Enum IsolationLevel 

pub enum IsolationLevel {
    RepeatableRead,
    Snapshot,
    ReadCommitted,
    Serializable,
}

Transaction isolation level (spec §10.2, S1B-002). MongrelDB defaults to RepeatableRead (snapshot isolation).

• RepeatableRead: one snapshot fixed at begin; own staged writes are visible to the transaction; write/write conflicts abort one transaction (first-committer-wins). This is the engine’s historical Snapshot (SI) semantics under its SQL-standard name.
• Snapshot: deprecated alias of RepeatableRead, kept so existing call sites compile unchanged. The two are interchangeable everywhere via Self::canonical.
• ReadCommitted: each statement obtains a new snapshot at the latest visible epoch, so committed concurrent changes may appear between statements. Commit-time conflict validation still uses the begin epoch (conservative first-committer-wins).
• Serializable: repeatable-read snapshot plus SSI-style certification — the commit sequencer tracks read dependencies (point reads), predicate/ range reads (table granularity), and write dependencies, and aborts with a serialization failure when a concurrent commit invalidated a tracked read (the rw-antidependency dangerous structure).

Variants

RepeatableRead

Snapshot

👎Deprecated:

renamed to RepeatableRead (spec §10.2 S1B-002); identical semantics, kept for compatibility

ReadCommitted

Serializable

Implementations

impl IsolationLevel

pub fn canonical(self) -> Self

Collapse aliases onto their canonical variant: Snapshot behaves exactly as RepeatableRead.

Trait Implementations

impl Clone for IsolationLevel

fn clone(&self) -> IsolationLevel

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for IsolationLevel

impl Debug for IsolationLevel

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

Formats the value using the given formatter.

impl Default for IsolationLevel

fn default() -> IsolationLevel

Returns the “default value” for a type.

impl Eq for IsolationLevel

impl PartialEq for IsolationLevel

fn eq(&self, other: &IsolationLevel) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for IsolationLevel