From 6843cce7025292d4174996a3fcadc4fd1f03ff72 Mon Sep 17 00:00:00 2001
From: meiyi <meiyi@selectdb.com>
Date: Sat, 27 Dec 2025 01:59:36 +0800
Subject: [PATCH] [fix](fe) modify tablet cooldownConfLock to reduce memory
 (#59356)

### What problem does this PR solve?

the usage of `cooldownConfLock` is simple, does not need
ReentrantReadWriteLock because it cost too much memory, especially when
a cluster has many tablets.

before:
<img width="1280" height="575" alt="1"
src="https://github.com/user-attachments/assets/df626e1e-84ef-4078-8da7-d857ac960678"
/>

after:
<img width="1280" height="510" alt="2"
src="https://github.com/user-attachments/assets/3fee7407-0743-4d07-9462-a9f0e101765f"
/>
---
 .../java/org/apache/doris/catalog/Tablet.java    | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/catalog/Tablet.java b/fe/fe-core/src/main/java/org/apache/doris/catalog/Tablet.java
index 379cc0a17da716..0a07ffe82d3865 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/catalog/Tablet.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/catalog/Tablet.java
@@ -25,7 +25,6 @@
 import org.apache.doris.common.FeConstants;
 import org.apache.doris.common.Pair;
 import org.apache.doris.common.UserException;
-import org.apache.doris.common.lock.MonitoredReentrantReadWriteLock;
 import org.apache.doris.resource.Tag;
 import org.apache.doris.system.Backend;
 import org.apache.doris.system.SystemInfoService;
@@ -123,7 +122,7 @@ public TabletHealth() {
     private long cooldownReplicaId = -1;
     @SerializedName(value = "ctm", alternate = {"cooldownTerm"})
     private long cooldownTerm = -1;
-    private MonitoredReentrantReadWriteLock cooldownConfLock = new MonitoredReentrantReadWriteLock();
+    private final Object cooldownConfLock = new Object();
 
     // last time that the tablet checker checks this tablet.
     // no need to persist
@@ -184,10 +183,10 @@ public boolean isConsistent() {
     }
 
     public void setCooldownConf(long cooldownReplicaId, long cooldownTerm) {
-        cooldownConfLock.writeLock().lock();
-        this.cooldownReplicaId = cooldownReplicaId;
-        this.cooldownTerm = cooldownTerm;
-        cooldownConfLock.writeLock().unlock();
+        synchronized (cooldownConfLock) {
+            this.cooldownReplicaId = cooldownReplicaId;
+            this.cooldownTerm = cooldownTerm;
+        }
     }
 
     public long getCooldownReplicaId() {
@@ -195,11 +194,8 @@ public long getCooldownReplicaId() {
     }
 
     public Pair<Long, Long> getCooldownConf() {
-        cooldownConfLock.readLock().lock();
-        try {
+        synchronized (cooldownConfLock) {
             return Pair.of(cooldownReplicaId, cooldownTerm);
-        } finally {
-            cooldownConfLock.readLock().unlock();
         }
     }