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https://issues.apache.org/jira/browse/DRILL-4286?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16186614#comment-16186614
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ASF GitHub Bot commented on DRILL-4286:
---------------------------------------
Github user sudheeshkatkam commented on a diff in the pull request:
https://github.com/apache/drill/pull/921#discussion_r141981097
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/coord/zk/ZKClusterCoordinator.java
---
@@ -200,11 +206,47 @@ public void unregister(RegistrationHandle handle) {
}
}
+ /**
+ * Update drillbit endpoint state. Drillbit advertises its
+ * state in Zookeeper when a shutdown request of drillbit is
+ * triggered. State information is used during planning and
+ * initial client connection phases.
+ */
+ public RegistrationHandle update(RegistrationHandle handle, State state)
{
+ ZKRegistrationHandle h = (ZKRegistrationHandle) handle;
+ try {
+ endpoint = h.endpoint.toBuilder().setState(state).build();
+ ServiceInstance<DrillbitEndpoint> serviceInstance =
ServiceInstance.<DrillbitEndpoint>builder().name(serviceName).id(h.id).payload(endpoint).build();
+ discovery.updateService(serviceInstance);
+ } catch (Exception e) {
+ e.printStackTrace();
+ }
+ return handle;
+ }
+
@Override
public Collection<DrillbitEndpoint> getAvailableEndpoints() {
return this.endpoints;
}
+ /*
+ * Get a collection of ONLINE Drillbit endpoints by excluding the
drillbits
+ * that are in QUIESCENT state (drillbits shutting down). Primarily used
by the planner
+ * to plan queries only on ONLINE drillbits and used by the client
during initial connection
+ * phase to connect to a drillbit (foreman)
+ * @return A collection of ONLINE endpoints
+ */
+ @Override
+ public Collection<DrillbitEndpoint> getOnlineEndPoints() {
+ Collection<DrillbitEndpoint> runningEndPoints = new ArrayList<>();
+ for (DrillbitEndpoint endpoint: endpoints){
+ if(endpoint.getState().equals(State.ONLINE)) {
--- End diff --
(more relevant in this case)
This check should be:
if(!endpoint.hasState() || endpoint.getState().equals(State.ONLINE)) {
to not break backward compatibility (new client and old cluster of bits).
So the assumption is that old server is ONLINE.
> Have an ability to put server in quiescent mode of operation
> ------------------------------------------------------------
>
> Key: DRILL-4286
> URL: https://issues.apache.org/jira/browse/DRILL-4286
> Project: Apache Drill
> Issue Type: New Feature
> Components: Execution - Flow
> Reporter: Victoria Markman
> Assignee: Venkata Jyothsna Donapati
>
> I think drill will benefit from mode of operation that is called "quiescent"
> in some databases.
> From IBM Informix server documentation:
> {code}
> Change gracefully from online to quiescent mode
> Take the database server gracefully from online mode to quiescent mode to
> restrict access to the database server without interrupting current
> processing. After you perform this task, the database server sets a flag that
> prevents new sessions from gaining access to the database server. The current
> sessions are allowed to finish processing. After you initiate the mode
> change, it cannot be canceled. During the mode change from online to
> quiescent, the database server is considered to be in Shutdown mode.
> {code}
> This is different from shutdown, when processes are terminated.
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