onst gen_data = async () => {
                reset_strings_cache();
                let nrows = num_rows.value;
                let rows = [];
                const batch_size = Math.floor(nrows / num_batches.value);
                const batch_freq = batch_delay.value;
                const tbl = await client.table(new_schema());
                (function batch() {
                    while (nrows > 0) {
                        rows.push(new_row());
                        nrows--;
                       