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https://issues.apache.org/jira/browse/HELIX-599?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14621765#comment-14621765
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ASF GitHub Bot commented on HELIX-599:
--------------------------------------
Github user lei-xia commented on a diff in the pull request:
https://github.com/apache/helix/pull/31#discussion_r34328471
--- Diff:
helix-core/src/main/java/org/apache/helix/spectator/RoutingTableProvider.java
---
@@ -73,6 +75,73 @@ public RoutingTableProvider() {
}
/**
+ * returns the instances for {resource,partition} pair that are in a
specific {state} if
+ * aggregateGrouping is turned on, find all resources belongs to the
given resourceGroupName and
+ * aggregate all partition states from all these resources.
+ *
+ * @param resourceName
+ * @param partitionName
+ * @param state
+ * @param groupingEnabled
+ *
+ * @return empty list if there is no instance in a given state
+ */
+ public List<InstanceConfig> getInstances(String resourceName, String
partitionName, String state,
+ boolean groupingEnabled) {
+ if (!groupingEnabled) {
+ return getInstances(resourceName, partitionName, state);
+ }
+
+ List<InstanceConfig> instanceList = null;
+ RoutingTable _routingTable = _routingTableRef.get();
+ ResourceGroupInfo resourceGroupInfo =
_routingTable.getResourceGroup(resourceName);
+ if (resourceGroupInfo != null) {
+ PartitionInfo keyInfo = resourceGroupInfo.get(partitionName);
+ if (keyInfo != null) {
+ instanceList = keyInfo.get(state);
+ }
+ }
+ if (instanceList == null) {
+ instanceList = Collections.emptyList();
+ }
+ return instanceList;
+ }
+
+ /**
+ * returns the instances for {resource,partition} pair that are in a
specific {state} if
+ * aggregateGrouping is turned on, find all resources belongs to the
given resourceGroupName and
+ * having the given resource tags and return the aggregated partition
states from all these
+ * resources.
+ *
+ * @param resourceGroupName
+ * @param partitionName
+ * @param state
+ * @param resourceTags
+ *
+ * @return empty list if there is no instance in a given state
+ */
+ public List<InstanceConfig> getInstances(String resourceGroupName,
String partitionName,
--- End diff --
Once the isGroupRoutingEnabled is true in IdealState, it implicitly means:
1) All resource in the same resource group will have same ResourceGroupName
2) Resource tag is identical in resources belongs to same group (resource
tag is the way to differentiate different resources in the same resource group).
3) The partition name for all resources in the same group are same
(otherwise, they will be treated as different partition in routing table).
> Support creating/maintaining/routing resources with same names in different
> instance groups
> -------------------------------------------------------------------------------------------
>
> Key: HELIX-599
> URL: https://issues.apache.org/jira/browse/HELIX-599
> Project: Apache Helix
> Issue Type: New Feature
> Components: helix-core, helix-webapp-admin
> Reporter: Lei Xia
> Assignee: Lei Xia
> Original Estimate: 168h
> Remaining Estimate: 168h
>
> In LinkedIn, we have a new use scenario that there will be multiple databases
> sitting in the same Helix cluster with the same name, but on different
> instance groups. What we need are:
> 1) Allow resources (databases) with the same name, these resources are on
> different instance groups (with different tags).
> 2) Routing table (Spectator) is able to aggregate and return all instance
> (from multiple instance groups) that hold the database with given name.
> Our proposed solution is:
> 1) Add a "Resource Group" field in IdealState for the databases with the
> same names from different instance groups
> 2) Use Instance Group Tag (or new "Resource Tag") to differentiate databases
> (with same name) from different instance groups.
> 3) Use name mangling for Idealstate, for example, with database TestDB in
> instance group "testGroup", the IdealState and ExternalView id would be
> "TestDB$testGroup".
> 4) Change Helix Routing Table to be able to aggregate databases from the
> same resource group.
>
> Four new APIs are going to be added to RoutingTableProvider:
> public class RoutingTableProvider {
>
> /**
> * returns the instances that contain the given partition in a specific state
> from all resources with given resource name
> */
> public List<InstanceConfig> getInstances(String resource, String partition,
> String state);
>
> /**
> * returns the instances that contain the given partition in a specific state
> from selected resources with given name and tags
> */
> public List<InstanceConfig> getInstances(String resource, String partition,
> String state, List<String> resourceTags);
>
> /**
> * returns instances that contain given resource that are in a specific state
> */
> public Set<InstanceConfig> getInstances(String resource, String state);
>
> /**
> * returns instances that contain given resource with tags that are in a
> specific state
> */
> public Set<InstanceConfig> getInstances(String resource, String state,
> List<String> groupTags);
> }
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