未验证 提交 5283e54d 编写于 作者: O OS 提交者: GitHub

[cherry-pick][6774] fix snowflake bug (#6752)

* Use nanoTime replace currentTimemill to avoid clock backwards (#6740)

* [Bug][SnowFlakeUtils] fix snowFlake bug (#6744)

* fix snowFlake bug

* fix hash machine
Co-authored-by: NWenjun Ruan <wenjun@apache.org>
Co-authored-by: NJinYong Li <42576980+JinyLeeChina@users.noreply.github.com>
上级 4baa211e
......@@ -24,20 +24,23 @@ import java.util.Objects;
public class SnowFlakeUtils {
// start timestamp
private static final long START_TIMESTAMP = 1609430400000L; //2021-01-01 00:00:00
// Number of digits
private static final long SEQUENCE_BIT = 13;
// Each machine generates 32 in the same millisecond
private static final long SEQUENCE_BIT = 5;
private static final long MACHINE_BIT = 2;
private static final long MAX_SEQUENCE = ~(-1L << SEQUENCE_BIT);
// The displacement to the left
private static final long MACHINE_LEFT = SEQUENCE_BIT;
private static final long TIMESTAMP_LEFT = SEQUENCE_BIT + MACHINE_BIT;
private static final long MACHINE_LEFT = SEQUENCE_BIT + MACHINE_BIT;
private static final long TIMESTAMP_LEFT = SEQUENCE_BIT + MACHINE_BIT + MACHINE_LEFT;
private final int machineId;
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;
this.machineId = Math.abs(Objects.hash(InetAddress.getLocalHost().getHostName())) % 4;
} catch (UnknownHostException e) {
throw new SnowFlakeException(e.getMessage());
}
......@@ -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 {
......
......@@ -23,7 +23,8 @@ public class SnowFlakeUtilsTest {
@Test
public void testNextId() {
try {
for (int i = 0; i < 5; i++) {
for (int i = 0; i < 100; i++) {
Thread.sleep(1);
System.out.println(SnowFlakeUtils.getInstance().nextId());
}
} catch (Exception e) {
......
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