[HBASE-17330] SnapshotFileCache will always refresh the file cache

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.3.1, 0.98.23, 2.0.0
• Fix Version/s: 1.4.0, 2.0.0
• Component/s: snapshots
• Hadoop Flags: Reviewed
• Assignee: Jianwei Cui
• Reporter: Jianwei Cui
• Created: 17/Dec/16 10:00
• Updated: 23/Dec/16 03:10
• Resolved: 22/Dec/16 10:31

Description

In SnapshotFileCache#refreshCache, the hasChanges will be judged as:

    try {
      FileStatus dirStatus = fs.getFileStatus(snapshotDir);
      lastTimestamp = dirStatus.getModificationTime();
      hasChanges |= (lastTimestamp >= lastModifiedTime); // >= will make hasChanges always be true

The (lastTimestamp >= lastModifiedTime) will make hasChanges always be true because lastTimestamp will be updated as:

this.lastModifiedTime = lastTimestamp;

So, SnapshotFileCache will always refresh the file cache.