8 items tagged “migrations”
How to Create an Index in Django Without Downtime (via) Excellent advanced tutorial on Django migrations, which uses a desire to create indexes in PostgreSQL without locking the table (with CREATE INDEX CONCURRENTLY) to explain the SeparateDatabaseAndState and atomic features of Django’s migration framework. # 11th April 2019, 3:06 pm
Migrations are both essential and frustratingly frequent as your codebase ages and your business grows: most tools and processes only support about one order of magnitude of growth before becoming ineffective, so rapid growth makes them a way of life. [...] As a result you switch tools a lot, and your ability to migrate to new software can easily become the defining constraint for your overall velocity. [...] Migrations matter because they are usually the only available avenue to make meaningful progress on technical debt.
How Balanced does Database Migrations with Zero-Downtime. I’m fascinated by the idea of “pausing” traffic during a blocking site maintenance activity (like a database migration) and then un-pausing when the operation is complete—so end clients just see some of their requests taking a few seconds longer than expected. I first saw this trick described by Braintree. Balanced wrote about a neat way of doing this just using HAproxy, which lets you live reconfigure the maxconns to your backend down to zero (causing traffic to be queued up) and then bring the setting back up again a few seconds later to un-pause those requests. # 7th November 2017, 11:36 am
On Django And Migrations. South author Andrew Godwin on the plans for migrations in Django. His excellent South migration library will be split in to two parts—one handling database abstraction, dependency resolution and history tracking and the other providing autodetection and the South user interface. The former will go in to Django proper, encouraging other migration libraries to share the same core abstractions. # 2nd June 2010, 4:27 pm
Southerly Breezes. Andrew Godwin is slowly assimilating the best ideas from other Django migration systems in to South—the latest additions include ORM Freezing from Migratory and automatic change detection. Exciting stuff. # 15th March 2009, 1:17 pm