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MatrixOne into Apache Arrow with ADBC

MatrixOne 4.2 (MySQL 8.0.30 wire), 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

MySQL Connector/ODBC 9.4 (MySQL wire)

Wire

MySQL wire

adbcBridge

0.1.1 (release)

The connection string the matrix used, as the connection strings reference records it (MySQL 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=16001;User=dump;Password=111;{plugin_dir}{no_ssps}

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=16001;User=dump;Password=111;")
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 MatrixOne 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

mysql_native_password only, so run from the tarball the connector needs PLUGIN_DIR=; server side: a table without a PRIMARY KEY gets a hidden __mo_fake_pk_col that SQLColumns reports in GetObjects; a parameter array bound into a BIT column aborts the server once it holds NULLs (malloc(): unaligned fastbin chunk detected; single parameters and NULL-free arrays are fine), so ingest sends booleans as TINYINT — fixed on MatrixOne main by matrixorigin/matrixone#27645 (2026-08-26): on the 2026-08-28 nightly a bound NULL stores as NULL and the same 999-set array runs clean, so the mapping is for the released 4.2.0; driver quirk handled: MatrixOne describes a TEXT column as SQL_WLONGVARCHAR one third of its widest value's byte length wide (5 characters for the benchmark's 16-byte strings, 0 for an empty result set), so binding at that width truncates every row; a no-declared-length column is bound at long_bind_bytes instead of re-reading every row (2.05M rows/s in the fix's own measurement).

What this stack needed

• SHOW VARIABLES and SHOW COLLATION kill the client with SIGFPE inside Connector/ODBC 9.4's get_column_size (a zero charset width in the result metadata); the bridge issues neither; ingest 97.5k rows/s (86.5k with array binding), fetch 1.97M rows/s

Native ADBC driver, compared

MatrixOne speaks the MySQL wire protocol, so the ADBC Driver Foundry's native MySQL ADBC driver (0.6.0) 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 MatrixOne; the full table for all 28 wire-compatible databases, with each first error, is in the note.

Read next

• What MySQL Connector/ODBC does to a DATETIME(6), and six other findings
• A Unicode string parameter cannot reach a MySQL-wire warehouse's prepare