⚡️ Speed up function trigger_vector_segments_max_seq_id_migration by 6%

[codeflash-ai]

📄 6% (0.06x) speedup for trigger_vector_segments_max_seq_id_migration in chromadb/ingest/impl/utils.py

⏱️ Runtime : 1.70 milliseconds → 1.61 milliseconds (best of 5 runs)

📝 Explanation and details

The optimized code achieves a 5% speedup through three key Python micro-optimizations that reduce overhead in the performance-critical loop:

Key optimizations:

1. Pre-converted UUID list: Instead of calling UUID(collection_id) inside the loop 2000+ times, UUIDs are batch-converted upfront with uuid_list = [UUID(cid) for cid in collection_ids_with_unmigrated_segments]. This eliminates repeated UUID constructor calls during iteration.

2. Hoisted attribute lookups: VectorReader and segment_manager.get_segment are stored in local variables before the loop. This avoids Python's attribute resolution overhead on each iteration - the profiler shows over 2000 hits on the loop line.

3. Faster empty check: Changed len(collection_ids_with_unmigrated_segments) == 0 to if not collection_ids_with_unmigrated_segments, which is more idiomatic and slightly faster for empty list detection.

Why this works:
The line profiler shows 97% of time is spent in segment_manager.get_segment() calls, but even small per-iteration savings (avoiding attribute lookups and UUID conversions) compound across 2000+ iterations. Local variable access is faster than attribute resolution in Python's execution model.

Test case performance:
The optimization performs best on large-scale scenarios like test_large_number_of_unmigrated_segments_with_duplicates (5.25% faster with 1000 segments), while smaller cases show mixed results due to the overhead of the upfront UUID conversion becoming proportionally larger.

✅ Correctness verification report:

Test	Status
⚙️ Existing Unit Tests	🔘 None Found
🌀 Generated Regression Tests	✅ 12 Passed
⏪ Replay Tests	🔘 None Found
🔎 Concolic Coverage Tests	🔘 None Found
📊 Tests Coverage	100.0%

🌀 Generated Regression Tests and Runtime

from uuid import UUID, uuid4

# imports
import pytest
from chromadb.ingest.impl.utils import \
    trigger_vector_segments_max_seq_id_migration

# --- Mocks and minimal stubs for dependencies ---

# Minimal stub for System (not used in logic, just for constructor compatibility)
class System:
    pass

# Minimal stub for VectorReader (not used directly)
class VectorReader:
    pass

# Minimal stub for SegmentManager
class SegmentManager:
    def __init__(self):
        self.loaded_segments = []
    def get_segment(self, collection_id, reader_type):
        # Record the call for test verification
        self.loaded_segments.append((collection_id, reader_type))
from chromadb.ingest.impl.utils import \
    trigger_vector_segments_max_seq_id_migration

# --- Helper classes for mocking cursor behavior ---

class MockCursor:
    """
    Mocks a DBAPI2 Cursor for use in tests.
    You can set .fetchall() return value and record .execute() calls.
    """
    def __init__(self, fetchall_return=None):
        self._fetchall_return = fetchall_return or []
        self.executed = []
        self.closed = False
    def execute(self, sql, params=None):
        self.executed.append((sql, params))
        return self
    def fetchall(self):
        return self._fetchall_return
    def close(self):
        self.closed = True

# --- Unit tests ---

# ========== BASIC TEST CASES ==========













#------------------------------------------------
from uuid import UUID, uuid4

# imports
import pytest
from chromadb.ingest.impl.utils import \
    trigger_vector_segments_max_seq_id_migration

# --- Mocks for dependencies ---

# Mock Cursor implementing the required interface
class MockCursor:
    def __init__(self, rows=None):
        self._sql = None
        self._params = None
        self._rows = rows if rows is not None else []
        self._executed = []
        self.closed = False

    def execute(self, sql, params=None):
        self._sql = sql
        self._params = params
        self._executed.append((sql, params))
        return self

    def fetchall(self):
        return self._rows

    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        self.closed = True

# Mock SqlDB with context manager for tx()
class MockSqlDB:
    def __init__(self, cursor_rows=None):
        self.cursor = MockCursor(cursor_rows)
        self.tx_called = 0

    def tx(self):
        self.tx_called += 1
        return self.cursor

# Mock SegmentManager with tracking of get_segment calls
class MockSegmentManager:
    def __init__(self):
        self.get_segment_calls = []

    def get_segment(self, collection_uuid, reader_type):
        self.get_segment_calls.append((collection_uuid, reader_type))
        # Simulate migration by doing nothing

# Dummy VectorReader class
class VectorReader:
    pass
from chromadb.ingest.impl.utils import \
    trigger_vector_segments_max_seq_id_migration

# --- Unit Tests ---

# 1. Basic Test Cases

def test_no_unmigrated_segments():
    """Test when there are no unmigrated segments (should be a no-op)."""
    db = MockSqlDB(cursor_rows=[])  # fetchall returns empty list
    segment_manager = MockSegmentManager()
    trigger_vector_segments_max_seq_id_migration(db, segment_manager) # 4.05μs -> 3.54μs (14.5% faster)

def test_one_unmigrated_segment():
    """Test when there is a single unmigrated segment."""
    unmigrated_id = str(uuid4())
    db = MockSqlDB(cursor_rows=[(unmigrated_id,)])
    segment_manager = MockSegmentManager()
    trigger_vector_segments_max_seq_id_migration(db, segment_manager) # 6.90μs -> 7.27μs (5.16% slower)
    call_uuid, call_type = segment_manager.get_segment_calls[0]

def test_multiple_unmigrated_segments():
    """Test with several unmigrated segments."""
    ids = [str(uuid4()) for _ in range(5)]
    db = MockSqlDB(cursor_rows=[(i,) for i in ids])
    segment_manager = MockSegmentManager()
    trigger_vector_segments_max_seq_id_migration(db, segment_manager) # 10.1μs -> 10.3μs (2.39% slower)

# 2. Edge Test Cases

def test_unmigrated_segment_id_is_not_uuid():
    """Test that non-UUID strings are handled (should raise ValueError)."""
    db = MockSqlDB(cursor_rows=[("not-a-uuid",)])
    segment_manager = MockSegmentManager()
    with pytest.raises(ValueError):
        trigger_vector_segments_max_seq_id_migration(db, segment_manager) # 5.25μs -> 5.87μs (10.4% slower)

def test_segment_manager_raises_exception():
    """Test that an exception in segment_manager.get_segment is propagated."""
    class FailingSegmentManager(MockSegmentManager):
        def get_segment(self, collection_uuid, reader_type):
            raise RuntimeError("Migration failed")
    db = MockSqlDB(cursor_rows=[(str(uuid4()),)])
    segment_manager = FailingSegmentManager()
    with pytest.raises(RuntimeError, match="Migration failed"):
        trigger_vector_segments_max_seq_id_migration(db, segment_manager) # 7.22μs -> 7.69μs (6.12% slower)

def test_cursor_returns_duplicate_ids():
    """Test that duplicate collection ids are handled (should call get_segment for each occurrence)."""
    dup_id = str(uuid4())
    db = MockSqlDB(cursor_rows=[(dup_id,), (dup_id,)])
    segment_manager = MockSegmentManager()
    trigger_vector_segments_max_seq_id_migration(db, segment_manager) # 7.50μs -> 7.89μs (5.00% slower)

def test_cursor_returns_none():
    """Test that None values in the cursor rows are handled (should raise TypeError)."""
    db = MockSqlDB(cursor_rows=[(None,)])
    segment_manager = MockSegmentManager()
    with pytest.raises(TypeError):
        trigger_vector_segments_max_seq_id_migration(db, segment_manager) # 4.37μs -> 4.64μs (5.82% slower)

def test_cursor_returns_empty_tuples():
    """Test that empty tuples in the cursor rows are handled (should raise IndexError)."""
    db = MockSqlDB(cursor_rows=[()])
    segment_manager = MockSegmentManager()
    with pytest.raises(IndexError):
        trigger_vector_segments_max_seq_id_migration(db, segment_manager) # 3.22μs -> 3.19μs (0.939% faster)

def test_cursor_returns_extra_columns():
    """Test that extra columns in the cursor row are ignored (only first is used)."""
    id1 = str(uuid4())
    db = MockSqlDB(cursor_rows=[(id1, "extra", 42)])
    segment_manager = MockSegmentManager()
    trigger_vector_segments_max_seq_id_migration(db, segment_manager) # 6.22μs -> 6.66μs (6.56% slower)

# 3. Large Scale Test Cases


def test_large_number_of_unmigrated_segments_with_duplicates():
    """Test with a large number of unmigrated segments, including duplicates."""
    base_ids = [str(uuid4()) for _ in range(500)]
    # Duplicate each id once
    ids = base_ids + base_ids
    db = MockSqlDB(cursor_rows=[(i,) for i in ids])
    segment_manager = MockSegmentManager()
    trigger_vector_segments_max_seq_id_migration(db, segment_manager) # 804μs -> 764μs (5.25% faster)

def test_performance_with_empty_list_large_scale():
    """Test performance when no unmigrated segments in large scale (should be a no-op)."""
    db = MockSqlDB(cursor_rows=[])
    segment_manager = MockSegmentManager()
    trigger_vector_segments_max_seq_id_migration(db, segment_manager) # 2.89μs -> 3.12μs (7.41% slower)
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.
#------------------------------------------------
from chromadb.ingest.impl.utils import trigger_vector_segments_max_seq_id_migration

To edit these changes git checkout codeflash/optimize-trigger_vector_segments_max_seq_id_migration-mh1t0915 and push.