add mapsize option

1 files changed, 1 insertions, 0 deletions

diff --git a/README.md b/README.md
index b4db243..7f4aa46 100644
--- a/README.md
+++ b/README.md
@@ -11,6 +11,7 @@ create a new environment handle and open the database at the `path`. returns the
 `opt` is an optional table of options:
 
 * `maxdbs`: number: the maximum number of databases in the environment. must be set if multiple databases will be used.
+* `mapsize`: number: the memory map size used for this environment. this is also the maximum size of the database. default: 1GiB (`1024^3`).
 * `rdonly`: boolean: open the environment in read-only mode.
 * `nosubdir`: boolean: the `path` is used for the database file itself and not its containing directory.
 * `nosync`: boolean: don't flush buffers to disk when committing.