EdColeman commented on code in PR #2778:
URL: https://github.com/apache/accumulo/pull/2778#discussion_r935008451
##########
server/base/src/main/java/org/apache/accumulo/server/conf/ServerConfigurationFactory.java:
##########
@@ -140,4 +163,119 @@ public void connectionEvent() {
// no-op. changes handled by prop store impl
}
}
+
+ private class ConfigRefreshRunner {
+ private static final long MIN_JITTER_DELAY = 1;
+ private static final long MAX_JITTER_DELAY = 23;
+ private final ScheduledFuture<?> refreshTaskFuture;
+
+ ConfigRefreshRunner() {
+
+ Runnable refreshTask = this::verifySnapshotVersions;
+
+ ScheduledThreadPoolExecutor executor = ThreadPools.getServerThreadPools()
+ .createScheduledExecutorService(1, "config-refresh", false);
+
+ // staggering the initial delay prevents synchronization of Accumulo
servers communicating
+ // with ZooKeeper for the sync process. (Value is 25% -> 100% of the
refresh period.)
+ long randDelay = jitter(REFRESH_PERIOD_MINUTES / 4,
REFRESH_PERIOD_MINUTES);
+ refreshTaskFuture =
+ executor.scheduleWithFixedDelay(refreshTask, randDelay,
REFRESH_PERIOD_MINUTES, MINUTES);
+ }
+
+ /**
+ * Check that the stored version in ZooKeeper matches the version held in
the local snapshot.
+ * When a mismatch is detected, a change event is sent to the prop store
which will cause a
+ * re-load. If the Zookeeper node has been deleted, the local cache
entries are removed.
+ * <p>
+ * This method is designed to be called as a scheduled task, so it does
not propagate exceptions
+ * other than interrupted Exceptions so the scheduled tasks will continue
to run.
+ */
+ private void verifySnapshotVersions() {
+
+ // short circuit if refresh in progress
+ if (isConfigRefreshRunning.get()) {
+ return;
+ }
+
+ // allow only one thread if missed short circuit check.
+ refreshLock.lock();
Review Comment:
Removed in 2ae1730977
##########
server/base/src/main/java/org/apache/accumulo/server/conf/ServerConfigurationFactory.java:
##########
@@ -51,9 +65,18 @@ public class ServerConfigurationFactory extends
ServerConfiguration {
private final SiteConfiguration siteConfig;
private final DeleteWatcher deleteWatcher = new DeleteWatcher();
+ private static final int REFRESH_PERIOD_MINUTES = 15;
+
+ private final ConfigRefreshRunner refresher;
+ private static final AtomicBoolean isConfigRefreshRunning = new
AtomicBoolean(false);
+ private static final Lock refreshLock = new ReentrantLock();
+
public ServerConfigurationFactory(ServerContext context, SiteConfiguration
siteConfig) {
this.context = context;
this.siteConfig = siteConfig;
+
+ refresher = new ConfigRefreshRunner();
+ Runtime.getRuntime().addShutdownHook(new Thread(refresher::shutdown));
Review Comment:
Fixed in 2ae1730977
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