This section describes some recommended performance tuning configurations to optimize WSO2 AS. It assumes that you have set up WSO2 AS on a server running Unix/Linux, which is recommended for a production deployment.
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Within the WSO2 platform, we use Tomcat JDBC pooling as the default pooling framework due to its production ready stability and high performance. The table below indicates some recommendations on how to configure the JDBC pool using the <AS The goal of tuning the pool properties is to maintain a pool that is large enough to handle peak load without unnecessarily utilising resources. These pooling configurations can be tuned for your production server in general in the <DSS_HOME>/repository/conf/datasources/master-datasources.xml file file.
The following parameters should be considered when tuning the connection pool:
- The application's concurrency requirement.
- The average time taken to run a database query.
- The maximum number of connections the database server can support.
The table below indicates some recommendations on how to configure the JDBC pool. For more details about recommended JDBC configurations, see The Tomcat JDBC Connection Pool.
| Property | DescriptionRecommendation | Tuning Recommendations |
|---|---|---|
| maxActive | The maximum number of active connections that can be allocated from the connection pool at the same time. The default value is | This value should match the maximum number of requests that can be expected at a time in your production environment. This is to ensure that, whenever there is a sudden increase in the number of requests to the server, all of them can be connected successfully without causing any delays. The maximum latency (approximately) = (P / M) * T , where,
Therefore, by increasing the maxActive value (up to the expected highest number of concurrency), the time that requests wait in the queue for a connection to be released will decrease. But before increasing the Max. Active value, consult the database administrator, as it will create up to maxActive connections from a single node during peak times, and it may not be possible for the DBMS to handle the accumulated count of these active connections. Note that this value should not exceed the maximum number of requests allowed for your database. |
| maxWait | The maximum time that requests are expected to wait in the queue for a connection to be released. This property comes into effect when the maximum number of active connections allowed in the connection pool (see maxActive property) is used up. | Adjust this to a value slightly higher than the maximum latency for a request, so that a buffer time is added to the maximum latency. That is, If the maximum latency (approximately) = (P / M) * T , where,
then, the maxWait = (P / M) * T + buffer time. |
| minIdle | The minimum number of connections that can remain idle in the pool, without extra ones being created. The connection pool can shrink below this number if validation queries fail. Default value is 0. | This value should be similar or near to the average number of requests that will be received by the server at the same time. With this setting, you can avoid having to open and close new connections every time a request is received by the server. |
| maxIdle | The maximum number of connections that can remain idle in the pool. | The value should be less than the maxActive value. For high performance, tune maxIdle to match the number of average, concurrent requests to the pool. If this value is set to a large value, the pool will contain unnecessary idle connections. |
| testOnBorrow | The indication of whether connection objects will be validated before they are borrowed from the pool. If the object validation fails, it will be the connection is dropped from the pool, and we there will be an attempt to borrow another connection. | Setting this property to 'true' is recommended as it will avoid connection requests from failing. The |
| validationInterval | To avoid excess validation, run validation at most at this frequency This parameter controls how frequently a given validation query is executed (time in milliseconds). If The default value is | Deciding the value for the "validationInterval" depends on the target application's behavior. Therefore, selecting a value for this property is a trade-off and ultimately depends on what is acceptable for the application. If a larger value is set, the frequency of executing the Validation Query is low, which results in better performance. Note that this value can be as high as the time it takes for your DBMS to declare a connection as stale. For example, MySQL will keep a connection open for as long as 8 hours, which requires the validation interval to be within that range. However, note that having a low value for validation interval will not incur a big performance penalty, specially when the validation query execution is usually fast. Therefore, even if this value is only large by a few seconds, there will not be a big penalty on performance. Also, specially when the database requests have a high throughput, the negative impact on performance is negligible. For example, a single extra validation query run every 30 seconds is usually negligible. If a smaller value is set, a stale connection will be identified quickly when it is presented. This maybe important if you need connections repaired instantly, e.g. during a database server restart. |
| validationQuery | The SQL query used to validate connections from this pool before returning them to the caller. If specified, this query does not have to return any data, it just can't throw an SQLException. The default value is null. Example values are SELECT 1(mysql), select 1 from dual(oracle), SELECT 1(MS Sql Server). | Specify an SQL query, which will validate the availability of a connection in the pool. This query is necessary when testOnBorrow property is true. |
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When it comes to web applications, users are free to experiment and package their own pooling framework such BoneCP. |