[CASSANDRA-5534] Writing wide row causes high CPU usage after compaction

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 2.0.0
• Severity: Normal
• Assignee: Sylvain Lebresne
• Reporter: Ryan McGuire

Authors

Sylvain Lebresne

• Tester: Alex Zarutin
• Created: 02/May/13 18:53
• Updated: 13/Dec/22 12:21
• Resolved: 05/Jul/13 08:44

Description

Introduced in commit e74c13ff08663d306dcc5cdc99c07e9e6c12ca21 (see below) there is a significant slow down when creating a wide row with cassandra-stress:

Testing with the prior (good) commit I used this to write a single wide row, which completed rather quickly:

$ ccm create -v git:60f09f0121e0801851b9ab017eddf7e326fa05fb wide-row
Fetching Cassandra updates...
Cloning Cassandra (from local cache)
Checking out requested branch (60f09f0121e0801851b9ab017eddf7e326fa05fb)
Compiling Cassandra 60f09f0121e0801851b9ab017eddf7e326fa05fb ...
Current cluster is now: wide-row
$ ccm populate -n 1
$ ccm start
$ time ccm node1 stress -c 10000 -S 1000 -n 1
Created keyspaces. Sleeping 1s for propagation.
total,interval_op_rate,interval_key_rate,latency/95th/99th,elapsed_time
1,0,0,273.3,273.3,273.3,0
END

real	0m7.106s
user	0m1.710s
sys	0m0.120s

Using the bugged commit (e74c13ff08663d306dcc5cdc99c07e9e6c12ca21) I get a significant slow down:

02:42 PM:~$ ccm create -v git:e74c13ff08663d306dcc5cdc99c07e9e6c12ca21 wide-row
Fetching Cassandra updates...
Current cluster is now: wide-row
02:42 PM:~$ ccm populate -n 1
02:42 PM:~$ ccm start
02:42 PM:~$ time ccm node1 stress -c 10000 -S 1000 -n 1
Created keyspaces. Sleeping 1s for propagation.
total,interval_op_rate,interval_key_rate,latency,95th,99th,elapsed_time
1,0,0,423.2,423.2,423.2,0
Total operation time      : 00:00:00
END

real	4m16.394s
user	0m2.230s
sys	0m0.137s

Interestingly, the commit in question just says it's a merge from cassandra-1.2, but I do not see this same slowdown using that branch, this only occurs in trunk.

Issue Links

• is related to: CASSANDRA-5125 Support indexes on composite column components (clustered columns)