Hi,
LMDB seems to be quite the right database I am looking for in order to speed up my application. However, I still need to figure some things out. While I could get many answers to my questions by skimming through the archive, the following things are still unclear to me, and it would be quite nice if someone could clarify them:
- in the documentation, I saw two limits: the key is limited to 511 bytes (by default) and the data is limited to 16777215 bytes. Is this correct? For larger data sizes, is the data still maintained in one contiguous block, so that the application can still access it directly without any need of copying within LMDB? Or it is better to split larger data into multiple key/value pairs?
- I discovered the return code "MDB_TXN_FULL". By what means are transactions limited? I might consider to use few, but quite large transactions dealing with hundreds of thousands key/value pairs to be created, updated or deleted in some circumstances.
- I saw the discussion about the predefined database size, and that it is recommended to use a never-to-be-reached size and to rely on the sparse file capabilities of the underlying OS. If I would not want to go this way: Is it correct that if I encounter an "MDB_MAP_FULL" return code, it would be sufficient to abort the current transaction, resize the database using mdp_env_set_mapsize and repeat the transaction?
Thanks in advance and regards,
Klaus