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| stage | group | info |
|---|---|---|
| Data Stores | Database | To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/product/ux/technical-writing/#assignments |
Database guides
Database Reviews
-
If you're creating a database MR for review, check out our Database review guidelines.
It provides an introduction on database-related changes, migrations, and complex SQL queries.
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If you're a database reviewer or want to become one, check out our introduction to reviewing database changes.
Tooling
- Understanding EXPLAIN plans
- explain.depesz.com or explain.dalibo.com for visualizing the output of
EXPLAIN - pgFormatter a PostgreSQL SQL syntax beautifier
- db:check-migrations job
- Database migration pipeline
Migrations
- Adding required stops
- Avoiding downtime in migrations
- Batched background migrations guidelines
- Create a regular migration, including creating new models
- Deleting migrations
- Different types of migrations
- Legacy background migrations guidelines
- Migrations for multiple databases
- Migrations style guide for creating safe SQL migrations
- Partitioning tables
- Post-deployment migrations guidelines and how to create one
- Running database migrations
- SQL guidelines for working with SQL queries
- Swapping tables
- Testing Rails migrations guide
- When and how to write Rails migrations tests
Debugging
- Accessing the database
- Resetting the database
- Troubleshooting and debugging the database
- Tracing the source of an SQL query:
- In Rails console using Verbose Query Logs
- Using query comments with Marginalia
Best practices
- Adding database indexes
- Adding a foreign key constraint to an existing column
- Check for background migrations before upgrading
- Client-side connection-pool
- Constraints naming conventions
- Creating enums
- Data layout and access patterns
- Efficient
INoperator queries - Foreign keys & associations
- Hash indexes
- Insert into tables in batches
- Iterating tables in batches
NOT NULLconstraints- Ordering table columns
- Pagination guidelines
- Polymorphic associations
- Query count limits
- Query performance guidelines
- Serializing data
- Single table inheritance
- Storing SHA1 hashes as binary
- Strings and the Text data type
- Updating multiple values
- Verifying database capabilities
Case studies
PostgreSQL information for GitLab administrators
- Configure GitLab using an external PostgreSQL service
- Configuring PostgreSQL for scaling
- Database Load Balancing
- Moving GitLab databases to a different PostgreSQL instance
- Replication and failover with Omnibus GitLab
- Standalone PostgreSQL using Omnibus GitLab
- Troubleshooting PostgreSQL
- Working with the bundled PgBouncer service
User information for scaling
For GitLab administrators, information about configuring PostgreSQL for scaling is available, including the major methods: