2019-05-08 08:00 UTC

Fun MySQL fact of the day: block nested-loop joins

Yesterday, we introduced MySQL's Nested-Loop Join algorithm, which it uses to join tables. In many cases, this is a fairly simple and powerful implementation, but as you may appreciate, sometimes this simplicity may end up being rather inefficient. ... read more

2019-05-10 08:00 UTC

Fun MySQL fact of the day: batched key access

We took a small detour from discussing table joins yesterday to take a look at Disk-Sweep Multi-Range Read Optimisation (MRR). If you're wondering why, it's was so that we have a better understanding of how the third of the 3 join algorithms MySQL can use to join tables: the Batched ... read more

2019-06-19 12:29 UTC

Fun MySQL fact of the day: the buffer pool

Since February, we've been intentionally working off a half-formed mental model about InnoDB. In just about all cases, we considered a model wherein InnoDB always reads from and writes to the on-disk index files to serve each query. And while considering a mental model like this can certainly simplify ... read more

2019-05-09 08:00 UTC

Fun MySQL fact of the day: multi-range read optimisation

So far this week, we've looked at 2 of the 3 Nested-Loop Join algorithms MySQL can use to join tables. Before we look at the third one, we need to take a quick detour. ... read more