sha,message,author_date,committer_date,raw_author,raw_committer,repo,author,committer
31b21f5c5e15fc3acab7fabb170c1da71dc3c98c,"Moved all SQLite queries to threads

SQLite operations are blocking, but we're running everything in Sanic, an
asyncio web framework, so blocking operations are bad - a long-running DB
operation could hold up the entire server.

Instead, I've moved all SQLite operations into threads. These are managed by a
concurrent.futures ThreadPoolExecutor. This means I can run up to X queries in
parallel, and I can continue to queue up additional incoming HTTP traffic
while the threadpool is busy.

Each thread is responsible for managing its own SQLite connections - one per
database. These are cached in a threadlocal.

Since we are working with immutable, read-only SQLite databases it should be
safe to share SQLite objects across threads. On this assumption I'm using the
check_same_thread=False option. Opening a database connection looks like this:

    conn = sqlite3.connect(
        'file:filename.db?immutable=1',
        uri=True,
        check_same_thread=False,
    )

The following articles were helpful in figuring this out:

* https://pymotw.com/3/asyncio/executors.html
* https://marlinux.wordpress.com/2017/05/19/python-3-6-asyncio-sqlalchemy/

Closes #45. Refs #38.",2017-11-05T02:21:44Z,2017-11-05T02:21:44Z,2946d096d0cdefdc017559e6b57e87658736e843,2946d096d0cdefdc017559e6b57e87658736e843,107914493,9599,9599