[HDFS-3456] blockReportInterval is long value but when we take the random value it uses getRandom().nextInt,it is causing frequently BR

• Type: Bug
• Status: Patch Available
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 2.0.0-alpha
• Component/s: datanode
• Labels: BB2015-05-TBR
• Assignee: Tsz-wo Sze
• Reporter: Brahma Reddy Battula
• Created: 23/May/12 04:47
• Updated: 08/May/15 06:56

Description

blockReportInterval is long value but when we take the random value it uses getRandom().nextInt.

Due to this, offerService can throw exception as long may get rotated to negative value.
So, block report may send very frequently.

      if (resetBlockReportTime) {
        lastBlockReport = startTime - DFSUtil.getRandom().nextInt((int)(dnConf.blockReportInterval));
      resetBlockReportTime = false;

Issue Links

• is related to: HDFS-2541 For a sufficiently large value of blocks, the DN Scanner may request a random number with a negative seed value.