Alan Guo Xiang Tan fe5cd479eb PERF: Add index on topic_id and created_at to posts table (#22818) ... Why this change? In `PostDestroyer#make_previous_post_the_last_one` and `Topic.reset_highest`, we have a query that looks something like this: ``` SELECT user_id FROM posts WHERE topic_id = :topic_id AND deleted_at IS NULL AND post_type <> 4 #{post_type} ORDER BY created_at desc LIMIT 1 ``` However, we currently don't have an index that caters directly to this query. As a result, we have seen this query performing poorly on large sites if the PG planner ends up using an index that is suboptimal for the query. This commit adds an index to the `posts` table on `topic_id` and then `created_at`. For the query above, PG will be able to do a backwards index scan efficiently.		2023-07-27 10:55:10 +08:00
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fixtures	UX: Update badge icons (#20462)	2023-02-28 10:42:05 +08:00
migrate	PERF: Add index on topic_id and created_at to posts table (#22818)	2023-07-27 10:55:10 +08:00
post_migrate	DEV: Promote historic post_deploy migrations	2023-07-26 10:36:37 +02:00
api_test_seeds.rb	DEV: Apply syntax_tree formatting to db/*	2023-01-09 11:59:41 +00:00