tiflash VS avx_qsort

This is great, and can definitely help quite a lot database and big data projects. I can immediately imagine this is a perfect match to one open source HTAP system (https://github.com/tigraph/tidb) which uses SIMD in their columnar processing engine TiFlash (https://github.com/pingcap/tiflash).

One of the founder of TiDB/TiKV here from [PingCAP](https://pingcap.com)

I have been thinking about this problem with my peers when I started to build [TiDB](https://github.com/pingcap/tidb) seven years ago. At that time, nearly all of us were familiar with Go language, so we decided to use Go to build the SQL layer of TiDB. Thanks to Go, we could develop TiDB very quickly and released the first MVP in half a year. I remembered clearly the sense when we ran TPC-C successfully, although the TPMC was just 1 at that time, this was a good start for us.

But Go had some problems, e.g. the GC was not good before, the fair scheduling might cause some latency problem, or data racing may happen sometimes. So when we decided to build a distributed storage (aha, [TiKV](https://githbu.com/tikv/tikv), we wanted use another language to guarantee safety. I really admire our courage - we chose Rust which was just released 1.0 and missed lots of libraries at that time. Now it seems that this is an awesome choice, TiKV has been graduated from CNCF, and been used as building block not only for TiDB, but also for other distributed systems. Thanks Rust.

When TiDB started being used in many companies, we found that our customer not only ran lots of online transactions in TiDB, but also they wanted to ran some realtime analytic queries directly because the data has been in TiDB already. So we decided to build a HTAP database, to introduce a column storage beside TiKV, this is [TiFlash](https://github.com/pingcap/tiflash). We build TiFlash based on Clickhouse, so of course, we use C++.

As you can see, to build only one integrated database - TiDB, we at least use three languages, every language has its own reason to be introduced. We can treat the distributed database as a service system, each service can be built with your favorite language and the services are linked by gRPC like TiDB does now. You may doubt that - “hey, guys, you are building a database, performance is very importance”. Yes, this is true, but we also build a complex distributed system, especially on the cloud. Scale-out, elastic, user experience must be important too. This is trade off for an engineer :-)

The original (AFAICT) work on SIMD quick sort, also mentioned in the google post also implemented pointer sort by loading a pointed key using gather instructions and the method can be used for an array of structs. https://github.com/vkrasnov/avx_qsort/blob/master/qsort_AVX2...

I'm the co-author of one of the papers referenced in the blogpost, (Fast Quicksort Implementation Using AVX Instructions), we did write the AVX512 code back in 2015, just had nowhere to run it, at least publicly. The paper also very explicitly says that the lookup tables can be instead replaced by the AVX512 compress instructions. The code for that paper is available in https://github.com/vkrasnov/avx_qsort