I'm using the gomdb interface so I'll do my best to translate this to the C calls. I'm performing an mdb_txn_put(), committing the transaction and then later I'm opening a new read-only transaction where I do an mdb_txn_get() and I receive a "MDB_BAD_RSLOT: Invalid reuse of reader locktable slot" error.

When I switch the second transaction to not be read-only then the error goes away and it works fine. I checked the LMDB code and on line 1798, it's checking:

if (r->mr_pid != env->me_pid || r->mr_txnid != (txnid_t)-1)
  return MDB_BAD_RSLOT;

The r->mr_pid == env->me_pid (I'm only running one process) and the r->mr_txnid is 0 and the txnid_t is 0 (so the txnid_t - 1 is -1). I started going down the rabbit hole to figure this out further but I don't understand the locktable setup entirely.

Am I doing something wrong with how I'm creating read-only transactions?

Ben Johnson