Glide Freaking Query Wow

Author

Jace Benson
May 24, 2020

A month ago I wrote about GlideQuery, asking "... is GlideRecord going away? No. I don't think so. "

Well, I need to revise my thoughts on this. Before I go into why, lets first link to the sources and you can watch the 20+ minute video of the genius (Peter Bell) behind GlideQuery.

Okay. Now that is out of the way lets talk about some of the major points here so if we lose the video we still have this somewhere since as of right now this is not documented anywhere.

GlideQuery is a server-side api for querying, updating, and deleting data. It's in Orlando, and Paris. Behind the scenes it uses GlideRecord but with smart defaults that often will cause generally problems.

This api follows three guiding principals;

  • Fail Fast

  • Be JavaScript

  • Expressive

Here's some considerations;

  • Performance

Improving the feedback loop

Here's a GlideRecord script with a problem
By default if a field name is wrong in GlideRecord, it queries everything.

In GlideQuery, this will fail and not execute on error.

GlideRecord Example

GlideQuery Example

Here's another example where unless you check your code you may miss it. This is because it returns no results.

If the api said, hey that value is not valid, that could help you faster.

GlideRecord Example

GlideQuery Example

Travis Toulson wrote a whole post about Is GlideRecord GetValue the king of the string... It's great but this SOLVES that whole issue.

GlideRecord Examples

GlideQuery Example

Isolation from Java

Type assumptions in are a real headache in ServiceNow with GlideRecord. It seems you get back a string type when you should get a number type.

GlideRecord Examples

GlideQuery Example

GlideRecord

GlideQuery

Queries that use both "AND" and "OR" logic. How is this evaluated?

In SQL "AND" has priority over "OR". In GlideRecord, "OR" has priority over "AND" and this causes problems. In GlideQuery they solve this by being allowing nested GlideQuery methods.

Do more with less

When reading data with GlideQuery there are two classes used; Stream and Optional

Stream

Optional

Used for reading records

Used for reading a single record

Returned by select(1)

"Empty" if a record isn't found by a query

Lazily evaluated

Returned by selectOne(), insert(), and update()

Common Stream methods: - map - flatMap - forEach - reduce - some - any

Common Optional methods: - get [throws if empty] - map - isEmpty - isPresent - ifPresent - orElse

Examples;

Examples;

This is important for currency and display values.

Flags mentioned $DISPLAY and $CURRENCY_CODE

With business rules disabled here's how GlideQuery stacks up to GlideRecord.

Method

GlideRecord

GlideQuery

Insert 100 records

829 ms median

850 ms median (+2.5%)

Reading 1 record

2ms median

3ms median (+1 ms)

Reading 1,000 record

86.5 ms median

90.5 ms median (+4.62%)

Reading 10,000 record

842.5 ms median

890 ms median (+5.64%)

It's important to note that GlideQuery avoids common performance mistakes.

  • Scoped table permission checking

  • Allow opting out of field/choice checking

  • Better join support

  • Field casting

  • Parsing encoded queries

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