Struct GroupCommitManager 

pub struct GroupCommitManager { /* private fields */ }

Manages batched transaction commits for improved throughput.

Multiple concurrent transactions queue their commits, and a “leader” thread performs the actual WAL sync for the entire batch. This amortizes the cost of fsync across many transactions.

Algorithm

1. Transaction calls commit(lsn) after writing to WAL
2. If no leader is active, this thread becomes the leader
3. Leader waits up to max_wait or until max_batch_size reached
4. Leader performs WAL sync
5. Leader notifies all pending commits of completion
6. Non-leader threads wait on condvar until notified

Thread Safety

This struct is designed for concurrent access from multiple threads.

Implementations

impl GroupCommitManager

pub fn new(config: GroupCommitConfig, wal: Arc<Mutex<Wal>>) -> Self

Creates a new group commit manager.

pub fn commit(&self, lsn: Lsn) -> Result<()>

Queues a commit and waits for group sync.

This function blocks until the WAL has been synced to disk, guaranteeing durability of the commit.

Arguments

• lsn - The LSN of the committed transaction

Returns

Ok(()) when the WAL sync completes successfully.

pub fn batch_count(&self) -> u64

Returns the number of batch syncs performed.

pub fn commit_count(&self) -> u64

Returns the total number of commits processed.

pub fn avg_batch_size(&self) -> f64

Returns the average commits per batch.