Trying some DB indexes.

This commit is contained in:
Dessalines 2020-01-10 23:09:38 -05:00
parent 6d89f6f955
commit 8fe034c320
4 changed files with 168 additions and 0 deletions

1
server/.gitignore vendored
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.env
.idea
env_setup.sh
query_testing/*.json

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-- This file should undo anything in `up.sql`
drop index idx_post_creator;
drop index idx_post_community;
drop index idx_post_like_post;
drop index idx_post_like_user;
drop index idx_comment_creator;
drop index idx_comment_parent;
drop index idx_comment_post;
drop index idx_comment_like_comment;
drop index idx_comment_like_user;
drop index idx_comment_like_post;
drop index idx_community_creator;
drop index idx_community_category;
drop index idx_community_follower_community;
drop index idx_community_follower_user;
drop index idx_community_user_ban_community;
drop index idx_community_user_ban_user;
drop view post_view;
create view post_view as
with all_post as
(
select
p.*,
(select u.banned from user_ u where p.creator_id = u.id) as banned,
(select cb.id::bool from community_user_ban cb where p.creator_id = cb.user_id and p.community_id = cb.community_id) as banned_from_community,
(select name from user_ where p.creator_id = user_.id) as creator_name,
(select avatar from user_ where p.creator_id = user_.id) as creator_avatar,
(select name from community where p.community_id = community.id) as community_name,
(select removed from community c where p.community_id = c.id) as community_removed,
(select deleted from community c where p.community_id = c.id) as community_deleted,
(select nsfw from community c where p.community_id = c.id) as community_nsfw,
(select count(*) from comment where comment.post_id = p.id) as number_of_comments,
coalesce(sum(pl.score), 0) as score,
count (case when pl.score = 1 then 1 else null end) as upvotes,
count (case when pl.score = -1 then 1 else null end) as downvotes,
hot_rank(coalesce(sum(pl.score) , 0), p.published) as hot_rank
from post p
left join post_like pl on p.id = pl.post_id
group by p.id
)
select
ap.*,
u.id as user_id,
coalesce(pl.score, 0) as my_vote,
(select cf.id::bool from community_follower cf where u.id = cf.user_id and cf.community_id = ap.community_id) as subscribed,
(select pr.id::bool from post_read pr where u.id = pr.user_id and pr.post_id = ap.id) as read,
(select ps.id::bool from post_saved ps where u.id = ps.user_id and ps.post_id = ap.id) as saved
from user_ u
cross join all_post ap
left join post_like pl on u.id = pl.user_id and ap.id = pl.post_id
union all
select
ap.*,
null as user_id,
null as my_vote,
null as subscribed,
null as read,
null as saved
from all_post ap
;

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-- Go through all the tables joins, optimize every view, CTE, etc.
create index idx_post_creator on post (creator_id);
create index idx_post_community on post (community_id);
create index idx_post_like_post on post_like (post_id);
create index idx_post_like_user on post_like (user_id);
create index idx_comment_creator on comment (creator_id);
create index idx_comment_parent on comment (parent_id);
create index idx_comment_post on comment (post_id);
create index idx_comment_like_comment on comment_like (comment_id);
create index idx_comment_like_user on comment_like (user_id);
create index idx_comment_like_post on comment_like (post_id);
create index idx_community_creator on community (creator_id);
create index idx_community_category on community (category_id);
create index idx_community_follower_community on community_follower (community_id);
create index idx_community_follower_user on community_follower (user_id);
create index idx_community_user_ban_community on community_user_ban (community_id);
create index idx_community_user_ban_user on community_user_ban (user_id);
-- optimize post_view
drop view post_view;
create view post_view as
with all_post as
(
select
p.*,
u.banned as banned,
(select cb.id::bool from community_user_ban cb where p.creator_id = cb.user_id and p.community_id = cb.community_id) as banned_from_community,
u.name as creator_name,
u.avatar as creator_avatar,
c.name as community_name,
c.removed as community_removed,
c.deleted as community_deleted,
c.nsfw as community_nsfw,
(select count(*) from comment where comment.post_id = p.id) as number_of_comments,
coalesce(sum(pl.score), 0) as score,
count (case when pl.score = 1 then 1 else null end) as upvotes,
count (case when pl.score = -1 then 1 else null end) as downvotes,
hot_rank(coalesce(sum(pl.score) , 0), p.published) as hot_rank
from post p
left join post_like pl on p.id = pl.post_id
inner join user_ u on p.creator_id = u.id
inner join community c on p.community_id = c.id
group by p.id, u.banned, u.name, u.avatar, c.name, c.removed, c.deleted, c.nsfw
)
select
ap.*,
u.id as user_id,
coalesce(pl.score, 0) as my_vote,
(select cf.id::bool from community_follower cf where u.id = cf.user_id and cf.community_id = ap.community_id) as subscribed,
(select pr.id::bool from post_read pr where u.id = pr.user_id and pr.post_id = ap.id) as read,
(select ps.id::bool from post_saved ps where u.id = ps.user_id and ps.post_id = ap.id) as saved
from user_ u
cross join all_post ap
left join post_like pl on u.id = pl.user_id and ap.id = pl.post_id
union all
select
ap.*,
null as user_id,
null as my_vote,
null as subscribed,
null as read,
null as saved
from all_post ap
;

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#!/bin/sh
# Do the views first
echo "explain (analyze, format json) select * from user_view" > explain.sql
psql -qAt -U lemmy -f explain.sql > user_view.json
echo "explain (analyze, format json) select * from post_view where user_id is null order by hot_rank desc" > explain.sql
psql -qAt -U lemmy -f explain.sql > post_view.json
echo "explain (analyze, format json) select * from comment_view where user_id is null" > explain.sql
psql -qAt -U lemmy -f explain.sql > comment_view.json
echo "explain (analyze, format json) select * from community_view where user_id is null order by hot_rank desc" > explain.sql
psql -qAt -U lemmy -f explain.sql > community_view.json
grep "Execution Time" *.json
rm explain.sql