lemmy/migrations/2023-07-26-000217_create_co.../up.sql

98 lines
4.1 KiB
PL/PgSQL

-- Need to add immutable to the controversy_rank function in order to index by it
-- Controversy Rank:
-- if downvotes <= 0 or upvotes <= 0:
-- 0
-- else:
-- (upvotes + downvotes) * min(upvotes, downvotes) / max(upvotes, downvotes)
create or replace function controversy_rank(upvotes numeric, downvotes numeric)
returns float as $$
begin
if downvotes <= 0 or upvotes <= 0 then
return 0;
else
return (upvotes + downvotes) *
case when upvotes > downvotes
then downvotes::float / upvotes::float
else upvotes::float / downvotes::float
end;
end if;
end; $$
LANGUAGE plpgsql
IMMUTABLE;
-- Aggregates
alter table post_aggregates add column controversy_rank float not null default 0;
alter table comment_aggregates add column controversy_rank float not null default 0;
-- Populate them initially
-- Note: After initial population, these are updated with vote triggers
update post_aggregates set controversy_rank = controversy_rank(upvotes::numeric, downvotes::numeric);
update comment_aggregates set controversy_rank = controversy_rank(upvotes::numeric, downvotes::numeric);
-- Create single column indexes
create index idx_post_aggregates_featured_local_controversy on post_aggregates (featured_local desc, controversy_rank desc);
create index idx_post_aggregates_featured_community_controversy on post_aggregates (featured_community desc, controversy_rank desc);
create index idx_comment_aggregates_controversy on comment_aggregates (controversy_rank desc);
-- Update post_aggregates_score trigger function to include controversy_rank update
create or replace function post_aggregates_score()
returns trigger language plpgsql
as $$
begin
IF (TG_OP = 'INSERT') THEN
update post_aggregates pa
set score = score + NEW.score,
upvotes = case when NEW.score = 1 then upvotes + 1 else upvotes end,
downvotes = case when NEW.score = -1 then downvotes + 1 else downvotes end,
controversy_rank = controversy_rank(pa.upvotes + case when NEW.score = 1 then 1 else 0 end::numeric,
pa.downvotes + case when NEW.score = -1 then 1 else 0 end::numeric)
where pa.post_id = NEW.post_id;
ELSIF (TG_OP = 'DELETE') THEN
-- Join to post because that post may not exist anymore
update post_aggregates pa
set score = score - OLD.score,
upvotes = case when OLD.score = 1 then upvotes - 1 else upvotes end,
downvotes = case when OLD.score = -1 then downvotes - 1 else downvotes end,
controversy_rank = controversy_rank(pa.upvotes + case when NEW.score = 1 then 1 else 0 end::numeric,
pa.downvotes + case when NEW.score = -1 then 1 else 0 end::numeric)
from post p
where pa.post_id = p.id
and pa.post_id = OLD.post_id;
END IF;
return null;
end $$;
-- Update comment_aggregates_score trigger function to include controversy_rank update
create or replace function comment_aggregates_score()
returns trigger language plpgsql
as $$
begin
IF (TG_OP = 'INSERT') THEN
update comment_aggregates ca
set score = score + NEW.score,
upvotes = case when NEW.score = 1 then upvotes + 1 else upvotes end,
downvotes = case when NEW.score = -1 then downvotes + 1 else downvotes end,
controversy_rank = controversy_rank(ca.upvotes + case when NEW.score = 1 then 1 else 0 end::numeric,
ca.downvotes + case when NEW.score = -1 then 1 else 0 end::numeric)
where ca.comment_id = NEW.comment_id;
ELSIF (TG_OP = 'DELETE') THEN
-- Join to comment because that comment may not exist anymore
update comment_aggregates ca
set score = score - OLD.score,
upvotes = case when OLD.score = 1 then upvotes - 1 else upvotes end,
downvotes = case when OLD.score = -1 then downvotes - 1 else downvotes end,
controversy_rank = controversy_rank(ca.upvotes + case when NEW.score = 1 then 1 else 0 end::numeric,
ca.downvotes + case when NEW.score = -1 then 1 else 0 end::numeric)
from comment c
where ca.comment_id = c.id
and ca.comment_id = OLD.comment_id;
END IF;
return null;
end $$;