[CASSANDRA-9662] compactionManager reporting wrong pendingtasks

• Type: Bug
• Status: Resolved
• Priority: Low
• Resolution: Fixed
• Fix Version/s: 2.0.17, 2.1.9
• Component/s: Legacy/CQL

Environment

OS: Amazon Linux AMI release 2015.03
Cassandra: 2.0.16
JVM: Java HotSpot(TM) 64-Bit Server VM (25.40-b25, mixed mode)
Java: version 1.8.0_40, vendor Oracle Corporation
CPU: 8 core Intel(R) Xeon(R) CPU E5-2670 v2 @ 2.50GHz
Memory: 32G

• Severity: Low
• Assignee: Yuki Morishita
• Reporter: Tony Xu

Authors

Yuki Morishita

Reviewers

Benedict Elliott Smith

• Created: 26/Jun/15 16:13
• Updated: 16/Apr/19 09:31
• Resolved: 08/Jul/15 17:25

Description

Yesterday I upgraded my Cassandra cluster from 2.0.14 to 2.0.16, after upgrade, I am start seeing some strange behaviours of "PendingTasks" reporting.

The Cassandra repository I am using is datastax, steps I performed for upgrade:

yum update -y cassandra20

The upgrade went fine, after upgrade cluster is operating okay. "nodetool info and nodetool status" results looked fine. "nodetool version" is reporting the correct version.

But our monitoring system start reporting some crazy "pendingtasks". For example, "pending taks" for node1 sometimes jump from 0 to 15K for about 1 minute, then drop back to 0. This issue keeps occurring, didn't have this issue with 2.0.14. Our monitoring system is checking the value of "MBeans" -> "CompactionManager" -> "PendingTasks".

Issue Links

• is duplicated by: CASSANDRA-9683 Get mucher higher load and latencies after upgrading from 2.1.6 to cassandra 2.1.7
• is duplicated by: CASSANDRA-9744 unrealistic pending compactions displayed
• is duplicated by: CASSANDRA-9914 Millions of fake pending compaction tasks + high CPU
• is duplicated by: CASSANDRA-11025 Too many compactions on certain node when too many empty tables are created