From 6f31434f858ed0ca2e0c2526e7ced374a3452ade Mon Sep 17 00:00:00 2001 From: Poojita Raj Date: Wed, 30 Aug 2023 10:23:25 -0700 Subject: [PATCH] add comments Signed-off-by: Poojita Raj --- .../opensearch/cluster/metadata/Metadata.java | 1 + .../cluster/routing/RoutingNodes.java | 17 +++++++++++++++++ 2 files changed, 18 insertions(+) diff --git a/server/src/main/java/org/opensearch/cluster/metadata/Metadata.java b/server/src/main/java/org/opensearch/cluster/metadata/Metadata.java index bd6fec9c90d5c..146193b8d22c4 100644 --- a/server/src/main/java/org/opensearch/cluster/metadata/Metadata.java +++ b/server/src/main/java/org/opensearch/cluster/metadata/Metadata.java @@ -110,6 +110,7 @@ public class Metadata implements Iterable, Diffable, To /** * Utility to identify whether input index uses SEGMENT replication strategy in established cluster state metadata. + * Note: Method intended for use by other plugins as well. * * @param indexName Index name * @return true if index uses SEGMENT replication, false otherwise diff --git a/server/src/main/java/org/opensearch/cluster/routing/RoutingNodes.java b/server/src/main/java/org/opensearch/cluster/routing/RoutingNodes.java index 772e81fb9d52c..4f7b935f15f93 100644 --- a/server/src/main/java/org/opensearch/cluster/routing/RoutingNodes.java +++ b/server/src/main/java/org/opensearch/cluster/routing/RoutingNodes.java @@ -366,6 +366,14 @@ public ShardRouting activePrimary(ShardId shardId) { return null; } + /** + * Returns one active replica shard for the given shard id or null if + * no active replica is found. + * + * Since replicas could possibly be on nodes with an older version of OpenSearch than + * the primary is, this will return replicas on the highest version of OpenSearch when document + * replication is enabled. + */ public ShardRouting activeReplicaWithHighestVersion(ShardId shardId) { // It's possible for replicaNodeVersion to be null, when disassociating dead nodes // that have been removed, the shards are failed, and part of the shard failing @@ -384,6 +392,15 @@ public ShardRouting activeReplicaWithHighestVersion(ShardId shardId) { .orElse(null); } + /** + * Returns one active replica shard for the given shard id or null if + * no active replica is found. + * + * Since replicas could possibly be on nodes with a higher version of OpenSearch than + * the primary is, this will return replicas on the oldest version of OpenSearch when segment + * replication is enabled to allow for replica to read segments from primary. + * + */ public ShardRouting activeReplicaWithOldestVersion(ShardId shardId) { // It's possible for replicaNodeVersion to be null. Therefore, we need to protect against the version being null // (meaning the node will be going away).