0.8.0 id=-1 is returned when total count < topk

[sunyaofei]

Describe the bug
for example:

1. insert 100 record to milvus
2. search with topk=200, i got 100 ids followed by 100 -1s, as below

[
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118200,
  1588236398893118200,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118200,
  1588236398893118200,
  1588236398893118200,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118200,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118200,
  1588236398893118000,
  1588236398893118200,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118200,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118200,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118200,
  1588236398893118200,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118200,
  1588236398893118200,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118200,
  1588236398893118200,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118200,
  1588236398893118000,
  1588236398893118000,
  1588236398893118200,
  1588236398893118200,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  1588236398893118000,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1,
  -1
]

Steps/Code to reproduce behavior
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Expected behavior
just as 0.6.0, return only 100 ids

Environment details
milvus 0.8.0, java sdk

Screenshots
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Additional context
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[sunyaofei]

returned distance has the same problem

[tinkerlin]

When the number of results is less than topk, the insufficient part will be filled with -1, which is an expected behavior.
@sunyaofei

[sunyaofei]

When the number of results is less than topk, the insufficient part will be filled with -1, which is an expected behavior.
@sunyaofei

what is the consideration of this strategy ? why not retain the strategy as 0.6.0 ?
now we have to filter useless result with extra code

[tinkerlin]

I have reproduced this problem. There are indeed different behaviors between 060 and 080. We are working hard to find code changes and redefine this behavior.

[JinHai-CN]

@scsven As we discussed, this issue should be solved in SDK.

[sahuang]

This has been implemented in Java SDK and will be available with Milvus 0.9.0 Release.

[fishpenguin]

This has been implemented in Go SDK and will be available with Milvus 0.9.0 Release.

[BossZou]

This issue has been implemented in python SDK.