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)?
Thank in advance, Leonid.