lemmy/migrations/2022-04-04-183652_update_community_aggregates_on_soft_delete/up.sql
Rens Groothuijsen 9c1b9ff3cf
Update community statistics after post or comment is deleted by user (#2193)
* Update community statistics after post or comment is deleted by user

* Update triggers for site and person aggregates

* Restore comment counts when post is restored

* Simplify insertion/deletion trigger checks before updating statistics
2022-04-27 16:12:41 +00:00

328 lines
10 KiB
PL/PgSQL

drop trigger if exists community_aggregates_post_count on post;
drop trigger if exists community_aggregates_comment_count on comment;
drop trigger if exists site_aggregates_comment_insert on comment;
drop trigger if exists site_aggregates_comment_delete on comment;
drop trigger if exists site_aggregates_post_insert on post;
drop trigger if exists site_aggregates_post_delete on post;
drop trigger if exists site_aggregates_community_insert on community;
drop trigger if exists site_aggregates_community_delete on community;
drop trigger if exists person_aggregates_post_count on post;
drop trigger if exists person_aggregates_comment_count on comment;
create or replace function was_removed_or_deleted(TG_OP text, OLD record, NEW record)
RETURNS boolean
LANGUAGE plpgsql
as $$
begin
IF (TG_OP = 'INSERT') THEN
return false;
end if;
IF (TG_OP = 'DELETE') THEN
return true;
end if;
return TG_OP = 'UPDATE' AND (
(OLD.deleted = 'f' AND NEW.deleted = 't') OR
(OLD.removed = 'f' AND NEW.removed = 't')
);
END $$;
create or replace function was_restored_or_created(TG_OP text, OLD record, NEW record)
RETURNS boolean
LANGUAGE plpgsql
as $$
begin
IF (TG_OP = 'DELETE') THEN
return false;
end if;
IF (TG_OP = 'INSERT') THEN
return true;
end if;
return TG_OP = 'UPDATE' AND (
(OLD.deleted = 't' AND NEW.deleted = 'f') OR
(OLD.removed = 't' AND NEW.removed = 'f')
);
END $$;
-- Community aggregate functions
create or replace function community_aggregates_post_count()
returns trigger language plpgsql
as $$
begin
IF (was_restored_or_created(TG_OP, OLD, NEW)) THEN
update community_aggregates
set posts = posts + 1 where community_id = NEW.community_id;
IF (TG_OP = 'UPDATE') THEN
-- Post was restored, so restore comment counts as well
update community_aggregates ca
set posts = coalesce(cd.posts, 0),
comments = coalesce(cd.comments, 0)
from (
select
c.id,
count(distinct p.id) as posts,
count(distinct ct.id) as comments
from community c
left join post p on c.id = p.community_id and p.deleted = 'f' and p.removed = 'f'
left join comment ct on p.id = ct.post_id and ct.deleted = 'f' and ct.removed = 'f'
where c.id = NEW.community_id
group by c.id
) cd
where ca.community_id = NEW.community_id;
END IF;
ELSIF (was_removed_or_deleted(TG_OP, OLD, NEW)) THEN
update community_aggregates
set posts = posts - 1 where community_id = OLD.community_id;
-- Update the counts if the post got deleted
update community_aggregates ca
set posts = coalesce(cd.posts, 0),
comments = coalesce(cd.comments, 0)
from (
select
c.id,
count(distinct p.id) as posts,
count(distinct ct.id) as comments
from community c
left join post p on c.id = p.community_id and p.deleted = 'f' and p.removed = 'f'
left join comment ct on p.id = ct.post_id and ct.deleted = 'f' and ct.removed = 'f'
where c.id = OLD.community_id
group by c.id
) cd
where ca.community_id = OLD.community_id;
END IF;
return null;
end $$;
-- comment count
create or replace function community_aggregates_comment_count()
returns trigger language plpgsql
as $$
begin
IF (was_restored_or_created(TG_OP, OLD, NEW)) THEN
update community_aggregates ca
set comments = comments + 1 from comment c, post p
where p.id = c.post_id
and p.id = NEW.post_id
and ca.community_id = p.community_id;
ELSIF (was_removed_or_deleted(TG_OP, OLD, NEW)) THEN
update community_aggregates ca
set comments = comments - 1 from comment c, post p
where p.id = c.post_id
and p.id = OLD.post_id
and ca.community_id = p.community_id;
END IF;
return null;
end $$;
-- Community aggregate triggers
create trigger community_aggregates_post_count
after insert or delete or update of removed, deleted on post
for each row
execute procedure community_aggregates_post_count();
create trigger community_aggregates_comment_count
after insert or delete or update of removed, deleted on comment
for each row
execute procedure community_aggregates_comment_count();
-- Site aggregate functions
create or replace function site_aggregates_post_insert()
returns trigger language plpgsql
as $$
begin
IF (was_restored_or_created(TG_OP, OLD, NEW)) THEN
update site_aggregates sa
set posts = posts + 1
from site s
where sa.site_id = s.id;
END IF;
return null;
end $$;
create or replace function site_aggregates_post_delete()
returns trigger language plpgsql
as $$
begin
IF (was_removed_or_deleted(TG_OP, OLD, NEW)) THEN
update site_aggregates sa
set posts = posts - 1
from site s
where sa.site_id = s.id;
END IF;
return null;
end $$;
create or replace function site_aggregates_comment_insert()
returns trigger language plpgsql
as $$
begin
IF (was_restored_or_created(TG_OP, OLD, NEW)) THEN
update site_aggregates sa
set comments = comments + 1
from site s
where sa.site_id = s.id;
END IF;
return null;
end $$;
create or replace function site_aggregates_comment_delete()
returns trigger language plpgsql
as $$
begin
IF (was_removed_or_deleted(TG_OP, OLD, NEW)) THEN
update site_aggregates sa
set comments = comments - 1
from site s
where sa.site_id = s.id;
END IF;
return null;
end $$;
create or replace function site_aggregates_community_insert()
returns trigger language plpgsql
as $$
begin
IF (was_restored_or_created(TG_OP, OLD, NEW)) THEN
update site_aggregates sa
set communities = communities + 1
from site s
where sa.site_id = s.id;
END IF;
return null;
end $$;
create or replace function site_aggregates_community_delete()
returns trigger language plpgsql
as $$
begin
IF (was_removed_or_deleted(TG_OP, OLD, NEW)) THEN
update site_aggregates sa
set communities = communities - 1
from site s
where sa.site_id = s.id;
END IF;
return null;
end $$;
-- Site aggregate triggers
create trigger site_aggregates_post_insert
after insert or update of removed, deleted on post
for each row
when (NEW.local = true)
execute procedure site_aggregates_post_insert();
create trigger site_aggregates_post_delete
after delete or update of removed, deleted on post
for each row
when (OLD.local = true)
execute procedure site_aggregates_post_delete();
create trigger site_aggregates_comment_insert
after insert or update of removed, deleted on comment
for each row
when (NEW.local = true)
execute procedure site_aggregates_comment_insert();
create trigger site_aggregates_comment_delete
after delete or update of removed, deleted on comment
for each row
when (OLD.local = true)
execute procedure site_aggregates_comment_delete();
create trigger site_aggregates_community_insert
after insert or update of removed, deleted on community
for each row
when (NEW.local = true)
execute procedure site_aggregates_community_insert();
create trigger site_aggregates_community_delete
after delete or update of removed, deleted on community
for each row
when (OLD.local = true)
execute procedure site_aggregates_community_delete();
-- Person aggregate functions
create or replace function person_aggregates_post_count()
returns trigger language plpgsql
as $$
begin
IF (was_restored_or_created(TG_OP, OLD, NEW)) THEN
update person_aggregates
set post_count = post_count + 1 where person_id = NEW.creator_id;
ELSIF (was_removed_or_deleted(TG_OP, OLD, NEW)) THEN
update person_aggregates
set post_count = post_count - 1 where person_id = OLD.creator_id;
-- If the post gets deleted, the score calculation trigger won't fire,
-- so you need to re-calculate
update person_aggregates ua
set post_score = pd.score
from (
select u.id,
coalesce(0, sum(pl.score)) as score
-- User join because posts could be empty
from person u
left join post p on u.id = p.creator_id and p.deleted = 'f' and p.removed = 'f'
left join post_like pl on p.id = pl.post_id
group by u.id
) pd
where ua.person_id = OLD.creator_id;
END IF;
return null;
end $$;
create or replace function person_aggregates_comment_count()
returns trigger language plpgsql
as $$
begin
IF (was_restored_or_created(TG_OP, OLD, NEW)) THEN
update person_aggregates
set comment_count = comment_count + 1 where person_id = NEW.creator_id;
ELSIF (was_removed_or_deleted(TG_OP, OLD, NEW)) THEN
update person_aggregates
set comment_count = comment_count - 1 where person_id = OLD.creator_id;
-- If the comment gets deleted, the score calculation trigger won't fire,
-- so you need to re-calculate
update person_aggregates ua
set comment_score = cd.score
from (
select u.id,
coalesce(0, sum(cl.score)) as score
-- User join because comments could be empty
from person u
left join comment c on u.id = c.creator_id and c.deleted = 'f' and c.removed = 'f'
left join comment_like cl on c.id = cl.comment_id
group by u.id
) cd
where ua.person_id = OLD.creator_id;
END IF;
return null;
end $$;
-- Person aggregate triggers
create trigger person_aggregates_post_count
after insert or delete or update of removed, deleted on post
for each row
execute procedure person_aggregates_post_count();
create trigger person_aggregates_comment_count
after insert or delete or update of removed, deleted on comment
for each row
execute procedure person_aggregates_comment_count();