-- pg_trickle 0.62.0 -> 0.63.0 upgrade migration
--
-- v0.63.0 — Fused Multi-Node Refresh
--
-- Changes in this release:
--
--   PERF-2: CTE-fused multi-node refresh.
--     The scheduler can now compose the delta SQL for multiple stream-table
--     nodes in a single topological batch into one `WITH … MERGE` statement,
--     reducing per-node SPI round-trips and giving the PostgreSQL planner
--     visibility across the entire batch.
--
--     The feature is controlled by two new GUCs:
--
--       pg_trickle.enable_fused_refresh (bool, default on)
--         Enable CTE-fused multi-node refresh.  Set to off to revert to the
--         v0.62.0 sequential-per-node behaviour.
--
--       pg_trickle.fused_refresh_max_delta_rows (int, default 500000)
--         A node whose estimated pending-row count exceeds this threshold is
--         excluded from the fused batch and refreshed sequentially.  Set to 0
--         to disable the size gate (all DIFFERENTIAL nodes are always eligible).
--
--     No SQL schema changes are required; the fused path is purely an
--     execution-engine optimisation within the scheduler background workers.
--
-- No SQL schema changes in this release.
-- All v0.63.0 changes are in the Rust extension binary (GUCs + scheduler).