v0.3.1

Performance

• Migration 5 adds covering indexes for the repository metrics and
  leaderboards: pull requests by repository and creation date, check-run
  outcomes, review and issue comments, and reviews per pull request; and
  per-author merged pull requests and pull-request conversation comments. On a
  warehouse whose pages are not cached, repo_metrics and repo_aggregations
  previously read every pull-request, comment and check-run row they touched,
  including the wide title and body columns; they now read index pages only. On a 16 GB test warehouse the
  slowest queries went from tens of seconds to under two seconds on a cold
  page cache, and the comment counts from about 1 s to under 0.2 s warm.
• Repository comment counts and the top-commenters leaderboard restrict each
  side of the review/issue comment union to the repository's pull requests
  before combining them, instead of reading every comment in the warehouse.
  Results are unchanged.

Upgrade notes

• Migration 5 builds the indexes the first time a warehouse is opened, which
  takes minutes on a large warehouse, followed by the one-time foreign key
  check every schema change triggers. The migration runs in one transaction:
  if interrupted, the warehouse stays at version 4 and the next open retries.
• The indexes add about 1.6% to the database size, most of it check runs. As
  with every migration, a binary built before this release refuses to open a
  warehouse that has been upgraded.