⚡️ Speed up method _LegacyExperimentService._execution_to_column_named_metadata by 20%

[codeflash-ai]

📄 20% (0.20x) speedup for _LegacyExperimentService._execution_to_column_named_metadata in google/cloud/aiplatform/metadata/metadata.py

⏱️ Runtime : 1.17 milliseconds → 976 microseconds (best of 203 runs)

📝 Explanation and details

The optimization replaces the expensive ".".join([metadata_type, key]) string operation with simple string concatenation using the + operator.

Key changes:

• Pre-computes metadata_type_dot = metadata_type + '.' once outside the loop instead of creating a list and joining it for every key
• Uses direct concatenation metadata_type_dot + key instead of ".".join([metadata_type, key])

Why this is faster:

• str.join() has overhead for creating a temporary list [metadata_type, key] and then iterating through it to build the final string
• Simple string concatenation with + is a more direct operation that avoids the list creation and iteration overhead
• Pre-computing the dot-appended metadata type eliminates redundant string operations in the loop

Performance gains:
The optimization shows consistent 6-30% speedups across test cases, with the largest gains (17-30%) appearing in scenarios with many keys where the loop runs frequently. The line profiler shows the critical line (string concatenation) improved from 36.8% to 32.3% of total runtime, with overall function time reduced by ~10%. Small metadata collections (empty dicts) show slight regressions due to the overhead of pre-computing the string, but all meaningful workloads benefit significantly.

✅ Correctness verification report:

Test	Status
⚙️ Existing Unit Tests	🔘 None Found
🌀 Generated Regression Tests	✅ 57 Passed
⏪ Replay Tests	🔘 None Found
🔎 Concolic Coverage Tests	🔘 None Found
📊 Tests Coverage	100.0%

🌀 Generated Regression Tests and Runtime

from typing import Dict, Optional, Union

# imports
import pytest  # used for our unit tests
from aiplatform.metadata.metadata import _LegacyExperimentService

# unit tests

# Basic Test Cases

def test_basic_single_key():
    # Single key-value pair, no filter
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"alpha": 0.1}
    ); result = codeflash_output # 1.02μs -> 963ns (6.13% faster)

def test_basic_multiple_keys():
    # Multiple key-value pairs, no filter
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "metric", {"accuracy": 0.95, "loss": 0.05}
    ); result = codeflash_output # 1.11μs -> 1.06μs (4.51% faster)

def test_basic_with_filter_prefix():
    # Keys with filter prefix, should remove prefix
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"input:alpha": 1, "input:beta": 2}, filter_prefix="input:"
    ); result = codeflash_output # 2.04μs -> 1.95μs (5.09% faster)

def test_basic_with_partial_prefix():
    # Only keys starting with prefix should be filtered
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"input:alpha": 1, "gamma": 2}, filter_prefix="input:"
    ); result = codeflash_output # 1.89μs -> 1.75μs (8.05% faster)

def test_basic_empty_metadata():
    # Empty metadata dict should return empty dict
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "metric", {}, filter_prefix="input:"
    ); result = codeflash_output # 734ns -> 866ns (15.2% slower)

def test_basic_different_types():
    # Values can be int, float, str
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"a": 1, "b": 2.5, "c": "hello"}
    ); result = codeflash_output # 1.24μs -> 1.16μs (7.45% faster)

# Edge Test Cases

def test_edge_prefix_not_present():
    # Prefix provided but no keys start with it
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"alpha": 1, "beta": 2}, filter_prefix="input:"
    ); result = codeflash_output # 1.49μs -> 1.43μs (3.77% faster)

def test_edge_prefix_is_empty_string():
    # Empty string as prefix, should not filter anything
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"input:alpha": 1, "beta": 2}, filter_prefix=""
    ); result = codeflash_output # 1.33μs -> 1.20μs (11.0% faster)

def test_edge_key_is_only_prefix():
    # Key is exactly the prefix, should become empty string
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"input:": 42}, filter_prefix="input:"
    ); result = codeflash_output # 1.57μs -> 1.49μs (5.59% faster)

def test_edge_key_is_prefix_and_more():
    # Key is prefix plus more, should remove only the prefix
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"input:alpha": 10, "input:": 20}, filter_prefix="input:"
    ); result = codeflash_output # 1.95μs -> 1.76μs (10.2% faster)

def test_edge_key_is_empty():
    # Key is empty string
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"": "empty"}
    ); result = codeflash_output # 949ns -> 884ns (7.35% faster)

def test_edge_metadata_type_empty():
    # Metadata type is empty string
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "", {"alpha": 1, "beta": 2}
    ); result = codeflash_output # 1.11μs -> 974ns (14.1% faster)

def test_edge_metadata_type_special_chars():
    # Metadata type contains special characters
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "type$", {"alpha": 1}
    ); result = codeflash_output # 920ns -> 884ns (4.07% faster)

def test_edge_key_special_chars():
    # Keys contain special characters
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"a.b": 1, "c-d": 2}
    ); result = codeflash_output # 1.14μs -> 1.05μs (8.48% faster)

def test_edge_key_with_dot():
    # Key contains dot, should not split
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"input.alpha": 7}, filter_prefix="input."
    ); result = codeflash_output # 1.73μs -> 1.61μs (7.25% faster)

def test_edge_key_with_multiple_prefixes():
    # Key contains multiple prefixes, only first occurrence is removed
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"input:input:alpha": 5}, filter_prefix="input:"
    ); result = codeflash_output # 1.56μs -> 1.44μs (8.36% faster)

def test_edge_value_is_none():
    # Value is None, should be preserved
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"alpha": None}
    ); result = codeflash_output # 953ns -> 931ns (2.36% faster)

def test_edge_value_is_bool():
    # Value is boolean
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"alpha": True, "beta": False}
    ); result = codeflash_output # 1.14μs -> 1.04μs (9.00% faster)

def test_edge_value_is_list_or_dict():
    # Value is list or dict (should be preserved as is)
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"alpha": [1,2,3], "beta": {"x": 1}}
    ); result = codeflash_output # 1.08μs -> 1.03μs (4.46% faster)

def test_edge_filter_prefix_is_none():
    # filter_prefix is None, should not filter anything
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"input:alpha": 1, "beta": 2}, filter_prefix=None
    ); result = codeflash_output # 1.39μs -> 1.26μs (10.5% faster)

def test_edge_metadata_is_not_dict():
    # Metadata is not a dict, should raise AttributeError
    with pytest.raises(AttributeError):
        _LegacyExperimentService._execution_to_column_named_metadata(
            "param", ["alpha", "beta"], filter_prefix="input:"
        ) # 1.45μs -> 1.48μs (2.56% slower)


def test_edge_metadata_type_is_none():
    # metadata_type is None, should raise TypeError in join
    with pytest.raises(TypeError):
        _LegacyExperimentService._execution_to_column_named_metadata(
            None, {"alpha": 1}
        ) # 3.01μs -> 1.54μs (95.5% faster)


def test_large_many_keys():
    # Large number of keys, check performance and correctness
    metadata = {f"input:key_{i}": i for i in range(1000)}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix="input:"
    ); result = codeflash_output # 191μs -> 163μs (17.4% faster)

def test_large_no_filter_prefix():
    # Large number of keys, no filtering
    metadata = {f"key_{i}": i for i in range(1000)}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "metric", metadata
    ); result = codeflash_output # 94.9μs -> 73.5μs (29.1% faster)

def test_large_mixed_prefix():
    # Large number of keys, some with prefix, some without
    metadata = {}
    for i in range(500):
        metadata[f"input:key_{i}"] = i
    for i in range(500, 1000):
        metadata[f"key_{i}"] = i
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix="input:"
    ); result = codeflash_output # 161μs -> 133μs (20.7% faster)
    expected = {f"param.key_{i}": i for i in range(1000)}

def test_large_long_keys_and_values():
    # Large keys and string values
    metadata = {f"input:{'x'*50}_{i}": "y"*100 for i in range(100)}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix="input:"
    ); result = codeflash_output # 23.4μs -> 20.0μs (17.4% faster)
    expected = {f"param.{('x'*50)}_{i}": "y"*100 for i in range(100)}

def test_large_all_keys_are_prefix():
    # All keys are exactly the prefix
    metadata = {"input:": i for i in range(100)}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix="input:"
    ); result = codeflash_output # 1.62μs -> 1.52μs (6.99% faster)
    expected = {"param.": i for i in range(100)}

def test_large_all_keys_empty():
    # All keys are empty string
    metadata = {"": i for i in range(100)}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata
    ); result = codeflash_output # 972ns -> 919ns (5.77% faster)
    expected = {"param.": i for i in range(100)}

def test_large_values_are_large_lists():
    # Values are large lists
    metadata = {f"input:key_{i}": list(range(100)) for i in range(10)}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix="input:"
    ); result = codeflash_output # 3.76μs -> 3.33μs (12.8% faster)
    expected = {f"param.key_{i}": list(range(100)) for i in range(10)}

def test_large_keys_with_special_chars():
    # Large number of keys with special characters
    metadata = {f"input:key_{i}@!": i for i in range(100)}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix="input:"
    ); result = codeflash_output # 22.7μs -> 19.4μs (17.0% faster)
    expected = {f"param.key_{i}@!": i for i in range(100)}
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.
#------------------------------------------------
from typing import Dict, Optional, Union

# imports
import pytest  # used for our unit tests
from aiplatform.metadata.metadata import _LegacyExperimentService

# unit tests

# Basic Test Cases

def test_basic_single_entry_no_prefix():
    # Single key-value, no prefix filtering
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"foo": 42}
    ); result = codeflash_output # 950ns -> 951ns (0.105% slower)

def test_basic_multiple_entries_no_prefix():
    # Multiple key-value pairs, no prefix filtering
    metadata = {"foo": 1, "bar": "baz", "qux": 3.14}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "metric", metadata
    ); result = codeflash_output # 1.27μs -> 1.19μs (7.32% faster)

def test_basic_with_prefix_removal():
    # Keys with prefix, should be removed
    metadata = {"input:foo": 123, "input:bar": 456}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix="input:"
    ); result = codeflash_output # 1.97μs -> 1.81μs (8.82% faster)

def test_basic_with_partial_prefix_removal():
    # Only keys that start with prefix should be changed
    metadata = {"input:foo": 1, "bar": 2}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix="input:"
    ); result = codeflash_output # 1.84μs -> 1.77μs (4.06% faster)

def test_basic_empty_metadata():
    # Empty dict should return empty dict
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {}
    ); result = codeflash_output # 572ns -> 690ns (17.1% slower)

def test_basic_empty_prefix_string():
    # Empty prefix string should not remove anything
    metadata = {"foo": 1, "bar": 2}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix=""
    ); result = codeflash_output # 1.29μs -> 1.22μs (6.26% faster)

def test_basic_non_string_values():
    # Test with various value types
    metadata = {"foo": 0, "bar": 1.1, "baz": "test"}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata
    ); result = codeflash_output # 1.22μs -> 1.12μs (8.18% faster)

# Edge Test Cases

def test_edge_prefix_longer_than_key():
    # Prefix longer than key, should not match and not remove
    metadata = {"f": 1}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix="foobar"
    ); result = codeflash_output # 1.26μs -> 1.24μs (1.29% faster)

def test_edge_prefix_matches_entire_key():
    # Prefix is exactly the key, should remove all and leave empty key
    metadata = {"foo": 5, "bar": 6}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {"foo": 5}, filter_prefix="foo"
    ); result = codeflash_output # 1.62μs -> 1.52μs (6.86% faster)

def test_edge_prefix_is_none():
    # Prefix is None, should not remove anything
    metadata = {"input:foo": 1}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix=None
    ); result = codeflash_output # 1.12μs -> 1.06μs (5.83% faster)

def test_edge_key_with_multiple_prefixes():
    # Key contains prefix multiple times, only leading prefix is removed
    metadata = {"input:input:foo": 99}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix="input:"
    ); result = codeflash_output # 1.62μs -> 1.58μs (2.54% faster)

def test_edge_metadata_type_empty_string():
    # Empty metadata_type should result in keys starting with "."
    metadata = {"foo": 1}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "", metadata
    ); result = codeflash_output # 983ns -> 881ns (11.6% faster)

def test_edge_key_is_empty_string():
    # Key is empty string
    metadata = {"": 123}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata
    ); result = codeflash_output # 958ns -> 891ns (7.52% faster)

def test_edge_value_is_none():
    # Value is None, should be preserved
    metadata = {"foo": None}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata
    ); result = codeflash_output # 977ns -> 886ns (10.3% faster)

def test_edge_non_ascii_characters():
    # Key and value contain non-ASCII characters
    metadata = {"输入:测试": "值"}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix="输入:"
    ); result = codeflash_output # 2.28μs -> 2.16μs (5.65% faster)

def test_edge_key_with_dot_in_name():
    # Key contains a dot, should not be split
    metadata = {"foo.bar": 77}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata
    ); result = codeflash_output # 959ns -> 919ns (4.35% faster)

def test_edge_value_is_bool():
    # Value is boolean
    metadata = {"foo": True, "bar": False}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata
    ); result = codeflash_output # 1.08μs -> 1.05μs (2.66% faster)

def test_edge_value_is_list_or_dict():
    # Value is a list or dict (should be preserved as is)
    metadata = {"foo": [1, 2], "bar": {"baz": 3}}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata
    ); result = codeflash_output # 1.07μs -> 1.05μs (1.91% faster)

def test_edge_prefix_is_empty_and_key_is_prefix():
    # Prefix is empty and key is empty, should result in "param."
    metadata = {"": 111}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix=""
    ); result = codeflash_output # 1.12μs -> 1.06μs (6.23% faster)

# Large Scale Test Cases

def test_large_scale_many_keys_no_prefix():
    # Large number of keys, no prefix
    metadata = {f"key{i}": i for i in range(1000)}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata
    ); result = codeflash_output # 94.6μs -> 72.7μs (30.1% faster)
    # All keys should be present and correctly mapped
    for i in range(1000):
        pass

def test_large_scale_many_keys_with_prefix():
    # Large number of keys with prefix
    metadata = {f"input:key{i}": i for i in range(1000)}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix="input:"
    ); result = codeflash_output # 190μs -> 160μs (18.2% faster)
    for i in range(1000):
        pass

def test_large_scale_mixed_keys_with_and_without_prefix():
    # Mix of keys with and without prefix
    metadata = {f"input:key{i}": i for i in range(500)}
    metadata.update({f"key{i}": i for i in range(500, 1000)})
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix="input:"
    ); result = codeflash_output # 160μs -> 133μs (20.4% faster)
    for i in range(500):
        pass
    for i in range(500, 1000):
        pass

def test_large_scale_empty_metadata():
    # Empty metadata at large scale (should still be empty)
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", {}
    ); result = codeflash_output # 576ns -> 702ns (17.9% slower)

def test_large_scale_long_prefix():
    # Prefix is long, only matching keys should be changed
    prefix = "verylongprefix:"
    metadata = {f"{prefix}key{i}": i for i in range(500)}
    metadata.update({f"otherkey{i}": i for i in range(500, 1000)})
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix=prefix
    ); result = codeflash_output # 162μs -> 137μs (18.0% faster)
    for i in range(500):
        pass
    for i in range(500, 1000):
        pass

def test_large_scale_all_keys_are_prefix():
    # All keys are exactly the prefix
    prefix = "foo"
    metadata = {"foo": i for i in range(1000)}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata, filter_prefix=prefix
    ); result = codeflash_output # 1.65μs -> 1.58μs (4.63% faster)

def test_large_scale_different_metadata_types():
    # Test with different metadata_type values
    metadata = {f"key{i}": i for i in range(10)}
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "param", metadata
    ); result_param = codeflash_output # 2.05μs -> 1.88μs (8.93% faster)
    codeflash_output = _LegacyExperimentService._execution_to_column_named_metadata(
        "metric", metadata
    ); result_metric = codeflash_output # 1.47μs -> 1.35μs (8.90% faster)
    # Keys should be different
    for i in range(10):
        pass
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.

To edit these changes git checkout codeflash/optimize-_LegacyExperimentService._execution_to_column_named_metadata-mglgx3jd and push.