On Tue, 2015-05-19 at 17:05 +0100, Howard Chu wrote: > Timur Kristóf wrote: > > On Mon, 2015-05-18 at 23:03 +0200, Hallvard Breien Furuseth wrote: > > > 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 > > > > > transaction. > > > > > 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? > > > > > > > > Yes. > > > > > > ...No. I expect he means v = the MDB_val returned by mdb_get(). > > > mdb_put() can modify the data it points at. > > Since he's using "v+1" in his example I assumed he's making a local > copy of > the returned values. Anyway, the plain answer to the question in the > Subject > is Yes. > > > > 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. > > > What exactly does a subsequent update operation mean? Overwriting > > the > > value of the same key, > > If we meant "same key" we would have said so.
Okay, thanks for the clarification! > > > or any mdb_put or mdb_cursor_put operation at > > all, regardless of which key they touch? >
