l0CompactionTask failed to build compaction request

[rere950303]

• milvus version : v2.4.20
• mode: cluster

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This warning log below is appearing every minute — is this something to be concerned about? Or is it an issue that resolves itself naturally?

[datacoord/compaction_task_l0.go:73] ["l0CompactionTask failed to build compaction request"] [triggerID=456409032569113665] [nodeID=38] [error="segment not found[segment=456409032499143124]"]
[datacoord/compaction_task_l0.go:73] ["l0CompactionTask failed to build compaction request"] [triggerID=456409032569113657] [nodeID=28] [error="segment not found[segment=456409032499143123]"]

[rere950303]

@yhmo @xiaofan-luan could you check this issue plz... 🙏

[rere950303]

There are cases like node_id: -1 as shown in the attached screenshot — could this be related to #39956?
Is there any way to resolve this using Birdwatcher or any restarting pod?

[yhmo]

"l0CompactionTask failed to build compaction request" is not a critical error; it just reports that a compaction task is invalid, and this task will not be executed.

There is a bug fix in v2.4.21 that might be related:

• Cleaned up compaction tasks in compactionhandler (#38848)

You can restart the datacoord to see if the warning message still occurs.
If restarting datacoord doesn't help, you can upgrade to v2.4.23.

"node_id = -1" means the compaction task is not ready to be executed. The task is still in the pipeline, waiting to be assigned to a datanode.

There are more improvements for compaction in v2.5.x. Upgrade to v2.5.11 is also an option.

[rere950303]

Ah, I see. I've confirmed that restarting datacoord clears the logs for now.
It seems like upgrading as soon as possible would be the best approach.
Thank you so much for the detailed response!

[secsilm]

@yhmo I have already upgraded to 2.5.11, but this warning still persists:

milvus-standalone  | [2025/05/26 09:40:42.610 +00:00] [WARN] [datacoord/compaction_task_l0.go:103] ["l0CompactionTask failed to build compaction request"] [triggerID=458293863704891266] [nodeID=4910] [error="Selected zero L1/L2 segments for the position=channel_name:\"by-dev-rootcoord-dml_8_458222654905193157v0\" msgID:\"\\xf3\\x11\\x8c\\x88\\xed\\xf4Z\\x06\" msgGroup:\"by-dev-rootcoord-dml_8-1-1748250795180760339\" timestamp:458293589688188929"] [errorVerbose="Selected zero L1/L2 segments for the position=channel_name:\"by-dev-rootcoord-dml_8_458222654905193157v0\" msgID:\"\\xf3\\x11\\x8c\\x88\\xed\\xf4Z\\x06\" msgGroup:\"by-dev-rootcoord-dml_8-1-1748250795180760339\" timestamp:458293589688188929\n(1) attached stack trace\n  -- stack trace:\n  | github.com/milvus-io/milvus/internal/datacoord.(*l0CompactionTask).BuildCompactionRequest\n  | \t/workspace/source/internal/datacoord/compaction_task_l0.go:360\n  | github.com/milvus-io/milvus/internal/datacoord.(*l0CompactionTask).processPipelining\n  | \t/workspace/source/internal/datacoord/compaction_task_l0.go:101\n  | github.com/milvus-io/milvus/internal/datacoord.(*l0CompactionTask).Process\n  | \t/workspace/source/internal/datacoord/compaction_task_l0.go:81\n  | github.com/milvus-io/milvus/internal/datacoord.(*compactionPlanHandler).checkCompaction\n  | \t/workspace/source/internal/datacoord/compaction.go:735\n  | github.com/milvus-io/milvus/internal/datacoord.(*compactionPlanHandler).loopCheck\n  | \t/workspace/source/internal/datacoord/compaction.go:447\n  | runtime.goexit\n  | \t/usr/local/go/src/runtime/asm_amd64.s:1700\nWraps: (2) Selected zero L1/L2 segments for the position=channel_name:\"by-dev-rootcoord-dml_8_458222654905193157v0\" msgID:\"\\xf3\\x11\\x8c\\x88\\xed\\xf4Z\\x06\" msgGroup:\"by-dev-rootcoord-dml_8-1-1748250795180760339\" timestamp:458293589688188929\nError types: (1) *withstack.withStack (2) *errutil.leafError"]