[Bug]: Mmap manager has not been init

[benraha]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I'm trying to run Milvus in memory mode for quick and ephemeral queries.
When I run the quickstart on a remote machine (a DataProc worker machine, that is kind of hard to debug), I get the following errors:

I get the following exception:

<MilvusException: (code=2000, message=Assert "init_flag_ == true"  => Mmap manager has not been init. at /workspace/milvus-lite/thirdparty/milvus/internal/core/src/storage/MmapManager.h:96
: segcore error)>
Traceback (most recent call last):
  File "/python_env/lib/python3.10/site-packages/pymilvus/milvus_client/milvus_client.py", line 97, in create_collection
    return self._create_collection_with_schema(
  File "/python_env/lib/python3.10/site-packages/pymilvus/milvus_client/milvus_client.py", line 922, in _create_collection_with_schema
    raise ex from ex
  File "/python_env/lib/python3.10/site-packages/pymilvus/milvus_client/milvus_client.py", line 918, in _create_collection_with_schema
    conn.create_collection(collection_name, schema, timeout=timeout, **kwargs)
  File "/python_env/lib/python3.10/site-packages/pymilvus/decorators.py", line 141, in handler
    raise e from e
  File "/python_env/lib/python3.10/site-packages/pymilvus/decorators.py", line 137, in handler
    return func(*args, **kwargs)
  File "/python_env/lib/python3.10/site-packages/pymilvus/decorators.py", line 173, in handler
    return func(self, *args, **kwargs)
  File "/python_env/lib/python3.10/site-packages/pymilvus/decorators.py", line 116, in handler
    raise e from e
  File "/python_env/lib/python3.10/site-packages/pymilvus/decorators.py", line 86, in handler
    return func(*args, **kwargs)
  File "/python_env/lib/python3.10/site-packages/pymilvus/client/grpc_handler.py", line 318, in create_collection
    check_status(status)
  File "/python_env/lib/python3.10/site-packages/pymilvus/client/utils.py", line 65, in check_status
    raise MilvusException(status.code, status.reason, status.error_code)
pymilvus.exceptions.MilvusException: <MilvusException: (code=2000, message=Assert "init_flag_ == true"  => Mmap manager has not been init. at /workspace/milvus-lite/thirdparty/milvus/internal/core/src/storage/MmapManager.h:96
: segcore error)>

I tried setting the mmap off to fix it, but without success.

Expected Behavior

No response

Steps/Code To Reproduce behavior

from pymilvus import MilvusClient, DataType

client = MilvusClient("/tmp/milvus_demo2.db")
schema = MilvusClient.create_schema()

schema.add_field(
    field_name="id",
    datatype=DataType.INT64,
    is_primary=True,
    mmap_enabled=False
)

# Add the vector field
schema.add_field(
    field_name="vector",
    datatype=DataType.FLOAT_VECTOR,
    dim=32,
    mmap_enabled=False
)

client.create_collection(
    collection_name="demo_collection",
    schema=schema
)

Environment details

- Hardware/Softward conditions (OS, CPU, GPU, Memory):
- Method of installation (Docker, or from source): pip install pymilvus
- Milvus version (v0.3.1, or v0.4.0): pymilvus-2.6.1-py3-none-any.whl, milvus_lite-2.5.1-py3-none-manylinux2014_x86_64.whl
- Milvus configuration (Settings you made in `server_config.yaml`): no server_config.yaml

Anything else?

No response

[benraha]

The issue was that the user had no access to a hard-coded cache path that is not exposed anywhere ...

https://github.com/milvus-io/milvus-lite/blob/d0ffebfa43fc681b93db86a03a7688ec67f93fb6/src/segcore_wrapper.h#L40

My workaround was to set the HOME environment variable to another directory in order to write the cache files.