Enum IndexKey 

pub enum IndexKey {
    Int(i64),
    Text(String),
    Bool(bool),
    Uuid([u8; 16]),
    Bytes(Vec<u8>),
    Numeric(Box<NumericKey>),
    Null,
}

Key type accepted by secondary indices. Float / NULL / Vector values can’t participate in a B-tree index — f64 is only PartialOrd, NULL has SQL-three-valued semantics, and Vector belongs to the (future) HNSW path. Index lookups on those columns fall back to full scan.

Variants

Int(i64)

Text(String)

Bool(bool)

Uuid([u8; 16])

v7.17.0 — Value::Uuid index key. Comparison is byte-wise (RFC 4122 byte order) so PRIMARY KEY UUID lookups land on the same fast-path as Int / Text.

Bytes(Vec<u8>)

r1039 — Value::Bytes (bytea). PG orders bytea by plain byte comparison, shorter-prefix first ('' < \x00 < \x0000 < \x01ff < \xff, measured on 18.4), which is exactly Vec<u8>’s Ord.

Numeric(Box<NumericKey>)

r1039 — exact decimal, in the canonical form described on NumericKey.

r1040 — BOXED, and the box is load-bearing for every OTHER index. A NumericKey is 48 bytes against Text(String)’s 24, so inline it set the size of the whole enum and every B-tree node in every index grew with it: 32 bytes per key to 48, align 8 to 16. Measured through the release sweep, SELECT pad FROM t ORDER BY id over 400,000 rows — a walk of the primary key’s index — went 39.4-40.6 ms to 42.3-44.1, in both leg orders. The indirection is charged to numeric keys, which are new, instead of to every index that existed already.

Null

v7.38.1 (L12) — a NULL component INSIDE a composite key, and nothing else. IndexKey::from_value(Value::Null) still returns None, so single-column B-trees never hold one, and no probe path ever BUILDS one (col = NULL is not a match in SQL) — the variant is only reachable through a composite key’s component list, where it exists so that a row like (2, 3, NULL) stays findable by a PREFIX probe on (w, d). Declared last: slice Ord then sorts NULL components after every value, PG’s NULLS LAST.

Implementations

impl IndexKey

pub fn from_i64(n: i64) -> Self

v7.37.43 (INSUBQ B-4) — inline-friendly BigInt fast path. try_count_star_pk_in_subquery_fast (and any other hot loop probing an integer PK) already holds an i64; this builds the IndexKey without going through the generic from_value dispatch tree.

pub fn from_value_for_column(v: &Value<'_>, ty: DataType) -> Option<Self>

r1039 — the key a value takes when the INDEXED COLUMN is ty, or None when it takes none (→ the caller falls back to a scan).

Every key under one index comes from one column, so they all live in one key SPACE. A probe built in a different space finds nothing — and “nothing” is indistinguishable from “no matching rows”, which is how round 564 and r1037 both turned an index into a wrong answer (a TEXT key sought against a DATE-keyed and a UUID-keyed index).

The two spaces this round adds make that trap reachable again from a new direction: WHERE n = 2 on a NUMERIC column produces Value::Int, and an integer key would look in a space nothing lives in. So NUMERIC columns take integers by converting them exactly, and refuse anything they cannot convert; BYTEA columns take only Value::Bytes; and no other column may be keyed in either of the two new spaces.

Use this wherever the key comes from a LITERAL or from another table’s value. IndexKey::from_value stays right for building the index itself, where the value is the column’s own.

pub fn from_value(v: &Value<'_>) -> Option<Self>

Trait Implementations

impl Clone for IndexKey

fn clone(&self) -> IndexKey

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for IndexKey

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

Formats the value using the given formatter.

impl Eq for IndexKey

impl Ord for IndexKey

fn cmp(&self, other: &IndexKey) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for IndexKey

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for IndexKey

fn partial_cmp(&self, other: &IndexKey) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for IndexKey