Python Client Documentation
QuestDB supports the Python ecosystem.
The QuestDB Python client provides ingestion high performance and is insert only.
The client, in combination with QuestDB, offers peak performance time-series ingestion and analysis.
Apart from blazing fast ingestion, our clients provide these key benefits:
- Automatic table creation: No need to define your schema upfront.
- Concurrent schema changes: Seamlessly handle multiple data streams with on-the-fly schema modifications
- Optimized batching: Use strong defaults or curate the size of your batches
- Health checks and feedback: Ensure your system's integrity with built-in health monitoring
- Automatic write retries: Reuse connections and retry after interruptions
This quick start will help you get started.
It covers basic connection, authentication and some insert patterns.
View full docs
View source codeRequirements
Requires Python >= 3.8 Assumes QuestDB is running. Not running? See the general quick start.
Client installation
To install the client (or update it) globally:
python3 -m pip install -U questdb
Or, from from within a virtual environment:
pip install -U questdb
If you’re using poetry, you can add questdb as a dependency:
poetry add questdb
Or to update the dependency:
poetry update questdb
Using dataframes?
Add following dependencies:
pandaspyarrownumpy
Authentication
Passing in a configuration string with basic auth:
from questdb.ingress import Sender
conf = "http::addr=localhost:9000;username=admin;password=quest;"
with Sender.from_conf(conf) as sender:
...
Passing via the QDB_CLIENT_CONF env var:
export QDB_CLIENT_CONF="http::addr=localhost:9000;username=admin;password=quest;"
Basic insert
Consider something such as a temperature sensor.
Basic insertion (no-auth):
from questdb.ingress import Sender, TimestampNanos
conf = f'http::addr=localhost:9000;'
with Sender.from_conf(conf) as sender:
sender.row(
'sensors',
symbols={'id': 'toronto1'},
columns={'temperature': 20.0, 'humidity': 0.5},
at=TimestampNanos.now())
sender.flush()
The same temperature senesor, but via a Pandas dataframe:
import pandas as pd
from questdb.ingress import Sender
df = pd.DataFrame({
'id': pd.Categorical(['toronto1', 'paris3']),
'temperature': [20.0, 21.0],
'humidity': [0.5, 0.6],
'timestamp': pd.to_datetime(['2021-01-01', '2021-01-02'])})
conf = f'http::addr=localhost:9000;'
with Sender.from_conf(conf) as sender:
sender.dataframe(df, table_name='sensors', at='timestamp')
What about market data?
A "full" example, with timestamps and auto-flushing:
from questdb.ingress import Sender, IngressError, TimestampNanos
import sys
import datetime
def example():
try:
conf = f'http::addr=localhost:9000;'
with Sender.from_conf(conf) as sender:
# Record with provided designated timestamp (using the 'at' param)
# Notice the designated timestamp is expected in Nanoseconds,
# but timestamps in other columns are expected in Microseconds.
# The API provides convenient functions
sender.row(
'trades',
symbols={
'pair': 'USDGBP',
'type': 'buy'},
columns={
'traded_price': 0.83,
'limit_price': 0.84,
'qty': 100,
'traded_ts': datetime.datetime(
2022, 8, 6, 7, 35, 23, 189062,
tzinfo=datetime.timezone.utc)},
at=TimestampNanos.now())
# You can call `sender.row` multiple times inside the same `with`
# block. The client will buffer the rows and send them in batches.
# You can flush manually at any point.
sender.flush()
# If you don't flush manually, the client will flush automatically
# when a row is added and either:
# * The buffer contains 75000 rows (if HTTP) or 600 rows (if TCP)
# * The last flush was more than 1000ms ago.
# Auto-flushing can be customized via the `auto_flush_..` params.
# Any remaining pending rows will be sent when the `with` block ends.
except IngressError as e:
sys.stderr.write(f'Got error: {e}\n')
if __name__ == '__main__':
example()
The above generates rows of InfluxDB Line Protocol (ILP) flavoured data:
trades,pair=USDGBP,type=sell traded_price=0.82,limit_price=0.81,qty=150,traded_ts=1659784523190000000\n
trades,pair=EURUSD,type=buy traded_price=1.18,limit_price=1.19,qty=200,traded_ts=1659784523191000000\n
trades,pair=USDJPY,type=sell traded_price=110.5,limit_price=110.4,qty=80,traded_ts=1659784523192000000\n
Limitations
Transactionality
The client does not provide full transactionality in all cases:
- Data for the first table in an HTTP request will be committed even if the second table's commit fails.
- An implicit commit occurs each time a new column is added to a table. This action cannot be rolled back if the request is aborted or encounters parse errors.
Timestamp column
The underlying ILP protocol sends timestamps to QuestDB without a name.
Therefore, if you provide it one, say my_ts, you will find that the timestamp
column is named timestamp.
To address this, issue a CREATE TABLE statement to create the table in advance:
CREATE TABLE temperatures (
ts timestamp,
sensorID symbol,
sensorLocation symbol,
reading double
) timestamp(my_ts);
Now, when you can send data to the specified column.
Health check
To monitor your active connection, there is a ping endpoint:
curl -I http://localhost:9000/ping
Returns (pong!):
HTTP/1.1 204 OK
Server: questDB/1.0
Date: Fri, 2 Feb 2024 17:09:38 GMT
Transfer-Encoding: chunked
Content-Type: text/plain; charset=utf-8
X-Influxdb-Version: v2.7.4
Determine whether an instance is active and confirm the version of InfluxDB Line Protocol with which you are interacting.
Next steps
For full docs, checkout ReadTheDocs.
With data flowing into QuestDB, now it's time to for analysis.
To learn The Way of QuestDB SQL, see the Query & SQL Overview.
Alone? Stuck? Want help? Visit us in our Community Forum.