Every time I've relaxed consistency guarantees internally in systems I've worked on (or heard …
… Every time I've relaxed consistency guarantees internally in systems I've worked on (or heard coworkers doing the same) we've come to regret it. At a startup several years ago, we needed to build an external search index for a database. The database updated live - and we had a change feed that updated the browsers live as records changed. The engineer in charge did a "good enough" job - he wrote a scrappy script that was only mostly correct. But it sometimes left the index inconsistent with the data. We got constant reports from our users about items not showing up in the search results. He would dutifully go back and fiddle with things to try and fix the problem. Eventually one of our senior engineers went in and rewrote the whole indexing script to be strictly correct. We never heard a peep about it after that - it just worked, every time. Even putting aside the frustration of our users, writing it correctly was a big win for us in terms of maintenance. Once it was correct, we didn't need to keep pulling engineering time away to fix problems. …
Original discussionData Consistency Is Overrated71 source comments · at import