From 263bb42091b7b62ebbc55dcdc96d5d19188a4d18 Mon Sep 17 00:00:00 2001
From: zy-kkk <zhongyk10@gmail.com>
Date: Fri, 5 Dec 2025 14:02:30 +0800
Subject: [PATCH]  [fix](jdbc) Fix JNI global reference leak in JdbcConnector
 close (#58574)

## Problem
JNI Global References may not be deleted when `JdbcConnector::close()`
fails
midway due to early returns from `RETURN_IF_ERROR` macros. This prevents
Java
GC from collecting `BaseJdbcExecutor` and its associated `ResultSet`
objects,
  causing old generation heap to grow to 99%+.

  ## Solution
- C++: Always delete all three Global References regardless of Java
close() failure
- Java: Always clear member variable references (`resultSet`, `stmt`,
`conn`) in finally block
---
 be/src/vec/exec/vjdbc_connector.cpp           | 50 +++++++++++++++----
 .../apache/doris/jdbc/BaseJdbcExecutor.java   | 19 +++++--
 2 files changed, 54 insertions(+), 15 deletions(-)

diff --git a/be/src/vec/exec/vjdbc_connector.cpp b/be/src/vec/exec/vjdbc_connector.cpp
index d4cf31f4f78674..d55dd4b48e1055 100644
--- a/be/src/vec/exec/vjdbc_connector.cpp
+++ b/be/src/vec/exec/vjdbc_connector.cpp
@@ -68,23 +68,51 @@ JdbcConnector::~JdbcConnector() {
 
 Status JdbcConnector::close(Status /*unused*/) {
     SCOPED_RAW_TIMER(&_jdbc_statistic._connector_close_timer);
-    _closed = true;
+    if (_closed) {
+        return Status::OK();
+    }
     if (!_is_open) {
+        _closed = true;
         return Status::OK();
     }
+
+    JNIEnv* env = nullptr;
+    Status status = JniUtil::GetJNIEnv(&env);
+    if (!status.ok() || env == nullptr) {
+        LOG(WARNING) << "Failed to get JNIEnv in close(): " << status.to_string();
+        _closed = true;
+        return status;
+    }
+
+    // Try to abort transaction and call Java close(), but don't block cleanup
     if (_is_in_transaction) {
-        RETURN_IF_ERROR(abort_trans());
+        Status abort_status = abort_trans();
+        if (!abort_status.ok()) {
+            LOG(WARNING) << "Failed to abort transaction: " << abort_status.to_string();
+        }
     }
-    JNIEnv* env = nullptr;
-    RETURN_IF_ERROR(JniUtil::GetJNIEnv(&env));
+
     env->CallNonvirtualVoidMethod(_executor_obj, _executor_clazz, _executor_close_id);
-    RETURN_ERROR_IF_EXC(env);
-    env->DeleteGlobalRef(_executor_factory_clazz);
-    RETURN_ERROR_IF_EXC(env);
-    env->DeleteGlobalRef(_executor_clazz);
-    RETURN_IF_ERROR(JniUtil::GetJniExceptionMsg(env));
-    env->DeleteGlobalRef(_executor_obj);
-    RETURN_ERROR_IF_EXC(env);
+    if (env->ExceptionCheck()) {
+        LOG(WARNING) << "Java close() failed: " << JniUtil::GetJniExceptionMsg(env).to_string();
+        env->ExceptionClear();
+    }
+
+    // Always delete Global References to allow Java GC
+    if (_executor_factory_clazz != nullptr) {
+        env->DeleteGlobalRef(_executor_factory_clazz);
+        _executor_factory_clazz = nullptr;
+    }
+    if (_executor_clazz != nullptr) {
+        env->DeleteGlobalRef(_executor_clazz);
+        _executor_clazz = nullptr;
+    }
+    if (_executor_obj != nullptr) {
+        env->DeleteGlobalRef(_executor_obj);
+        _executor_obj = nullptr;
+    }
+
+    _closed = true;
     return Status::OK();
 }
 
diff --git a/fe/be-java-extensions/jdbc-scanner/src/main/java/org/apache/doris/jdbc/BaseJdbcExecutor.java b/fe/be-java-extensions/jdbc-scanner/src/main/java/org/apache/doris/jdbc/BaseJdbcExecutor.java
index 3e71cc5abddb0b..151e9cffe1af22 100644
--- a/fe/be-java-extensions/jdbc-scanner/src/main/java/org/apache/doris/jdbc/BaseJdbcExecutor.java
+++ b/fe/be-java-extensions/jdbc-scanner/src/main/java/org/apache/doris/jdbc/BaseJdbcExecutor.java
@@ -127,7 +127,11 @@ public BaseJdbcExecutor(byte[] thriftParams) throws Exception {
 
     public void close() throws Exception {
         if (outputTable != null) {
-            outputTable.close();
+            try {
+                outputTable.close();
+            } finally {
+                outputTable = null;
+            }
         }
         try {
             if (stmt != null && !stmt.isClosed()) {
@@ -143,10 +147,17 @@ public void close() throws Exception {
             }
         } finally {
             closeResources(resultSet, stmt, conn);
+            // Always clear references to help GC, even if close() failed
+            resultSet = null;
+            stmt = null;
+            conn = null;
             if (config.getConnectionPoolMinSize() == 0 && hikariDataSource != null) {
-                hikariDataSource.close();
-                JdbcDataSource.getDataSource().getSourcesMap().remove(config.createCacheKey());
-                hikariDataSource = null;
+                try {
+                    hikariDataSource.close();
+                    JdbcDataSource.getDataSource().getSourcesMap().remove(config.createCacheKey());
+                } finally {
+                    hikariDataSource = null;
+                }
             }
         }
     }