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This section describes some recommended performance tuning configurations to optimize WSO2 CEP. It assumes that you have set up WSO2 CEP on a server running Unix/Linux, which is recommended for a production deployment.

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  1. To optimize network and OS performance, configure the following settings in /etc/sysctl.conf file of Linux. These settings specify a larger port range, a more effective TCP connection timeout value, and a number of other important parameters at the OS-level.

    Code Block
    net.ipv4.tcp_fin_timeout = 30
    fs.file-max = 2097152
    net.ipv4.tcp_tw_recycle = 1
    net.ipv4.tcp_tw_reuse = 1
    net.core.rmem_default = 524288
    net.core.wmem_default = 524288
    net.core.rmem_max = 67108864
    net.core.wmem_max = 67108864
    net.ipv4.tcp_rmem = 4096 87380 16777216
    net.ipv4.tcp_wmem = 4096 65536 16777216
    net.ipv4.ip_local_port_range = 1024 65535      
    Info

    When we have the localhost port range configuration lower bound to 1024, there is a possibility that some processes may pick the ports which are already used by WSO2 servers. Therefore, it's good to increase the lower bound as sufficient for production, e.g., 10,000.

  2. To alter the number of allowed open files for system users, configure the following settings in /etc/security/limits.conf file of Linux.

    Code Block
    * soft nofile 4096
    * hard nofile 65535

    Optimal values for these parameters depend on the environment.

  3. To alter the maximum number of processes your user is allowed to run at a given time, configure the following settings in  /etc/security/limits.conf file of Linux (be sure to include the leading * character). Each carbon server instance you run would require upto 1024 threads (with default thread pool configuration). Therefore, you need to increase the nproc value by 1024 per each carbon server (both hard and soft).

    Code Block
    * soft nproc 20000
    * hard nproc 20000

JVM settings

When an XML element has a large number of sub-elements and the system tries to process all the sub-elements, the system can become unstable due to a memory overhead. This is a security risk.

To avoid this issue, you can define a maximum level of entity substitutions that the XML parser allows in the system. You do this using the entity expansion limit attribute that is in the <CEP_HOME>/bin/wso2server.bat file (for Windows) or the <CEP_HOME>/bin/wso2server.sh file (for Linux/Solaris). The default entity expansion limit is 64000.

Code Block
languagexml
-DentityExpansionLimit=100000

In a clustered environment, the entity expansion limit has no dependency on the number of worker nodes

WSO2 Carbon platform-level settings

In multitenant mode, the WSO2 Carbon runtime limits the thread execution time. That is, if a thread is stuck or taking a long time to process, Carbon detects such threads, interrupts and stops them. Note that Carbon prints the current stack trace before interrupting the thread. This mechanism is implemented as an Apache Tomcat valve. Therefore, it should be configured in the <PRODUCT_HOME>/repository/conf/tomcat/catalina-server.xml file as shown below.

 

Code Block
languagexml
<Valve className="org.wso2.carbon.tomcat.ext.valves.CarbonStuckThreadDetectionValve" threshold="600"/>

 

  • The className is the Java class used for the implementation. Set it to org.wso2.carbon.tomcat.ext.valves.CarbonStuckThreadDetectionValve.
  • The threshold gives the minimum duration in seconds after which a thread is considered stuck. The default value is 600 seconds.

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PropertyDescriptionRecommendation
maxActive

The maximum number of active connections that can be allocated from the connection pool at the same time. The default value is  100.

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.
minIdleThe 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 validationQuery property should be used if testOnBorrow is set to true. To increase the efficiency of connection validation and to improve performance, validationInterval property should also be used.

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  30000  (30 seconds).

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.

validationQueryThe 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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of . This /wiki/spaces/TESB/pages/3260425310000 if you want to increase the throughput by receiving a higher number of events
PropertyDescriptionDefault ValueRecommendation
workerThreads The number of threads reserved to handle the load of events received.10This value should be increased if you want to increase the throughput by 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.eventBufferCapacity
maxEventBufferCapacityThe 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 stream10This 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.
eventBufferSizeThe number of messages that is allowed in the receiving queue at a given time.
PropertyDescriptionRecommendation
workerThreads

Number of threads in consumer to handle the load. Default value is 10.

Value should be higher when receiving throughput is high. Should to consider number of CPU cores.
eventBufferCapacitySize of the receiving event buffer. Default value is 10000.Needs to be higher value when receiving throughput is high. When increasing the value heap memory size also needs to be increased accordingly.  2000This value should be increased when there is an increase in the receiving throughput .
Publishing events

The following parameters which affect the performance relating to publishing events are configured in the <CEP_HOME>/repository/conf/data-bridge/data-agent-config.xml file. These configurations are common for both thrift and binary protocols.

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