milvus: [Bug]: Recall is only 0.384 for first search, which is expected to be 0.97~0.98, but for the late search , the recall can be 0.984

Is there an existing issue for this?

• I have searched the existing issues

Environment

- Milvus version:master-20230116-836773f1
- Deployment mode(standalone or cluster):cluster and standalone
- MQ type(rocksmq, pulsar or kafka):Kafka and pulsar    
- SDK version(e.g. pymilvus v2.0.0rc2):
- OS(Ubuntu or CentOS): 
- CPU/Memory: 
- GPU: 
- Others:

Current Behavior

[2023-01-17T10:11:37.991Z] Search...

[2023-01-17T10:11:37.991Z] search cost  3.9131 seconds

[2023-01-17T10:11:37.991Z] Traceback (most recent call last):

[2023-01-17T10:11:37.991Z]   File "scripts/first_recall_test.py", line 136, in <module>

[2023-01-17T10:11:37.991Z]     milvus_recall_test(host)

[2023-01-17T10:11:37.991Z]   File "scripts/first_recall_test.py", line 117, in milvus_recall_test

[2023-01-17T10:11:37.991Z]     assert recall >= 0.95

[2023-01-17T10:11:37.991Z] AssertionError

collection name: sift_128_euclidean

Expected Behavior

[2023-01-15T09:28:45.814Z] Insert 1000000 vectors cost 32.9921 seconds

[2023-01-15T09:28:45.814Z] 

[2023-01-15T09:28:45.814Z] Get collection entities...

[2023-01-15T09:28:45.814Z] 1000000

[2023-01-15T09:28:45.814Z] 

[2023-01-15T09:28:45.814Z] Get collection entities cost 2.5327 seconds

[2023-01-15T09:28:45.814Z] 

[2023-01-15T09:28:45.814Z] Create index...

[2023-01-15T09:28:45.814Z] 

[2023-01-15T09:28:45.814Z] Create index cost 3.5314 seconds

[2023-01-15T09:28:45.814Z] 

[2023-01-15T09:28:45.814Z] load collection...

[2023-01-15T09:28:45.814Z] 

[2023-01-15T09:28:45.814Z] load collection cost 6.5466 seconds

[2023-01-15T09:28:45.814Z] 

[2023-01-15T09:28:45.814Z] Search...

[2023-01-15T09:28:45.814Z] search cost  4.1557 seconds

[2023-01-15T09:28:45.814Z] recall=0.983

[2023-01-15T09:28:45.814Z] {'float': 2.0, 'int64': 2}

[2023-01-15T09:28:45.814Z] {'float': 4.0, 'int64': 4}

[2023-01-15T09:28:45.814Z] {'float': 6.0, 'int64': 6}

[2023-01-15T09:28:45.814Z] {'float': 8.0, 'int64': 8}

Steps To Reproduce

No response

Milvus Log

failed job: https://qa-jenkins.milvus.io/blue/organizations/jenkins/deploy_test_cron/detail/deploy_test_cron/225/pipeline log: artifacts-pulsar-cluster-reinstall-225-server-logs.tar.gz artifacts-pulsar-cluster-reinstall-225-pytest-logs.tar.gz

Anything else?

No response