DataSync for ServiceNow FAQ

The Perspectium DataSync Agent leverages two Java virtual machine instances, or processes, to run.

These Java processes can be started as a service or interactively through the executables in the Agent's bin folder.

If you find that your DataSync Agent is running slowly due to a large number of SQL statements being processed, you may want to configure the Agent to perform SQL statements in batches. To do this, open the agent.xml file that was created upon installation of your Agent in a text editing application. Within the <task> directive of the agent.xml file, nest the following directives:

When you received your Perspectium Mesh credentials, you may have been given two different addresses. Such as:

• https://user.perspectium.net

• amqps://user.perspectium.net

The choice between these different protocols will vary per customer (largely firewall rules). ServiceNow does not handle AMQP connections, so do not include AMQP within the ServiceNow instance URL for any of your <instance_connection> directives.

The DataSync Agent handles schema changes in your ServiceNow instance as follows:

• Columns that are added to a ServiceNow table will be automatically added to the table in the database.

• When a column's max size is increased, the Agent will automatically increase the column's size to the maximum size for that database. In the case of MySQL, the column will automatically transition to a CLOB data type.

• If a column is changed from a different data type to another data type, the data in this column will be skipped (the record itself will insert/update all other columns).

Do one of the following:

• If you are expecting multibyte characters from ServiceNow it is recommended to turn on multibyte encryption within the Perspectium Properties page.

• If you are running a MySQL agent it is recommended to place characterEncoding=UTF-8 within the database_parms tag.

• If you are running a SQL Server agent on Windows then you must be using at least Agent V3.11.0 and include SendStringParametersAsUnicode=false within the Database Parms tag.

The format is:

<!-- MySQL multibyte decryption -->
<database_parms>characterEncoding=UTF-8</database_parms>

<!-- SQL Server multibyte decryption (Windows) -->
<!-- Note: Requires Agent V3.11.0 or greater -->
<database_parms>SendStringParametersAsUnicode=false</database_parms>

You can alter the default <connection_request_timeout> by setting it to 120000. This should give your connection plenty more room to handle all the IO of large transaction. You would place it within your agent.xml like so:

<config>
    <agent>
        <subscribe>
            <task>
                <task_name>timeout_example</task_name>
                <message_connection connection_request_timeout="120000" user="XXX" password="XXX" >your_url</message_connection>
                ...
            <task>
        <subscribe>
    </agent>
</config>

This should be placed on the <message_connection> within the task level of the desired connection. This attribute will only be set for the specified <message_connection>, so if you have separate connections for monitoring or replicating data they will use the default unless specified.

Another option is if you have firewall access to both your https and AMQPS connections (https://your_instance.perspectium.net & amqps://your_instance-amqp.perspectium.net) you can try either

• Setting your <max_reads_per_connect> to 1 and use the HTTPS connection

• Setting your <max_reads_per_connect> to 4000 and use the AMQPS connection

You can add a loginTimeout database parameter to the agent.xml configuration file to control the DB connection timeout.

In your agent.xml, under each <task> entry, add <database_parms>loginTimeout=NN</database_parms> where nn is in seconds.

For example:

 <database_parms>loginTimeout=30</database_parms>

If you already have <database_parms> configured, then append the loginTimeout parameter using:

 <database_parms>integratedSecurity=true;loginTimeout=30</database_parms>

Open the wrapper.conf file located in the Agent's conf folder and change the following configuration:

#wrapper.java.maxmemory=64

Removing the “#” and putting a numeric value higher than 64. This numeric value is a size in MB for the Java memory heap space the agent can use. Generally, you would base this value on the memory available on the server where the Agent is running. For example, if the server has 1GB of memory, you can set it to be 512MB here:

wrapper.java.maxmemory=512

The DataSync AQL Agent leverages the default connection commit strategy of the JDBC driver for which Oracle is auto commit. The agent does not explicitly decide when to perform a commit. The JDBC driver makes this decision.

The Agent retrieves a message from the message store in the order they were published, performs the required processing such as decryption, validation etc., possibly determines the type of SQL operation required (such as update or insert), and then issues the request to the database. The Agent then determines the response and does any further processing required. Once completed, the Agent will fetch the next message from the message store in the queue.

 NOTE: You can configure either multiple tasks to run against a single queue or you can configure multiple instances of a single task to run against a single queue. This is done primarily when throughput of the Agent is an issue. Both of these configurations introduce more than a single consumer of the queue and so the order in which the database transaction occurs could be different than the order of the messages within the message store due to scheduling of the task or thread.

The reason the you're receiving this error is due to Oracle's parameters for SHARED_POOL_SIZE. Note that when SGA_TARGET is set and the parameter is not specified, then the default is 0 (internally determined by the Oracle Database), but if the parameter is specified, then your specified value indicates a minimum value for the memory pool.

In the case where a value was set for SGA_TARGET, that would be the value you would need to update rather than the SHARED_POOL_SIZE since by setting SGA_TARGET, you are using automatic SGA management. Hence, there is no need to manually set the value of SHARED_POOL_SIZE because Oracle will internally transfer memory between the SGA components.

In the case where you are more concerned with setting a larger value for SGA_TARGET, you can also make a larger value for SHARED_POOL_SIZE but the value must be smaller than SGA_TARGET to avoid encountering the following issue:

SGA_TARGET = 1GB
SHARED_POOL_SIZE = no value

You will encounter an issue when the value of SHARED_POOL_SIZE exceeds the value of SGA_TARGET.

It is recommended to set the SGA_TARGET value at a minimum of 5GB. Therefore, if the SHARED_POOL_SIZE value is at 1GB, the SGA_TARGET will still have at least 4GB for allocation of other memory components that are concurrently stored in SGA_TARGET.

 NOTE: Be sure to restart the Oracle Database after making the described value changes. For additional information, refer to SHARED_POOL_SIZE or SGA_TARGET.

ServiceNow provides an option for Database Encryption where data is encrypted at rest in the database. Since Database Encryption happens at the database layer and the Perspectium application runs at the application layer, by the time we call to get data from ServiceNow, the data will be accessible to our application to be shared out.  ServiceNow's documentation mentions with Database Encryption that you can add another level of encryption by also encrypting at the application layer which is what our application supports as well.