Developer war stories, and so much less! One-time paid software developer, occasional open source contributor, lover of cheap coffee and Portuguese egg ta...
"Your program is an interpreter", I once posited to a concerned engineering manager who called me to complain that her team's application failed for the first time in a long time. This manager owned a critical data processing job that failed that morning. This job ran inside a virtual machine, and since I was the on-call person that week for the hypervisor, she thought to give me a call. She…
After three years at my first job, several decades ago, I confidently believed I was useful. In particular, I had developed a reputation for disentangling knotty problems. But mid-way through my 4th year, I began to worry that I was actually hurting my employer. My company ran a heavily modified version of a proprietary system 1 that we licensed from IBM. My team's job was to maintain the local…
The last time I put my name on a job search service, I received a pretty bizarre email from a recruiter. The position was for a senior-level web developer. Besides being willing to provide 24/7 support for the web sites, the candidate would need to demonstrate "expert" knowledge in 16 areas: Java Persistence EJB3 Swing Struts Hibernate Spring XML schemas Java/J2EE Servlets JSP Perl PHP Python…
How my cheap Windows laptop performs: +----------------------------------------------------+ | Windows | +----------------------------------------------------+ | VM hypervisor | | written in Javascript | | emulating x86 | +----------------------------------------------------+ | Javascript interpreter | +----------------------------------------------------+ | VM hypervisor emulating SPARC |…
Table of Contents Introduction First Case Second Case Third Case Introduction These are some of my notes on the optimizer rule RewriteDistinctAggregate . At the time I jotted down these notes, Apache Spark was at version 3.3.x, but I think these notes largely still hold true (as of some preview release of 4.1.0). These notes help to remind me what RewriteDistinctAggregate is trying to achieve, so…