Title: Performance metrics anomalies Author: WordPress VIP Documentation Published: September 16, 2024 Last modified: January 15, 2026 --- 1. [Performance](https://docs.wpvip.com/performance/) 2. [Insights & Metrics](https://docs.wpvip.com/performance/insights-metrics/) 3. Performance metrics anomalies # Performance metrics anomalies Performance metrics anomalies are events that indicate a degradation in performance related to a production environment’s object cache hit rate, slow queries, number of `5xx` responses from the origin server, or the rate of `429` responses from the edge server—as measured against the known range of metrics for a performant application. Performance metrics anomalies are one of several significant types of events (e. g., detected anomaly, code deployment, software update) that can occur on an environment. The occurrence of any of those events on an environment are indicated by [Event Types](https://docs.wpvip.com/performance/insights-metrics/#Event-Types) markers in the [**Insights & Metrics** panel](https://docs.wpvip.com/performance/insights-metrics/). The appearance of the Anomaly Event Type differs depending on the currently selected [display format for the data](https://docs.wpvip.com/performance/insights-metrics/#Display-data-as-a-chart-or-a-table). * **In chart format**, Anomaly Event Types are represented by a capital “**A**” within a red circle. Select the Event Type marker to access more information about the event. * **In table format**, linked text descriptions of Anomaly Event Types are located in the column labeled “**Events**”. Select the linked text to access more information about the event. Automated [Notifications can also be configured](https://docs.wpvip.com/notifications/) to communicate Anomaly Event Types when they occur on an environment. **Note** In addition to the performance metrics for anomalies that are monitored on an application by default, [User-Defined Thresholds for anomalies](https://docs.wpvip.com/performance/insights-metrics/anomalies/user-defined-thresholds/) can be configured in the **Insights & Metrics** panel. ## Access **Prerequisites** * Anomaly Event Types are only provided for applications with an [Enhanced, Signature, or Premier package](https://wpvip.com/pricing/). * Anomaly Event Types are only available for production environments. * To access the **Insights & Metrics** panel, a user must have at minimum an [Org member role](https://docs.wpvip.com/manage-user-access/vip-dashboard/org-roles) or an [App read role](https://docs.wpvip.com/app-role/) for that application. Anomaly Event Types are indicated in specific sections of the **Insights & Metrics** panel. * **Edge 429 Response Codes Rate** anomalies are indicated in the “[Edge Response Codes](https://docs.wpvip.com/performance/insights-metrics/http-metrics/#HTTP-Edge-Response-Codes)” section, located in the tab labeled “**HTTP**“. * **5xx Response Codes Rate** anomalies are indicated in the “[Origin Response Codes](https://docs.wpvip.com/performance/insights-metrics/http-metrics/#HTTP-Origin-Response-Codes)” section, located in the tab labeled “**HTTP**“. * **Object Cache Hit Rate** anomalies are indicated in the “[Object Cache Hit Rate](https://docs.wpvip.com/performance/insights-metrics/cache-metrics/#Object-Cache-Hit-Rate)” section, located in the tab labeled “**Cache**“. * **Slow Queries Count** anomalies are indicated in the “[Slow Queries](https://docs.wpvip.com/performance/insights-metrics/database-metrics/#Database-Slow-Queries)” section, located in the tab labeled “**Database**“. ## Edge HTTP 429 Response Codes Rate The **Edge HTTP 429 Response Codes Rate** Anomaly Event Type indicates a sudden and significant increase in the number of an application’s HTTP responses with [`429 Too Many Requests` response status codes](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/429). Several different types of events may cause a sudden increase in requests to a site. This could be a malicious attempt to compromise a site’s performance, [an incorrectly configured reverse proxy](https://docs.wpvip.com/reverse-proxy/), or even an overly aggressive bot scraping a site’s content. The WPVIP Platform has built-in brute-force protections that monitor for this type of behavior and dynamically applies restrictions to suspicious traffic patterns. Though these safeguards are in place to mitigate the negative effects on an application’s performance and stability, it is strongly recommended to [optimize an application’s server performance](https://docs.wpvip.com/docs-vip/performance/analyze-server-performance/) under normal conditions in order to improve its resilience when traffic spikes occur. ![](https://docs.wpvip.com/wp-content/uploads/sites/2/2025/07/429-Response-1024x498. png) Example screenshot of an Edge HTTP 429 Response Code Rate Anomaly Event Type in the “HTTP: Edge Response Codes” section of Insights & Metrics. ### **More Details for 429 Edge Response Code Anomalies** More details about 429 edge response code anomalies that have occurred in the last 5 days can be accessed by selecting the Anomaly Event Type marker. A dialog will appear displaying the range of time in which this anomaly was detected as well as a link to “Find out more details about this anomaly”. Selecting this link will bring up a second dialog box, showing further information about the event. For single sites, this will include the total number of HTTP requests with `429` status code observed for the anomaly duration as well as the top 5 IP addresses and top 5 user agents attached to these requests. For multisite applications, this dialog includes the top network sites impacted by this event. ![](https://docs.wpvip.com/wp-content/uploads/sites/2/2024/11/Screenshot-2024-11- 20-at-9.16.56 AM.png) Example screenshot of the extra details which are displayed when selecting “Find out more details about this anomaly” in the initial dialog box. ## 5xx Response Codes Rate The **5xx Response Codes Rate** Anomaly Event Type indicates a significant increase in the number of an application’s [`500`–`599` HTTP response codes](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status#server_error_responses), also referred to as “`5xx`“. `5xx` responses indicate a server error on a PHP (WordPress) or Node.js origin server. Server errors are a strong indication that the application— or the server it is running on—is in an unhealthy state and requires investigation and intervention. Server errors can also cause end users to experience service disruptions. Consistently low numbers of `5xx` responses on an application are not usually evidence of serious performance issues and will typically not be indicated as an anomaly. The **5xx Response Codes Rate** Anomaly Event Type most often indicates large spikes in `5xx` responses in a short amount of time, or a consistently increasing trend in `5xx` responses. `5xx` responses almost always generate a log entry in an environment’s **[Runtime Logs](https://docs.wpvip.com/logs/runtime-logs/)**, retrievable in the VIP Dashboard or with VIP-CLI. In most cases, the timestamp of a recent **5xx Response Codes Rate** Anomaly Event Type can be correlated with the timestamp of an entry in **[Runtime Logs](https://docs.wpvip.com/logs/runtime-logs/)**. Runtime Logs do not persist for any specific length of time and are cleared due to a variety of events. For this reason, this method is most useful only for real- time reference. For [environments that have New Relic enabled](https://docs.wpvip.com/performance/new-relic/), more historic analysis can be performed with [New Relic’s Error Tracking](https://docs.newrelic.com/docs/errors-inbox/errors-inbox/). For environments that have [HTTP request Log Shipping enabled](https://docs.wpvip.com/logs/log-shipping/), application errors can be analyzed more deeply in the shipped request logs.  ![](https://docs.wpvip.com/wp-content/uploads/sites/2/2026/01/Origin-Response-Codes- Anomalies-1024x563.png) Example screenshot of an Origin HTTP 5xx Response Codes Rate Anomaly Event Type in the “HTTP: Origin Response Codes” section of Insights & Metrics. ## Object Cache Hit Rate The **Object Cache Hit Rate** Anomaly Event Type indicates a drop in cache hit rate for the environment’s [object cache](https://docs.wpvip.com/caching/object-cache/). A drop in cache hit rate often occurs after a code deployment that includes modifications to object cache logic. If there is evidence that a recent code deployment has caused significant negative effects on application performance, a rollback to the previous code deployment is recommended. [A rollback to a previous deployment](https://docs.wpvip.com/github-repository/code-deployments/rollbacks/) can be performed in the **Deployments** panel of the VIP Dashboard. The effect of application code on the performance of its [object cache can be investigated in Query Monitor](https://docs.wpvip.com/query-monitor/#13-object-cache). To diagnose a cache logic issue, load a site’s recently updated page with Query Monitor enabled. The [“Object Cache” panel](https://docs.wpvip.com/performance/query-monitor/#3-object-cache) in Query Monitor displays a wide range of object cache statistics for a page including the amount of time the object cache took to retrieve all requested data and the total size of all objects stored in memory. Look for cache entries that are set and added, verifying the cache group and key for reference. Refresh the page and use the cache group and key for reference to check if any of those entries are being added again. Entries added on every page refresh indicate a cache logic issue. If an Anomaly Event Type occurs in the “Object Cache Hit Rate” section within a range of time that does not immediately follow a code deployment, additional investigation will be needed to identify the cause for the event. If a particular URL has an intermittently slow issue due to object caches expiring, [New Relic](https://docs.wpvip.com/performance/new-relic/)( if enabled) can capture a trace. Traces can be reviewed to determine where the most time is being spent. ![](https://docs.wpvip.com/wp-content/uploads/sites/2/2026/01/Object-Cache-Hit-Rate- 1-1024x548.png) Example screenshot of an Object Cache Hit Rate Anomaly Event Type in the “Cache: Object Cache Hit Rate” section of Insights & Metrics. ## Slow Query Rate The **Slow Query Rate** Anomaly Event Type indicates an unusually large volume of SQL queries made by an application that take an unusually long time to execute. [Identifying slow queries](https://docs.wpvip.com/databases/optimize-queries/identify-slow-queries/) and optimizing their performance can improve database efficiency and the overall responsiveness of an application. The underlying causes for a query’s poor performance might not be immediately apparent, and more in-depth debugging might be needed to improve the query’s performance. To begin, the timestamp of a recent Anomaly Event Type occurring in the “Slow Queries” section of the **Insights & Metrics** panel can be correlated with the timestamp of a slow query listed in [the **Slow Query Logs** panel](https://docs.wpvip.com/logs/slow-query/) of an environment’s VIP Dashboard. Only the 100 most recent slow SQL queries can be found in the **Slow Query Logs** panel, so not all occurrences of Anomaly Event Types will have a correlating log entry. A **Request URL** value is provided for each slow query listed in the **Slow Query Logs** panel. Stack traces for the **Request URL** value can be reviewed by [loading the URL in a browser window with Query Monitor enabled](https://docs.wpvip.com/query-monitor/#2-queries). The Queries panel available in Query Monitor can provide detailed information about the Query, Caller, and Time elapsed for execution for each SQL query sent to the database by the current page. ![](https://docs.wpvip.com/wp-content/uploads/sites/2/2026/01/Slow-Queries-1024x573. png) Example screenshot of a Database Slow Query Rate Anomaly Event Type in the “Database: Slow Queries” section of Insights & Metrics. Last updated: January 15, 2026