API Manager-level settings

1 Timeout configurations for an API call
2 General APIM-level recommendations
3 Registry indexing configurations
4 Registry Caching based configurations
5 Tuning carbon.xml parameters
6 Tuning data-agent parameters
7 Example
8 Example

Timeout configurations for an API call

The following diagram shows the communication/network paths that occur when an API is called. The timeout configurations for each network call are explained below.

Key validation
Key validation occurs via a Servlet HTTP call and the connection timeout can be configured by changing the following configuration details in the <WSO2_OB_APIM_HOME>/repository/conf/axis2/axis2_client.xml file. All timeout values are in milliseconds.
<transportSender name="https" class="org.apache.axis2.transport.http.CommonsHTTPTransportSender"> <parameter name="SO_TIMEOUT">60000</parameter> <parameter name="CONNECTION_TIMEOUT">60000</parameter> </transportSender>
If the Key Manager caching is enabled, the calls between the API Gateway and Key Manager are cached. As a result, the Key Manager is not invoked for each API call.
Client call API Gateway + API Gateway call Backend
For backend communication, the API Manager uses PassThrough transport. This is configured in the <WSO2_OB_APIM_HOME>/repository/conf/passthru-http.properties file. For more information, see Configuring passthru-http.properties in the EI documentation.

General APIM-level recommendations

Some general APIM-level recommendations are listed below:

Improvement Area	Performance Recommendations

Improvement Area

Performance Recommendations

API Gateway nodes

Increase memory allocated by modifying the /bin/wso2server. sh file with the following setting:

-Xms2048m -Xmx2048m -XX:MaxPermSize=1024m

Set the following in the <WSO2_OB_APIM_HOME>/repository/conf/axis2/axis2_client.xml file:

The following Axis2 client configurations are only applicable when Web Services key validation (WS key validation) is enabled.
The default values mentioned are the values identified at the time of releasing API-M. However, if you want high concurrency, use the values mentioned below:

<parameter name="defaultMaxConnPerHost">1000</parameter> 
<parameter name="maxTotalConnections">30000</parameter>

The above configurations are only applicable when WS key validation is enabled.

NHTTP transport of API Gateway

Recommended values for the <<WSO2_OB_APIM_HOME>/repository/conf/nhttp.properties file are given below. Note that the commented out values in this file are the default values that will be applied if you do not change anything.

Property descriptions:

snd_t_core	Transport sender worker pool's initial thread count
snd_t_max	Transport sender worker pool's maximum thread count
snd_io_threads	Sender-side IO workers, which is recommended to be equal to the number of CPU cores. I/O reactors usually employ a small number of dispatch threads (often as few as one) to dispatch I/O event notifications to a greater number (often as many as several thousands) of I/O sessions or connections. Generally, one dispatch thread is maintained per CPU core.
snd_alive_sec	Sender-side keep-alive seconds
snd_qlen	Sender queue length, which is infinite by default

Recommended values:

HTTP Sender thread pool parameters
- snd_t_core=200
- snd_t_max=250
- snd_alive_sec=5
- snd_qlen=-1
- snd_io_threads=16
HTTP Listener thread pool parameters
- lst_t_core=200
- lst_t_max=250
- lst_alive_sec=5
- lst_qlen=-1
- lst_io_threads=16
timeout parameters
- http.socket.timeout.receiver: Recommended socket timeout for listener is 180000 ms.
- http.socket.timeout.sender: Recommended socket timeout for sender is 180000 ms.

PassThrough transport of API Gateway

Recommended values for the <WSO2_OB_APIM_HOME>/repository/conf/passthru-http.properties file are given below. Note that the commented out values in this file are the default values that will be applied if you do not change anything.

Property descriptions

`worker_thread_keepalive_sec`	Defines the keep-alive time for extra threads in the worker pool
`worker_pool_queue_length`	Defines the length of the queue that is used to hold runnable tasks to be executed by the worker pool
`io_threads_per_reactor`	Defines the number of IO dispatcher threads used per reactor
`http.max.connection.per.host.port`	Defines the maximum number of connections per host port
`worker_pool_queue_length`	Determines the length of the queue used by the PassThrough transport thread pool to store pending jobs.
`http.connection.timeout`	Defines a maximum time period to establish a connection with the remote host. The `http.connection.timeout` and the `http.socket.timeout`, which is explained below, are two different configuration definitions used to handle connection time out and read timeout for sockets respectively.
`http.socket.timeout`	Defines the waiting time for data after establishing the connection, which refers to the maximum time of inactivity between two data packets.

Recommended values

worker_thread_keepalive_sec: Default value is 60s. This should be less than the socket timeout.
worker_pool_queue_length: Set to -1 to use an unbounded queue. If a bound queue is used and the queue gets filled to its capacity, any further attempts to submit jobs will fail, causing some messages to be dropped by Synapse. The thread pool starts queuing jobs when all the existing threads are busy and the pool has reached the maximum number of threads. So, the recommended queue length is -1.
io_threads_per_reactor: Value is based on the number of processor cores in the system. (Runtime.getRuntime().availableProcessors())
http.max.connection.per.host.port : Default value is 32767, which works for most systems but you can tune it based on your operating system (for example, Linux supports 65K connections).
worker_pool_size_core: 400
worker_pool_size_max: 500
io_buffer_size: 16384
http.socket.timeout: 180000

Make the number of threads equal to the number of processor cores.

Timeout configurations

The API Gateway routes the requests from your client to an appropriate endpoint. The most common reason for your client getting a timeout is when the Gateway's timeout is larger than the client's timeout values. You can resolve this by either increasing the timeout on the client's side or by decreasing it on the API Gateway's side.

Here are a few parameters, in addition to the timeout parameters discussed in the previous sections.

synapse.global_timeout_interval

Defines the maximum time that a callback waits in the Gateway for a response from the backend. If no response is received within this time, the Gateway drops the message and clears out the callback. This is a global level parameter that affects all the endpoints configured in the Gateway.

The global timeout is defined in the <WSO2_OB_APIM_HOME>/repository/conf/synapse.properties file. The recommended value is 120000 ms.

Endpoint-level timeout

You can define timeouts per endpoint for different backend services, along with the action to be taken in case of a timeout.

The example below sets the endpoint to 50 seconds (50000 ms) and executes the fault handler in case of a timeout.

<timeout>
   <duration>50000</duration>
   <responseAction>fault</responseAction>
</timeout>

Alternatively, you can set this through the Publisher UI as well, by following the steps below:

Log in to the API Publisher (https://<HostName>:9443/publisher). Select your API and click Edit API.
Click the Implement tab and click the cogwheel icon next to the endpoint you want to re-configure.
In the Advanced Settings dialog box that appears, increase the duration by modifying the default property set as 30000 ms.
Click Save and re-publish the API.

The http.socket.timeout parameter needs to be adjusted based on the endpoint-level timeout so that it's value is equal or higher than the highest endpoint-level timeout.

If your API is marked as the default version, it has a different template (without the version number) that comes with a pre-defined timeout for the endpoint. This timeout does not change with the changes you do to the API by editing the Advanced Endpoint Configuration. Therefore, if this predefined timeout (60 seconds) is less than the actual API timeout, it triggers the timeout before the actual configured API timeout.

To overcome this, update the default_api_template.xml residing in the <WSO2_OB_APIM_HOME>/ repository/resources/api_templates directory by removing the endpoint timeout configuration from the default API. Then, the APIs marked as the default version also trigger the timeout when the actual API timeout is met.

Follow the steps below to update the default_api_template.xml to remove the endpoint configuration for the default APIs.

Open the <WSO2_OB_APIM_HOME>/repository/resources/api_templates/default_api_template.xml file and remove the following configuration:
<timeout> <duration>60000</duration> <responseAction>fault</responseAction> </timeout> <suspendOnFailure> <progressionFactor>1.0</progressionFactor> </suspendOnFailure> <markForSuspension> <retriesBeforeSuspension>0</retriesBeforeSuspension> <retryDelay>0</retryDelay> </markForSuspension>
Add the following configuration to the same place in the default_api_template.xml file.
<suspendOnFailure> <errorCodes>-1</errorCodes> <initialDuration>0</initialDuration> <progressionFactor>1.0</progressionFactor> <maximumDuration>0</maximumDuration> </suspendOnFailure> <markForSuspension> <errorCodes>-1</errorCodes> </markForSuspension>
Go to the API Publisher and republish the default API by clicking Save and Publish.

Key Manager nodes

Set the MySQL maximum connections:

mysql> show variables like "max_connections"; 
 max_connections was 151 
 set to global max_connections = 250;

Set the open files limit to 200000 by editing the /etc/sysctl.conf file:

sudo sysctl -p

Set the following in the <WSO2_OB_APIM_HOME>/repository/conf/tomcat/catalina-server.xml file.

If you use WSO2 Identity Server (WSO2 IS) as the Key Manager, then the root location of the above path and the subsequent path needs to change from <WSO2_OB_APIM_HOME> to <WSO2_OB_KM_HOME>.

maxThreads="750" 
minSpareThreads="150" 
disableUploadTimeout="false" 
enableLookups="false" 
connectionUploadTimeout="120000" 
maxKeepAliveRequests="600" 
acceptCount="600"

Set the following connection pool elements in the <WSO2_OB_APIM_HOME>/repository/conf/datasources/master-datasources.xml file. Time values are defined in milliseconds.

<maxActive>50</maxActive>
<maxWait>60000</maxWait>
<testOnBorrow>true</testOnBorrow>
<validationQuery>SELECT 1</validationQuery>
<validationInterval>30000</validationInterval>

Note that you set the <testOnBorrow> element to true and provide a validation query (e.g., in Oracle, SELECT 1 FROM DUAL), which is run to refresh any stale connections in the connection pool. Set a suitable value for the <validationInterval> element, which defaults to 30000 milliseconds. It determines the time period after which the next iteration of the validation query will be run on a particular connection. It avoids excess validations and ensures better performance.