Python Flight SQL DBAPI client
The Python flightsql-dbapi Flight SQL DBAPI library integrates with Python applications using SQL to query data stored in an InfluxDB 3 Core database. The flightsql-dbapi library uses the Flight SQL protocol to query and retrieve data.
Use InfluxDB 3 client libraries
We recommend using the influxdb3-python Python client library for integrating InfluxDB 3 with your Python application code.
InfluxDB 3 client libraries wrap Apache Arrow Flight clients and provide convenient methods for writing, querying, and processing data stored in InfluxDB 3 Core. Client libraries can query using SQL or InfluxQL.
Installation
The flightsql-dbapi Flight SQL library for Python provides a
DB API 2 interface and
SQLAlchemy dialect for
Flight SQL.
Installing flightsql-dbapi also installs the pyarrow library that you’ll use for working with Arrow data.
In your terminal, use pip to install flightsql-dbapi:
pip install flightsql-dbapiImporting the module
The flightsql-dbapi package provides the flightsql module. From the module, import the FlightSQLClient class method:
from flightsql import FlightSQLClientflightsql.FlightSQLClientclass: an interface for initializing a client and interacting with a Flight SQL server.
API reference
Class FlightSQLClient
Provides an interface for initializing a client and interacting with a Flight SQL server.
Syntax
__init__(self, host=None, token=None, metadata=None, features=None)Initializes and returns a FlightSQLClient instance for interacting with the server.
Initialize a client
The following example shows how to use Python with flightsql-dbapi
and the DB API 2 interface to instantiate a Flight SQL client configured for an InfluxDB database.
from flightsql import FlightSQLClient
# Instantiate a FlightSQLClient configured for a database
client = FlightSQLClient(host='localhost:8181',
token='DATABASE_TOKEN',
metadata={'database': 'DATABASE_NAME'},
features={'metadata-reflection': 'true'})Replace the following:
DATABASE_TOKEN: an InfluxDB 3 Core database token with read permissions on the databases you want to queryDATABASE_NAME: the name of your InfluxDB 3 Core database
Instance methods
FlightSQLClient.execute
Sends a Flight SQL RPC request to execute the specified SQL Query.
Syntax
execute(query: str, call_options: Optional[FlightSQLCallOptions] = None)Example
# Execute the query
info = client.execute("SELECT * FROM home")The response contains a flight.FlightInfo object that contains metadata and an endpoints: [...] list. Each endpoint contains the following:
- A list of addresses where you can retrieve query result data.
- A
ticketvalue that identifies the data to retrieve.
FlightSQLClient.do_get
Passes a Flight ticket (obtained from a FlightSQLClient.execute response) and retrieves Arrow data identified by the ticket.
Returns a pyarrow.flight.FlightStreamReader for streaming the data.
Syntax
do_get(ticket, call_options: Optional[FlightSQLCallOptions] = None)Example
The following sample shows how to use Python with flightsql-dbapi and pyarrow to query InfluxDB and retrieve data.
from flightsql import FlightSQLClient
# Instantiate a FlightSQLClient configured for a database
client = FlightSQLClient(host='localhost:8181',
token='DATABASE_TOKEN',
metadata={'database': 'DATABASE_NAME'},
features={'metadata-reflection': 'true'})
# Execute the query to retrieve FlightInfo
info = client.execute("SELECT * FROM home")
# Extract the token for retrieving data
ticket = info.endpoints[0].ticket
# Use the ticket to request the Arrow data stream.
# Return a FlightStreamReader for streaming the results.
reader = client.do_get(ticket)
# Read all data to a pyarrow.Table
table = reader.read_all()
print(table)do_get(ticket) returns a pyarrow.flight.FlightStreamReader for streaming Arrow record batches.
To read data from the stream, call one of the following FlightStreamReader methods:
read_all(): Read all record batches as apyarrow.Table.read_chunk(): Read the next RecordBatch and metadata.read_pandas(): Read all record batches and convert them to apandas.DataFrame.
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