Add more non-unique indices for read performance

[julianweng]

Asked Claude Code to read through our read queries and add indices as recommended. In general, the app is read-heavy (or at the very least write-light with the possible exception of applications, but even then the degraded application write performance seemed to be from system-wide constraints), so adding these queries is low risk from a performance standpoint. However, these could increase storage costs somewhat.

Here is the list of indices + usages it came up with:

Database Index Changes (vs master)

Club Model

• archived — Excludes archived clubs (views.py:1224)
• approved_on — Existing index for approval date queries
• (approved, archived) — Combined filtering for active, non-archived clubs (views.py:1224)
• Removed: approved (single-column; covered by composite and low selectivity) (views.py:1234)

Event Model

• type — Fair event filtering (views.py:739, views.py:913)
• ics_uuid — ICS event lookups (models.py:481)

EventShowing Model

• end_time — Event end time filtering with ranges (views.py:3138)
• (start_time, end_time) — Time range queries (views.py:3138, views.py:5121)
• (event, start_time) — Event-scoped time queries (filtering showings via parent event) (views.py:913, views.py:915, views.py:3204)
• Removed: start_time (single-column; covered by composites)

ClubFair Model

• end_time — Current/active fair filtering (views.py:699)
• (end_time, start_time) — Composite to support upcoming/current lists and ordering (views.py:1096)

Membership Model

• role — Officer/member permission checks (views.py:2471)
• Removed: (person, club, role) — Low benefit given existing unique (club, person) and observed query patterns

ClubVisit Model

• (club, visit_type, created_at) — Time-series visit analytics (views.py:1637)
• Removed: visit_type (single-column; analytics use composite)

ClubApplication Model

• application_start_time — Application period filtering (views.py:7343)
• application_end_time — Deadline checking (views.py:7343)
• result_release_time — Result release scheduling

ApplicationSubmission Model

• status — Filter/aggregate by acceptance/rejection status (views.py:7714)

Ticket Model

• type — Ticket type filtering (views.py:3494)
• (showing, type) — Available tickets by type per showing (views.py:3494)
• (showing, owner) — Ticket ownership queries (views.py:3333)
• (showing, holder) — Held ticket queries
• (showing, type) WHERE owner IS NULL AND holder IS NULL AND buyable = TRUE — Partial index for fast “available tickets” lookups (views.py:3493)

Badge Model

• purpose — Fair badge filtering (views.py:924)

[Copilot]

Pull Request Overview

This PR adds database indices to improve read performance across multiple models in the penn-clubs application. The changes focus on fields that are frequently used in filtering, ordering, and JOIN operations based on analysis of existing query patterns.

• Adds single-field indices on boolean and datetime fields used for filtering
• Creates composite indices for commonly combined filter conditions
• Targets models like Club, Event, Membership, and Ticket that are central to the application's read-heavy workload

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[Copilot]

[nitpick] The composite index on ['event', 'start_time'] may be redundant since 'event' is already a ForeignKey which typically has an implicit index. Consider whether a single-field index on 'start_time' would be sufficient for the query patterns, or if the composite index provides additional optimization for specific queries that filter by both event and start_time together.

Suggested change

models.Index(fields=["event", "start_time"]),

[Copilot]

Pull Request Overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.60%. Comparing base (6737000) to head (3728c0c).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #845      +/-   ##
==========================================
+ Coverage   74.57%   74.60%   +0.02%     
==========================================
  Files          33       33              
  Lines        7852     7861       +9     
==========================================
+ Hits         5856     5865       +9     
  Misses       1996     1996              

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[Copilot]

Pull Request Overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

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