List Collections in Milvus

In the Milvus vector database, a collection refers to the data structures that are used to organize and store the vectors efficiently. A collection in Milvus represents a logical container with a set of high-dimensional vectors, each associated with a unique identifier. Think of a collection like a table in the context of relation databases.

Under the hood, Milvus collections are implemented using various data structures such as indexing methods, storage formats, and more. This helps to facilitate and optimize the vector similarity search and retrieval.

Therefore, before you can store any data in a Milvus database, you need to create a collection with the schema of your data.

In this tutorial, we will explore the various methods that you can use to list the available collections on the server.

Requirements:

Before diving into the methods of listing the collections in the Milvus server, ensure that you have the following:

Milvus server
Milvus CLI
Attu for Graphical Administration

With the given requirements met, we can proceed to the next step.

Create a Collection in Milvus

Before learning how to drop an existing Milvus collection, let us start by setting up a sample Milvus collection for demonstration purposes.

Start by opening the Milvus CLI with the following command:

$ milvus_cli

Next, login to your Milvus instance with the following command:

milvus_cli > connect -h <host> -p <port> -a <alias>

For example, the following command logs into a locally hosted Milvus instance on the default port and alias.

milvus_cli > connect -h 127.0.0.1 -p 19530 -a default

Output:

Once logged in, we can create a sample Milvus collection as shown in the following command:

milvus_cli > create collection -c film -f id:INT64:primary_field -f film_name:VARCHAR:100 -f release_year:INT64:release_year -f vector:FLOAT_VECTOR:8 -p id -d 'fiml_collection'

The given command should create a new film collection with the defined schema fields and types.

If you are new to Milvus collections, check the tutorial on creating the Milvus collections in the following link:

https://linuxhint.com/milvus-create-collection

List the Collections in Milvus Using the Milvus CLI

The first and most common method of interacting with the Milvus server is using the Milvus CLI.

Once connected to the Milvus CLI, you can run the “list collections” command as shown in the following syntax:

list collections [-t (float)][-l (boolean)]

The parameters are explained as follows:

-t – This sets the maximum duration of an RPC call in seconds. If this parameter is missing, the client waits until the server responds or an error occurs.
-l – It shows the loaded collections only.

For example, to show all the collections in the server, we can run the following command:

milvus_cli > list collections

Resulting Output:

+----+-------------------+
| | Collection Name |
+====+===================+
| 0 | articles |
+----+-------------------+
| 1 | images |
+----+-------------------+

The given output shows two collections on the server.

List the Collections in Milvus Using Attu

The second method that we can use to list the collections in the Milvus server is using the Attu manager for Milvus.

If you don’t have Milvus installed, you can check the tutorial on https://linuxhint.com/milvus-install-attu.

Once installed, launch Attu and connect to the Milvus server. In the left-hand pane, select the “Collection” tab to view all the available collections on the server.

Conclusion

You learned the two main methods of viewing all the available collections in the Milvus server using the Milvus CLI and the Attu GUI Manager.