ASOF JOIN with LIMIT hangs indefinitely when input has ≥ 64 rows #368

What happens?

ASOF JOIN combined with a LIMIT clause causes the query to hang forever (never returns) when the input CTEs/tables contain 64 or more rows. With fewer than 64 rows it produces correct results. Removing LIMIT works correctly for any number of rows.

To Reproduce

import duckdb

con = duckdb.connect()

sql = """
WITH trades AS (
    SELECT
        'AAPL' AS symbol,
        TIMESTAMP '2024-01-01 10:00:00' + idx * INTERVAL 10 SECONDS AS trade_time,
        100 AS quantity
    FROM range(64) AS trade_rows(idx)   -- hangs; change to 63 to succeed
),
quotes AS (
    SELECT
        'AAPL' AS symbol,
        TIMESTAMP '2024-01-01 09:59:50' + idx * INTERVAL 10 SECONDS AS quote_time,
        150.0 AS price
    FROM range(64) AS quote_rows(idx)
)
SELECT
    t.symbol,
    t.trade_time,
    t.quantity,
    q.quote_time,
    q.price,
    t.quantity * q.price AS notional
FROM trades AS t
ASOF LEFT JOIN quotes AS q
    ON t.symbol = q.symbol
   AND t.trade_time >= q.quote_time
LIMIT 5
"""

df = con.execute(sql).df()   # <-- hangs here forever
print(df)

OS:

OSX, Windows

DuckDB Package Version:

1.5

Python Version:

3.10-3.14

Full Name:

Aliaksandr Zhura

Affiliation:

Infio

What is the latest build you tested with? If possible, we recommend testing with the latest nightly build.

I have tested with a stable release

Did you include all relevant data sets for reproducing the issue?

No - Other reason (please specify in the issue body)

Did you include all code required to reproduce the issue?

• Yes, I have

Did you include all relevant configuration to reproduce the issue?

• Yes, I have