[CASSANDRA-20073] AbstractCommitLogService#lastSyncedAt initialized with currentTimeMillis() but later compared and updated with System.nanoTime()

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Duplicate
• Component/s: Local/Commit Log
• Platform: All
• Assignee: Unassigned
• Reporter: Dmitry Konstantinov
• Created: 4 days ago 13:12
• Updated: 4 days ago 15:16
• Resolved: 4 days ago 15:16

Description

Within org.apache.cassandra.db.commitlog.AbstractCommitLogService

we use System.currentMillis()-based time to initialize lastSyncedAt field:

protected volatile long lastSyncedAt = currentTimeMillis();

but later we use clock.now() = System.nanoTime() to compare and update the field value:

long pollStarted = clock.now();
boolean flushToDisk = lastSyncedAt + syncIntervalNanos <= pollStarted || state != NORMAL || syncRequested; 

As of now we are lucky that in the current JDK implementation System.nanoTime() is much bigger than currentTimeMillis() but it is not guaranteed.

Issue Links

• duplicates: CASSANDRA-20074 AbstractCommitLogService#lastSyncedAt initialized with currentTimeMillis() but later compared and updated with System.nanoTime()