Versioning Documents without Migrations - 013

Schema marindi, ippudu 1 Million documents update cheyyala? Avasaram ledu. Versioning Schema pattern vadandi.

Core Explanation: Prati document lo schema_version field pettandi. App code lo logic rayandi: Version 1 vasthe ela handle cheyyali, Version 2 vasthe ela. Read chesinappudu, avasaram aithe appude migrate cheyyandi (Justin-Time Migration) or Write chesetappudu upgrade cheyyandi.

Wrong Practice: Downtime migration script running on Sunday night.

// Updating 10M records at once... DB Locks... CPU Spike... Alerts!

Best Practice: Schema Versioning Pattern.

// Doc
{
  "schema_v": 2,
  "name": "Pavan",
  "contact": { "phone": "..." } // v2 structure
}

App Logic: if (doc.schema_v == 1) { return convertV1toV2(doc); }

Closing Insight: "Changes ni Lazy ga apply cheyyandi. Batch migrations production killers."