InfluxDB's IOx database engine solves the cardinality problem for time series data by storing each tag and field as a column, significantly reducing the total number of columns and improving performance. Cardinality issues arise when unbounded data creates unique combinations of measurement and tags, resulting in high cardinality. InfluxDB's schema-on-write approach allows flexibility in data shape, but also requires consideration to avoid cardinality issues. The IOx engine introduces a limit of 200 columns per measurement to prevent wide schemas from impacting performance. Additionally, sparse schemas with many null values can be optimized by splitting data into multiple measurements or using more efficient storage formats. With the new IOx engine, InfluxDB can now ingest and analyze large workloads in real-time, providing consistent performance across various time series use cases.