> For the complete documentation index, see [llms.txt](https://docs.soda.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.soda.io/data-observability/metric-monitoring-dashboard/dataset-monitors/metadata-based.md).

# Based on metadata

These monitors are derived directly from the data platform’s system metadata, without scanning row-level values. They surface structural signals, such as:

* [**Last modification time**](/data-observability/metric-monitoring-dashboard/dataset-monitors/metadata-based/last-modification-time.md): when the dataset was last updated
* [**Schema changes**](/data-observability/metric-monitoring-dashboard/dataset-monitors/metadata-based/schema-changes.md): any alterations to the schema
* [**Total row count**](/data-observability/metric-monitoring-dashboard/dataset-monitors/metadata-based/total-row-count.md): the overall number of records in the dataset
* [**Total row count change**](/data-observability/metric-monitoring-dashboard/dataset-monitors/metadata-based/total-row-count-change.md): the delta in row count compared to the previous observation

Because they read only metadata, these monitors are extremely lightweight to compute and ideal for continuous, real-time dashboarding of dataset activity.

> Learn more about which features are supported in **each** [**metadata data source**](/data-observability/metadata-data-sources.md), such as historical backfilling or partition row count.

## Metric Monitoring on table views

{% hint style="warning" %}
Depending on your data source(s), **metadata-based Metric Monitors may only be supported on Tables**, and not on other data objects e.g. **Views**.

Alternatives could be to setup these metadata-based Metric Monitors on the source Tables of your non-Table data objects, and/or store these data objects as Tables instead.
{% endhint %}

Metric Monitoring on table views is currently available on:

* BigQuery
* Databricks
* Postgres
* Redshift
* Snowflake

{% hint style="info" %}

* **Metric Monitors on table views do not use metadata**; metadata is not provided for views.
* All monitors are supported except [Last modification time](/data-observability/metric-monitoring-dashboard/dataset-monitors/metadata-based/last-modification-time.md).
  * Last modification time must be **turned off manually**; Soda will attempt to enable it automatically as there is no structural difference between tables and table views.
    {% endhint %}

## Unavailable metadata

When Soda Cloud cannot obtain the underlying metadata required to calculate a dataset-level metric, it prevents you from configuring or viewing a metric that would always fail. There are two cases:

### **Non-retrievable metadata from data source**

If a connected data source cannot provide the required metadata for a given dataset-level metric, such as row counts or schema timestamps, **Soda will automatically disable that metric** both on the Metric Monitors dashboard and in the **Configure Dataset Monitors** panel so you only see and configure metrics that your source can actually collect.

<figure><img src="/files/QkZbhi4yHJfsnvVcsgcs" alt=""><figcaption></figcaption></figure>

<figure><img src="/files/2WfuD2zlE3NQElx6NfJE" alt=""><figcaption></figcaption></figure>

### Unavailable metadata (history)

Some warehouses expose current metadata but don’t provide historical snapshots (for example, systems that only track the latest row count). In this case, **Soda will compute the metric starting from your very first scan**, but it cannot backfill any history prior to that point. As a result, anomaly detection baselines for that metric begin only at scan #1 and there is **no retroactive historical data** to train against.

<figure><img src="/files/Ayj6Qq2tb45pzqgVFB1Y" alt=""><figcaption></figcaption></figure>

The **Schema changes** monitor will not add historical metadata and backfilling will not be available, unlike with other metrics. The monitor only starts recording from the moment the dataset is onboarded.

## Supported data sources

<table><thead><tr><th width="185.79998779296875">Data source</th><th width="171.20001220703125">Onboarding</th><th>Metadata</th><th>Metadata history</th><th>Querying data</th></tr></thead><tbody><tr><td><a data-mention href="/pages/ctP9k7n5AxdoMIBmXxD2">/pages/ctP9k7n5AxdoMIBmXxD2</a></td><td>✅</td><td>✅</td><td>—</td><td>✅</td></tr><tr><td><a data-mention href="/pages/xlK0ugO80HSregboFQUM">/pages/xlK0ugO80HSregboFQUM</a></td><td>✅</td><td>✅</td><td>✅</td><td>✅</td></tr><tr><td><a data-mention href="/pages/jggdwLvBUVJjJlkdmGUe">/pages/jggdwLvBUVJjJlkdmGUe</a></td><td>✅</td><td>✅</td><td>✅</td><td>✅</td></tr><tr><td><a data-mention href="/pages/qQQSBTgs2jlSAdkxg3mF">/pages/qQQSBTgs2jlSAdkxg3mF</a></td><td>✅</td><td>Upcoming</td><td>—</td><td>✅</td></tr><tr><td><a data-mention href="/pages/dESWjWE03JmceyspJhlb">/pages/dESWjWE03JmceyspJhlb</a> (<a href="/pages/eW38AlRtSFOjYNj9fD11">Pandas</a>, <a href="/pages/lA3k9OMWjmbLKD1OfPPA">Polars</a>, etc.)</td><td>Partial/Python only</td><td>—</td><td>—</td><td>✅</td></tr><tr><td><a data-mention href="/pages/eCdm3TE8crsXRy3LKZpO">/pages/eCdm3TE8crsXRy3LKZpO</a></td><td>✅</td><td>✅</td><td>—</td><td>✅</td></tr><tr><td>MySQL</td><td>Upcoming</td><td>—</td><td>—</td><td>✅</td></tr><tr><td><a data-mention href="/pages/yymUzQ59nkr9L3YddiK0">/pages/yymUzQ59nkr9L3YddiK0</a></td><td>✅</td><td>✅</td><td>—</td><td>✅</td></tr><tr><td><a data-mention href="/pages/xqU5pcfJVCubI3BL8MAH">/pages/xqU5pcfJVCubI3BL8MAH</a></td><td>✅</td><td>✅</td><td>—</td><td>✅</td></tr><tr><td><a data-mention href="/pages/AUAQ8kj87Q98kRNninUy">/pages/AUAQ8kj87Q98kRNninUy</a></td><td>✅</td><td>✅</td><td>✅</td><td>✅</td></tr><tr><td><a data-mention href="/pages/KxwupsjjHWfxegxEzjwS">/pages/KxwupsjjHWfxegxEzjwS</a></td><td>Partial/Python only</td><td>—</td><td>—</td><td>✅</td></tr><tr><td><a data-mention href="/pages/jmuttQi4HNCqZoA6ehA6">/pages/jmuttQi4HNCqZoA6ehA6</a></td><td>✅</td><td>✅</td><td>—</td><td>✅</td></tr><tr><td><a data-mention href="/pages/hnAwM7zDdGkq4RkDqhBt">/pages/hnAwM7zDdGkq4RkDqhBt</a></td><td>✅</td><td>✅</td><td>—</td><td>✅</td></tr><tr><td><a data-mention href="/pages/GzT8YXwoPxHYCfTPHap4">/pages/GzT8YXwoPxHYCfTPHap4</a></td><td>✅</td><td>✅</td><td>—</td><td>✅</td></tr><tr><td><a data-mention href="/pages/2aL0YaZUaMgSp9hJMghh">/pages/2aL0YaZUaMgSp9hJMghh</a></td><td>✅</td><td>—</td><td>—</td><td>✅</td></tr></tbody></table>

***

{% if visitor.claims.plan === 'datasetStandard' %}
{% hint style="success" %}
You are **logged in to Soda** and seeing the **Dataset Standard license** documentation. Learn more about [Documentation access & licensing](/reference/documentation-access-and-licensing.md).
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{% endhint %}
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{% if !(visitor.claims.plan === 'enterprise' || visitor.claims.plan === 'enterpriseUserBased' || visitor.claims.plan === 'datasetStandard') %}
{% hint style="info" %}
You are **not logged in to Soda** and are viewing the default public documentation. Learn more about [Documentation access & licensing](/reference/documentation-access-and-licensing.md).

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---

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