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 with_metrics_if(self, enabled: bool) -> Self

Enables metrics on the database if requested.

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

Creates all the tables defined in Tables, if necessary.

This keeps tracks of the created table handles and stores them for better efficiency.

pub fn create_and_track_tables_for<TS: TableSet>( &mut self, ) -> Result<(), DatabaseError>

Creates all the tables defined in the given TableSet, if necessary.

This keeps tracks of the created table handles and stores them for better efficiency.

pub fn create_tables_for<TS: TableSet>( self: &mut Arc<Self>, ) -> Result<(), DatabaseError>

Creates all the tables defined in Tables, if necessary.

If this type is unique the created handle for the tables will be updated.

This is recommended to be called during initialization to create and track additional tables after the default Self::create_tables are created.

pub fn drop_orphan_table(&self, name: &str) -> Result<bool, DatabaseError>

Drops an orphaned table by name.

This is used to clean up tables that are no longer defined in the schema but may still exist on disk from previous versions.

Returns Ok(true) if the table existed and was dropped, Ok(false) if the table was not found.

Safety

This permanently deletes the table and all its data. Only use for tables that are confirmed to be obsolete.

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

Records version that accesses the database with write privileges.

pub const fn with_disable_long_read_transaction_safety(self) -> Self

Disables timeouts and long-read backtrace reporting for transactions opened through this handle. Existing transactions and other previously cloned handles are unaffected.

Use for offline work that intentionally holds transactions open.

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.

Reuses a previously-reset transaction handle from the internal pool when available, avoiding the lck_rdt_lock mutex in MDBX’s mvcc_bind_slot on each new transaction.

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 Clone for DatabaseEnv

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

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 path(&self) -> PathBuf

Returns the path to the database directory.

fn oldest_reader_txnid(&self) -> Option<u64>

Returns the transaction ID of the oldest active reader, if available.

fn last_txnid(&self) -> Option<u64>

Returns the ID of the most recently committed transaction, if available.

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

where F: FnOnce(&mut 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 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: 64 bytes