[CASSANDRA-5584] Incorrect use of System.nanoTime()

• Type: Bug
• Status: Resolved
• Priority: Low
• Resolution: Fixed
• Fix Version/s: 1.2.6
• Severity: Low
• Assignee: Mikhail Mazursky
• Reporter: Mikhail Mazursky

Authors

Mikhail Mazursky

Reviewers

Jonathan Ellis

• Created: 21/May/13 18:04
• Updated: 16/Apr/19 09:32
• Resolved: 21/May/13 19:19

Description

From System.nanoTime() JavaDoc:

For example, to measure how long some code takes to execute:
 long startTime = System.nanoTime();
 // ... the code being measured ...
 long estimatedTime = System.nanoTime() - startTime; 

To compare two nanoTime values
 long t0 = System.nanoTime();
 ...
 long t1 = System.nanoTime();
one should use t1 - t0 < 0, not t1 < t0, because of the possibility of numerical overflow.

I found one place with such incorrect use that can result in overflow and in incorrect timeout handling. See attached patch.