diff --git a/src/backend/storage/lmgr/he3db_logindex.c b/src/backend/storage/lmgr/he3db_logindex.c
index a426e80..6c9ce93 100644
--- a/src/backend/storage/lmgr/he3db_logindex.c
+++ b/src/backend/storage/lmgr/he3db_logindex.c
@@ -606,7 +606,8 @@ TagNode *GetBufTagByLsnRange(XLogRecPtr start_lsn, XLogRecPtr end_lsn)
         }else if(mem_tbl->meta.min_lsn >= end_lsn)
         {
             // there is no suitability lsn_list after this mem table
-            break;
+            LWLockRelease(LogIndexMemListLock);
+            return head_node;
         }
         else
         {
@@ -627,7 +628,7 @@ TagNode *GetBufTagByLsnRange(XLogRecPtr start_lsn, XLogRecPtr end_lsn)
                     page_min_lsn = LOG_INDEX_COMBINE_LSN(mem_tbl, first_seg->suffix_lsn[0]);
                     uint8 id = Min(LOG_INDEX_MEM_ITEM_SEG_LSN_NUM - 1, last_seg->number - 1);
                     page_max_lsn = LOG_INDEX_COMBINE_LSN(mem_tbl, last_seg->suffix_lsn[id]);
-                    if(page_min_lsn > end_lsn || page_max_lsn < start_lsn)
+                    if(page_min_lsn >= end_lsn || page_max_lsn < start_lsn)
                     {
                         continue;
                     }
@@ -637,6 +638,7 @@ TagNode *GetBufTagByLsnRange(XLogRecPtr start_lsn, XLogRecPtr end_lsn)
                     }
                 }
             }
+            LWLockRelease(LogIndexMemListLock);
             return head_node;
         }
     }
@@ -663,7 +665,7 @@ TagNode *GetBufTagByLsnRange(XLogRecPtr start_lsn, XLogRecPtr end_lsn)
                     page_min_lsn = LOG_INDEX_COMBINE_LSN(mem_tbl, first_seg->suffix_lsn[0]);
                     uint8 id = Min(LOG_INDEX_MEM_ITEM_SEG_LSN_NUM - 1, last_seg->number - 1);
                     page_max_lsn = LOG_INDEX_COMBINE_LSN(mem_tbl, last_seg->suffix_lsn[id]);
-                    if(page_min_lsn > end_lsn || page_max_lsn < start_lsn)
+                    if(page_min_lsn >= end_lsn || page_max_lsn < start_lsn)
                     {
                         continue;
                     }
@@ -680,6 +682,140 @@ TagNode *GetBufTagByLsnRange(XLogRecPtr start_lsn, XLogRecPtr end_lsn)
     return head_node;
 }
 
+bool CheckBufTagExistByLsnRange(const BufferTag *page, XLogRecPtr start_lsn, XLogRecPtr end_lsn)
+{
+    uint64 tbl_index;
+    LogIndexMemItemSeg *first_seg;
+    LogIndexMemItemSeg *last_seg;
+    XLogRecPtr page_min_lsn;
+    XLogRecPtr page_max_lsn;
+    uint32 hash_key;
+    LogIndexMemItemHead *page_head;
+
+    // Prevent metadata changes during discovery.
+    LWLockAcquire(LogIndexMemListLock,LW_SHARED);
+    tbl_index = log_index_mem_list->table_start_index;
+loop:
+    while(tbl_index != log_index_mem_list->active_table_index)
+    {
+        LogIndexMemTBL *mem_tbl = &(log_index_mem_list->mem_table[tbl_index]);
+        tbl_index = (tbl_index + 1)%(log_index_mem_list->table_cap);
+        // current mem table no suitability lsn_list
+        if(mem_tbl->meta.max_lsn < start_lsn)
+        {
+            continue;
+        }else if(mem_tbl->meta.min_lsn >= end_lsn)
+        {
+            // there is no suitability lsn_list after this mem table
+            goto outerloop;
+        }
+        else
+        {
+            // find page from current mem table
+            hash_key = LOG_INDEX_MEM_TBL_HASH_PAGE(page);
+            if(mem_tbl->hash[hash_key] != LOG_INDEX_TBL_INVALID_SEG)
+            {
+                page_head = &(mem_tbl->page_head[mem_tbl->hash[hash_key]-1]);
+                while(!BUFFERTAGS_EQUAL(page_head->tag, *page)){
+                    if(page_head->next_item == LOG_INDEX_TBL_INVALID_SEG)
+                    {
+                        // cannot find page from current mem table
+                        goto loop;
+                    }
+                    page_head = &(mem_tbl->page_head[page_head->next_item-1]);
+                }
+                // find request page, but not lsn
+                if(page_head->next_seg == LOG_INDEX_TBL_INVALID_SEG || page_head->tail_seg == LOG_INDEX_TBL_INVALID_SEG)
+                {
+                    continue;
+                }
+                else
+                {
+                    first_seg = &(mem_tbl->seg_item[page_head->next_seg - 1]);
+                    last_seg = &(mem_tbl->seg_item[page_head->tail_seg - 1]);
+                    page_min_lsn = LOG_INDEX_COMBINE_LSN(mem_tbl, first_seg->suffix_lsn[0]);
+                    uint8 id = Min(LOG_INDEX_MEM_ITEM_SEG_LSN_NUM - 1, last_seg->number - 1);
+                    page_max_lsn = LOG_INDEX_COMBINE_LSN(mem_tbl, last_seg->suffix_lsn[id]);
+                    // lsn not correspond with request
+                    if(page_min_lsn >= end_lsn || page_max_lsn < start_lsn)
+                    {
+                        continue;
+                    }
+                    else
+                    {
+                        // find one
+                        LWLockRelease(LogIndexMemListLock);
+                        return true;
+                    }
+                }
+            }else
+            {
+                continue;
+            }
+        }
+    }
+    
+    if (tbl_index == log_index_mem_list->active_table_index){
+        LogIndexMemTBL *mem_tbl = &(log_index_mem_list->mem_table[tbl_index]);
+        tbl_index = (tbl_index + 1)%(log_index_mem_list->table_cap);
+        // current mem table no suitability lsn_list
+        if(mem_tbl->meta.max_lsn < start_lsn)
+        {
+            goto outerloop;
+        }else if(mem_tbl->meta.min_lsn >= end_lsn)
+        {
+            // there is no suitability lsn_list after this mem table
+            goto outerloop;
+        }
+        else
+        {
+            // find page from current mem table
+            hash_key = LOG_INDEX_MEM_TBL_HASH_PAGE(page);
+            if(mem_tbl->hash[hash_key] != LOG_INDEX_TBL_INVALID_SEG)
+            {
+                page_head = &(mem_tbl->page_head[mem_tbl->hash[hash_key]-1]);
+                while(!BUFFERTAGS_EQUAL(page_head->tag, *page)){
+                    if(page_head->next_item == LOG_INDEX_TBL_INVALID_SEG)
+                    {
+                        // cannot find page from current mem table
+                        goto outerloop;
+                    }
+                    page_head = &(mem_tbl->page_head[page_head->next_item-1]);
+                }
+                // find request page
+                if(page_head->next_seg == LOG_INDEX_TBL_INVALID_SEG || page_head->tail_seg == LOG_INDEX_TBL_INVALID_SEG)
+                {
+                    goto outerloop;
+                }
+                else
+                {
+                    first_seg = &(mem_tbl->seg_item[page_head->next_seg - 1]);
+                    last_seg = &(mem_tbl->seg_item[page_head->tail_seg - 1]);
+                    page_min_lsn = LOG_INDEX_COMBINE_LSN(mem_tbl, first_seg->suffix_lsn[0]);
+                    uint8 id = Min(LOG_INDEX_MEM_ITEM_SEG_LSN_NUM - 1, last_seg->number - 1);
+                    page_max_lsn = LOG_INDEX_COMBINE_LSN(mem_tbl, last_seg->suffix_lsn[id]);
+                    if(page_min_lsn >= end_lsn || page_max_lsn < start_lsn)
+                    {
+                        goto outerloop;
+                    }
+                    else
+                    {
+                        // find one
+                        LWLockRelease(LogIndexMemListLock);
+                        return true;
+                    }
+                }
+            }else
+            {
+                goto outerloop;
+            }
+        }
+    }
+outerloop:
+    LWLockRelease(LogIndexMemListLock);
+    return false;
+}
+
 void FreeTagNode(TagNode *head)
 {
     TagNode* tn;
diff --git a/src/include/storage/he3db_logindex.h b/src/include/storage/he3db_logindex.h
index 7e84dae..2722b22 100644
--- a/src/include/storage/he3db_logindex.h
+++ b/src/include/storage/he3db_logindex.h
@@ -116,4 +116,5 @@ extern LsnNode *GetLogIndexByPage(const BufferTag *page, XLogRecPtr start_lsn, X
 extern void FreeLsnNode(LsnNode *head);
 extern TagNode *GetBufTagByLsnRange(XLogRecPtr start_lsn, XLogRecPtr end_lsn);
 extern void FreeTagNode(TagNode *head);
+extern bool CheckBufTagExistByLsnRange(const BufferTag *page, XLogRecPtr start_lsn, XLogRecPtr end_lsn);
 #endif							/* HE3DB_LOGINDEX_H */
\ No newline at end of file