`home_directory` won't be set after duplicating a JDBC connection

[goldmedal]

What happens?

I attempted to utilize DuckDBConnection#duplicate in order to obtain a new connection. However, I noticed that the home_directory is not set in the duplicated connection. This issue does not arise in other configurations.

To Reproduce

Sample Code:

import org.duckdb.DuckDBConnection;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class JdbcTest
{
    public static void main(String[] args)
    {
        try {
            Connection connection = DriverManager.getConnection("jdbc:duckdb:");
            Statement statement = connection.createStatement();
            statement.execute("set home_directory='/tmp/duckdb'");
            statement.execute("set temp_directory='/tmp/duckdb'");
            statement.execute("select * from duckdb_settings() where name = 'home_directory' or name = 'temp_directory'");
            ResultSet resultSet = statement.getResultSet();
            while (resultSet.next()) {
                System.out.println(resultSet.getString(1));
                System.out.println(resultSet.getString(2));
            }

            Connection duplicate = ((DuckDBConnection) connection).duplicate();
            Statement statement1 = duplicate.createStatement();
            statement1.execute("select * from duckdb_settings() where name = 'home_directory' or name = 'temp_directory'");
            ResultSet resultSet1 = statement1.getResultSet();
            while (resultSet1.next()) {
                System.out.println(resultSet1.getString(1));
                System.out.println(resultSet1.getString(2));
            }

            statement.execute("select * from duckdb_settings() where name = 'home_directory' or name = 'temp_directory'");
            ResultSet resultSet2 = statement.getResultSet();
            while (resultSet2.next()) {
                System.out.println(resultSet2.getString(1));
                System.out.println(resultSet2.getString(2));
            }
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }
}

STD Output

home_directory
/tmp/duckdb
temp_directory
/tmp/duckdb
home_directory

temp_directory
/tmp/duckdb
home_directory
/tmp/duckdb
temp_directory
/tmp/duckdb

OS:

MacOS

DuckDB Version:

0.9.2

DuckDB Client:

JDBC

Full Name:

Jax Liu

Affiliation:

Canner

Have you tried this on the latest main branch?

I have tested with a release build (and could not test with a main build)

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

• Yes, I have

[goldmedal]

I attempted to analyze the source code and identified two types of configurations in DuckDB: DUCKDB_GLOBAL and DUCKDB_LOCAL. Could you explain the distinction between these two configurations?
https://github.com/duckdb/duckdb/blob/7b21da29d4d0691c0983f2b70aea95d4f5e91473/src/main/config.cpp#L88-L90

Upon inspection, I discovered that home_directory falls under the DUCKDB_LOCAL configuration. Consequently, I experimented with other local configurations, such as integer_division and log_query_path. Surprisingly, all of them failed to persist after duplication.

Is this behavior intentional for DuckDB? In my opinion, DuckDB is an in-process database, and I'm curious about the necessity of distinguishing between local and global configurations.

[github-actions]

This issue is stale because it has been open 90 days with no activity. Remove stale label or comment or this will be closed in 30 days.

[github-actions]

This issue was closed because it has been stale for 30 days with no activity.

[staticlibs]

@goldmedal

two types of configurations in DuckDB: DUCKDB_GLOBAL and DUCKDB_LOCAL. Could you explain the distinction between these two configurations?

Basically, DUCKDB_GLOBAL settings are set on a database instance, that may be shared between multiple connections. And DUCKDB_LOCAL are set on a connection instance itself. I've added copying of local settings on connection duplication in #176 that should fix the problem with home_directory.