Hi guys,

It’s time for ServiceNow go on air, all lights pointed at him now please.

The topics for today’s post are scripting (Server-side Glide, Business Rules, Client Scripting) and how to troubleshoot some performance issues. This are basic key points for any SN admin.

If you know how to answer the questions below, probably you should jump straight away to my next post I am going to post regarding this category.

Review questions:

• How can I obtain a list of distinct incidents?
• How can I measure performance of a request?
• What’s the difference between client script and server-side script?
• What is a business rule?
• What is a client script?

Scripting

The ServiceNow Glide classes expose JavaScript APIs that enable you to conveniently work with tables using scripts.

Using the Glide APIs, you can perform database operations without writing SQL queries, display UI pages, and define UI actions. The following tables provide brief descriptions of the Glide classes and links to detailed information.

I will focus in server-side scripting at this moment because 70% of the cases is what you need.

Scoped GlideRecord is used for database operations.

A GlideRecord contains both records and fields. For information about GlideRecordSecure, which is a class inherited from GlideRecord that performs the same functions as GlideRecord, and also enforces ACLs, see the GlideRecordSecure documentation.

Always test queries on a sub-production instance prior to deploying them on a production instance. An incorrectly constructed encoded query, such as including an invalid field name, produces an invalid query. When the invalid query is run, the invalid part of the query condition is dropped, and the results are based on the valid part of the query, which may return all records from the table. Using an insert(), update(), deleteRecord(), or deleteMultiple() method on bad query results can result in data loss.

Imagine the following scenario, you want to retrieve the incidents with priority 1.

Example:

var gr = new GlideRecord('incident');
gr.addQuery('priority','1');
gr.query();
while (gr.next()) {
  gs.addInfoMessage(gr.number);
}

Honestly for large queries I prefer to use addEncodedQuery(String query) instead of addQuery(String name, Object value). Much easier and safe.

Example:

var queryString = "priority=1^ORpriority=2";
var gr = new GlideRecord('incident');
gr.addEncodedQuery(queryString);
gr.query();
while (gr.next()) {
  gs.addInfoMessage(gr.number);
}

If for example, you want to look for Problem records that have associated Incident records

Example:

var gr = new GlideRecord('problem');
var grSQ = gr.addJoinQuery('incident');
 
// Where the Problem records are "active=false"
gr.addQuery('active', 'false');
 
// And the Incident records are "active=true"
grSQ.addCondition('active', 'true');
 
gr.query();
 
// Iterate and output results
while (gr.next()) {
    gs.info(gr.getValue('number'));
}

To do queries that group by something you’ll need to use GlideAggregate instead of GlideRecord. The GlideAggregate class is an extension of GlideRecord and allows database aggregation (COUNT, SUM, MIN, MAX, AVG) queries to be done. This can be helpful in creating customized reports or in calculations for calculated fields.

Here is an example to get distinct count of a field on a group query.

var agg = new GlideAggregate('incident');
agg.addAggregate('count');
agg.addAggregate('count(distinct','category');
agg.addQuery('opened_at', '>=', 'javascript:gs.monthsAgoStart(2)');
agg.addQuery('opened_at', '<=', 'javascript:gs.monthsAgoEnd(2)');
//
agg.groupBy('priority');
agg.query();
while (agg.next()) {
// Expected count of incidents and count of categories within each priority value (group)
  gs.info('Incidents in priority ' + agg.priority + ' = ' + agg.getAggregate('count') + 
            ' (' + agg.getAggregate('count(distinct','category') + ' categories)');
}

How to face and troubleshoot your performance issues

Diagnosing Service Now performance issues can be challenging sometimes. I still have a lot to learn about troubleshooting when things go wrong but I will share some of the things I have commonly seen cause performance issues in the Service Now so that if you run into performance issues, you’ll know where to look in order to start diagnosing the problem and figuring out how to deal with it.

Business rules vs Client Script

A business rule is a server-side script that runs when a record is displayed, inserted, updated, or deleted, or when a table is queried.Use business rules to accomplish tasks like automatically changing values in form fields when certain conditions are met, or to create events for email notifications and script actions. Business rules can make use of scripts to take actions on records in the database. However, there are several other scripting options available on the platform, such as client scripts and UI actions.

Hope this can you help you to do a proper push up on your ServiceNow skills.

Thank you,

Kind regards.
Rafael