-- pg_turbovec v1.8.0 -- competitive-parity feature minor release.
--
-- This file is a *reference mirror*. The authoritative install
-- script is generated by `cargo pgrx schema`.
--
-- v1.8.0 lands four competitive-parity features (driven by
--  vs pgvector 0.8.2 + Qdrant):
--
--   1. Iterative index scan (parity gap #1) -- the one true
--      correctness fix. amgettuple now re-runs the search with a
--      doubled k and feeds new candidates when a selective WHERE
--      filter + ORDER BY dist LIMIT k would otherwise under-return.
--      New GUCs: turbovec.iterative_scan (off | relaxed_order,
--      default relaxed_order) and turbovec.max_scan_tuples
--      (default 20000).
--
--   2. Parallel index build (parity gap #2) -- ambuild's encode +
--      repack phases are rayon-parallelised over heap-scan chunks.
--      New GUC: turbovec.build_parallelism (default 0 = auto).
--      Byte-for-byte identical relfiles regardless of thread count.
--
--   3. Cold-scan latency (parity gap #3) -- the read path now skips
--      the O(n) id_to_slot HashMap build (deferred to first
--      mutation), cutting the dominant residual cold-scan term.
--
--   4. Vector arithmetic parity (parity gap #4) -- adds || concat
--      for turbovec.vector and turbovec.halfvec, and +/-/*
--      element-wise for turbovec.halfvec. These ARE new SQL
--      objects (operators + functions); cargo pgrx schema emits
--      their CREATE OPERATOR / CREATE FUNCTION into the
--      authoritative 1.8.0 install script. This reference mirror
--      does not duplicate them.
--
-- The on-disk relfile format is byte-identical to v1.6.x / v1.7.x
-- (MetaPageData::version = 3). The new SQL surface is purely
-- additive; the new GUCs default to pgvector-equivalent behaviour.
-- There is no on-disk migration. The upgrade path
-- `ALTER EXTENSION pg_turbovec UPDATE TO '1.8.0';` resolves cleanly;
-- the additive operators/functions are created by the generated
-- 1.7.3--1.8.0 upgrade script.
--
-- No REINDEX is needed -- existing indexes work unchanged.