Assertion failed in sql_transaction_commit with pgsql driver

Hi!

Next code from driver_pgsql_transaction_commit cause assertion failed in do_query function - i_assert(SQL_DB_IS_READY(&db->api))

} else {
    /* multiple queries, use a transaction */
    ctx->refcount++;
    sql_query(_ctx->db, "BEGIN", transaction_begin_callback, ctx);               <- first sql_query changes db state to SQL_DB_STATE_BUSY
    while (_ctx->head != NULL) {
        ctx->refcount++;
        sql_query(_ctx->db, _ctx->head->query,                                          <- second query cause assertion failed due to SQL_DB_IS_READY returns false
              transaction_update_callback, _ctx->head);
        _ctx->head = _ctx->head->next;
    }
    sql_query(_ctx->db, "COMMIT", transaction_commit_callback, ctx);
}

Next transaction query should be called after previous is finished and driver state changed to SQL_DB_STATE_IDLE