When delete by partition_key, Milvus will generates L0 segments
globally. During L0 Compaction, those L0 segments will touch all
partitions collection wise. Due to the false-positive rate of segment
bloomfilters, L0 compactions will append false deltalogs to completed
irrelevant partitions, which causes *partition deletion amplification.
This PR uses partition_key to set targeted partitionID when producing
deleteMsgs into MsgStreams. This'll narrow down L0 segments scope to
partition level, and remove the false-positive influence
collection-wise.
However, due to DeleteMsg structure, we can only label one partition to
one deleteMsg, so this enhancement fails if user wants to delete over 2
partition_keys in one deletion.
pr: #38231
See also: #34665
Signed-off-by: yangxuan <xuan.yang@zilliz.com>
