Potential Inefficiency in Connection Management Leading to "Too Many Connections" Error

[AbdullahSaquib]

In a highly refactored codebase using the Database class from databases/core.py, I've encountered a "too many connections" error. While investigating, I found comment on Stack Overflow suggesting that the library's connection management might be inefficient. Reviewing the code, I suspect the way connections are managed per task might be a contributing factor.

The current implementation uses a _connection_map keyed by asyncio.current_task(). This means each coroutine, including nested ones, gets its own connection. This can potentially result in a large number of connections being opened in complex applications.

To potentially address this, can we use contextvars to manage a single connection among parent and nested tasks. By storing the connection in a context variable, nested coroutines can reuse their parent task's connection, reducing the need to open multiple connections.