re: Why Uber Engineering Switched from Postgres to MySQL - Ayende @ Rahien

re: Why Uber Engineering Switched from Postgres to MySQL - Ayende @ Rahien

time to read 6 min | 1173 words The Uber Engineering group have posted a really great blog post about their move from Postgres to MySQL. I mean that quite literally, it is a pleasure to read, especially since they went into such details as the on-disk format and the implications of that on their performance. For fun, there is another great post from Uber, about moving from MySQL to Postgres , which also has interesting content. Go ahead and read both, and we'll talk when you are done. I want to compare their discussion to what we have been doing. In general, Uber's issue fall into several broad categories: Secondary indexes cost on write Replication format Connection handling Secondary indexes Postgres maintain a secondary index that points directly to the data on disk, while MySQL has a secondary index that has another level of indirection. The images show the difference quite clearly:

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