From 843afccdf9097ff628e82007cb1fce99dc6ac61e Mon Sep 17 00:00:00 2001
From: Mingyu Chen <morningman@163.com>
Date: Wed, 7 Aug 2024 14:09:06 +0800
Subject: [PATCH] [fix](catalog) remove backend in black list from candidate
 backends for external table (#38984)

When select backends for external table's query,
skip the backends in black list
---
 .../java/org/apache/doris/system/BeSelectionPolicy.java     | 6 ++++++
 .../java/org/apache/doris/system/SystemInfoServiceTest.java | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/system/BeSelectionPolicy.java b/fe/fe-core/src/main/java/org/apache/doris/system/BeSelectionPolicy.java
index 8c7c1d816a894a..8c823eb75ee4d2 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/system/BeSelectionPolicy.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/system/BeSelectionPolicy.java
@@ -17,6 +17,8 @@
 
 package org.apache.doris.system;
 
+import org.apache.doris.common.Config;
+import org.apache.doris.qe.SimpleScheduler;
 import org.apache.doris.resource.Tag;
 import org.apache.doris.thrift.TStorageMedium;
 
@@ -209,6 +211,10 @@ public List<Backend> getCandidateBackends(ImmutableCollection<Backend> backends)
         } else {
             candidates.addAll(filterBackends);
         }
+        // filter out backends in black list
+        if (!Config.disable_backend_black_list) {
+            candidates = candidates.stream().filter(b -> SimpleScheduler.isAvailable(b)).collect(Collectors.toList());
+        }
         Collections.shuffle(candidates);
         return candidates;
     }
diff --git a/fe/fe-core/src/test/java/org/apache/doris/system/SystemInfoServiceTest.java b/fe/fe-core/src/test/java/org/apache/doris/system/SystemInfoServiceTest.java
index eb1f33c288902f..d14cdd2a865e05 100644
--- a/fe/fe-core/src/test/java/org/apache/doris/system/SystemInfoServiceTest.java
+++ b/fe/fe-core/src/test/java/org/apache/doris/system/SystemInfoServiceTest.java
@@ -21,6 +21,7 @@
 import org.apache.doris.catalog.Env;
 import org.apache.doris.catalog.ReplicaAllocation;
 import org.apache.doris.common.AnalysisException;
+import org.apache.doris.common.Config;
 import org.apache.doris.common.FeMetaVersion;
 import org.apache.doris.common.Pair;
 import org.apache.doris.meta.MetaContext;
@@ -133,6 +134,7 @@ public void testBackendHbResponseSerialization() throws IOException {
 
     @Test
     public void testSelectBackendIdsByPolicy() throws Exception {
+        Config.disable_backend_black_list = true;
         // 1. no backend
         BeSelectionPolicy policy = new BeSelectionPolicy.Builder().needLoadAvailable().build();
         Assert.assertEquals(0, infoService.selectBackendIdsByPolicy(policy, 1).size());