Struct ReplicaStream 

pub struct ReplicaStream { /* private fields */ }

Tracks the state of receiving replication data from the master.

The replica stream receives log entries from the master, buffers them in a pending queue, and tracks which VLSNs have been received vs. applied to the local database.

Implementations

impl ReplicaStream

pub fn new() -> Self

Create a new replica stream in the idle state.

pub fn get_state(&self) -> ReplicaStreamState

Return the current stream state.

pub fn set_state(&self, state: ReplicaStreamState)

Set the stream state.

pub fn get_applied_vlsn(&self) -> u64

Return the last VLSN that has been applied to the local database.

pub fn get_received_vlsn(&self) -> u64

Return the last VLSN received from the master (may be ahead of applied_vlsn if entries are buffered).

pub fn get_master_vlsn(&self) -> u64

Return the master’s latest known VLSN (from heartbeat updates).

pub fn set_master(&self, name: &str)

Set the master node name.

pub fn get_master(&self) -> Option<String>

Return the master node name, if set.

pub fn receive_entry(&self, vlsn: u64, entry_type: u8, data: Vec<u8>)

Receive a log entry from the master.

The entry is added to the pending queue and received_vlsn is updated if the new VLSN is greater than the current value.

pub fn mark_applied(&self, vlsn: u64)

Mark a VLSN as applied to the local database.

The applied_vlsn is updated if the new VLSN is greater than the current value (applied VLSNs should advance monotonically).

pub fn update_master_vlsn(&self, vlsn: u64)

Update the master’s known latest VLSN (typically from a heartbeat message).

pub fn get_lag(&self) -> u64

Return the replication lag: the difference between the master’s latest VLSN and the last applied VLSN.

A lag of 0 means the replica is fully caught up with the master.

pub fn drain_pending(&self) -> Vec<(u64, u8, Vec<u8>)>

Drain all pending entries for processing.

Returns the entries in the order they were received and leaves the pending queue empty.

pub fn is_caught_up(&self) -> bool

Check if the replica is caught up with the master.

Returns true if all of the following are true:

• the master VLSN is non-zero (i.e. at least one master VLSN has been observed; a stream that has never received a master VLSN reports false),
• the applied VLSN equals or exceeds the master’s latest known VLSN, and
• there are no pending entries.

Trait Implementations

impl Debug for ReplicaStream

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

Formats the value using the given formatter.

impl Default for ReplicaStream

fn default() -> Self

Returns the “default value” for a type.