h.b.furuseth@usit.uio.no wrote:

Full_Name: Hallvard B Furuseth Version: lmdb 0.9.14 OS: URL: Submission from: (NULL) (81.191.45.22) Submitted by: hallvard

mdb_env_sync() works with MDB_RDONLY at least on Unix, but it syncs MDB_WRITEMAP changes incorrectly: fdatasync instead of msync because mdb_env_open() cleared MDB_WRITEMAP.

Users are likely doing the same thing anyway: Using MDB_RDONLY instead of MDB_RDONLY|MDB_WRITEMAP on WRITEMAP-written DBs.

mdb_env_sync() shouldn't even be doing any work at all if the env was opened RDONLY. We should return nop in that case. RDONLY means RDONLY! No writes, no calls that will alter the storage layer.