surgeCreationInterval 30 $AdminControl getAttribute $objectname surgeThreshold $AdminControl setAttribute $objectname surgeThreshold 15
Data type integer Default value -1 Range -1 to max int - Surge creation interval
- Amount of time between connection creates when you are in surge protection mode.
When the number of connections specified for the surge threshold property is reached, the surge creation interval property dictates how much time each new connection request must wait before fulfillment.
Surge protection does not work for a connection pool that is managed through an activation specification that coordinates with a JMS queue connection factory and default messaging provider.
Data type integer Default value 0 Range 0 to max int - Stuck time
- A stuck connection is an active connection that is not responding or returning to the connection pool. If the pool appears to be stuck (you have reached the stuck threshold), a resource exception is given to all new connection requests until the pool is unstuck. The stuck time property is the interval, in seconds, allowed for a single active connection to be in use to the backend resource before it is considered to be stuck.
Data type integer Default value 0 Range 0 to max int - Stuck threshold
- A stuck connection is an active connection that is not responding or returning to the connection pool. If the pool appears to be stuck (you have reached the stuck threshold), a resource exception is given to all new connection requests until the pool is unstuck. An application can explicitly catch this exception and continue processing. The pool will continue to periodically check for stuck connections when the number of stuck connections is past the threshold. If the number of stuck connections drops below the stuck threshold, the pool will detect this during its periodic checks and enable the pool to begin servicing requests again. The stuck threshold is the number of connections that need to be considered stuck for the pool to be in stuck mode.
Data type integer Default value 0 Range 0 to max int - Stuck timer time
- A stuck connection is an active connection that is not responding or returning to the connection pool. If the pool appears to be stuck (you have reached the stuck threshold), a resource exception is given to all new connection requests until the pool is unstuck. The stuck timer time property is the interval for the timer. This is how often the connection pool checks for stuck connections. The default value is 0 seconds.
If an attempt to change the stuck time, stuck timer time, or stuck threshold properties using the wsadmin scripting tool fails, an IllegalState exception occurs. The pool cannot have any active requests or active connections during this request. For the stuck connection support to start, the stuck time and the stuck threshold property values must be greater than 0 and maximum connections must be greater than 0.
Also, the stuck timer time, if it is set, must be less than the stuck time value. In fact, it is suggested that the stuck timer time should be one-quarter to one-sixth the value of stuck time so that the connection pool checks for stuck connections 4 to 6 times before a connection is declared stuck. This reduces the likelihood of false positives.
wsadmin examples
$AdminControl getAttribute $objectname stuckTime $AdminControl setAttribute $objectname stuckTime 30 $AdminControl getAttribute $objectname stuckTimerTime $AdminControl setAttribute $objectname stuckTimerTime 15 $AdminControl getAttribute $objectname stuckThreshold $AdminControl setAttribute $objectname stuckThreshold 10
Data type integer Default value 0 Range 0 to max int
Related concepts
Resource adapters
JDBC providers
Related tasks
Configure J2EE Connector connection factories in the administrative console