1.解决主机新加段页式文件，备机更新时没有初始化的问题

2.解决debug模式下cm_agent由于u_sess上的globalxmin是无效值，导致异常的问题
3.解决主机drop db/drop tablespace，广播到备机后，备机mes如果异常退出，不释放锁的问题

src/gausskernel/ddes/adapter/ss_transaction.cpp

@@ -102,6 +102,10 @@ Snapshot SSGetSnapshotData(Snapshot snapshot)
     /* For cm agent, it only query the system status using the parameter in memory. So don't need MVCC */
     if (u_sess->libpq_cxt.IsConnFromCmAgent) {
         snapshot = SnapshotNow;
+        if (!TransactionIdIsNormal(u_sess->utils_cxt.RecentGlobalXmin)) {
+            u_sess->utils_cxt.RecentGlobalXmin = FirstNormalTransactionId;
+        }
+        u_sess->utils_cxt.RecentGlobalDataXmin = u_sess->utils_cxt.RecentGlobalXmin;
         return snapshot;
     }
 

src/gausskernel/storage/smgr/segment/data_file.cpp

@@ -155,6 +155,11 @@ bool df_ss_update_segfile_size(SegLogicFile *sf, BlockNumber target_block)
     }
 
     uint32 flags = O_RDWR | PG_BINARY;
+    /* need palloc segfiles if file_num is 0 */
+    if (sf->vector_capacity == 0) {
+        df_extend_file_vector(sf);
+    }
+
     if (sf->file_num == 0) {
         char *filename = slice_filename(sf->filename, 0);
         int fd = dv_open_file(filename, flags, (int)SEGMENT_FILE_MODE);

src/gausskernel/storage/smgr/segment/space.cpp

@@ -413,19 +413,22 @@ static void SSClose_seg_files(SegSpace *spc)
 
 void SSDrop_seg_space(Oid spcNode, Oid dbNode)
 {
-    SegSpace *spc = spc_init_space_node(spcNode, dbNode);
-    AutoMutexLock spc_lock(&spc->lock);
+    SegSpace *entry = NULL;
+    AutoMutexLock spc_lock(&segspace_lock);
+    SegSpcTag tag = {.spcNode = spcNode, .dbNode = dbNode};
+    SegmentCheck(t_thrd.storage_cxt.SegSpcCache != NULL);
     spc_lock.lock();
-
-    SpaceDataFileStatus dataStatus = spc_status(spc);
-    if (dataStatus == SpaceDataFileStatus::EMPTY) {
-        spc_lock.unLock();
-        return;
-    }
-
-    SegDropSpaceMetaBuffers(spcNode, dbNode);
-    SSClose_seg_files(spc);
+    entry = (SegSpace *)hash_search(t_thrd.storage_cxt.SegSpcCache, (void *)&tag, HASH_FIND, NULL);
     spc_lock.unLock();
+
+    if (entry != NULL) {
+        if(entry->status == OPENED) {
+            SSClose_seg_files(entry);
+            SegDropSpaceMetaBuffers(spcNode, dbNode);
+        }
+        spc_lock.lock();
+        (void)hash_search(t_thrd.storage_cxt.SegSpcCache, (void *)&tag, HASH_REMOVE, NULL);
+    }
     return;
 }