bugfix: fix readonly branch commit errors in Oracle XA transactions.

changes/en-us/2.x.md

@@ -16,6 +16,7 @@ Add changes here for all PR submitted to the 2.x branch.
 - [[#6668](https://github.com/apache/incubator-seata/pull/6668)] thread safety issue when adding and removing instances
 - [[#6678](https://github.com/apache/incubator-seata/pull/6678)] fix the same record has different lowkeys due to mixed case of table names yesterday
 - [[#6697](https://github.com/apache/incubator-seata/pull/6697)] v0 ByteBuf should not decode by super class
+- [[#6707](https://github.com/apache/incubator-seata/pull/6707)] fix readonly branch commit errors in Oracle XA transactions
 
 ### optimize:
 - [[#6499](https://github.com/apache/incubator-seata/pull/6499)] split the task thread pool for committing and rollbacking statuses

changes/zh-cn/2.x.md

@@ -17,6 +17,7 @@
 - [[#6668](https://github.com/apache/incubator-seata/pull/6668)] 解决namingserver同一个集群下instance添加和删除时的线程安全问题
 - [[#6678](https://github.com/apache/incubator-seata/pull/6678)] 修复由于表名大小写问题导致的相同记录生成不同RowKey的问题
 - [[#6697](https://github.com/apache/incubator-seata/pull/6697)] v0版本的ByteBuf不应由父类先解码
+- [[#6707](https://github.com/apache/incubator-seata/pull/6707)] 修复Oracle XA事务中只读分支提交出错的问题
 
 
 ### optimize:

console/src/main/resources/static/console-fe/src/pages/TransactionInfo/TransactionInfo.tsx

@@ -224,6 +224,12 @@ const branchSessionStatusList:Array<StatusType> = [
     iconType: 'error',
     iconColor: '#FF3333',
   },
+  {
+    label: 'PhaseOne_RDONLY',
+    value: 13,
+    iconType: 'ellipsis',
+    iconColor: 'rgb(3, 193, 253)',
+  },
 ];
 
 class TransactionInfo extends React.Component<GlobalProps, TransactionInfoState> {

core/src/main/java/org/apache/seata/core/model/BranchStatus.java

@@ -101,7 +101,14 @@ public enum BranchStatus {
      * The Phase two rollback failed retryable because of XAException.XAER_NOTA.
      * description:rollback logic is failed because of XAException.XAER_NOTA but retryable.
      */
-    PhaseTwo_RollbackFailed_XAER_NOTA_Retryable(12);
+    PhaseTwo_RollbackFailed_XAER_NOTA_Retryable(12),
+
+
+    /**
+     * The results of the Phase one are read-only.
+     * Description: After the branch prepare in the Oracle database, only purely read-only query statements were executed.
+     */
+    PhaseOne_RDONLY(13);
 
     private int code;
 

rm-datasource/src/main/java/org/apache/seata/rm/datasource/xa/ConnectionProxyXA.java

@@ -226,7 +226,14 @@ public synchronized void commit() throws SQLException {
             long now = System.currentTimeMillis();
             checkTimeout(now);
             setPrepareTime(now);
-            xaResource.prepare(xaBranchXid);
+            int prepare = xaResource.prepare(xaBranchXid);
+            // Based on the four databases: MySQL (8), Oracle (12c), Postgres (16), and MSSQL Server (2022),
+            // only Oracle has read-only optimization; the others do not provide read-only feedback.
+            // Therefore, the database type check can be eliminated here.
+            if (prepare == XAResource.XA_RDONLY) {
+                // Branch Report to TC: RDONLY
+                reportStatusToTC(BranchStatus.PhaseOne_RDONLY);
+            }
         } catch (XAException xe) {
             // Branch Report to TC: Failed
             reportStatusToTC(BranchStatus.PhaseOne_Failed);

serializer/seata-serializer-protobuf/src/main/resources/protobuf/org/apache/seata/protocol/transcation/branchStatus.proto

@@ -90,5 +90,10 @@ enum BranchStatusProto {
      */
     // Rollback logic is failed but NOT retryable.
     PhaseTwo_RollbackFailed_Unretryable = 10;
+    /**
+     * The results of the Phase one are read-only.
+     */
+    // In the branch transaction, only purely read-only query statements were executed.
+    PhaseOne_RDONLY = 13;
 
 }

server/src/main/java/org/apache/seata/server/coordinator/DefaultCore.java

@@ -212,6 +212,14 @@ public boolean doGlobalCommit(GlobalSession globalSession, boolean retrying) thr
                     SessionHelper.removeBranch(globalSession, branchSession, !retrying);
                     return CONTINUE;
                 }
+                // Only databases with read-only optimization, such as Oracle,
+                // will report the RDONLY status during XA transactions.
+                // At this point, the branch transaction can be ignored.
+                if (currentStatus == BranchStatus.PhaseOne_RDONLY
+                        && branchSession.getBranchType() == BranchType.XA) {
+                    SessionHelper.removeBranch(globalSession, branchSession, !retrying);
+                    return CONTINUE;
+                }
                 try {
                     BranchStatus branchStatus = getCore(branchSession.getBranchType()).branchCommit(globalSession, branchSession);
                     if (isXaerNotaTimeout(globalSession,branchStatus)) {