ctubbsii commented on code in PR #2778:
URL: https://github.com/apache/accumulo/pull/2778#discussion_r929378827
##########
server/base/src/main/java/org/apache/accumulo/server/conf/ServerConfigurationFactory.java:
##########
@@ -140,4 +158,114 @@ 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;
+ // staggering the initial delay prevents synchronization of Accumulo
servers communicating
+ // with ZooKeeper for the sync process.
+ long randDelay = jitter(REFRESH_PERIOD_MINUTES / 4,
REFRESH_PERIOD_MINUTES);
+
+ ScheduledThreadPoolExecutor executor = ThreadPools.getServerThreadPools()
+ .createScheduledExecutorService(4, "config-refresh", false);
+ 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 synchronized void verifySnapshotVersions() {
Review Comment:
I think this synchronized isn't helping unless you make this method static.
##########
server/base/src/main/java/org/apache/accumulo/server/conf/ServerConfigurationFactory.java:
##########
@@ -140,4 +158,114 @@ 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;
+ // staggering the initial delay prevents synchronization of Accumulo
servers communicating
+ // with ZooKeeper for the sync process.
+ long randDelay = jitter(REFRESH_PERIOD_MINUTES / 4,
REFRESH_PERIOD_MINUTES);
+
+ ScheduledThreadPoolExecutor executor = ThreadPools.getServerThreadPools()
+ .createScheduledExecutorService(4, "config-refresh", false);
Review Comment:
Only have one task to repeat, so we only need 1 thread in the pool.
```suggestion
.createScheduledExecutorService(1, "config-refresh", false);
```
##########
server/base/src/main/java/org/apache/accumulo/server/conf/ServerConfigurationFactory.java:
##########
@@ -140,4 +158,114 @@ 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;
+ // staggering the initial delay prevents synchronization of Accumulo
servers communicating
+ // with ZooKeeper for the sync process.
+ long randDelay = jitter(REFRESH_PERIOD_MINUTES / 4,
REFRESH_PERIOD_MINUTES);
+
+ ScheduledThreadPoolExecutor executor = ThreadPools.getServerThreadPools()
+ .createScheduledExecutorService(4, "config-refresh", false);
+ 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 synchronized void verifySnapshotVersions() {
+ long refreshStart = System.nanoTime();
+ int keyCount = 0;
+ int keyChangedCount = 0;
+
+ PropStore propStore = context.getPropStore();
+ keyCount++;
+
+ // rely on store to propagate change event if different
+ propStore.validateDataVersion(SystemPropKey.of(context),
+ ((ZooBasedConfiguration) getSystemConfiguration()).getDataVersion());
+ // small yield - spread out ZooKeeper calls
+ jitterDelay();
+
+ for (Map.Entry<NamespaceId,NamespaceConfiguration> entry :
namespaceConfigs.entrySet()) {
+ keyCount++;
+ PropStoreKey<?> propKey = NamespacePropKey.of(context, entry.getKey());
+ if (!propStore.validateDataVersion(propKey,
entry.getValue().getDataVersion())) {
+ keyChangedCount++;
+ namespaceConfigs.remove(entry.getKey());
+ }
+ // small yield - spread out ZooKeeper calls between namespace config
checks
+ jitterDelay();
+ }
+
+ for (Map.Entry<TableId,TableConfiguration> entry :
tableConfigs.entrySet()) {
+ keyCount++;
+ TableId tid = entry.getKey();
+ PropStoreKey<?> propKey = TablePropKey.of(context, tid);
+ if (!propStore.validateDataVersion(propKey,
entry.getValue().getDataVersion())) {
+ keyChangedCount++;
+ tableConfigs.remove(tid);
+ tableParentConfigs.remove(tid);
+ log.debug("data version sync: difference found. forcing
configuration update for {}}",
+ propKey);
+ }
+ // small yield - spread out ZooKeeper calls between table config checks
+ jitterDelay();
+ }
+
+ log.debug("data version sync: Total runtime {} ms for {} entries,
changes detected: {}",
+ NANOSECONDS.toMillis(System.nanoTime() - refreshStart), keyCount,
keyChangedCount);
+ }
+
+ /**
+ * Generate a small random integer for jitter between [min,max).
+ *
+ * @param min
+ * minimum number (inclusive)
+ *
+ * @param max
+ * maximum number (exclusive)
+ *
+ * @return random number between min and MAJ_JITTER_DELAY
+ */
+ @SuppressFBWarnings(value = "PREDICTABLE_RANDOM",
+ justification = "random number not used in secure context")
+ private long jitter(final long min, final long max) {
+ return ThreadLocalRandom.current().nextLong(min, max);
+ }
Review Comment:
There's a lot of lines for the javadoc and boilerplate method, for a
one-line method body that's only called in one place. I think it could be
inline'd, and the javadoc isn't necessary, since the function is obvious once
all the surrounding noise is removed.
##########
server/base/src/main/java/org/apache/accumulo/server/conf/store/impl/ZooPropStore.java:
##########
@@ -117,7 +121,12 @@ private ZooPropStore(final InstanceId instanceId, final
ZooReaderWriter zrw) {
throw new IllegalStateException("Instance may not have been
initialized, root node: " + path
+ " does not exist in ZooKeeper");
}
- } catch (InterruptedException | KeeperException ex) {
+ } catch (InterruptedException ex) {
+ Thread.currentThread().interrupt();
+ ;
Review Comment:
extra semicolon
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