<p></p>
<p><b>@tomhughes</b> commented on this pull request.</p>

<hr>

<p>In <a href="https://github.com/openstreetmap/openstreetmap-website/pull/5304#discussion_r1833109950">db/migrate/20241023004427_backfill_note_subscriptions.rb</a>:</p>
<pre style='color:#555'>> @@ -0,0 +1,14 @@
+class BackfillNoteSubscriptions < ActiveRecord::Migration[7.2]
+  class NoteComment < ApplicationRecord; end
+  class NoteSubscription < ApplicationRecord; end
+
+  disable_ddl_transaction!
+
+  def up
+    NoteComment.in_batches(:of => 1000) do |note_comments|
+      rows = note_comments.distinct.where.not(:author_id => nil).pluck(:author_id, :note_id)
+      attrs = %w[user_id note_id]
</pre>
<p dir="auto">There's no need to initialise this for every batch, it could go before the loop?</p>

<p style="font-size:small;-webkit-text-size-adjust:none;color:#666;">—<br />Reply to this email directly, <a href="https://github.com/openstreetmap/openstreetmap-website/pull/5304#pullrequestreview-2421727032">view it on GitHub</a>, or <a href="https://github.com/notifications/unsubscribe-auth/AAK2OLJP3JKCNW2PVB4W4WLZ7OQMVAVCNFSM6AAAAABRIPZOLSVHI2DSMVQWIX3LMV43YUDVNRWFEZLROVSXG5CSMV3GSZLXHMZDIMRRG4ZDOMBTGI">unsubscribe</a>.<br />You are receiving this because you are subscribed to this thread.<img src="https://github.com/notifications/beacon/AAK2OLOURY7JPXT36D4PHWTZ7OQMVA5CNFSM6AAAAABRIPZOLSWGG33NNVSW45C7OR4XAZNRKB2WY3CSMVYXKZLTORJGK5TJMV32UY3PNVWWK3TUL5UWJTUQLCPTQ.gif" height="1" width="1" alt="" /><span style="color: transparent; font-size: 0; display: none; visibility: hidden; overflow: hidden; opacity: 0; width: 0; height: 0; max-width: 0; max-height: 0; mso-hide: all">Message ID: <span><openstreetmap/openstreetmap-website/pull/5304/review/2421727032</span><span>@</span><span>github</span><span>.</span><span>com></span></span></p>
<script type="application/ld+json">[
{
"@context": "http://schema.org",
"@type": "EmailMessage",
"potentialAction": {
"@type": "ViewAction",
"target": "https://github.com/openstreetmap/openstreetmap-website/pull/5304#pullrequestreview-2421727032",
"url": "https://github.com/openstreetmap/openstreetmap-website/pull/5304#pullrequestreview-2421727032",
"name": "View Pull Request"
},
"description": "View this Pull Request on GitHub",
"publisher": {
"@type": "Organization",
"name": "GitHub",
"url": "https://github.com"
}
}
]</script>