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ZOOKEEPER-4712: Follower.shutdown() and Observer.shutdown() do not correctly shutdown the syncProcessor, which may lead to data inconsistency #2032

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AlphaCanisMajoris wants to merge 2 commits into from
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ZOOKEEPER-4712: Follower.shutdown() and Observer.shutdown() do not correctly shutdown the syncProcessor, which may lead to data inconsistency #2032

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ZOOKEEPER-4712: Follower.shutdown() and Observer.shutdown() do not co…
AlphaCanisMajoris Jul 6, 2023
7a10112
ZOOKEEPER-4712: Follower.shutdown() and Observer.shutdown() do not co…
AlphaCanisMajoris Jul 6, 2023
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25 changes: 21 additions & 4 deletions zookeeper-server/src/main/java/org/apache/zookeeper/server/ZooKeeperServer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -933,12 +933,23 @@ public void shutdown() {
* @param fullyShutDown true if another server using the same database will not replace this one in the same process
*/
public synchronized void shutdown(boolean fullyShutDown) {
if (shutdownZKServer(fullyShutDown)) {
updateZKDatabase(fullyShutDown);
}
}

/**
* Shut down the server instance
* @param fullyShutDown true if another server using the same database will not replace this one in the same process
* @return true if the server is successfully shutdown, false if the server cannot be shutdown.
*/
protected synchronized boolean shutdownZKServer(boolean fullyShutDown) {
if (!canShutdown()) {
if (fullyShutDown && zkDb != null) {
zkDb.clear();
}
LOG.debug("ZooKeeper server is not running, so not proceeding to shutdown!");
return;
return false;
}
LOG.info("shutting down");

Expand All @@ -965,7 +976,16 @@ public synchronized void shutdown(boolean fullyShutDown) {
if (jvmPauseMonitor != null) {
jvmPauseMonitor.serviceStop();
}
requestPathMetricsCollector.shutdown();
unregisterJMX();
return true;
}

/**
* Update zk database during shutdown
* @param fullyShutDown true if another server using the same database will not replace this one in the same process
*/
protected synchronized void updateZKDatabase(boolean fullyShutDown) {
if (zkDb != null) {
if (fullyShutDown) {
zkDb.clear();
Expand All @@ -984,9 +1004,6 @@ public synchronized void shutdown(boolean fullyShutDown) {
}
}
}

requestPathMetricsCollector.shutdown();
unregisterJMX();
}

protected void unregisterJMX() {
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14 changes: 14 additions & 0 deletions ...eeper-server/src/main/java/org/apache/zookeeper/server/quorum/LearnerZooKeeperServer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -172,4 +172,18 @@ public synchronized void shutdown() {
}
}

@Override
public void shutdown(boolean fullyShutDown) {
if (shutdownZKServer(fullyShutDown)) {
try {
if (syncProcessor != null) {
syncProcessor.shutdown();

@sonatype-lift sonatype-lift Bot Jul 6, 2023

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7% of developers fix this issue

THREAD_SAFETY_VIOLATION: Unprotected write. Non-private method LearnerZooKeeperServer.shutdown(...) indirectly writes to field this.syncProcessor.lastFlushTime outside of synchronization.
Reporting because another access to the same memory occurs on a background thread, although this access may not.

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}
} catch (Exception e) {
LOG.warn("Ignoring unexpected exception in syncprocessor shutdown", e);
}
updateZKDatabase(fullyShutDown);
}
}

}