Oh, yes... it documented in doxygen as options for mdb_dbi_open(). Unfortunately I had looked only to comments near of MDB_INTEGERDUP definition.
Leonid. 2015-05-01 4:57 GMT+03:00 Howard Chu <h...@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. > >> >> Leonid. >> >> 2015-05-01 4:42 GMT+03:00 Howard Chu <h...@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 >>>> fsck >>>> tool. >>>> 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 >>>> 'entryCSN'. >>>> >>>> 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 >>>> table. >>>> - under debugger I see that md_dcmp is pointed to the default. >>>> - assert for key-size in default comparators was not failed while >>>> "make >>>> test". >>>> - all test are passed without MDB_INTEGERDUP. >>>> - but you told MDB_INTEGERDUP is necessary >>>> >>>> So, >>>> - how and when MDB_INTEGERDUP will have an impact? >>>> - in which cases keys in the table definitely should be sizeof(int) or >>>> sizeof(long)? >>> >>> >>> >>> 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/
