MySQL LEFT JOIN with OR: Match Semantics Before Plans
Distinguish OR matching from priority fallback, control row multiplication, and validate MySQL join rewrites with execution plans and semantic tests.
Peng
I’m Peng, a Java backend developer and the author of TechShare. My project experience includes online classroom systems and student fitness data platforms. I write about Java, distributed systems, databases, and AI engineering, focusing on implementation decisions, troubleshooting, and practical trade-offs. Articles distinguish firsthand project experience from illustrative examples and explanations based on technical documentation.
Java Heap OOM with Arthas: Find Retained Data Before Raising -Xmx
A reproducible Arthas workflow for Java heap OOMs: identify retained objects, connect them to an import path, and verify chunked processing with memory checks.
Java Performance: Remove Repeated Searches and Unnecessary Work
Reduce repeated searches, unnecessary sorting, eager fallback calls, and excess memory retention, then verify changes with correctness tests, JFR, and JMH.
Java Transactions: Orders, Stock, and Outbox Events
A practical Spring and MySQL order workflow: define transaction boundaries, reserve stock safely, deduplicate retries, and deliver committed events through an outbox.