static get instance() {
        const s = Symbol.for('pgPromiseDatabasePool');
        let scope = global[s];
        if (!scope) {
            scope = {
                dbMap: {}, // map of used database context keys (connection + dc)
                dbs: [] // all database objects
            };
            global[s] = scope;
        }
        return scope;
    }
Global instance of the database pool repository.

@returns {{dbMap: {}, dbs: Array}}