LMDB works like this. The MDB_env struct keeps pointers to both meta pages: https://github.com/LMDB/lmdb/blob/30288c72573ceac719627183f1058cad1dd08b74/librarie

LMDB works like this. The MDB_env struct keeps pointers to both meta pages: https://github.com/LMDB/lmdb/blob/30288c72573ceac719627183f1058cad1dd08b74/libraries/liblmdb/mdb.c#L1520 https://github.com/LMDB/lmdb/blob/30288c72573ceac719627183f1... Which meta-page used is determined by the transaction ID (even IDs use first, odd IDs second). This is the earliest description I can find of the "shadow paging" concept: https://dl.acm.org/doi/10.1145/320521.320540 https://dl.acm.org/doi/10.1145/320521.320540 And I believe its first implementation was in IBM's System R.