v1.8.4 — CDX INDEX ON speedups (single-pass + OEM upper)

1.8.4 — 2026-07-09

CDX — further INDEX ON speedups (#128)

• Single-pass batching for sibling tag rebuilds using the new
  Table::collect_keys_for_multiple_expressions prototype. When multiple
  tags in a bag need a full rebuild (common after ORDLSTCLEAR + repeated
  INDEX ON), we now do one DBF scan instead of N.
• Fast paths + OEM upper-casing for UPPER(barefield) and similar common
  expressions (skips per-row Parser + UTF-8 work; uses proper CP-852
  upper table for NTXPL852/PL852 data).
• Added oem_upper / lookup_oem_upper_table support in oem_collation.
• More unit test coverage: wide tables (100+ cols), composite expressions,
  additional FOR clauses, deleted records during AdsCreateIndex61.
• CI now builds and runs dbf_cdx_bench as a multi-tag smoke on every job.
• Enhanced dbf_cdx_bench to time realistic 4-tag INDEX ON sequences.

These changes attack the remaining per-row expression cost and multi-tag
scan cost after the initial read-ahead fix.

1.8.3 — 2026-07-09

CDX — INDEX ON / REINDEX performance for local rddads (#128)

Significant speedup for local DBFCDX index creation when using Harbour
contrib/rddads (ADSCDX) or direct AdsCreateIndex* calls.

Root cause: Key collection for the bulk B+tree builder did
goto_record(r) for every record. This unconditionally called
invalidate_read_cache() on the CdxDriver and performed active index
cursor repositioning, defeating the 64 KB read-ahead block cache.

Fix:

• New internal helper Table::load_record_for_bulk_scan().
• Changed the full-table scan loops in:

Full Changelog: v1.8.3...v1.8.4