pg_any_where patches Arel so that `where(column: array)` emits `column = ANY($1::type[])` instead of `column IN ($1, $2, …)`. This yields a stable prepared-statement shape (one bind parameter regardless of array size), better PostgreSQL plan cache utilisation, and cleaner pg_stat_statements output. Empty arrays are handled correctly without the `1=0` / `1=1` footguns.