Storing graph data structure with MDB_FIXEDMAP

Hi,

I'm new in this list.

I plan to store graph data structure (vertex and edge) in LMDB. The "edge" data value of a record will contain a pointer which is pointing to the address of "vertex" data value. So, I must make it sure that data value address is not changing during operation. According to the doc, I can use MDB_FIXEDMAP.

And from the doc:

"... the memory map will always reside at the same virtual address and pointers used to reference data items in the database will be constant across multiple invocations. ..."

Spesifically: "... pointers used to reference data items in the database will be constant ..."

Is this mean that I must allocate memory to write data using mdb_put with MDB_RESERVE flag?