On 12/05/15 19:36, Howard Chu wrote:
Dmytro Milinevskyy wrote:
> Basically I need to have an opportunity to call mdb_get while in write
> The sequence is smth like:
> - txn = mdb_txn_begin(flags=0)
> for i in 0..x:
> - v = mdb_get(txn, i)
> - mdb_put(txn, x+i, v)
> - mdb_put(txn, i, v+1)
> - mdb_txn_commit(txn)
> Will it be always valid data?
...No. I expect he means v = the MDB_val returned by mdb_get().
mdb_put() can modify the data it points at.
See the MDB_val documentation in ldmb.h:
* Values returned from the database are valid only until a subsequent
* update operation, or the end of the transaction. Do not modify or
* free them, they commonly point into the database itself.