This section describes some recommended performance tuning configurations to optimize the performance of WSO2 DAS. It assumes that you have set up WSO2 DAS 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 <PRODUCT_HOME>/repository/conf/datasources/master-datasources.xml file. For more details about recommended JDBC configurations, see The Tomcat JDBC Connection Pool.
| Property | Description | RecommendationRecommendations |
|---|---|---|
| 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. Note that this value should not exceed the maximum number of requests allowed for your database. |
| 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. |
| 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 dropped from the pool, and we will 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 (time in milliseconds). If a connection is due for validation, but has been validated previously within this interval, it will not be validated again. The default value is | This time out 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 database requests have a high throughput. For example, a single extra validation query run every 30 seconds is usually negligible. |
| 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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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 dropped from the pool, and there will be an attempt to borrow another connection. | When the connection to the database is broken, the connection pool does not know that the connection has been lost. As a result, the connection pool will continue to distribute connections to the application until the application actually tries to use the connection. To resolve this problem, set "Test On Borrow" to "true" and make sure that the "ValidationQuery" property is set. To increase the efficiency of connection validation and to improve performance, |
| validationInterval | To avoid excess validation, run validation at most at this frequency (time in milliseconds). If a connection is due for validation, but has been validated previously within this interval, it will not be validated again. 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 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. |
| MaxPermSize | The memory size allocated for the WSO2 product. | The default memory allocated for the product via this parameter is as follows: You can increase the performance by increasing this value in the |
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When it comes to web applications, users are free to experiment and package their own pooling framework such BoneCP. If you are using an Oracle database, you may sometimes come across an error (ORA-04031) indicating that you have not allocated enough memory for the shared pool of connections. To overcome this, you can allocate more memory to the shared pool by adjusting the following parameters in the |
DAS-Level settings
Performance tuning can be tried out in the following areas at the DAS level.
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| Property | Description | Default Value | Recommendation |
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workerThreads | The number of threads reserved to handle the load of events received. | 10 | This value should be increased if you want to increase the throughput by receiving a higher number of events at a given time. The number of available CPU cores should be considered when specifying this value. If the value specified exceeds the number of CPU cores, higher latency would occur as a result of context switching taking place more often. |
maxEventBufferCapacity | The maximum size allowed for the event receiving buffer in mega bytes. The event receiving buffer temporarily stores the events received before they are forwarded to an event stream . | 10 | This value should be increased when there is an increase in the receiving throughput. When increasing the value heap memory size also needs to be increased accordingly. |
eventBufferSize | The number of messages that is allowed in the receiving queue at a given time. | 2000 | This value should be increased when there is an increase in the receiving throughput . |
Publishing events
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The following parameters which affect the performance relating to publishing events are configured in the <DAS_HOME>/repository/conf/data-bridge/data-agent-config.xml file. These configurations are common for both thrift and binary protocols.
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