Dmitry Ivanov 257ade0688 Extract PostgreSQL connection logic into PgProtocol ...

This patch aims to:

* Unify connection & querying logic of ZenithPagerserver and Postgres.
* Mitigate changes to transaction machinery introduced in `psycopg2 >= 2.9`.

Now it's possible to acquire db connection using the corresponding
method:

```python
pg = postgres.create_start('main')
conn = pg.connect()
...
conn.close()
```

This pattern can be further improved with the help of `closing`:

```python
from contextlib import closing

pg = postgres.create_start('main')

with closing(pg.connect()) as conn:
    ...
```

All connections produced by this method will have autocommit
enabled by default.

2021-06-17 20:19:04 +03:00

..

test_isolation.py

Extract PostgreSQL connection logic into PgProtocol

2021-06-17 20:19:04 +03:00

test_pg_regress.py

Extract PostgreSQL connection logic into PgProtocol

2021-06-17 20:19:04 +03:00

test_zenith_regress.py

Extract PostgreSQL connection logic into PgProtocol

2021-06-17 20:19:04 +03:00