[HDFS-17309] RBF: Fix Router Safemode check contidition error

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.4.0
• Fix Version/s: 3.4.0
• Component/s: rbf
• Labels: pull-request-available
• Target Version/s: 3.4.0, 3.3.6
• Hadoop Flags: Reviewed
• Assignee: liuguanghua
• Reporter: liuguanghua
• Created: 29/Dec/23 07:22
• Updated: 27/Jan/24 00:50
• Resolved: 05/Jan/24 10:40

Description

With HDFS-17116, Router safemode check contidition use monotonicNow(). 

For code in  RouterSafemodeService.periodicInvoke()

long now = monotonicNow();

long cacheUpdateTime = stateStore.getCacheUpdateTime();
boolean isCacheStale = (now - cacheUpdateTime) > this.staleInterval;

 

Function monotonicNow() is implemented with System.nanoTime(). 

System.nanoTime() in javadoc description:

This method can only be used to measure elapsed time and is not related to any other notion of system or wall-clock time. The value returned represents nanoseconds since some fixed but arbitrary origin time (perhaps in the future, so values may be negative). 

 

The following situation maybe exists ：

If refreshCaches not success in the beginning, cacheUpdateTime will be 0 , and now - cacheUpdateTime is arbitrary origin time，so isCacheStale maybe  be true or false. 

Issue Links

• links to: GitHub Pull Request #6390