murblanc commented on a change in pull request #2318:
URL: https://github.com/apache/lucene-solr/pull/2318#discussion_r573680423
##########
File path:
solr/core/src/java/org/apache/solr/cloud/api/collections/CreateCollectionCmd.java
##########
@@ -264,8 +299,8 @@ public void call(ClusterState clusterState, ZkNodeProps
message, @SuppressWarnin
log.info("Cleaned up artifacts for failed create collection for [{}]",
collectionName);
throw new SolrException(ErrorCode.BAD_REQUEST, "Underlying core
creation failed while creating collection: " + collectionName);
} else {
- log.debug("Finished create command on all shards for collection: {}",
collectionName);
+ log.debug("Finished create command on all shards for collection: {}",
collectionName);
Review comment:
When we get here for a PRS collection, the `ZkStateReader` cluster state
for the collection is fine, as are the ZK structures, but the Overseer cluster
state updater does not know about the collection. Any new operation on the
collection through the Collection API would fail in the cluster state updater.
##########
File path:
solr/core/src/java/org/apache/solr/cloud/api/collections/CreateCollectionCmd.java
##########
@@ -149,27 +143,38 @@ public void call(ClusterState clusterState, ZkNodeProps
message, @SuppressWarnin
}
createCollectionZkNode(stateManager, collectionName, collectionParams);
-
- ocmh.overseer.offerStateUpdate(Utils.toJSON(message));
-
- // wait for a while until we see the collection
- TimeOut waitUntil = new TimeOut(30, TimeUnit.SECONDS, timeSource);
- boolean created = false;
- while (! waitUntil.hasTimedOut()) {
- waitUntil.sleep(100);
- created =
ocmh.cloudManager.getClusterStateProvider().getClusterState().hasCollection(collectionName);
- if(created) break;
- }
- if (!created) {
- throw new SolrException(SolrException.ErrorCode.SERVER_ERROR, "Could
not fully create collection: " + collectionName);
+
+ if(isPrs) {
+ ZkWriteCommand command = new
ClusterStateMutator(ocmh.cloudManager).createCollection(clusterState, message);
+ byte[] data = Utils.toJSON(Collections.singletonMap(collectionName,
command.collection));
+ ocmh.zkStateReader.getZkClient().create(collectionPath, data,
CreateMode.PERSISTENT, true);
+ clusterState = clusterState.copyWith(collectionName,
command.collection);
+ newColl = command.collection;
+ } else {
+ ocmh.overseer.offerStateUpdate(Utils.toJSON(message));
+
+ // wait for a while until we see the collection
+ TimeOut waitUntil = new TimeOut(30, TimeUnit.SECONDS, timeSource);
+ boolean created = false;
+ while (!waitUntil.hasTimedOut()) {
+ waitUntil.sleep(100);
+ created =
ocmh.cloudManager.getClusterStateProvider().getClusterState().hasCollection(collectionName);
+ if (created) break;
+ }
+ if (!created) {
+ throw new SolrException(SolrException.ErrorCode.SERVER_ERROR, "Could
not fully create collection: " + collectionName);
+ }
+
+ // refresh cluster state
+ clusterState =
ocmh.cloudManager.getClusterStateProvider().getClusterState();
Review comment:
This call does nothing and can be removed.
The command already has the instance of `ClusterState` returned by the call
(it is passed to it as a `call` parameter by OCMH).
The only way the clusterState is refreshed is when the watchers on the node
get called and fetch the latest updates from ZK (that in this case were done by
the Overseer, and we know the watchers fired and updated our local state
because we've waited for it in the `while` loop ~10 lines above).
##########
File path:
solr/core/src/java/org/apache/solr/cloud/api/collections/CreateCollectionCmd.java
##########
@@ -149,27 +143,38 @@ public void call(ClusterState clusterState, ZkNodeProps
message, @SuppressWarnin
}
createCollectionZkNode(stateManager, collectionName, collectionParams);
-
- ocmh.overseer.offerStateUpdate(Utils.toJSON(message));
-
- // wait for a while until we see the collection
- TimeOut waitUntil = new TimeOut(30, TimeUnit.SECONDS, timeSource);
- boolean created = false;
- while (! waitUntil.hasTimedOut()) {
- waitUntil.sleep(100);
- created =
ocmh.cloudManager.getClusterStateProvider().getClusterState().hasCollection(collectionName);
- if(created) break;
- }
- if (!created) {
- throw new SolrException(SolrException.ErrorCode.SERVER_ERROR, "Could
not fully create collection: " + collectionName);
+
+ if(isPrs) {
+ ZkWriteCommand command = new
ClusterStateMutator(ocmh.cloudManager).createCollection(clusterState, message);
Review comment:
Calling this method here (or more specifically using its output in the
`create()` call below) breaks the cluster state updater contract in Overseer.
This call updates a `state.json` from a thread other than the cluster state
updater thread in Overseer, the cluster state updater will not know about the
new Json being written (the fact that this thread running this method is
executing on the Overseer node is irrelevant, except passing stats, cluster
state updater and Collection API execution are totally independent and could be
running on different nodes).
Overseer has two copies of the cluster state: the cluster state maintained
in `ZkStateReader` like any node has (this is the state passed to Collection
API calls), and another copy of the state maintained in `ZkStateWriter` which
initially is obtained from `ZkStateReader` but quickly diverges and then used
as the "source of truth" by the cluster state updater that keeps writing back
that state to Zookeeper for the whole life of the Overseer on the node. The
cluster updater state has no watches is only updated by the cluster state
updater when processing messages and then the updated value written to ZK.
To achieve the effect of dealing with the Per Replica States directly from
this thread rather than from the ClusterStateUpdater single thread, the
state.json would have to be created by the Overseer (i.e. through a classic
`ocmh.overseer.offerStateUpdate(Utils.toJSON(message));`) and once done the PRS
could be created from here. This is complicated to do because of the way
`ZkStateWriter` is implemented to write the `state.json` as well as handle the
PRS operations in the same method (when it calls `cmd.ops.persist` in
`writePendingUpdates()`) and would require quite some refactoring.
##########
File path:
solr/core/src/java/org/apache/solr/cloud/api/collections/CreateCollectionCmd.java
##########
@@ -213,7 +218,16 @@ public void call(ClusterState clusterState, ZkNodeProps
message, @SuppressWarnin
ZkStateReader.NODE_NAME_PROP, nodeName,
ZkStateReader.REPLICA_TYPE, replicaPosition.type.name(),
CommonAdminParams.WAIT_FOR_FINAL_STATE,
Boolean.toString(waitForFinalState));
- ocmh.overseer.offerStateUpdate(Utils.toJSON(props));
+ if(isPrs) {
+ ZkWriteCommand command = new
SliceMutator(ocmh.cloudManager).addReplica(clusterState, props);
+ byte[] data = Utils.toJSON(Collections.singletonMap(collectionName,
command.collection));
+// log.info("collection updated : {}", new String(data,
StandardCharsets.UTF_8));
+ ocmh.zkStateReader.getZkClient().setData(collectionPath, data, true);
Review comment:
This call bypasses the cluster state updater to update the `state.json`.
If it tried to do so through the Overseer cluster state updater, the update
would fail as the collection is unknown there.
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