Manage Last Value Caches with InfluxDB 3 Explorer

Use InfluxDB 3 Explorer to manage Last Value Caches (LVCs) in an InfluxDB 3 instance or cluster. To navigate to the Last Value Cache management page, in the left navigation bar, select Configure > Caches.

• View Last Value Caches
• Create a Last Value Cache
• Query a Last Value Cache
• Delete a Last Value Cache

View Last Value Caches

To view LVCs associated with a database, navigate to the Last Value Cache management page and select the database from the Select Database dropdown menu. The page lists all LVCs associated with the selected database.

Create a Last Value Cache

On the Last Value Cache management page:

1. Click + Create Cache.

2. Provide the following:

   • Cache name: A unique name for the cache.

   • Database: The database the cache is associated with.

   • Table: The target table for the cache. As data is written to the table, it populates the cache. You must select a database before you can select a table.

   • Key columns: Select string-typed column columns to use as the primary key for the cache. These are typically InfluxDB tags, but you can also use fields. Each unique combination of key column values represents a distinct series. LVCs cache N (count) values per series.

   • Value columns: Select columns to cache values for. These are typically InfluxDB fields, but can also be tags. If no columns are selected as value columns, all non-key columns are used as value columns (excluding time).

   • Count: Specify the number of recently written values to cache per series.

     Higher cardinality (more unique series) in an LVC increases memory usage. Be selective about key columns and the number of values to cache per series to optimize performance.

3. Click Create.

Query a Last Value Cache

Use the Data Explorer to query a LVC:

1. In the left navigation, select Query Data > Data Explorer.
2. Select the database you want to query from the Select database dropdown menu.
3. Click the icon next to the table associated with the LVC you want to query to expand the table. Tables with LVCs have a LVC badge below the icon.
4. Under the Caches section of the expanded table, LVCs are identified by the LVC badge. Click the name of the LVC to generate a SQL query that queries everything from the LVC. You can also expand the LVC and select specific columns to query.
5. Click Run Query to execute the query and return results from the cache.

Delete a Last Value Cache

On the Last Value Cache management page:

1. Select the database associated with the cache you want to delete from the Select Database dropdown menu.
2. In the Active Caches table, click the icon next to the cache you want to delete.