it documented in doxygen as options for mdb_dbi_open().
Unfortunately I had looked only to comments near of MDB_INTEGERDUP definition.
2015-05-01 4:57 GMT+03:00 Howard Chu <hyc(a)symas.com>:
Леонид Юрьев wrote:
> Thanks, Howard.
> It would be nice if some clarification, like these, will be in the lmdb.h.
MDB_INTEGERDUP is already clearly documented.
> 2015-05-01 4:42 GMT+03:00 Howard Chu <hyc(a)symas.com>:
>> Леонид Юрьев wrote:
>>> Hi, Howard.
>>> I would like to refine my question.
>>> Currently I develop a mdb_chk tool for deep check LMDB-files, like a
>>> It is needed for us, but let this stay aside for now.
>>> On some step I plan to check the size of each key in each DBI with
>>> MDB_INTEGERKEY and/or MDB_INTEGERDUP flags.
>>> Initially I assumed - if one of these flags is set, the the length of
>>> all keys must be sizeof(int) or sizeof(long). As will be used the
>>> corresponding comparison functions (mdb_cmp_int, mdb_cmp_long) , which
>>> can handle only keys of such sizes.
>>> But this approach has failed. A dbi-tables created for attr by
>>> mdb_attr_dbs_open() have MDB_DUPSORT|MDB_DUPFIXED|MDB_INTEGERDUP flags
>>> and may contain records with a 5-byte keys. For instance as the
>>> Later you have written that MDB_INTEGERDUP is required.
>>> Now I do not understand how it all works:
>>> - MDB_INTEGERDUP is set for attr tables.
>>> - indexer could create a 5-byte keys.
>>> - mdb-backend set custom comparison function only for MDB_DN2ID
>>> - under debugger I see that md_dcmp is pointed to the default.
>>> - assert for key-size in default comparators was not failed while
>>> - all test are passed without MDB_INTEGERDUP.
>>> - but you told MDB_INTEGERDUP is necessary
>>> - how and when MDB_INTEGERDUP will have an impact?
>>> - in which cases keys in the table definitely should be sizeof(int) or
>> MDB_INTGERKEY means the *keys* must be int/long.
>> MDB_INTEGERDUP means the *values* must be int/long.
>> When either flag is set, all of the corresponding (keys|values) in the DB
>> must be the same size.
>> The indexer only uses MDB_INTEGERDUP - it doesn't care what size the keys
>> are, but the values must be (longs in this case).
>> -- Howard Chu
>> CTO, Symas Corp. http://www.symas.com
>> Director, Highland Sun http://highlandsun.com/hyc/
>> Chief Architect, OpenLDAP http://www.openldap.org/project/
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/