Struct VersionChain 

pub struct VersionChain { /* private fields */ }

Chain of versions for a single key, sorted by commit_ts descending

Optimized for:

• O(log V) reads via binary search
• O(1) writes (prepend to front)
• O(V) GC (linear scan with compaction)

Implementations

impl VersionChain

pub fn new() -> Self

Create empty version chain

pub fn add_uncommitted( &mut self, value: Option<Vec<u8>>, txn_id: u64, epoch: u32, )

Add uncommitted version

pub fn commit(&mut self, txn_id: u64, commit_ts: u64) -> bool

Commit the uncommitted version

Returns true if committed successfully

pub fn abort(&mut self, txn_id: u64)

Abort uncommitted version

pub fn read_at( &self, snapshot_ts: u64, current_txn_id: Option<u64>, ) -> Option<&VersionEntry>

Read at snapshot timestamp

Returns the most recent version visible at snapshot_ts. If current_txn_id is provided, also considers uncommitted writes from that txn.

Complexity: O(log V) via binary search

pub fn has_write_conflict(&self, my_txn_id: u64) -> bool

Check if there’s a write conflict

pub fn gc(&mut self, min_epoch: u32, min_snapshot_ts: u64) -> usize

Garbage collect old versions

Removes versions that are:

1. Older than min_visible_epoch AND
2. Older than min_snapshot_ts AND
3. Not the most recent version (we always keep at least one)

Returns number of versions reclaimed

pub fn len(&self) -> usize

Get number of versions

pub fn is_empty(&self) -> bool

Check if empty

Trait Implementations

impl Debug for VersionChain

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

Formats the value using the given formatter.

impl Default for VersionChain

fn default() -> VersionChain

Returns the “default value” for a type.