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OceanBase CE into Apache Arrow with ADBC

OceanBase CE 4.4.2 (MySQL 5.7.25 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=12881;Database=adbc;User=root@test;Password=adbc;{plugin_dir}

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=12881;Database=adbc;User=root@test;Password=adbc;")
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 OceanBase CE 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

no driver quirks and no tolerance flag the mysql entry does not already have (TINYINT(1) booleans, ANSI_QUOTES) — a distributed HTAP engine whose MySQL mode takes that entry's types unchanged; multi-tenant, so the login name carries the tenant (User=root@test), and mysql_native_password only, so run from the tarball the connector needs PLUGIN_DIR=; the container must boot with MODE=SLIM, which starts a prebuilt cluster — the default MODE=MINI builds its tenant from scratch and times out loading the timezone tables (117,043 rows in mysql.time_zone_transition), and is also the only path on which obd's open-files precheck (OBD-1007, nofile below 20000) fires; the SLIM path boots under Docker's default 1024, and the compose file raises nofile to 20000 anyway because at 1024 the observer quietly stops accepting connections once ~780 are open; ingest 105k rows/s at 20,000 rows (12.2k with adbc.odbc.rows_per_insert=1; adbc.odbc.array_binding changes nothing here -- Connector/ODBC walks a parameter array row by row, so the multi-row INSERT stays ahead and ingest takes it either way); fetch 1.32M rows/s.

What this stack needed

• One thing to know when writing NULLs here: on a server-side prepared INSERT the connector sends a NULL as MYSQL_TYPE_NULL until a non-NULL execute has fixed that parameter's type, and OceanBase refuses that execute with Object type error (4001) -- the NULL-carrying execute itself, not the ones after it; once a value has gone through on that statement, later NULLs are accepted, and a fresh statement starts over.
• NO_SSPS=1 avoids it entirely; MySQL itself is happy with the same sequence.
• Bulk ingest is where it shows: a multi-row INSERT whose first execute carries a NULL is refused, the ingest falls back to a parameter array, and Connector/ODBC answers SQL_PARAM_ERROR for the sets the server rejected -- adbcBridge re-runs those rows one at a time after the batch, by which point the types are fixed, so every row lands (0.1.0 dropped them silently and under-reported the count; a column that is NULL in every row raises the server's error)

Native ADBC driver, compared

OceanBase CE 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 OceanBase CE; 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