[sentry-junior]

Drops sentry_groupedmessage_times_seen_03d64079, the single-column btree index that db_index=True creates on Group.times_seen. This is a follow-up to #128156, which did the same for Group.level.

Why

• The Postgres callers that order Group by times_seen all filter by project or status as well:
  • seer/fetch_issues/by_function_name.py
  • tasks/summaries/utils.py (two queries)
• Those queries are served by the composite project/status indexes, so a standalone times_seen index only adds write overhead on a hot column. times_seen changes on every buffered group update.
• It's a plain CREATE INDEX ... (times_seen). It isn't unique and isn't a constraint.

How

Same pattern as 1228_drop_group_level_index:

• Removed db_index=True from Group.times_seen.
• Migration 1229_drop_group_times_seen_index uses SeparateDatabaseAndState:
  • The database side runs DROP INDEX CONCURRENTLY IF EXISTS for Django's name (..._03d64079) and for the South-era name (sentry_groupedmessage_times_seen). It drops these indexes by name instead of letting AlterField introspect and drop other indexes.
  • The state side is an AlterField matching the model.
  • use_statement_timeout=False, because the concurrent drop waits for open transactions.
  • is_post_deployment = True.
  • Reversible: the reverse SQL recreates the index under its current name with CREATE INDEX CONCURRENTLY IF NOT EXISTS.

Notes for reviewers

• SafeRunSQL needs sign-off from owners-migrations.
• I couldn't run makemigrations --check or sqlmigrate locally, so please rely on CI and the migration SQL comment.

via michal.

--

View Junior Session in Sentry

[github-actions]

This PR has a migration; here is the generated SQL for src/sentry/migrations/1229_drop_group_times_seen_index.py

for 1229_drop_group_times_seen_index in sentry

--
-- Custom state/database change combination
--
DROP INDEX CONCURRENTLY IF EXISTS "sentry_groupedmessage_times_seen_03d64079";
DROP INDEX CONCURRENTLY IF EXISTS "sentry_groupedmessage_times_seen";