Changelog

Unreleased

Added

• Streaming Parquet ingest (stratum.parquet/index-parquet!): reads a Parquet file row-group-by-row-group into chunked PersistentColumnIndex columns, syncing periodically to konserve so the chunk heap is reclaimable. Memory bounded by chunk-size × num-cols × 8 B during reading, independent of file size. Wired into stratum.files/index-file-into-store! so the --index and SQL read_parquet+--index paths use it automatically.

Changed

• stratum.parquet/from-parquet (heap path) rewritten on top of pre-allocated primitive arrays + dict-encoded strings at ingest. No more ArrayList<Object> boxing or per-row String materialization. Same public API; ~5× lower peak heap on column-heavy files.

Fixed

• Parquet OOM on large files: a 50M-row × 23-column file with two low-cardinality string columns previously needed ~43 GB just for the boxed-Long/Double/String intermediate state and OOM'd. After the changes above, the streaming path needs ~tens of MB during ingest and the heap path needs ~9 GB.
• All-NULL int64 chunk encoding: chunk/chunk-to-bytes cast Double/MAX_VALUE (compute-stats's "no values seen" sentinel) to long, throwing Value out of range for chunks where every row is NULL. Now guarded by null-count and encoded as constant-NULL (8 bytes).
• Self-joins and overlapping column names: JOINs between tables sharing column names (including self-joins) now produce correct results. The SQL layer rewrites qualified column references to unique internal keys, preventing right-side columns from silently overwriting left-side columns.
• Window frame dispatch: ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING now correctly routes to the sliding window path instead of falling through to the default running sum.
• CORR scalar aggregate: SELECT CORR(x, y) FROM t without GROUP BY no longer crashes.
• COALESCE with NULL literals: COALESCE(NULL, 1) and N-ary COALESCE(NULL, NULL, 42) now work correctly. Multi-argument COALESCE is nested into binary pairs.
• NOT IN with NULL: WHERE x NOT IN (1, NULL) now correctly returns no rows per SQL three-valued logic.

v0.1.0

Initial public release.