| """Build sorted parquet index copies so DuckDB zone-map pruning makes lookups fast. |
| |
| Unsorted 104GB parquet forces a full scan (~90s) per query. A copy sorted by the |
| search key lets DuckDB skip all but the matching row groups (ms-level lookups). |
| |
| Creates (skips files that already exist -> resumable): |
| idx_phone.parquet - sorted by phoneNumber |
| idx_aadhar.parquet - sorted by aadharNumber |
| idx_name.parquet - sorted by name |
| """ |
| import duckdb |
| import os |
| import time |
|
|
| FILES = ["part1.parquet", "part2a.parquet", "part2b_new.parquet"] |
| FILES_SQL = ", ".join(f"'{f}'" for f in FILES) |
|
|
| def build(con, field: str, out: str): |
| if os.path.exists(out) and os.path.getsize(out) > 0: |
| print(f"{out} already exists, skipping", flush=True) |
| return |
| print(f"START {out} (sort by {field})", flush=True) |
| t = time.time() |
| con.execute(f""" |
| COPY (SELECT * FROM people ORDER BY {field} NULLS LAST) |
| TO '{out}' (FORMAT PARQUET, COMPRESSION ZSTD) |
| """) |
| print(f"DONE {out} in {time.time()-t:.1f}s", flush=True) |
|
|
| con = duckdb.connect() |
| con.execute("INSTALL parquet; LOAD parquet;") |
| con.execute("SET threads = 12") |
| con.execute("SET memory_limit = '27GB'") |
| con.execute(f"CREATE VIEW people AS SELECT * FROM read_parquet([{FILES_SQL}])") |
|
|
| build(con, "phoneNumber", "idx_phone.parquet") |
| build(con, "aadharNumber", "idx_aadhar.parquet") |
| build(con, "name", "idx_name.parquet") |
| print("ALL DONE", flush=True) |
|
|
