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⚡ Optimized comment count subquery to avoid full table scan #26624

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Merged
9larsons merged 2 commits into from
Feb 26, 2026
Merged

⚡ Optimized comment count subquery to avoid full table scan #26624

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⚡ Optimized count__direct_replies query to avoid full table scan
9larsons Feb 26, 2026
bef5455
Update ghost/core/core/server/models/comment.js
9larsons Feb 26, 2026
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31 changes: 15 additions & 16 deletions ghost/core/core/server/models/comment.js
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Original file line number Diff line number Diff line change
Expand Up @@ -265,22 +265,21 @@ const Comment = ghostBookshelf.Model.extend({
},
direct_replies(modelOrCollection, options) {
const excludedCommentStatuses = options.isAdmin ? ['deleted'] : ['hidden', 'deleted'];

modelOrCollection.query('columns', 'comments.*', (qb) => {
qb.count('replies.id')
.from('comments AS replies')
.where(function () {
// Root comments: count direct replies (parent_id = this, in_reply_to_id IS NULL)
this.where(function () {
this.whereRaw('replies.parent_id = comments.id')
.whereNull('replies.in_reply_to_id');
})
// Child comments: count replies-to-this-child (in_reply_to_id = this)
.orWhereRaw('replies.in_reply_to_id = comments.id');
})
.whereNotIn('replies.status', excludedCommentStatuses)
.as('count__direct_replies');
});
const statusPlaceholders = excludedCommentStatuses.map(() => '?').join(',');

// Split into two separate indexed subqueries instead of a single OR-based query.
// The OR between parent_id and in_reply_to_id defeats MySQL index usage,
// causing full table scans. Two separate subqueries each use their own index.
modelOrCollection.query('columns', 'comments.*', ghostBookshelf.knex.raw(`(
(SELECT COUNT(*) FROM comments AS r1
WHERE r1.parent_id = comments.id
AND r1.in_reply_to_id IS NULL
AND r1.status NOT IN (${statusPlaceholders}))
+
(SELECT COUNT(*) FROM comments AS r2
WHERE r2.in_reply_to_id = comments.id
AND r2.status NOT IN (${statusPlaceholders}))
) as count__direct_replies`, [...excludedCommentStatuses, ...excludedCommentStatuses]));
},
likes(modelOrCollection) {
modelOrCollection.query('columns', 'comments.*', (qb) => {
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