MySQL (InnoDB) transactions are ACID, with A for atomicity. An atomic transaction is an indivisible and irreducible series of database operations such that either all occur, or nothing occurs The atomicity here is different from the atomicity in concurrent programming. An operation acting on shared memory is atomic if it completes in a single step relative to other threads. Suppose you want to read a number from a column, add it by an offset, and write it back to the same column.

When we started huijiwiki.com, PHP was the language of the choice. But it was not much a choice. MediaWiki was coded in PHP. It provided us a solid starting point to expand our idea. Since then I have touched many languages and am moderately proficient in some of them. Among them, Go is my current favorite. Rust is the language I want to explore more. Go as well as Rust has a very different nature compared to PHP.

DMP stands for Data Management Platform, and per Wikipedia, it is a technology platform used for collecting and managing data, mainly for digital marketing purposes. To put it simply, DMP is a collection of data about user attributes. As you might expect a DMP may contain more than millions of data. The DMP I worked on contained nearly a billion. Open source toolings such as Elasticsearch provided a good average baseline for data analytics, and reasonable response time for general-purpose querying.

I have to admit I am really clumsy when it comes to SQL related stuff. This is the year of 2019, and SQL is not a fancy technology to learn anymore. I managed to get away with not diving deep into SQL for a long time, but the lack of fluency in SQL bites me quite often recently. Yesterday I was forced into a binlog trace of the production MySQL database.

RxJS is bonkers! Imagine you have an unbounded stream of events. Each has a unique id. Now you want to throttle the stream based on id, ie. each id should not appear more often than X minutes. With RxJS: // Throttle each id in one minute. fromEvent(emitter, 'tick').pipe( groupBy((e: Event) => e.getId()), flatMap(group => group.pipe(throttleTime(60 * 1000))), ).subscribe( //Do your stuff ); Without RxJS: Too much to write.