Struct lmdb::Environment
source · pub struct Environment { /* private fields */ }Expand description
An LMDB environment.
An environment supports multiple databases, all residing in the same shared-memory map.
Implementations§
source§impl Environment
impl Environment
sourcepub fn new() -> EnvironmentBuilder
pub fn new() -> EnvironmentBuilder
Creates a new builder for specifying options for opening an LMDB environment.
sourcepub fn env(&self) -> *mut MDB_env
pub fn env(&self) -> *mut MDB_env
Returns a raw pointer to the underlying LMDB environment.
The caller must ensure that the pointer is not dereferenced after the lifetime of the environment.
sourcepub fn open_db<'env>(&'env self, name: Option<&str>) -> Result<Database>
pub fn open_db<'env>(&'env self, name: Option<&str>) -> Result<Database>
Opens a handle to an LMDB database.
If name is None, then the returned handle will be for the default database.
If name is not None, then the returned handle will be for a named database. In this
case the environment must be configured to allow named databases through
EnvironmentBuilder::set_max_dbs.
The returned database handle may be shared among any transaction in the environment.
This function will fail with Error::BadRslot if called by a thread which has an ongoing
transaction.
The database name may not contain the null character.
sourcepub fn create_db<'env>(
&'env self,
name: Option<&str>,
flags: DatabaseFlags
) -> Result<Database>
pub fn create_db<'env>(
&'env self,
name: Option<&str>,
flags: DatabaseFlags
) -> Result<Database>
Opens a handle to an LMDB database, creating the database if necessary.
If the database is already created, the given option flags will be added to it.
If name is None, then the returned handle will be for the default database.
If name is not None, then the returned handle will be for a named database. In this
case the environment must be configured to allow named databases through
EnvironmentBuilder::set_max_dbs.
The returned database handle may be shared among any transaction in the environment.
This function will fail with Error::BadRslot if called by a thread with an open
transaction.
sourcepub fn get_db_flags<'env>(&'env self, db: Database) -> Result<DatabaseFlags>
pub fn get_db_flags<'env>(&'env self, db: Database) -> Result<DatabaseFlags>
Retrieves the set of flags which the database is opened with.
The database must belong to to this environment.
sourcepub fn begin_ro_txn<'env>(&'env self) -> Result<RoTransaction<'env>>
pub fn begin_ro_txn<'env>(&'env self) -> Result<RoTransaction<'env>>
Create a read-only transaction for use with the environment.
sourcepub fn begin_rw_txn<'env>(&'env self) -> Result<RwTransaction<'env>>
pub fn begin_rw_txn<'env>(&'env self) -> Result<RwTransaction<'env>>
Create a read-write transaction for use with the environment. This method will block while there are any other read-write transactions open on the environment.
sourcepub fn sync(&self, force: bool) -> Result<()>
pub fn sync(&self, force: bool) -> Result<()>
Flush data buffers to disk.
Data is always written to disk when Transaction::commit is called, but the operating
system may keep it buffered. LMDB always flushes the OS buffers upon commit as well, unless
the environment was opened with MDB_NOSYNC or in part MDB_NOMETASYNC.
sourcepub unsafe fn close_db(&mut self, db: Database)
pub unsafe fn close_db(&mut self, db: Database)
Closes the database handle. Normally unnecessary.
Closing a database handle is not necessary, but lets Transaction::open_database reuse the
handle value. Usually it’s better to set a bigger EnvironmentBuilder::set_max_dbs, unless
that value would be large.
Safety
This call is not mutex protected. Databases should only be closed by a single thread, and
only if no other threads are going to reference the database handle or one of its cursors
any further. Do not close a handle if an existing transaction has modified its database.
Doing so can cause misbehavior from database corruption to errors like
Error::BadValSize (since the DB name is gone).