FEAT: C++ support for pooling

[gargsaumya]

This pull request introduces connection pooling to improve database connection management in the mssql_python project. Key changes include the addition of a ConnectionPool class, updates to the Connection class to support pooling, and modifications to the Python bindings to expose pooling functionality.

Connection Pooling Implementation:

• New ConnectionPool and ConnectionPoolManager classes: Added ConnectionPool for managing reusable database connections and ConnectionPoolManager as a singleton to manage multiple pools. These classes handle connection acquisition, release, and idle timeout logic. (mssql_python/pybind/connection/connection_pool.cpp - [1] mssql_python/pybind/connection/connection_pool.h - [2]

Updates to Connection Class:

• Support for connection pooling: Refactored Connection class to include attributes and methods for pooling, such as _lastUsed, isAlive(), and reset(). Added ConnectionHandle as a wrapper for pooled connections. (mssql_python/pybind/connection/connection.cpp - [1] [2] [3] [4] [5] mssql_python/pybind/connection/connection.h - [6] [7]

Python Bindings:

• Exposed pooling functionality: Updated Python bindings to replace the Connection class with ConnectionHandle and added a global enable_pooling function for configuring pooling parameters. (mssql_python/pybind/ddbc_bindings.cpp - [1] [2]

Build System:

• Updated build configuration: Modified CMakeLists.txt to include the new connection_pool.cpp file in the build process. (mssql_python/pybind/CMakeLists.txt - mssql_python/pybind/CMakeLists.txtL93-R93)

Header File Updates:

• Included new headers: Added connection_pool.h to relevant files for access to pooling functionality. (mssql_python/pybind/connection/connection.cpp - [1] mssql_python/pybind/ddbc_bindings.cpp - [2]

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Checklist

• Tests Passed (if applicable)

[Copilot]

Pull Request Overview

Refactors database connection and cursor management by replacing low-level ODBC handle code with a high-level ddbc_bindings.Connection, introduces a connection pool, and streamlines transaction logic.

• Switches to ddbc_bindings.Connection and ConnectionPoolManager to manage connections and pooling.
• Removes legacy ODBC wrapper functions and simplifies cursor and transaction methods.
• Updates build configuration and tests to align with the new abstraction.

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tests/test_005_exceptions.py	Adjust expected exception type and message
mssql_python/pybind/ddbc_bindings.h/.cpp	Added pybind11 includes, cleaned up wrappers, and implemented SqlHandle destructor
mssql_python/pybind/connection/connection_pool.h/.cpp	Added ConnectionPool and ConnectionPoolManager
mssql_python/pybind/connection/connection.h/.cpp	Updated Connection and ConnectionHandle to support pooling and attribute logic
mssql_python/pybind/CMakeLists.txt	Included connection_pool.cpp in the build
mssql_python/cursor.py	Simplified statement handle allocation and removal of closed-check
mssql_python/connection.py	Replaced manual handle management with ddbc_bindings.Connection

Comments suppressed due to low confidence (2)

tests/test_005_exceptions.py:128

• [nitpick] Matching the full error message is brittle. Consider asserting substring or using a regex to validate key parts (e.g. "keyword supplied").

with pytest.raises(RuntimeError) as excinfo:

mssql_python/cursor.py:425

• _reset_cursor frees hstmt but does not reallocate a new statement handle. Consider calling self._initialize_cursor() after free() to restore hstmt.

self.hstmt.free()

[sumitmsft]

I have a few comments. Some of them can be put into backlog for future improvements. A couple of them can be thought to get fixed right away.