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
>>> 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.
Since he's using "v+1" in his example I assumed he's making a local copy
the returned values. Anyway, the plain answer to the question in the Subject
> See the MDB_val documentation in ldmb.h:
> * Values returned from the database are valid only until a
> * 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
value of the same key,
If we meant "same key" we would have said so.
or any mdb_put or mdb_cursor_put operation at
all, regardless of which key they touch?
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/