Sql

A quick reference for the four types of SQL JOIN operations in MySQL, with plain-language explanations and a simple example for each.

Percona XtraDB Cluster can recover a crashed node and rejoin it to the cluster using an incremental state transfer. This post walks through how GTID-based position recovery works under the hood and what you will see in the error log during the process.

A quick MySQL command to check the peak number of simultaneous connections your server has handled, useful for capacity planning and diagnosing connection bottlenecks.

A quick bash one-liner that pulls per-user CPU time, connection counts, and active session details from MySQL’s INFORMATION_SCHEMA and processlist tables.

Hive bundle logs in a cloud data warehouse are stored under a predictable S3 path. Knowing where to look saves time when troubleshooting query performance or diagnosing failed jobs.

A quick reference for querying MySQL information_schema to list all foreign key constraints in a given database, including the referencing and referenced columns.