Multiple SQLite Sources get overwritten and only last one is accessible

[Yax]

When configuring multiple SQLite databases in dbhub.toml, all source_id values query the same physical database (the last one configured).

Configuration

dbhub.toml:

[[sources]]
id = "database_a"
dsn = "sqlite:///app/database_a.db"
readonly = true

[[sources]]
id = "database_b"
dsn = "sqlite:///app/database_b.db"
readonly = true

docker-compose.yml:

services:
  dbhub:
    image: bytebase/dbhub:latest
    working_dir: /app
    ports:
      - "8080:8080"
    volumes:
      - type: bind
        source: ./database_a.db
        target: /app/database_a.db
        read_only: true
      - type: bind
        source: ./database_b.db
        target: /app/database_b.db
        read_only: true
      - type: bind
        source: ./dbhub.toml
        target: /app/dbhub.toml
        read_only: true
    command:
      - --transport
      - http
      - --port
      - "8080"
      - --config
      - /app/dbhub.toml

Expected Behavior

• source_id: "database_a" → queries database_a.db
• source_id: "database_b" → queries database_b.db

Actual Behavior

• Both source_ids query database_b.db (the last configured source)
• Only one database file is opened (confirmed via lsof)
• Both sources return identical tables despite files being different

Probably Cause

ConnectorRegistry.getConnectorForDSN() returns a singleton connector instance for SQLite:

static getConnectorForDSN(dsn) {
  for (const connector of _ConnectorRegistry.connectors.values()) {
    if (connector.dsnParser.isValidDSN(dsn)) {
      return connector;  // ← Same instance for all SQLite databases
    }
  }
}

When connectSource() loops through sources, it:

1. Gets the same SQLite connector instance for both databases
2. Calls connector.connect(actualDSN) which overwrites the previous connection
3. Stores the same connector instance for both source_ids

Result: Both source_ids reference the same connector connected to only the last database.

Probable Fix

ConnectorRegistry should create a new connector instance per source, not return a singleton.