Struct DatabaseEnv

pub struct DatabaseEnv { /* private fields */ }

Available on crate feature mdbx only.

Wrapper for the libmdbx environment: Environment

Implementations

impl DatabaseEnv

pub fn open( path: &Path, kind: DatabaseEnvKind, args: DatabaseArguments, ) -> Result<Self, DatabaseError>

Opens the database at the specified path with the given EnvKind.

It does not create the tables, for that call DatabaseEnv::create_tables.

pub fn with_metrics(self) -> Self

Enables metrics on the database.

pub fn create_tables(&self) -> Result<(), DatabaseError>

Creates all the defined tables, if necessary.

pub fn record_client_version( &self, version: ClientVersion, ) -> Result<(), DatabaseError>

Records version that accesses the database with write privileges.

Methods from Deref<Target = Environment>

pub fn is_write_map(&self) -> bool

Returns true if the environment was opened as WRITEMAP.

pub fn env_kind(&self) -> EnvironmentKind

Returns the kind of the environment.

pub fn is_read_write(&self) -> Result<bool, Error>

Returns true if the environment was opened in crate::Mode::ReadWrite mode.

pub fn is_read_only(&self) -> Result<bool, Error>

Returns true if the environment was opened in crate::Mode::ReadOnly mode.

pub fn timed_out_not_aborted_transactions(&self) -> usize

Available on crate feature read-tx-timeouts only.

Returns the number of timed out transactions that were not aborted by the user yet.

pub fn begin_ro_txn(&self) -> Result<Transaction<RO>, Error>

Create a read-only transaction for use with the environment.

pub fn begin_rw_txn(&self) -> Result<Transaction<RW>, Error>

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.

pub fn sync(&self, force: bool) -> Result<bool, Error>

Flush the environment data buffers to disk.

pub fn stat(&self) -> Result<Stat, Error>

Retrieves statistics about this environment.

pub fn info(&self) -> Result<Info, Error>

Retrieves info about this environment.

pub fn freelist(&self) -> Result<usize, Error>

Retrieves the total number of pages on the freelist.

Along with Environment::info(), this can be used to calculate the exact number of used pages as well as free pages in this environment.

let dir = tempfile::tempdir().unwrap();
let env = Environment::builder().open(dir.path()).unwrap();
let info = env.info().unwrap();
let stat = env.stat().unwrap();
let freelist = env.freelist().unwrap();
let last_pgno = info.last_pgno() + 1; // pgno is 0 based.
let total_pgs = info.map_size() / stat.page_size() as usize;
let pgs_in_use = last_pgno - freelist;
let pgs_free = total_pgs - pgs_in_use;

Note:

• MDBX stores all the freelists in the designated database 0 in each environment, and the freelist count is stored at the beginning of the value as uint32_t in the native byte order.

• It will create a read transaction to traverse the freelist database.

Trait Implementations

impl Database for DatabaseEnv

type TX = Tx<RO>

Read-Only database transaction

type TXMut = Tx<RW>

Read-Write database transaction

fn tx(&self) -> Result<Self::TX, DatabaseError>

Create read only transaction.

fn tx_mut(&self) -> Result<Self::TXMut, DatabaseError>

Create read write transaction only possible if database is open with write access.

fn view<T, F>(&self, f: F) -> Result<T, DatabaseError>

where F: FnOnce(&Self::TX) -> T,

Takes a function and passes a read-only transaction into it, making sure it’s closed in the end of the execution.

fn update<T, F>(&self, f: F) -> Result<T, DatabaseError>

where F: FnOnce(&Self::TXMut) -> T,

Takes a function and passes a write-read transaction into it, making sure it’s committed in the end of the execution.

impl DatabaseMetadata for DatabaseEnv

fn metadata(&self) -> DatabaseMetadataValue

Returns a metadata type, DatabaseMetadataValue for the database.

impl DatabaseMetrics for DatabaseEnv

fn report_metrics(&self)

Reports metrics for the database.

fn gauge_metrics(&self) -> Vec<(&'static str, f64, Vec<Label>)>

Returns a list of Gauge metrics for the database.

fn counter_metrics(&self) -> Vec<(&'static str, u64, Vec<Label>)>

Returns a list of Counter metrics for the database.

fn histogram_metrics(&self) -> Vec<(&'static str, f64, Vec<Label>)>

Returns a list of Histogram metrics for the database.

impl Debug for DatabaseEnv

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deref for DatabaseEnv

type Target = Environment

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 24 bytes