Re: (ITS#9097) lmdb: premature free of env->me_txn0

[madroach@gmerlin.de]

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.

Christopher


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