optimize direct timeline (#7614)

* optimize direct timeline

* fix typo in class name

* change filter condition for direct timeline

* fix codestyle issue

* revoke index_accounts_not_silenced because direct timeline does not use it.

* revoke index_accounts_not_silenced because direct timeline does not use it.

* fix rspec test condition.

* fix rspec test condition.

* fix rspec test condition.

* revoke adding column and partial index

* (direct timeline) move merging logic to model

* fix pagination parameter

* add method arguments that switches return array of status or cache_ids

* fix order by

* returns ActiveRecord.Relation in default behavor

* fix codestyle issue

1 files changed, 38 insertions, 5 deletions

diff --git a/app/models/status.rb b/app/models/status.rb
index 853e75b43..54f3f68f5 100644
--- a/app/models/status.rb
+++ b/app/models/status.rb
@@ -188,12 +188,45 @@ class Status < ApplicationRecord
       where(account: [account] + account.following).where(visibility: [:public, :unlisted, :private])
     end
 
-    def as_direct_timeline(account)
-      query = joins("LEFT OUTER JOIN mentions ON statuses.id = mentions.status_id AND mentions.account_id = #{account.id}")
-              .where("mentions.account_id = #{account.id} OR statuses.account_id = #{account.id}")
-              .where(visibility: [:direct])
+    def as_direct_timeline(account, limit = 20, max_id = nil, since_id = nil, cache_ids = false)
+      # direct timeline is mix of direct message from_me and to_me.
+      # 2 querys are executed with pagination.
+      # constant expression using arel_table is required for partial index
+
+      # _from_me part does not require any timeline filters
+      query_from_me = where(account_id: account.id)
+                      .where(Status.arel_table[:visibility].eq(3))
+                      .limit(limit)
+                      .order('statuses.id DESC')
+
+      # _to_me part requires mute and block filter.
+      # FIXME: may we check mutes.hide_notifications?
+      query_to_me = Status
+                    .joins(:mentions)
+                    .merge(Mention.where(account_id: account.id))
+                    .where(Status.arel_table[:visibility].eq(3))
+                    .limit(limit)
+                    .order('mentions.status_id DESC')
+                    .not_excluded_by_account(account)
+
+      if max_id.present?
+        query_from_me = query_from_me.where('statuses.id < ?', max_id)
+        query_to_me = query_to_me.where('mentions.status_id < ?', max_id)
+      end
+
+      if since_id.present?
+        query_from_me = query_from_me.where('statuses.id > ?', since_id)
+        query_to_me = query_to_me.where('mentions.status_id > ?', since_id)
+      end
 
-      apply_timeline_filters(query, account, false)
+      if cache_ids
+        # returns array of cache_ids object that have id and updated_at
+        (query_from_me.cache_ids.to_a + query_to_me.cache_ids.to_a).uniq(&:id).sort_by(&:id).reverse.take(limit)
+      else
+        # returns ActiveRecord.Relation
+        items = (query_from_me.select(:id).to_a + query_to_me.select(:id).to_a).uniq(&:id).sort_by(&:id).reverse.take(limit)
+        Status.where(id: items.map(&:id))
+      end
     end
 
     def as_public_timeline(account = nil, local_only = false)