The story

I grew up on '80s bulletin boards, running a BBS and, as a teenager, taking HyperCard classes every summer at Haverford and building HyperCard stacks, FileMaker and 4th Dimension databases (mostly D&D characters). Since then there's been a database in every job: Lotus Notes, MySQL behind WordPress hosting for 120+ enterprise accounts, MySQL in a HIPAA shop I helped take to HITRUST certification, and Lotus Notes again at Cognizant for TJ Maxx and HomeGoods. Now I build healthcare data pipelines in Scala and Apache Spark, security-first. The MongoDB Atlas lab below is earlier work that I keep because it shows how I verify things.

Earlier lab: Big Iron Bank (MongoDB Atlas)

A fictional Arizona community bank, and the MongoDB platform behind it: customers, accounts and card transactions as documents, money that moves in ACID transactions, a replica set that survives losing its primary, backups that are actually restored, and nobody reading an SSN they shouldn't.

db.accounts.find({ customer_id: "C00042" }).explain("executionStats")
winningPlan:  IXSCAN { customer_id: 1 }
nReturned:    2        totalDocsExamined: 2
executionTimeMillis: 0

What "fast" has to look like: an index scan, and only the documents it returns examined. See the plan and progress.

Why the name: Big Iron is Marty Robbins' 1959 ballad of an Arizona ranger.

Where I can help