The report discusses how we improved the YQL (YDB) engine on the popular OLAP benchmarks - ClickBench and TPCH. Even a year ago, we couldn't pass the TPCH tests on a dataset of 100 gigabytes, and the performance of ClickBench was unsatisfactory. I will talk about how we investigated bottlenecks using perf and bpftrace tools, what specific problems we found. I will talk about improvements in the join algorithm and improvements in the way data is transmitted.
I will also talk about how we rewrote TPCH plans for optimal execution.
I will show concrete performance numbers and comparisons to other systems.