yesodweb / yesodweb/persistent

Add Indexes automatically on Foreign Keys

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Dominant language
Haskell
Stars
486
Forks
306
PR merge metrics
No merged PRs in 30d

Description

In a schema like

TableB
    tableA TableAId OnDeleteCascade

Every time a TableA entry is deleted, TableB is scanned to find a matching case to cascade. It makes sense for persistent to add an Index on tableA column to make it faster. At least Postgres doesn't add one automatically and this solution is suggested here https://www.postgresql.org/message-id/20040430163539.74079.qmail@web13805.mail.yahoo.com

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First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

The issue does not name files, tests, or entry points. Start by tracing how Persistent represents foreign keys and indexes across its database backends, then compare the PostgreSQL behavior described here with existing index generation. Done means foreign-key columns receive appropriate automatic indexes without breaking backend-specific schema generation, with tests covering the generated schema.

Written by the indexing model from the issue text.

Assessment

Tech stack
haskell, postgresql
Domain
databases
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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