force sqlite to use rkey index to look up by rkey

app/firehose_stream.rb

···
 
   def process_post(msg, op)
     if op.action == :delete
-      if post = Post.find_by(repo: op.repo, rkey: op.rkey)
+      if post = Post.find_by_repo_rkey(op.repo, op.rkey)
         post.destroy
       end
     end

app/models/post.rb

···
 
   attr_writer :record
 
+  def self.find_by_repo_rkey(repo, rkey)
+    # the '+' is to make sure that SQLite uses the rkey index and not a different one
+    Post.where("+repo = ?", repo).where(rkey: rkey).first
+  end
+
   def self.find_by_at_uri(uri)
     parts = uri.gsub(%r(^at://), '').split('/')
     return nil unless parts.length == 3 && parts[1] == 'app.bsky.feed.post'
 
-    Post.find_by(repo: parts[0], rkey: parts[2])
+    find_by_repo_rkey(parts[0], parts[2])
   end
 
   def record