<commit_before>---
title: Troubleshooting Missing Data
keywords: query language
tags: [query language]
sidebar: doc_sidebar
permalink: missing_data_troubleshooting.html
summary: Learn how to troubleshoot when you expect to see data but they don't appear in charts
---

Sometimes users expect to see certain data in Tanzu Observability by Wavefront but, for some reason, it doesn't show up!  This can be a frustrating and confusing experience, especially when you urgently need the data. Wavefront does not delete data, and retains [metric data for 18 months](terms_of_service.html#data-retention). What could be the problem?

This doc page, based on the extensive experience of our customer success team, helps you
investigate, understand, and remedy possible causes.


## Problem: You Expect to See Data But They Aren't There

It's not uncommon that users expect to see data in a chart or an alert but the data aren't there.

**Symptoms**

* You do not see the data in charts and dashboards.
* Below a query, you might get a message like the following:
  - `Specified metric/histogram/span does not exist`
  - `Point tag does not exist`
  - `Nothing matching: <metric name> and source[]`
* Below a query, you see a syntax error message.

In this section, you learn how to investigate. Here's an overview of the steps:

![investigate missing data flowchart, content matches steps](images/missing_data_1.png)

{% include tip.html content="This section investigest only missing data. If your query returns a syntax error, look carefully at the [query language reference](query_language_reference.html), examine individual reference pages, and learn from other pages in that section such as [Fine Tune Queries with Point Tags](query_language_point_tags.html)." %}



### Step 1: Check the Time Window

At times, you're looking at a chart and the chart's time window is not set to the time during which data were flowing. For example, suppose you discovered a week ago that there were problems with networking data for a certain host. You replaced the host, and want to show last week's problem to a co-worker. You have to make sure that you look at a time window before the host was replaced.

As a first step, [expand the chart's time window](ui_examine_data.html#set-the-time-window) and see if the data of interest shows up. You try looking back up 28 days. If you still don't see your data, go to the next step and consider including obsolete metric.



### Step 2: Consider Include Obsolete Metrics

If a time series hasn't ingested any data points in the last 28 days (or longer), Wavefront considers the time series obsolete. By default, obsolete data are not included in charts to improve chart loading. If you want to see the data:

* In the chart, click **Advanced** and select **Obsolete Metrics**.
* In the dashboard, you can [turn on obsolete metrics for each chart](ui_examine_data.html#include-or-exclude-obsolete-metrics), but performance can suffer.

<!---rk: Might have to change the link above--->

![Advanced tab is selected, include obsolete metrics is checked](images/include_obsolete.png)


<!---
Recommend we don't link to this. Duplicate. See Where is My Old Data? for more details and tips.---><commit_msg>Add 3 new doc pages with content previously in KB.<commit_after>---
title: Troubleshooting Missing Data
keywords: query language
tags: [query language]
sidebar: doc_sidebar
permalink: missing_data_troubleshooting.html
summary: Learn how to troubleshoot when you expect to see data but they don't appear in charts
---

Sometimes users expect to see certain data in Tanzu Observability by Wavefront but, for some reason, it doesn't show up!  This can be a frustrating and confusing experience, especially when you urgently need the data. Wavefront does not delete data, and retains [metric data for 18 months](terms_of_service.html#data-retention). What could be the problem?

This doc page, based on the extensive experience of our customer success team, helps you
investigate, understand, and remedy possible causes.


## Problem: You Expect to See Data But They Aren't There

It's not uncommon that users expect to see data in a chart or an alert but the data aren't there.

**Symptoms**

* You do not see the data in charts and dashboards.
* Below a query, you might get a message like the following:
  - `Specified metric/histogram/span does not exist`
  - `Point tag does not exist`
  - `Nothing matching: <metric name> and source[]`
* Below a query, you see a syntax error message.

In this section, you learn how to investigate. Here's an overview of the steps:

![investigate missing data flowchart, content matches steps](images/missing_data_1.png)

{% include tip.html content="This section investigest only missing data. If your query returns a syntax error, look carefully at the [query language reference](query_language_reference.html), examine individual reference pages, and learn from other pages in that section such as [Fine Tune Queries with Point Tags](query_language_point_tags.html)." %} 



### Step 1: Check the Time Window

At times, you're looking at a chart and the chart's time window is not set to the time during which data were flowing. For example, suppose you discovered a week ago that there were problems with networking data for a certain host. You replaced the host, and want to show last week's problem to a co-worker. You have to make sure that you look at a time window before the host was replaced.

As a first step, [expand the chart's time window](ui_examine_data.html#set-the-time-window) and see if the data of interest shows up. You try looking back up 28 days. If you still don't see your data, go to the next step and consider including obsolete metric.



### Step 2: Consider Include Obsolete Metrics

If a time series hasn't ingested any data points in the last 28 days (or longer), Wavefront considers the time series obsolete. By default, obsolete data are not included in charts to improve chart loading. If you want to see the data:

* In the chart, click **Advanced** and select **Obsolete Metrics**.
* In the dashboard, you can [turn on obsolete metrics for each chart](ui_examine_data.html#include-or-exclude-obsolete-metrics), but performance can suffer.

<!---rk: Might have to change the link above--->

![Advanced tab is selected, include obsolete metrics is checked](images/include_obsolete.png)


<!---
Recommend we don't link to this. Duplicate. See Where is My Old Data? for more details and tips.--->
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