Struct Scan 

pub(crate) struct Scan<'a> {
    q: &'a Search,
    needle: Option<[u8; 16]>,
    probes: Vec<AttrProbe>,
    ranges: Vec<Probe>,
    after: Reverse<(i64, u32, u64, u32)>,
}

Everything the per-block half of a search reads, and nothing it writes.

One struct rather than five arguments because it crosses a thread boundary: shared by reference, immutable for the whole scan, and therefore Sync without a lock. What is left out is as deliberate — hits and stats are the only state a block scan produces, and both are returned rather than accumulated, which is what makes the blocks independent.

Fields

q: &'a Search

needle: Option<[u8; 16]>

probes: Vec<AttrProbe>

ranges: Vec<Probe>

after: Reverse<(i64, u32, u64, u32)>

Implementations

impl<'a> Scan<'a>

pub(crate) fn new(q: &'a Search) -> Scan<'a>

The per-block half of a query, prepared once.

Everything here is derived from q alone, which is what lets one Scan serve every block of a search and every thread scanning them.

pub(crate) fn wave( &self, refs: &[Src<'_>], from: usize, to: usize, ) -> Vec<Result<(Option<Block>, Vec<Hit>)>>

Blocks [from, to) scanned at once, answered in block order.

std::thread::scope and not a pool: the threads borrow the mapping, the query and each other’s nothing, and a scope is the one construct that lets them do that without an Arc around every field. They are also the wrong threads to pool — a pool exists to amortise spawns against short tasks, and a block scan is milliseconds against a spawn’s microseconds.

The caller’s own thread takes the first block, so a wave with no helpers — the first wave of every search, and every wave on a busy node — spawns nothing at all.

to is the wave the ramp asked for and the answer may be shorter: what SPARE hands out decides how many blocks this wave actually covers, and the caller advances by the number of answers rather than by the width it asked for.

pub(crate) fn block( &self, i: usize, bref: &Src<'_>, ) -> Result<(Option<Block>, Vec<Hit>)>

One block: prune it, or open it and find the rows that match.