Recently I was doing some small testing by using EC2 instances on AWS and I noticed the execution time and performance highly depend on which time of the day I am running my scripts. I was using t3.xlarge instance type as I didn’t need many CPUs and memory for my tests, but from time […]
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In MySQL 8.0.18 there is a new feature called how it works under the hood.
The high-level basics are the following: if there is a join, it will create an in-memory hash table based on one of the tables and will read the other table row by row, calculate a hash, and do a lookup […]
In MySQL 8.0.18 there is a new feature called new iterator executor for each step. That topic itself deserves its own blog post on how the new iterator executor works, and I will write a post about that as well. But if you cannot wait and you would like to read up, here are […]
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Recently I had a customer where every single query was running in a transaction, as well as even the simplest selects. Unfortunately, this is not unique and many connectors like Java love to do that.
In their case, the Java connector changed autocommit=off for the connection itself at the beginning, and as these were permanent […]
In this blog post, I am going to show why we have to be careful with stored functions in select list, as a single query can cause thousands of queries in the background if we aren’t cautious.
For this example, I am only going to use the SLEEP function to demonstrate the issue, but you […]
