WAL_CKPT_LOCK    49656 ext/sqlite3/libsqlite/sqlite3.c   }else if( lockIdx==WAL_CKPT_LOCK ){
WAL_CKPT_LOCK    49978 ext/sqlite3/libsqlite/sqlite3.c   assert( WAL_CKPT_LOCK==WAL_ALL_BUT_WRITE );
WAL_CKPT_LOCK    51889 ext/sqlite3/libsqlite/sqlite3.c   rc = walLockExclusive(pWal, WAL_CKPT_LOCK, 1, 0);
WAL_CKPT_LOCK    51958 ext/sqlite3/libsqlite/sqlite3.c   walUnlockExclusive(pWal, WAL_CKPT_LOCK, 1);