[Bug]: max_capacity does not allow update in collection field param: invalid parameter

[noob9527]

Is there an existing issue for this?

• I have searched the existing issues

Environment

- Milvus version:2.5.9
- Deployment mode(standalone or cluster):standalone
- MQ type(rocksmq, pulsar or kafka):    
- SDK version(e.g. pymilvus v2.0.0rc2):milvus-sdk-java v2.5.7
- OS(Ubuntu or CentOS): 
- CPU/Memory: 
- GPU: 
- Others:

Current Behavior

I'm trying to alter an array field's max_capacity, I did exactly the same thing according to the document.

https://milvus.io/docs/alter-collection-field.md#Alter-ARRAY-field

here's my code:

        client.alterCollectionField(
            AlterCollectionFieldReq.builder()
                .collectionName(collection_name)
                .fieldName("current_company_ids")
                .property("max_capacity", "20")
                .build()
        )

I got the following error:

max_capacity does not allow update in collection field param: invalid parameter
io.milvus.v2.exception.MilvusClientException: max_capacity does not allow update in collection field param: invalid parameter
	at io.milvus.v2.utils.RpcUtils.handleResponse(RpcUtils.java:63)
	at io.milvus.v2.service.collection.CollectionService.alterCollectionField(CollectionService.java:233)
	at io.milvus.v2.client.MilvusClientV2.lambda$alterCollectionField$10(MilvusClientV2.java:302)
	at io.milvus.v2.utils.RpcUtils.retry(RpcUtils.java:100)
	at io.milvus.v2.client.MilvusClientV2.alterCollectionField(MilvusClientV2.java:302)

Expected Behavior

succeefully alter the max_capacity of that field

Steps To Reproduce

Milvus Log

[2025/04/16 14:33:24.106 +00:00] [INFO] [proxy/impl.go:1347] ["AlterCollectionField received"] [traceID=b07f836cdd72621e334ae5b88537dfdf] [role=proxy] [db=default] [collection=expert_04_08] [fieldName=current_company_ids] [props="[{\"key\":\"max_capacity\",\"value\":\"20\"}]"]
[2025/04/16 14:33:24.106 +00:00] [WARN] [proxy/task_scheduler.go:508] ["Failed to pre-execute task: max_capacity does not allow update in collection field param: invalid parameter"] [traceID=b07f836cdd72621e334ae5b88537dfdf]
[2025/04/16 14:33:24.106 +00:00] [WARN] [proxy/impl.go:1365] ["AlterCollectionField failed to WaitToFinish"] [traceID=b07f836cdd72621e334ae5b88537dfdf] [role=proxy] [db=default] [collection=expert_04_08] [fieldName=current_company_ids] [props="[{\"key\":\"max_capacity\",\"value\":\"20\"}]"] [error="max_capacity does not allow update in collection field param: invalid parameter"] [errorVerbose="max_capacity does not allow update in collection field param: invalid parameter\n(1) attached stack trace\n  -- stack trace:\n  | github.com/milvus-io/milvus/pkg/v2/util/merr.WrapErrParameterInvalidMsg\n  | \t/workspace/source/pkg/util/merr/utils.go:948\n  | github.com/milvus-io/milvus/internal/proxy.(*alterCollectionFieldTask).PreExecute\n  | \t/workspace/source/internal/proxy/task.go:1231\n  | github.com/milvus-io/milvus/internal/proxy.(*taskScheduler).processTask\n  | \t/workspace/source/internal/proxy/task_scheduler.go:501\n  | github.com/milvus-io/milvus/internal/proxy.(*taskScheduler).definitionLoop.func1\n  | \t/workspace/source/internal/proxy/task_scheduler.go:542\n  | github.com/milvus-io/milvus/pkg/v2/util/conc.(*Pool[...]).Submit.func1\n  | \t/workspace/source/pkg/util/conc/pool.go:82\n  | github.com/panjf2000/ants/v2.(*goWorker).run.func1\n  | \t/go/pkg/mod/github.com/panjf2000/ants/[email protected]/worker.go:67\n  | runtime.goexit\n  | \t/go/pkg/mod/golang.org/[email protected]/src/runtime/asm_amd64.s:1695\nWraps: (2) max_capacity does not allow update in collection field param\nWraps: (3) invalid parameter\nError types: (1) *withstack.withStack (2) *errutil.withPrefix (3) merr.milvusError"] [BeginTs=457392522289217538] [EndTs=457392522289217538]

Anything else?

No response

[yanliang567]

for now, this is by design. @czs007 please help to check if there are any plans to support it.

/assign @czs007
/unassign

[xiaofan-luan]

what does max_capacity mean?

[yanliang567]

what does max_capacity mean?

means the max length of an array

[xiaofan-luan]

/assign @JsDove
please help on it

[JsDove]

/assign @yanliang567 please help test