zhuqi-lucas commented on code in PR #19042:
URL: https://github.com/apache/datafusion/pull/19042#discussion_r2581523202


##########
benchmarks/sort_clickbench.py:
##########
@@ -0,0 +1,253 @@
+#!/usr/bin/env python3
+
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+#!/usr/bin/env python3
+"""
+Sort ClickBench data by EventTime for reverse scan benchmark.
+Enhanced version with configurable row group size and optimization options.
+"""
+
+import sys
+import argparse
+from pathlib import Path
+
+try:
+    import pyarrow.parquet as pq
+    import pyarrow.compute as pc
+except ImportError:
+    print("Error: pyarrow is not installed.")
+    print("Please install it with: pip install pyarrow")
+    sys.exit(1)
+
+
+def sort_clickbench_data(
+        input_path: str,
+        output_path: str,
+        row_group_size: int = 1024 * 1024,  # 1M rows default
+        compression: str = 'snappy',
+        verify: bool = True
+):
+    """Sort parquet file by EventTime column with optimized settings."""
+
+    input_file = Path(input_path)
+    output_file = Path(output_path)
+
+    if not input_file.exists():
+        print(f"Error: Input file not found: {input_file}")
+        sys.exit(1)
+
+    if output_file.exists():
+        print(f"Sorted file already exists: {output_file}")
+        if verify:
+            verify_sorted_file(output_file)
+        return
+
+    try:
+        print(f"Reading {input_file.name}...")
+        table = pq.read_table(str(input_file))
+
+        print(f"Original table has {len(table):,} rows")
+        print("Sorting by EventTime...")
+
+        # Sort the table by EventTime
+        sorted_indices = pc.sort_indices(table, sort_keys=[("EventTime", 
"ascending")])
+        sorted_table = pc.take(table, sorted_indices)
+
+        print(f"Sorted table has {len(sorted_table):,} rows")
+
+        # Verify sort
+        event_times = sorted_table.column('EventTime').to_pylist()
+        if event_times and verify:
+            print(f"First EventTime: {event_times[0]}")
+            print(f"Last EventTime: {event_times[-1]}")
+            # Verify ascending order
+            is_sorted = all(event_times[i] <= event_times[i+1] for i in 
range(min(1000, len(event_times)-1)))
+            print(f"Sort verification (first 1000 rows): {'✓ PASS' if 
is_sorted else '✗ FAIL'}")
+
+        print(f"Writing sorted file to {output_file}...")
+        print(f"  Row group size: {row_group_size:,} rows")
+        print(f"  Compression: {compression}")
+
+        # Write sorted table with optimized settings
+        pq.write_table(
+            sorted_table,
+            str(output_file),
+            compression=compression,
+            use_dictionary=True,
+            write_statistics=True,
+            # Optimize row group size for better performance
+            row_group_size=row_group_size,
+            # Set data page size (1MB is good for most cases)
+            data_page_size=1024 * 1024,
+            # Use v2 data page format for better compression
+            use_deprecated_int96_timestamps=False,
+            coerce_timestamps='us',  # Use microsecond precision
+            # Batch size for writing
+            write_batch_size=min(row_group_size, 1024 * 64),
+            # Enable compression for all columns
+            compression_level=None,  # Use default compression level
+        )
+
+        # Report results
+        input_size_mb = input_file.stat().st_size / (1024**2)
+        output_size_mb = output_file.stat().st_size / (1024**2)
+
+        # Read metadata to verify row groups
+        parquet_file = pq.ParquetFile(str(output_file))
+        num_row_groups = parquet_file.num_row_groups
+
+        print(f"\n✓ Successfully created sorted file!")
+        print(f"  Input:  {input_size_mb:.1f} MB")
+        print(f"  Output: {output_size_mb:.1f} MB")
+        print(f"  Compression ratio: {input_size_mb/output_size_mb:.2f}x")
+        print(f"\nRow Group Statistics:")
+        print(f"  Total row groups: {num_row_groups}")
+        print(f"  Total rows: {len(sorted_table):,}")
+
+        # Show row group details
+        for i in range(min(3, num_row_groups)):
+            rg_metadata = parquet_file.metadata.row_group(i)
+            print(f"  Row group {i}: {rg_metadata.num_rows:,} rows, 
{rg_metadata.total_byte_size / 1024**2:.1f} MB")
+
+        if num_row_groups > 3:
+            print(f"  ... and {num_row_groups - 3} more row groups")
+
+        avg_rows_per_group = len(sorted_table) / num_row_groups if 
num_row_groups > 0 else 0
+        print(f"  Average rows per group: {avg_rows_per_group:,.0f}")
+
+    except Exception as e:
+        print(f"Error: {e}")
+        import traceback
+        traceback.print_exc()
+        sys.exit(1)
+
+
+def verify_sorted_file(file_path: Path):
+    """Verify that a parquet file is sorted by EventTime."""
+    try:
+        print(f"Verifying sorted file: {file_path}")
+        parquet_file = pq.ParquetFile(str(file_path))
+
+        num_row_groups = parquet_file.num_row_groups
+        file_size_mb = file_path.stat().st_size / (1024**2)
+
+        print(f"  File size: {file_size_mb:.1f} MB")
+        print(f"  Row groups: {num_row_groups}")
+
+        # Read first and last row group to verify sort
+        first_rg = parquet_file.read_row_group(0)
+        last_rg = parquet_file.read_row_group(num_row_groups - 1)
+
+        first_time = first_rg.column('EventTime')[0].as_py()
+        last_time = last_rg.column('EventTime')[-1].as_py()
+
+        print(f"  First EventTime: {first_time}")
+        print(f"  Last EventTime: {last_time}")
+        print(f"  Sorted: {'✓ YES' if first_time <= last_time else '✗ NO'}")
+
+    except Exception as e:
+        print(f"Error during verification: {e}")
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description='Sort ClickBench parquet file by EventTime',
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+        epilog="""
+Examples:
+  # Basic usage (1M rows per group)

Review Comment:
   Yes.



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