When autoID is enabled, the preimport task estimates row distribution by
evenly dividing the total row count (numRows) across all vchannels:
`estimatedCount = numRows / vchannelNum`.
However, the actual import task hashes real auto-generated IDs to
determine
the target vchannel. This mismatch can lead to inaccurate row
distribution estimation
in such corner cases:
- Importing 1 row into 2 vchannels:
• Preimport: 1 / 2 = 0 → both v0 and v1 are estimated to have 0 rows
• Import: real autoID (e.g., 457975852966809057) hashes to v1
→ actual result: v0 = 0, v1 = 1
To resolve such corner case, we now allocate at least one segment for
each vchannel
when autoID is enabled, ensuring all vchannels are prepared to receive
data even
if no rows are estimated for them.
issue: https://github.com/milvus-io/milvus/issues/41759
pr: https://github.com/milvus-io/milvus/pull/41771
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Signed-off-by: bigsheeper <yihao.dai@zilliz.com>
yihao.dai