Lifecycle of a WAL segment on Heroku Postgres Harold Giménez @hgmnz @herokupostgres

Heroku Postgres?

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Adding heroku-postgresql on demo-app… done, v129 (free) Attached as HEROKU_POSTGRESQL_ORANGE_URL Database has been created and is available Use `heroku addons:docs heroku-postgresql` to view documentation. $ $ heroku addons:add heroku-postgresql --app demo-app

Adding heroku-postgresql on demo-app… done, v129 (free) Attached as HEROKU_POSTGRESQL_ORANGE_URL Database has been created and is available Use `heroku addons:docs heroku-postgresql` to view documentation. $ $ heroku addons:add heroku-postgresql --app demo-app Plan: Dev Status: available Connections: 1 PG Version: 9.2.4 Data Size: 6.3 MB Tables: 0 Rows: 0/10000 (In compliance) Fork/Follow: Unsupported heroku pg:info -a demo-app

INSERT INTO … 1. Write to WAL ! ! 2. Data pages in memory 3. Respond to client 4. Flush data pages to heap

pg_xlog separate /wal partition 64GB ext4 options: nosuid, noatime, nodev

archive_command invoked by postgres to archive WAL segments we built WAL-E github.com/wal-e/wal-e

archive_command multi-datacenter storage

forks byte-by-byte copy of your database heroku addons:add heroku-postgresql --fork=blue

fork

followers read replicas heroku addons:add heroku-postgresql --follow=blue

follower

problem

eventual consistency auth issues instability

Archive reaper

Archive reaper

thanks! Harold Giménez @hgmnz @herokupostgres