4_index

Tutorial 4: Create and manage indexes

This standalone project creates one vector index and two scalar indexes with MilvusClientV2: HNSW with cosine distance for a float vector, INVERTED for text, and STL_SORT for a numeric field.

API flow

1. Create a collection without indexes so index creation is explicit.
2. Call CreateIndex with field, index name, type, metric, and HNSW build parameters.
3. Use ListIndexes to inspect all indexes and DescribeIndex for detailed metadata.
4. Drop one index, then drop the collection and remaining indexes.

Vector indexes require a compatible metric. Scalar choices include INVERTED for general filtering and STL_SORT for ordered numeric values; AutoIndex is a convenient server-selected alternative.

Prerequisites and run

Use a C++14 compiler, CMake 3.16+, Python 3, Conan 2, and Milvus 2.6 or later. Defaults are MILVUS_URI=http://localhost:19530 and MILVUS_TOKEN=root:Milvus.

make
make run

The project consumes milvus-sdk-cpp/3.0.3@milvus/dev by default. Package and connection settings can be overridden with the MILVUS_SDK_*, MILVUS_URI, and MILVUS_TOKEN environment variables.

Expected output

Index listing order and numeric type values may vary by server, but a successful run includes:

Calling Connect...
Connect succeeded.
Calling DropCollection for stale data...
Stale collection cleanup completed.
Calling CreateCollection...
CreateCollection succeeded.
Calling CreateIndex...
CreateIndex succeeded.
Calling ListIndexes...
ListIndexes succeeded.
embedding_hnsw_idx field=embedding type=...
category_inverted_idx field=category type=...
price_sort_idx field=price type=...
Calling DescribeIndex...
DescribeIndex succeeded.
Described vector indexes: 1
Calling DropIndex...
DropIndex succeeded.
Calling DropCollection...
DropCollection succeeded.

Troubleshooting

• index creation errors: verify field, index type, metric, and extra parameters are compatible.
• index timeout: check Milvus health and available CPU and memory.
• connection or authentication errors: check MILVUS_URI and MILVUS_TOKEN.
• rerunning after interruption: the fixed tutorial collection is removed first.