From b9987423bd718635e0849f46991cac00dbd229b5 Mon Sep 17 00:00:00 2001
From: lihangyu <lihangyu@selectdb.com>
Date: Mon, 23 Dec 2024 10:38:14 +0800
Subject: [PATCH] [Improve](Variant) pick random backend as coordinator
 (#45754)

pick random rpc coordinator to do fetch_remote_tablet_schema service
---
 .../common/util/FetchRemoteTabletSchemaUtil.java      | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/common/util/FetchRemoteTabletSchemaUtil.java b/fe/fe-core/src/main/java/org/apache/doris/common/util/FetchRemoteTabletSchemaUtil.java
index 0e96dc8c5930d1..de378c8b8e8a14 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/common/util/FetchRemoteTabletSchemaUtil.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/common/util/FetchRemoteTabletSchemaUtil.java
@@ -98,16 +98,19 @@ public List<Column> fetch() {
             if (!backend.isAlive()) {
                 continue;
             }
-            // need 2 be to provide a retry
-            if (coordinatorBackend.size() < 2) {
-                coordinatorBackend.add(backend);
-            }
+            coordinatorBackend.add(backend);
             PTabletsLocation.Builder locationBuilder = PTabletsLocation.newBuilder()
                                                         .setHost(backend.getHost())
                                                         .setBrpcPort(backend.getBrpcPort());
             PTabletsLocation location = locationBuilder.addAllTabletId(tabletIds).build();
             locations.add(location);
         }
+        // pick 2 random coordinator
+        Collections.shuffle(coordinatorBackend);
+        if (!coordinatorBackend.isEmpty()) {
+            coordinatorBackend = coordinatorBackend.subList(0, Math.min(2, coordinatorBackend.size()));
+            LOG.debug("pick coordinator backend {}", coordinatorBackend.get(0));
+        }
         PFetchRemoteSchemaRequest.Builder requestBuilder = PFetchRemoteSchemaRequest.newBuilder()
                                                                     .addAllTabletLocation(locations)
                                                                     .setIsCoordinator(true);