[CASSANDRA-13511] Compaction stats high with no CPU use.

• Type: Bug
• Status: Resolved
• Priority: Low
• Resolution: Cannot Reproduce
• Fix Version/s: 2.2.x
• Component/s: Local/Compaction

Environment

Red Hat Maipo 7.3

$ nodetool -h localhost version
ReleaseVersion: 2.2.8

$ nodetool describecluster
Cluster Information:
Name: XXXXXXX Production Cassandra Cluster
Snitch: org.apache.cassandra.locator.DynamicEndpointSnitch
Partitioner: org.apache.cassandra.dht.Murmur3Partitioner
Schema versions:
6938e859-955d-3ecb-aa0a-07bac9db1fc1: [172.16.121.4, 172.16.121.68, 172.16.121.5, 172.16.121.69, 172.16.121.6, 172.16.121.70, 172.16.121.7, 172.16.121.71]

$ nodetool status
Datacenter: DC1
===============
Status=Up/Down

/ State=Normal/Leaving/Joining/Moving – Address Load Tokens Owns (effective) Host ID Rack UN 172.16.121.4 1.59 TB 1 75.0% cbf7608f-fd8e-49c6-83d7-2ac5a5a9104c RAC1 UN 172.16.121.5 1.44 TB 1 75.0% fa10aa81-c336-4f8b-a6fe-09f7f92e2026 RAC1 UN 172.16.121.6 1.52 TB 1 75.0% d0ed7e9f-034f-490a-8112-30d0b0829c81 RAC1 UN 172.16.121.7 2.01 TB 1 75.0% e17ce089-d638-410e-816f-498567200c3d RAC1 Datacenter: DC2 =============== Status=Up/Down

/ State=Normal/Leaving/Joining/Moving – Address Load Tokens Owns (effective) Host ID Rack UN 172.16.121.68 2.3 TB 1 75.0% eb92ecdc-4be1-452f-b638-67cb8c9c32fd RAC1 UN 172.16.121.69 2.77 TB 1 75.0% cbd93cfc-48a4-4eb5-8015-d1d1f513d09c RAC1 UN 172.16.121.70 2.82 TB 1 75.0% f6d415cf-40c0-4da5-8996-5551dadf2640 RAC1 UN 172.16.121.71 1.65 TB 1 75.0% 160a7251-fe54-4d4d-8251-32abc6408753 RAC1

• Severity: Low
• Assignee: Unassigned
• Reporter: Raul Barroso
• Created: 09/May/17 11:41
• Updated: 16/Apr/19 09:30
• Resolved: 13/May/17 09:30

Description

Hi Team,

First of all, this is my first post on apache's JIRA and I'm not pretty sure if I'm doing it right. Excuse any inconvenience and let me know if there's some mistake from my side.

We currently are facing some problems at our company with the delivered productive environment. Right now I'm keen on compaction tasks.

We are having high compaction tasks on two nodes from our cluster. Currently 84/92 tasks on these nodes with low CPU usage and no activity on disk (1-2 Mb/s Read and write values on iostats).

I'm quite confused with the info shown at compactionstats & tpstats (see below):

• 83 pending compaction tasks + 10 running
• CompactionExecutor : 8 Active 151 Pending

Why doesn't these numbers match?
Why are the compactions being accumulated if the system CPU and I/O are low?
Why are we running a "unreleased" version and what does that mean?

Thanks for your time and help here. Greatly appreciated. Rbarroso.

$ nodetool compactionstats
pending tasks: 83
id compaction type keyspace table completed total unit progress
a3307690-3480-11e7-a556-b1cf2e788d44 Compaction revenue_events usage_events 29628223698 42281336944 bytes 70.07%
d67dde80-3321-11e7-a556-b1cf2e788d44 Validation revenue_events usage_events_by_agreement_id 884497156069 1000368079324 bytes 88.42%
925b4540-34a6-11e7-a556-b1cf2e788d44 Anticompaction after repair cm resources__history 2907492207 5106868634 bytes 56.93%
760fa550-3395-11e7-a556-b1cf2e788d44 Compaction revenue_events charging_balance_changes_by_source_id 195729008027 240875858343 bytes 81.26%
622374c0-3423-11e7-a556-b1cf2e788d44 Compaction revenue_events event_charges 93038948816 128189837056 bytes 72.58%
0b188320-3485-11e7-a556-b1cf2e788d44 Compaction revenue_events recharge_events_by_agreement_id 27485751628 40857511701 bytes 67.27%
e714bf40-3464-11e7-a556-b1cf2e788d44 Compaction revenue_events charging_balance_changes_by_target_id 51642077893 104669802576 bytes 49.34%
ef12b890-34a1-11e7-a556-b1cf2e788d44 Anticompaction after repair cm individuals 6276572787 6987894450 bytes 89.82%
f6073d80-34a4-11e7-a556-b1cf2e788d44 Anticompaction after repair cm agreements__history 4081490766 10168203433 bytes 40.14%
cc251310-3496-11e7-a556-b1cf2e788d44 Validation revenue_events usage_events_by_agreement_id 169361885289 907665793695 bytes 18.66%
Active compaction remaining time : 2h38m18s

$ nodetool tpstats
Pool Name Active Pending Completed Blocked All time blocked
MutationStage 0 0 2751211799 0 0
ReadStage 0 0 31316 0 0
RequestResponseStage 0 0 8071 0 0
ReadRepairStage 0 0 1 0 0
CounterMutationStage 0 0 0 0 0
Repair#26 1 139 137 0 0
HintedHandoff 0 0 566 0 0
MiscStage 0 0 0 0 0
CompactionExecutor 8 151 1617296 0 0
MemtableReclaimMemory 0 0 49919 0 0
PendingRangeCalculator 0 0 19 0 0
GossipStage 0 0 4248064 0 0
MigrationStage 0 0 68432 0 0
MemtablePostFlush 0 0 74595 0 0
ValidationExecutor 2 2 848 0 0
Sampler 0 0 0 0 0
MemtableFlushWriter 0 0 49705 0 0
InternalResponseStage 0 0 288 0 0
AntiEntropyStage 0 0 4181 0 0
CacheCleanupExecutor 0 0 0 0 0
Native-Transport-Requests 0 0 283879 0 0

Message type Dropped
READ 0
RANGE_SLICE 0
_TRACE 0
MUTATION 5
COUNTER_MUTATION 0
REQUEST_RESPONSE 0
PAGED_RANGE 0
READ_REPAIR 0