Christopher Zimmermann wrote:

Hi again,

I did some further debugging and now I'm afraid I am indeed finishing a transaction twice. I do call txn_commit() and after that I call txn_abort(). But the MDB_MAP_FULL event happens during mdb_txn_commit():

(gdb) frame 0 #0 mdb_page_alloc (mc=0x7f7ffffbd580, num=1, mp=0x7f7ffffbd228) at mdb.c:2286 2286 rc = MDB_MAP_FULL; (gdb) bt #0 mdb_page_alloc (mc=0x7f7ffffbd580, num=1, mp=0x7f7ffffbd228) at mdb.c:2286 #1 0x00000fb6fb6aa239 in mdb_page_touch (mc=0x7f7ffffbd580) at mdb.c:2428 #2 0x00000fb6fb6a9db3 in mdb_page_search (mc=0x7f7ffffbd580, key=0x0, flags=5) at mdb.c:5627 #3 0x00000fb6fb69e585 in mdb_freelist_save (txn=0xfb6bfb3ae00) at mdb.c:3087 #4 0x00000fb6fb69c2a4 in mdb_txn_commit (txn=0xfb6bfb3ae00) at mdb.c:3612

mdb_txn_commit() will return MDB_MAP_FULL.

It may be worth adding MDB_MAP_FULL and MDB_BAD_TXN to the possible error codes of mdb_txn_commit(), or in general provide some guidance on how to clean up a txn after some failure.

The doc for commit and abort is explicit. A txn must not be used again after calling commit or abort. There is nothing to clean up, the txn is always gone when commit or abort returns.