[CASSANDRA-1123] Allow tracing query details

• Type: New Feature
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 1.2.0 beta 1
• Assignee: David Alves Assign to me
• Reporter: Jonathan Ellis

Authors

David Alves

Reviewers

Jonathan Ellis

• Created: 24/May/10 21:54
• Updated: 16/Apr/19 09:33
• Resolved: 30/Aug/12 05:23

Description

In the spirit of CASSANDRA-511, it would be useful to tracing on queries to see where latency is coming from: how long did row cache lookup take? key search in the index? merging the data from the sstables? etc.

The main difference vs setting debug logging is that debug logging is too big of a hammer; by turning on the flood of logging for everyone, you actually distort the information you're looking for. This would be something you could set per-query (or more likely per connection).

We don't need to be as sophisticated as the techniques discussed in the following papers but they are interesting reading:

http://research.google.com/pubs/pub36356.html
http://www.usenix.org/events/osdi04/tech/full_papers/barham/barham_html/
http://www.usenix.org/event/nsdi07/tech/fonseca.html

Issue Links

• relates to: CASSANDRA-511 log abnormally long queries
• relates to: CASSANDRA-1305 Slow query log
• relates to: CASSANDRA-1355 Log RPC exceptions and timing data

Sub-Tasks

• Add tracing support for CQL3 bind variables: Resolved
• Add cqlsh syntax to enable request tracing: Resolved
• Add cqlsh support for tracing results: Resolved
• Add TRACE support to binary protocol: Resolved