diff --git a/src/sqlite3.c b/src/sqlite3.c
index ea2fbcb3e067fcb6c20922236ca24a629bb13ce4..37666c3537448a3845f89eb72315663e3c76601a 100644
--- a/src/sqlite3.c
+++ b/src/sqlite3.c
@@ -66072,6 +66072,7 @@ static int walBeginShmUnreliable(Wal *pWal, int *pChanged){
 ** so it takes care to hold an exclusive lock on the corresponding
 ** WAL_READ_LOCK() while changing values.
 */
+static void printLockInfoWhenReadWal(Wal *pWal);
 static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int cnt){
   volatile WalCkptInfo *pInfo;    /* Checkpoint information in wal-index */
   u32 mxReadMark;                 /* Largest aReadMark[] value */
@@ -66109,6 +66110,7 @@ static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int cnt){
       return SQLITE_PROTOCOL;
     }
     if( cnt>=10 ) nDelay = (cnt-9)*(cnt-9)*39;
+    if( cnt>=15 ) printLockInfoWhenReadWal(pWal);
     sqlite3OsSleep(pWal->pVfs, nDelay);
   }
 
@@ -71028,6 +71030,101 @@ static void pageReinit(DbPage *pData){
   }
 }
 
+static void printLockInfo(unixFile *uFile_db, unixFile *uFile_wal)
+{
+  sqlite3_log(SQLITE_WARNING, "[printLockInfo] begin\n");
+  char *lock_type[3] = {"F_RDLCK", "F_WRLCK", "F_UNLCK"};
+
+  sqlite3_log(SQLITE_WARNING, "*** DB file ***\n");
+  if( uFile_db==NULL ){
+    sqlite3_log(SQLITE_WARNING, "NO DB FILE !\n");
+    return;
+  }
+  int fd_db = uFile_db->h;
+
+  off_t start_list[3] = {PENDING_BYTE, RESERVED_BYTE, SHARED_FIRST};
+  off_t len_list[3] = {1, 1, SHARED_SIZE};
+  char *lock_name_list[3] = {"pending lock ", "reserved lock", "shared lock  "};
+
+  for(int i=0; i<3; ++i){
+    struct flock fl_db;
+    fl_db.l_type = F_WRLCK;
+    fl_db.l_start = start_list[i];
+    fl_db.l_len = len_list[i];
+    fl_db.l_whence = SEEK_SET;
+
+    int ret = osFcntl(fd_db, F_GETLK, &fl_db);
+    if( ret!=SQLITE_OK ){
+      sqlite3_log(SQLITE_WARNING, "osFcntl Fail in DB file!!!\n");
+      return;
+    }
+    if( fl_db.l_type!=F_UNLCK ){
+      sqlite3_log(SQLITE_WARNING, "lock name: %s, pos: 0x%x, len: 0x%x, lock type: %s, owner: %d\n",
+        lock_name_list[i], start_list[i], len_list[i], lock_type[fl_db.l_type], fl_db.l_pid);
+    }else{
+      sqlite3_log(SQLITE_WARNING, "lock name: %s, pos: 0x%x, len: 0x%x, lock type: %s\n",
+        lock_name_list[i], start_list[i], len_list[i], lock_type[fl_db.l_type]);
+    }
+  }
+
+  sqlite3_log(SQLITE_WARNING, "*** WAL file ***\n");
+  if( uFile_wal==NULL ){
+    sqlite3_log(SQLITE_WARNING, "NO WAL FILE !\n");
+    return;
+  }
+  int fd_wal = uFile_wal->h;
+  off_t start_pos = WALINDEX_LOCK_OFFSET;
+  char *lock_name_list_wal[8] = {"wal_write lock  ", "wal_ckpt lock   ", "wal_recover lock"};
+  for(int i=3; i<8; ++i){
+    lock_name_list_wal[i] = "wal_read lock   ";
+  }
+
+  for(int i=0; i<8; ++i){
+    struct flock fl_wal;
+    fl_wal.l_type = F_WRLCK;
+    fl_wal.l_start = start_pos;
+    fl_wal.l_len = 1;
+    fl_wal.l_whence = SEEK_SET;
+
+    int ret = osFcntl(fd_wal, F_GETLK, &fl_wal);
+    if( ret!=SQLITE_OK ){
+      sqlite3_log(SQLITE_WARNING, "osFcntl Fail in WAL file!!!\n");
+      return;
+    }
+    if( fl_wal.l_type!=F_UNLCK ){
+      sqlite3_log(SQLITE_WARNING, "lock name: %s, pos: 0x%x, len: 0x%x, lock type: %s, owner: %d\n",
+        lock_name_list_wal[i], start_pos, 1, lock_type[fl_wal.l_type], fl_wal.l_pid);
+    }else{
+      sqlite3_log(SQLITE_WARNING, "lock name: %s, pos: 0x%x, len: 0x%x, lock type: %s\n",
+        lock_name_list_wal[i], start_pos, 1, lock_type[fl_wal.l_type]);
+    }
+    start_pos++;
+  }
+  sqlite3_log(SQLITE_WARNING, "[printLockInfo] end\n");
+}
+
+static void printLockInfoWhenReadWal(Wal *pWal)
+{
+  printf("[printLockInfoWhenReadWal] begin\n");
+  unixFile *uFile_db = (unixFile *)(pWal->pDbFd);
+  unixFile *uFile_wal = (unixFile *)(pWal->pWalFd);
+  printLockInfo(uFile_db, uFile_wal);
+  printf("[printLockInfoWhenReadWal] end\n");
+}
+
+static void printLockInfoInBusyHandler(Pager *pPager)
+{
+  printf("[printLockInfoInBusyHandler] begin\n");
+  unixFile *uFile_db = (unixFile *)(pPager->fd);
+  if( pPager->pWal!=NULL ){
+    unixFile *uFile_wal = (unixFile *)(pPager->pWal->pWalFd);
+    printLockInfo(uFile_db, uFile_wal);
+  }else{
+    printLockInfo(uFile_db, NULL);
+  }
+  printf("[printLockInfoInBusyHandler] end\n");
+}
+
 /*
 ** Invoke the busy handler for a btree.
 */
@@ -71035,6 +71132,7 @@ static int btreeInvokeBusyHandler(void *pArg){
   BtShared *pBt = (BtShared*)pArg;
   assert( pBt->db );
   assert( sqlite3_mutex_held(pBt->db->mutex) );
+  printLockInfoInBusyHandler( pBt->pPager );
   return sqlite3InvokeBusyHandler(&pBt->db->busyHandler);
 }