Summary
dbt-duckdb 1.10.1 segfaults when running an external model that queries MySQL-attached tables with DuckDB 1.5.1. The same setup works on DuckDB 1.5.0. Raw DuckDB 1.5.1 (without dbt) executes the same query without issues, so the crash is specific to how dbt-duckdb manages the connection/materialization.
Environment
- dbt-duckdb: 1.10.1
- dbt-core: 1.11.7
- DuckDB: 1.5.1 (crash) / 1.5.0 (works)
- Python: 3.12
- Platform: Linux (Docker,
python:3.12-slim)
Minimal reproduction
Requires Docker and a MySQL instance. Full self-contained repro:
# Start a MySQL container
docker run -d --name test-mysql -e MYSQL_ROOT_PASSWORD=testpass -e MYSQL_DATABASE=ds_views mysql:8
# Seed test data
docker run --rm --link test-mysql:mysql python:3.12-slim bash -c "
pip install -q duckdb==1.5.0
python3 << 'PY'
import duckdb
con = duckdb.connect()
con.install_extension('mysql')
con.load_extension('mysql')
con.execute(\"ATTACH 'host=mysql port=3306 user=root password=testpass database=ds_views' AS db (TYPE mysql)\")
con.execute('CREATE TABLE db.t1 (id BIGINT, name VARCHAR(50))')
con.execute('CREATE TABLE db.t2 (id BIGINT, value INTEGER)')
con.execute(\"INSERT INTO db.t1 SELECT i, 'row' FROM generate_series(1, 1000) t(i)\")
con.execute('INSERT INTO db.t2 SELECT i, i % 100 FROM generate_series(1, 1000) t(i)')
con.close()
PY
"
# Test with DuckDB 1.5.1 — CRASHES
docker run --rm --link test-mysql:mysql python:3.12-slim bash -c "
pip install -q dbt-duckdb~=1.10.1 duckdb==1.5.1
mkdir -p /tmp/dbt/models /tmp/parquet
cat > /tmp/dbt/profiles.yml << 'YML'
test:
target: duckdb
outputs:
duckdb:
type: duckdb
path: /tmp/test.duckdb
external_root: /tmp/parquet
extensions: [mysql]
settings: {threads: 4}
attach:
- path: 'host=mysql port=3306 user=root password=testpass database=ds_views'
type: mysql
alias: ds_views
read_only: true
YML
cat > /tmp/dbt/dbt_project.yml << 'YML'
name: test
version: '1.0.0'
config-version: 2
profile: test
model-paths: ['models']
models:
test:
+materialized: external
YML
cat > /tmp/dbt/models/sources.yml << 'YML'
version: 2
sources:
- name: ds_views
database: ds_views
tables: [{name: t1}, {name: t2}]
YML
cat > /tmp/dbt/models/test_model.sql << 'SQL'
SELECT t1.id, t1.name, t2.value
FROM {{ source('ds_views', 't1') }} AS t1
JOIN {{ source('ds_views', 't2') }} AS t2 ON t1.id = t2.id
SQL
cd /tmp/dbt && dbt build --profiles-dir . --project-dir .
"
# Exit code: 139 (SIGSEGV)
# Test with DuckDB 1.5.0 — WORKS
# Same as above but: pip install -q dbt-duckdb~=1.10.1 duckdb==1.5.0
# Exit code: 0, PASS=1Observed behavior
DuckDB 1.5.1:
1 of 1 START sql external model main.test_model ......... [RUN]
Segmentation fault (core dumped)
Exit code: 139
DuckDB 1.5.0:
1 of 1 START sql external model main.test_model ......... [RUN]
1 of 1 OK created sql external model main.test_model .... [OK in 0.75s]
Completed successfully
Notes
- The same JOIN query runs fine with raw DuckDB 1.5.1 Python API (no dbt) — even with identical settings (
threads=4, storage_compatibility_version, COPY TO parquet)
- Crash occurs with both
read_only: true and read_only: false on the MySQL attach
- DuckDB 1.5.1 was released 2026-03-23
- Pinning
duckdb==1.5.0 is a workaround
Summary
dbt-duckdb 1.10.1 segfaults when running an external model that queries MySQL-attached tables with DuckDB 1.5.1. The same setup works on DuckDB 1.5.0. Raw DuckDB 1.5.1 (without dbt) executes the same query without issues, so the crash is specific to how dbt-duckdb manages the connection/materialization.
Environment
python:3.12-slim)Minimal reproduction
Requires Docker and a MySQL instance. Full self-contained repro:
Observed behavior
DuckDB 1.5.1:
Exit code: 139
DuckDB 1.5.0:
Notes
threads=4,storage_compatibility_version,COPY TO parquet)read_only: trueandread_only: falseon the MySQL attachduckdb==1.5.0is a workaround