What happens?

Prepared statement is still broken even after the fix in #147
Minor tweaks to an existing test results in failure

To Reproduce

Add a new test case test_prepared_new() to test/pycheck/prepared_test.py

def test_prepared_new(cur: Cursor):
    cur.sql("CREATE TEMP TABLE test_table (id int) USING duckdb")
    cur.sql("INSERT INTO test_table VALUES (1), (2), (3)")
    q2 = "SELECT count(*) FROM test_table where id = %s + 1"
    cur.sql("SET plan_cache_mode = 'force_custom_plan'")
    assert cur.sql(q2, (1,)) == 1

This is just a simplified version of test_prepared() with the following modifications:

1. Use DuckDB temp table to force DuckDB execution
2. Change from WHERE %s to WHERE %s + 1

Running the test with pytest test/pycheck/prepared_test.py::test_prepared_new results in the following error:

2024-12-06 09:16:14.947 UTC [47236] WARNING:  (PGDuckDB/GetPostgresDuckDBType) Could not convert DuckDB type: UNKNOWN to Postgres type
2024-12-06 09:16:14.947 UTC [47236] ERROR:  (PGDuckDB/CreatePlan) Cache lookup failed for type 0
2024-12-06 09:16:14.947 UTC [47236] STATEMENT:  SELECT count(*) FROM test_table where id = $1 + 1

OS:

Linux

pg_duckdb Version (if built from source use commit hash):

bb82c93

Postgres Version (if built from source use commit hash):

17.0

Hardware:

No response

Full Name:

Cheng Chen

Affiliation:

Mooncake Labs

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

I have tested with a source build

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

Not applicable - the reproduction does not require a data set

Did you include all code required to reproduce the issue?

• Yes, I have

Did you include all relevant configuration (e.g., CPU architecture, Linux distribution) to reproduce the issue?

• Yes, I have