You can use NRQL queries to create alert conditions. Once you've defined your signal, you can further define your warning and critical threshold levels. This determines when an alerts violation is created.
Read on to learn more about how to do this.
Go to one.newrelic.com, click Alerts & AI, in the left sidebar click Policies, select a policy, then Add a condition. Click NRQL, and then Next, define thresholds.
For more information on key concepts relating to NRQL alert conditions and streaming alerts, see Streaming alerts: key terms and concepts.
To create a NRQL alert condition for a policy:
- On one.newrelic.com, in the header click Alerts & AI, then in the left sidebar click Policies.
- Select an existing policy or click New alert policy to create a new policy.
- Click Add a condition.
- Under Select a product click NRQL, and then click Next, define thresholds.
You can use a chart to create a NRQL alert condition.
Once you've named and customized your condition, you can add it to an existing policy or create a new one.
A small number of our older charts don't include the option to create an alert condition.
Here's the basic syntax for creating all NRQL alert conditions. The
FACET clause is required for outlier condition types. It's optional for static and baseline.
SELECT function(attribute)FROM EventWHERE attribute [comparison] [AND|OR ...]
Supported functions that return numbers include:
Only one data type can be targeted.
Supported data types:
Required for outlier conditions
Include an optional
If the query returns more than the maximum number of values, the alert condition can't be created. If you create the condition and the query returns more than this number later, the alert will fail. Modify your query so that it returns a fewer number of values.
Some elements of NRQL used in charts don’t make sense in the streaming context of alerts. Here’s a list of the most common incompatible elements and suggestions for reformatting a NRQL alert query to achieve the same effect.
NRQL conditions produce a never-ending stream of windowed query results, so the
In NRQL queries, the
For NRQL conditions, the equivalent property of a signal is the aggregation duration window.
Multiple aggregation functions
Each condition can only target a single aggregated value. To alert on multiple values simultaneously, you’ll need to decompose them into individual conditions within the same policy.
Sliding windows are not currently supported in NRQL alerts.
In NRQL queries, the LIMIT clause is used to control the amount of data a query returns, either the maximum number of facet values returned by FACET queries or the maximum number of items returned by SELECT * queries.
LIMIT is not compatible with NRQL alerting: evaluation is always performed on the full result set.
By default, the aggregation window duration is 1 minute, but you can change the window to suit your needs. Whatever the aggregation window, New Relic will collect data for that window using the function in the NRQL condition’s query. The query is parsed and executed by our systems in the following order:
FROMclause – which event type needs to be grabbed?
WHEREclause – what can be filtered out?
SELECTclause – what information needs to be returned from the now-filtered data set?
Let's say this is your alert condition query:
SELECT count(*) FROM SyntheticCheck WHERE monitorName = 'My Cool Monitor' AND result = 'FAILURE'
If there are no failures for the aggregation window:
- The system will execute the
FROMclause by grabbing all
SyntheticCheckevents on your account.
- Then it will execute the
WHEREclause to filter through those events by looking only for the ones that match the monitor name and result specified.
- If there are still events left to scan through after completing the
SELECTclause will be executed. If there are no remaining events, the
SELECTclause will not be executed.
This means that aggregators like
uniqueCount() will never return a zero value. When there is a count of 0, the
SELECT clause is ignored and no data is returned, resulting in a value of
If you have a data source delivering legitimate numeric zeroes, the query will return zero values and not null values.
Let's say this is your alert condition query, and that
MyCoolEvent is an attribute that can sometimes return a zero value.
SELECT average(MyCoolAttribute) FROM MyCoolEvent
If, in the aggregation window being evaluated, there's at least one instance of
MyCoolEvent and if the average value of all
MyCoolAttribute attributes from that window is equal to zero, then a
0 value will be returned. If there are no
MyCoolEvent events during that minute, then a
NULL will be returned due to the order of operations.
For more information about this topic, you can check out our blog post on troubleshooting for zero versus null values.
You can determine how null values will be handled by adjusting loss of signal and gap filling settings in the Alert Conditions UI.
You can avoid
NULL values entirely with a query order of operations shortcut. Do this by using a
filter sub-clause, then including all filter elements within that sub-clause. The main body of the query will run and return data, at which point the
SELECT clause will then run and apply the filter elements. The query will return a value of
0 if the filter elements result in no matching data. Here's an example:
SELECT filter(count(*), WHERE result = 'SUCCESS' AND monitorName = 'My Favorite Monitor') FROM SyntheticCheck
Nested aggregation queries are a powerful way to query your data. However, they have a few restrictions that are important to note.
Here are some tips for creating and using a NRQL condition:
NRQL condition types include static, baseline, and outlier.
Create a description
For NRQL conditions, you can create a custom description to add to each violation. Descriptions can be enhanced with variable substitution based on metadata in the specific violation.
For details, see Description
Queries must return a number. The condition evaluates the returned number against the thresholds you've set.
NRQL conditions evaluate data based on how it's aggregated, using aggregation windows from 30 seconds to 15 minutes, in increments of 15 seconds. For best results, we recommend using the event flow or event timer aggregation methods.
For the cadence aggregation method, the implicit
Lost signal threshold (loss of signal detection)
You can use loss of signal detection to alert on when your data (a telemetry signal) should be considered lost. A signal loss can indicate that a service or entity is no longer online or that a periodic job failed to run. You can also use this to make sure that violations for sporadic data, such as error counts, are closed when no signal is coming in.
Advanced signal settings
These settings give you options for better handling continuous, streaming data signals that may sometimes be missing. These settings include the aggregation window duration, the delay/timer, and an option for filling data gaps. For more on using these, see Advanced signal settings.
Use the Condition settings to:
Limits on conditions
See the maximum values.
NRQL alert conditions don't affect an entity's health status display.
For more information, see:
When you create a NRQL alert, you can choose from different types of conditions:
NRQL alert condition types
This is the simplest type of NRQL condition. It allows you to create a condition based on a NRQL query that returns a numeric value.
Optional: Include a
Uses a self-adjusting condition based on the past behavior of the monitored values. Uses the same NRQL query form as the static type,
including the optional
Looks for group behavior and values that are outliers from those groups. Uses the same NRQL query form as the static type, but requires a
Available only for static (basic) condition types.
If a query returns intermittent or limited data, it may be difficult to set a meaningful threshold. Missing or limited data will sometimes generate false positives or false negatives. You can use loss of signal, aggregation duration, and gap filling settings to minimize these false notifications.
To avoid this problem when using the static threshold type, you can set the selector to sum of query results. This lets you set the alert on an aggregated sum instead of a value from a single harvest cycle. Up to two hours of one-minute data checks can be aggregated. The duration you select determines the width of the rolling sum and the preview chart will update accordingly.
Loss of signal occurs when no data matches the NRQL condition over a specific period of time. You can set your loss of signal threshold duration and and also what happens when the threshold is crossed.
Go to one.newrelic.com, click Alerts & AI, in the left sidebar click Policies, select a policy, then Add a condition. Loss of signal is only available for NRQL conditions.
You may also manage these settings using the GraphQL API (recommended), or the REST API. Go here for specific GraphQL API examples.
Loss of signal settings:
Loss of signal settings include a time duration and two possible actions.
- Signal loss expiration time
- UI label: Signal is lost after:
- GraphQL Node: expiration.expirationDuration
- Expiration duration is a timer that starts and resets when we receive a data point in the streaming alerts pipeline. If we don't receive another data point before your 'expiration time' expires, we consider that signal to be lost. This can be because no data is being sent to New Relic or the
WHEREclause of your NRQL query is filtering that data out before it is streamed to the alerts pipeline. Note that when you have a faceted query, each facet is a signal. So if any one of those signals ends during the duration specified, that will be considered a loss of signal.
- The loss of signal expiration time is independent of the threshold duration and triggers as soon as the timer expires.
- The maximum expiration duration is 48 hours. This is helpful when monitoring for the execution of infrequent jobs. The minimum is 30 seconds, but we recommend using at least 3-5 minutes.
- Loss of signal actions
Once a signal is considered lost, you can close open violations, open new violations, or both.
- Close all current open violations: This closes all open violations that are related to a specific signal. It won't necessarily close all violations for a condition. If you're alerting on an ephemeral service, or on a sporadic signal, you'll want to choose this action to ensure that violations are closed properly. The GraphQL node name for this is "closeViolationsOnExpiration"
- Open new violations: This will open a new violation when the signal is considered lost. These violations will indicate that they are due to a loss of signal. Based on your incident preferences, this should trigger a notification. The graphQL node name for this is "openViolationOnExpiration"
- When you enable both actions, we'll close all open violations first, and then open a new violation for loss of signal.
To create a NRQL alert configured with loss of signal detection in the UI:
- For a policy, when you create a condition, under Select a product, click NRQL, then click Next, define thresholds.
- Write a NRQL query that returns the values you want to alert on.
- For Threshold type, select Static or Baseline.
- Click + Add lost signal threshold, then set the signal expiration duration time in minutes or seconds in the Signal is lost after field.
- Choose what you want to happen when the signal is lost. You can check one or both of Close all current open violations and Open new "lost signal" violation. These control how loss of signal violations will be handled for the condition.
- Make sure you name your condition before you save it.
Violations open due to loss of signal close when
- the signal comes back. Newly opened lost signal violations will close immediately when new data is evaluated.
- the condition they belong to expires. By default, conditions expire after 3 days.
- you manually close the violation with the Close all current open violations option.
Loss of signal detection doesn't work on NRQL queries that use nested aggregation or sub-queries.
When creating a NRQL alert condition, use the advanced signal settings to control streaming alert data and avoid false alarms.
When creating a NRQL condition, there are several advanced signal settings:
- Aggregation window duration
- Fill data gaps
To read an explanation of what these settings are and how they relate to each other, see Streaming alerts concepts. Below are instructions and tips on how to configure them.
You can set the aggregation window duration to choose how long data is accumulated in a streaming time window before it's aggregated. You can set it to anything between 30 seconds and 15 minutes. The default is one minute.
Baseline alert condition thresholds don't support editing the aggregation window. They use the 1 minute default.
You can adjust the delay/timer to coordinate our streaming alerting algorithm with your data's behavior. If your data is sparse or inconsistent, you may want to use the event timer aggregation method.
For the cadence method, the total supported latency is the sum of the aggregation window duration and the delay.
If the data type comes from an APM language agent and is aggregated from many app instances (for example,
TransactionErrors, etc.), we recommend using the event flow method with the default settings.
When creating NRQL conditions for data collected from Infrastructure Cloud Integrations such as AWS Cloudwatch or Azure, we recommend that you use the event timer method.
Gap filling lets you customize the values to use when your signals don't have any data. You can fill gaps in your data streams with one of these settings:
- None: (Default) Choose this if you don't want to take any action on empty aggregation windows. On evaluation, an empty aggregation window will reset the threshold duration timer. For example, if a condition says that all aggregation windows must have data points above the threshold for 5 minutes, and 1 of the 5 aggregation windows is empty, then the condition won't be in violation.
- Custom static value: Choose this if you'd like to insert a custom static value into the empty aggregation windows before they're evaluated. This option has an additional, required parameter of
fillValue(as named in the API) that specifies what static value should be used. This defaults to
- Last known value: This option inserts the last seen value before evaluation occurs. We maintain the state of the last seen value for 2 hours.
The alerts system fills gaps in actively reported signals. This signal history is dropped after 2 hours of inactivity. For gap filling, data points received after this period of inactivity are treated as new signals.
To learn more about signal loss, gap filling, and how to request access to these features, see this Explorers Hub post.
Options for editing data gap settings:
- In the NRQL conditions UI, go to Condition settings > Advanced signal settings > fill data gaps with and choose an option.
- If using our Nerdgraph API (preferred), this node is located at:
actor : account : alerts : nrqlCondition : signal : fillOption | fillValue
- NerdGraph is our recommended API for this but if you're using our REST API, you can find this setting in the REST API explorer under the "signal" section of the Alert NRQL conditions API.
If you need more help, check out these support and learning resources:
- Browse the Explorers Hub to get help from the community and join in discussions.
- Find answers on our sites and learn how to use our support portal.
- Run New Relic Diagnostics, our troubleshooting tool for Linux, Windows, and macOS.
- Review New Relic's and and documentation.