Bugfix: UUIDGenerator generates duplicated id (apache#2972)

hicf · Nov 15, 2020 · b47e3e5 · b47e3e5
1 parent 920e837
commit b47e3e5
Showing 1 changed file with 9 additions and 10 deletions.
diff --git a/common/src/main/java/io/seata/common/util/IdWorker.java b/common/src/main/java/io/seata/common/util/IdWorker.java
@@ -94,25 +94,24 @@ public IdWorker(long workerId) {
      *
      * @return SnowflakeId
      */
-    public long nextId() {
+    public synchronized long nextId() {
         long timestamp = timeGen();
 
         if (timestamp < lastTimestamp) {
             throw new RuntimeException(String.format(
                 "clock moved backwards.  Refusing to generate id for %d milliseconds", lastTimestamp - timestamp));
         }
 
-        synchronized (this) {
-            if (lastTimestamp == timestamp) {
-                sequence = (sequence + 1) & sequenceMask;
-                if (sequence == 0) {
-                    timestamp = tilNextMillis(lastTimestamp);
-                }
-            } else {
-                sequence = 0L;
+        if (lastTimestamp == timestamp) {
+            sequence = (sequence + 1) & sequenceMask;
+            if (sequence == 0) {
+                timestamp = tilNextMillis(lastTimestamp);
             }
-            lastTimestamp = timestamp;
+        } else {
+            sequence = 0L;
         }
+        lastTimestamp = timestamp;
+
         return ((timestamp - twepoch) << timestampLeftShift) | (workerId << workerIdShift) | sequence;
     }