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QuestDB into Apache Arrow with ADBC

QuestDB 10, read and written through adbcBridge — the ADBC driver that loads the database's ODBC driver — verified on Linux, macOS arm64 and Windows x64. Everything below is the compatibility matrix's record for this row.

Status

Driver and connection string

ODBC driver

psqlodbc 16 (PG wire)

Wire

PostgreSQL wire

adbcBridge

0.1.1 (release)

The connection string the matrix used, as the connection strings reference records it (PostgreSQL wire); {drv} is the driver library or its name from odbcinst.ini, and the host, port and credentials are the test server's.

Driver={drv};Server=127.0.0.1;Port=18812;Database=qdb;Uid=admin;Pwd=quest;BoolsAsChar=0;Protocol=7.4-0;

Python

import adbcbridge

# {drv}: the ODBC driver library (path), or its name from odbcinst.ini
conn = adbcbridge.connect(uri="Driver={drv};Server=127.0.0.1;Port=18812;Database=qdb;Uid=admin;Pwd=quest;BoolsAsChar=0;Protocol=7.4-0;")
with conn.cursor() as cur:
    cur.execute("SELECT * FROM my_table")
    table = cur.fetch_arrow_table()      # pyarrow.Table

Polars and pandas

import polars as pl, pandas as pd

df = pl.read_database("SELECT * FROM my_table", connection=conn)   # Polars, Arrow-native
pdf = pd.read_sql("SELECT * FROM my_table", conn)                   # pandas 2.2+, ADBC connection

pip install adbcbridge brings the driver library; the QuestDB ODBC driver is installed the way its vendor documents, then named in Driver=. Rust, Go, C# and Java use the same connection string through their ADBC driver managers — see the docs.

What the matrix recorded

own type system behind the PG wire: standard-SQL ingest DDL, true/false boolean params, parameter arrays off (psqlodbc inlines their values as string literals, which QuestDB will not convert to BINARY or BOOLEAN); psqlodbc's SQLColumns fails here, so GetObjects falls back to SQLDescribeCol of a zero-row SELECT instead; a BINARY value holding a 0x00 byte comes back truncated at the first NUL through psqlodbc (the server keeps the whole value); on a manual-commit connection free a prepared statement only after the commit — psqlodbc's free sends SAVEPOINT …; DEALLOCATE …; RELEASE whatever Protocol says, QuestDB has no SAVEPOINT, the transaction aborts unreported and COMMIT still returns SQL_SUCCESS (the psqlodbc path already recorded for Materialize)

Native ADBC driver, compared

QuestDB speaks the PostgreSQL wire protocol, so Apache Arrow's native PostgreSQL ADBC driver (adbc-driver-postgresql 1.12.0) can be pointed at it too. On 2026-09-05 the same seven-step ADBC workload (connect, SELECT 1, DDL and inserts and a read, a 1,000-row adbc_ingest, table schema, catalog listing, read back) ran through both:

Where the native driver stops it is by design of that driver, not a defect of QuestDB; the full table for all 28 wire-compatible databases, with each first error, is in the note.

Read next

• Where the native PostgreSQL and MySQL ADBC drivers stop on wire-compatible databases
• Where PostgreSQL-wire servers part company with PostgreSQL
• Two psqlodbc bugs that lost rows and narrowed integers, and two traps