2_collection

Tutorial 2: Manage collections

This standalone C++ project demonstrates the collection lifecycle with MilvusClientV2. It creates a collection from a schema, checks and describes the collection, changes properties, loads it, reads state and statistics, releases it, renames it, truncates its data, and drops it. An AutoIndex is included only so Milvus can load the vector collection; Tutorial 4 covers index creation and administration in detail.

API flow

1. Connect authenticates the client.
2. CreateCollection stores the schema, adds the load prerequisite AutoIndex, and sets bounded consistency.
3. HasCollection and DescribeCollection inspect existence and metadata.
4. AlterCollectionProperties and DropCollectionProperties manage TTL configuration.
5. LoadCollection, GetLoadState, and GetCollectionStats inspect serving state.
6. ReleaseCollection, RenameCollection, TruncateCollection, and DropCollection finish cleanup.

Prerequisites and configuration

Install a C++14 toolchain, CMake 3.16+, Python 3, and Conan 2. Run Milvus 2.6 or later. The defaults are MILVUS_URI=http://localhost:19530 and MILVUS_TOKEN=root:Milvus.

MILVUS_URI="https://your-endpoint" MILVUS_TOKEN="your-token" make run

Build and run

make
make run

The project consumes milvus-sdk-cpp/3.0.3@milvus/dev by default. Override the package with MILVUS_SDK_VERSION, MILVUS_SDK_USER, and MILVUS_SDK_CHANNEL. The tutorial removes its temporary collection; use make clean to remove build outputs.

Expected output

Calling Connect...
Connect succeeded.
Calling DropCollection for stale collection CPP_TUTORIAL_COLLECTION...
DropCollection completed for CPP_TUTORIAL_COLLECTION.
Calling DropCollection for stale collection CPP_TUTORIAL_COLLECTION_RENAMED...
DropCollection completed for CPP_TUTORIAL_COLLECTION_RENAMED.
Calling CreateCollection...
CreateCollection succeeded.
Calling HasCollection...
HasCollection succeeded.
Collection exists: 1
Calling DescribeCollection...
DescribeCollection succeeded.
Collection ID: ...
Calling AlterCollectionProperties...
AlterCollectionProperties succeeded.
Calling DescribeCollection again...
DescribeCollection succeeded.
TTL: 3600
Calling DropCollectionProperties...
DropCollectionProperties succeeded.
Calling LoadCollection...
LoadCollection succeeded.
Calling GetLoadState...
GetLoadState succeeded.
Load state: ..., progress=100%
Calling GetCollectionStats...
GetCollectionStats succeeded.
Row count: 0
Calling ReleaseCollection...
ReleaseCollection succeeded.
Calling RenameCollection...
RenameCollection succeeded.
Calling HasCollection for CPP_TUTORIAL_COLLECTION_RENAMED...
HasCollection completed for CPP_TUTORIAL_COLLECTION_RENAMED.
Renamed collection exists: 1
Calling TruncateCollection...
TruncateCollection succeeded.
Calling DropCollection...
DropCollection succeeded.

Troubleshooting

• collection administration errors: use a token allowed to create and alter collections.
• load timeout: check server health and available resources.
• rerunning after interruption: the tutorial removes its fixed collection names first.
• connection or authentication errors: check MILVUS_URI and MILVUS_TOKEN.