From 0f94577d2613634b268b56b6dbd445bd5528542c Mon Sep 17 00:00:00 2001
From: Wenjun Ruan <wenjun@apache.org>
Date: Mon, 8 Nov 2021 22:26:17 +0800
Subject: [PATCH] Use nanoTime replace currentTimemill to avoid clock backwards
 (#6740)

---
 .../apache/dolphinscheduler/common/utils/SnowFlakeUtils.java | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/utils/SnowFlakeUtils.java b/dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/utils/SnowFlakeUtils.java
index 1fa14fd6cf..9bb360e02a 100644
--- a/dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/utils/SnowFlakeUtils.java
+++ b/dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/utils/SnowFlakeUtils.java
@@ -35,6 +35,9 @@ public class SnowFlakeUtils {
     private long sequence = 0L;
     private long lastTimestamp = -1L;
 
+    private static final long SYSTEM_TIMESTAMP = System.currentTimeMillis();
+    private static final long SYSTEM_NANOTIME  = System.nanoTime();
+
     private SnowFlakeUtils() throws SnowFlakeException {
         try {
             this.machineId = Math.abs(Objects.hash(InetAddress.getLocalHost().getHostName())) % 32;
@@ -80,7 +83,7 @@ public class SnowFlakeUtils {
     }
 
     private long nowTimestamp() {
-        return System.currentTimeMillis();
+        return SYSTEM_TIMESTAMP + (System.nanoTime() - SYSTEM_NANOTIME) / 1000000;
     }
 
     public static class SnowFlakeException extends Exception {