Crash when perfoming parallel metadata queries

[apage43]

What happens?

Noticed a segfault when trying to view tables in an attached .sqlite file in the DuckDB UI, found a minimal reproducer using the duckdb CLI only

Appears to be a multithreading issue (does not happen with threads=1)

Confirmed on latest main duckdb-sqlite (fb7cf51c)

To Reproduce

Note PRAGMA threads=1; avoids all of these

Setup

sqlite3 /tmp/repro_metadata_min.sqlite <<'SQL'
BEGIN;
CREATE TABLE t1(id INTEGER PRIMARY KEY, name TEXT);
CREATE TABLE t2(id INTEGER PRIMARY KEY, value TEXT);
COMMIT;
SQL

Repros

ATTACH '/tmp/repro_metadata_min.sqlite' AS cat (TYPE sqlite);
SELECT 1
FROM duckdb_columns(), duckdb_tables(), duckdb_constraints()
LIMIT 1;

often segfaults, sometimes also see

• Not implemented Error: Unimplemented constraint for duckdb_constraints
• Out of Memory Error: Allocation failure
• INTERNAL Error: Information loss on integer cast ...

ATTACH '/tmp/repro_metadata_min.sqlite' AS cat (TYPE sqlite);
SELECT t.table_oid
FROM duckdb_columns() columns
LEFT JOIN duckdb_tables() t USING (table_oid)
LEFT JOIN duckdb_constraints() c USING (table_oid)
WHERE NOT columns.internal
LIMIT 1;

often segfaults, sometimes also see

• Not implemented Error: Unimplemented constraint for duckdb_constraints.

Also tried:

• duckdb_columns(), duckdb_tables() alone: no crash.
• duckdb_columns(), duckdb_constraints() alone: no crash.
• duckdb_columns() LEFT JOIN duckdb_constraints(): no crash.
• duckdb_tables(), duckdb_constraints() alone: no crash.

The crashes appeared once duckdb_constraints() was involved together with both of the other metadata table functions in the same statement.

OS:

Ubuntu 24.04.3 LTS (WSL2 x64); Ubuntu 25.04 (x64)

SQLite Version:

3.45.1; 3.46.1

DuckDB Version:

1.5.0

DuckDB Client:

CLI

Full Name:

Aaron Miller

Affiliation:

Nomic AI

Have you tried this on the latest main branch?

• I agree

Have you tried the steps to reproduce? Do they include all relevant data and configuration? Does the issue you report still appear there?

• I agree

[staticlibs]

Hi, thanks for the report! I can reproduce this, yes something is wrong with catalog access around duckdb_constraints.

[staticlibs]

@apage43

Just FYI, this was fixed in #178, the updated version can be installed on 1.5.0 from core_nightly:

FORCE INSTALL sqlite FROM core_nightly