Enum IndexArm 

pub enum IndexArm {
    OneTableFourColumns,
    FourTables,
    PackedPayload,
}

Which payload layout sits behind the read stack’s stree.

This one is a type, not a value, and that is deliberate: it is the hot path. GitStore is generic over it (GitStore<S = OneTableFourColumns>), so a caller that knows its arm at compile time — which includes every existing caller, through the default — pays no dispatch at all. This enum exists so a runtime selector can pick one; see crate::git_ops::open_from_env, which monomorphises all three and hands back a Box<dyn GitOps>.

MEASURED 2026-08-07 (PLAN §13): a packed 25-byte column beats four columns by 19–76% on the payload gather but loses column scans by 3.3x–14.4x, and no git operation does a full-row fetch. That is why OneTableFourColumns is the default — and why the losing arms stay selectable, because that conclusion is a measurement and measurements get re-run.

Variants

OneTableFourColumns

OneTableFourColumns — the default. One Arrow IPC section, four columns.

FourTables

FourTables — four independent IPC sections joined on the ordinal.

PackedPayload

PackedPayload — one 25-byte fixed-size-binary column holding the whole row.

Implementations

impl IndexArm

pub const ALL: [IndexArm; 3]

pub fn as_str(self) -> &'static str

The spelling an operator types.

pub fn projection_name(self) -> &'static str

The name ObjectIndex::name reports for the projection this arm builds. Distinct from as_str on purpose: one is what an operator types, the other is what the built object calls itself, and a guard that compares them is comparing the selector against applied output.

pub fn parse(s: &str) -> Result<Self>

Trait Implementations

impl Clone for IndexArm

fn clone(&self) -> IndexArm

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for IndexArm

impl Debug for IndexArm

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

Formats the value using the given formatter.

impl Default for IndexArm

fn default() -> IndexArm

Returns the “default value” for a type.

impl Eq for IndexArm

impl PartialEq for IndexArm

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for IndexArm