Hi, I have a question regarding growing an LMDB database when a write transaction hits MDB_MAP_FULL. I would like to avoid defining a high mapsize value because my application will contain many MDB_envs, and because I have Windows users (Windows allocates the whole file on the disk).
Based on the intuition that MDB_MAP_FULL should not leave the database in a weird state, I have made the following little experiment. When MDB_MAP_FULL is encountered I tried to: * copy the current env (mdb_env_copy) into another directory (fine: it does not seem to contain uncommited data) * reset the transaction < error bit > (modified LMDB code to introduce a < txn->mt_flags &= ~MDB_TXN_ERROR > somewhere) * commit the transaction * close the database * close the env * reopen it with a higher mapsize value * reopen the database * create another transaction * continue writing ... and it seems to be working pretty well. Assuming I am ready to < relax > some of the ACID requirements, does it sound reasonable to think that MDB_MAP_FULL does not leave LMDB is a weird state? And that the < trick > described above should always be working? By < working > I mean: the copied environment will never contain uncommitted data (so I can rely on it to implement a kind of rollback), the reopened environment will always be valid and contain the expected data (data written before hitting MDB_MAP_FULL)? Thanks in advance for any insight, Best regards, Bruno.
