phoenixdb 0.4

Phoenix database adapter for Python

phoenixdb is a Python library for accessing the Phoenix SQL database using the remote query server introduced in Phoenix 4.4. The library implements the standard DB API 2.0 interface, which should be familiar to most Python programmers.

Installation

The easiest way to install the library is using pip:

pip install phoenixdb

You can also download the source code from Bitbucket, extract the archive and then install it manually:

cd /path/to/python-phoenix-x.y.z/
python setup.py install

Usage

The library implements the standard DB API 2.0 interface, so it can be used the same way you would use any other SQL database from Python, for example:

import phoenixdb

database_url = 'http://localhost:8765/'
conn = phoenixdb.connect(database_url, autocommit=True)

cursor = conn.cursor()
cursor.execute("CREATE TABLE users (id INTEGER PRIMARY KEY, username VARCHAR)")
cursor.execute("UPSERT INTO users VALUES (?, ?)", (1, 'admin'))
cursor.execute("SELECT * FROM users")
print cursor.fetchall()

Phoenix versions

Multiple Phoenix versions are supported, but because there is no way in the protocol to determine the version at runtime, you need to provide the version of Avatica used in the Phoenix version that you are using. Below is a table of the correct versions for the official Phoenix releases.

Phoenix version	Avatica version	Connection URL
4.4	1.2	http://localhost:8765/?v=1.2
4.5	1.3	http://localhost:8765/?v=1.3
4.6	1.3	http://localhost:8765/?v=1.3
4.7	1.6	http://localhost:8765/?v=1.6

Phoenix 4.7 uses a serialization based on Protocol Buffers (proto3) by default. This version of Protocol Buffers does not even have a stable release and is not generally available on Linux distributions.

This library only supports the older JSON serialization. In order for the library to work with Phoenix 4.7, you need to start the query server like this:

./bin/queryserver.py start -Dphoenix.queryserver.serialization=JSON

Setting up a development environment

If you want to quickly try out the included examples, you can set up a local virtualenv with all the necessary requirements:

virtualenv e
source e/bin/activate
pip install -r requirements.txt
python setup.py develop

If you need a Phoenix server for experimenting, you can get one running quickly using Vagrant:

vagrant up

You can connect to the virtual machine and work with the Phoenix shell from there:

vagrant ssh
/opt/phoenix/bin/sqlline.py localhost

Interactive SQL shell

There is a Python-based interactive shell include in the examples folder, which can be used to connect to Phoenix and execute queries:

./examples/shell.py http://localhost:8765/
db=> CREATE TABLE test (id INTEGER PRIMARY KEY, name VARCHAR);
no rows affected (1.363 seconds)
db=> UPSERT INTO test (id, name) VALUES (1, 'Lukas');
1 row affected (0.004 seconds)
db=> SELECT * FROM test;
+------+-------+
|   ID | NAME  |
+======+=======+
|    1 | Lukas |
+------+-------+
1 row selected (0.019 seconds)

Running the test suite

The library comes with a test suite for testing Python DB API 2.0 compliance and various Phoenix-specific features. In order to run the test suite, you need a working Phoenix database and set the PHOENIXDB_TEST_DB_URL environment variable:

export PHOENIXDB_TEST_DB_URL='http://localhost:8765/'
nosetests

Known issues

• In general, the library has not been battle-tested yet. You might encounter almost any problem. Use with care.

• You can only use the library in autocommit mode. The native Java Phoenix library also implements batched upserts, which can be committed at once, but this is not exposed over the remote server. (CALCITE-767)

• TIME and DATE columns in Phoenix are stored as full timestamps with a millisecond accuracy, but the remote protocol only exposes the time (hour/minute/second) or date (year/month/day) parts of the columns. (CALCITE-797, CALCITE-798)

• TIMESTAMP columns in Phoenix are stored with a nanosecond accuracy, but the remote protocol truncates them to milliseconds. (CALCITE-796)

• ARRAY columns are not supported. (CALCITE-1050, PHOENIX-2585)