Release Notes August 25, 2023

Monitors - Alerts and Shared Actions

The Monitors landing page now displays tabs for Alerts and Shared Actions providing “at a glance” overview of all of your Monitors configurations.

Figure 3 - Alerts Tab on the Monitor Landing Page

Figure 4 - Shared Actions Tab on the Monitor Landing Page

OPAL Language Updates

topk_aggr

Description

Returns an approximation of the top K most frequent values in the input, along with their approximate frequencies.

The output contains an array of arrays. In the inner arrays, the first entry is the value in the input, while the second entry is its frequency. The outer array contains k elements, sorted by frequencies in descending order.

Return type

array

Domain

This is an aggregate function (aggregates rows over a group in aggregate verbs.

This is a window function (calculates over a group of multiple input rows using windowing.)

Categories

• Aggregate

• Semistructured

• Window

Usage

topk_agg( expr, k )

Argument	Type	Required	Multiple
expr	any	Required	Only one
k	int64	Required	Only one

Examples

statsby top_names:topk_agg(name, 2), group_by(class)

Given the following input:

name	class
Jack	A
Joe	A
Alice	A
Alice	A
Tom	B
Joe	B
Kathy	B
Mike	A
Tom	B

It returns the following output:

class	top_names
A	[[“Alice”, 2], [“Jack”, 1]]
B	[[“Tom”, 2], [“Kathy”, 1]]

Note that if there is a tie in the last position the result can be non-deterministic. Any of the values with the same frequency may be included in the last position.