From ec56cac42da7c647c8b35714092f52a10c0bef0a Mon Sep 17 00:00:00 2001 From: Agniva De Sarker Date: Fri, 29 Oct 2021 09:07:10 +0530 Subject: [PATCH] Optimize TotalUnreadMentions (#18789) * Optimize TotalUnreadMentions We avoid joining with the Threads table entirely as ChannelId is available from Posts table directly. Also we replace left joins by inner joins. https://community-daily.mattermost.com/boards/workspace/zyoahc9uapdn3xdptac6jb69ic/285b80a3-257d-41f6-8cf4-ed80ca9d92e5/495cdb4d-c13a-4992-8eb9-80cfee2819a4?c=c9aa17f3-b918-4a78-86aa-01562e418634 Old plan ``` Finalize Aggregate (cost=30869.29..30869.30 rows=1 width=32) (actual time=27.216..31.674 rows=1 loops=1) -> Gather (cost=30869.18..30869.29 rows=1 width=32) (actual time=27.089..31.665 rows=2 loops=1) Workers Planned: 1 Workers Launched: 1 -> Partial Aggregate (cost=29869.18..29869.19 rows=1 width=32) (actual time=18.442..18.445 rows=1 loops=2) -> Nested Loop (cost=1881.68..29869.11 rows=25 width=8) (actual time=2.052..18.417 rows=72 loops=2) -> Hash Join (cost=1881.12..29771.45 rows=25 width=62) (actual time=2.028..17.744 rows=72 loops=2) Hash Cond: ((threads.channelid)::text = (channels.id)::text) -> Nested Loop (cost=0.84..27883.40 rows=2963 width=89) (actual time=0.220..15.849 rows=163 loops=2) -> Parallel Index Scan using threadmemberships_pkey on threadmemberships (cost=0.41..7423.65 rows=2963 width=35) (actual time=0.031..3.937 rows=2504 loops=2) Index Cond: ((userid)::text = 'tc3p1yqw67d8idcp3g98awexqe'::text) Filter: following -> Index Scan using threads_pkey on threads (cost=0.42..6.91 rows=1 width=54) (actual time=0.004..0.004 rows=0 loops=5007) Index Cond: ((postid)::text = (threadmemberships.postid)::text) -> Hash (cost=1866.60..1866.60 rows=1094 width=27) (actual time=1.763..1.764 rows=1002 loops=2) Buckets: 2048 Batches: 1 Memory Usage: 74kB -> Index Scan using idx_channels_team_id_type on channels (cost=0.42..1866.60 rows=1094 width=27) (actual time=0.022..1.493 rows=1002 loops=2) Index Cond: ((teamid)::text = '8ywxyw9ocp8smxrmjzrkqhrdwe'::text) -> Index Scan using posts_pkey on posts (cost=0.56..3.91 rows=1 width=27) (actual time=0.009..0.009 rows=1 loops=145) Index Cond: ((id)::text = (threads.postid)::text) Filter: (deleteat = 0) Planning Time: 2.415 ms Execution Time: 31.798 ms ``` New plan ``` ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Finalize Aggregate (cost=34717.01..34717.02 rows=1 width=32) (actual time=42.375..48.143 rows=1 loops=1) -> Gather (cost=34716.89..34717.00 rows=1 width=32) (actual time=42.249..48.117 rows=2 loops=1) Workers Planned: 1 Workers Launched: 1 -> Partial Aggregate (cost=33716.89..33716.90 rows=1 width=32) (actual time=30.960..30.962 rows=1 loops=2) -> Hash Join (cost=1881.25..33716.83 rows=25 width=8) (actual time=2.438..30.780 rows=1058 loops=2) Hash Cond: ((posts.channelid)::text = (channels.id)::text) -> Nested Loop (cost=0.98..31828.77 rows=2963 width=35) (actual time=0.091..27.374 rows=2504 loops=2) -> Parallel Index Scan using threadmemberships_pkey on threadmemberships (cost=0.41..6815.65 rows=2963 width=35) (actual time=0.034..4.674 rows=2504 loops=2) Index Cond: ((userid)::text = 'tc3p1yqw67d8idcp3g98awexqe'::text) Filter: following -> Index Scan using posts_pkey on posts (cost=0.56..8.44 rows=1 width=54) (actual time=0.008..0.008 rows=1 loops=5007) Index Cond: ((id)::text = (threadmemberships.postid)::text) Filter: (deleteat = 0) -> Hash (cost=1866.60..1866.60 rows=1094 width=27) (actual time=2.289..2.289 rows=1002 loops=2) Buckets: 2048 Batches: 1 Memory Usage: 74kB -> Index Scan using idx_channels_team_id_type on channels (cost=0.42..1866.60 rows=1094 width=27) (actual time=0.028..1.927 rows=1002 loops=2) Index Cond: ((teamid)::text = '8ywxyw9ocp8smxrmjzrkqhrdwe'::text) ``` ```release-note NONE ``` * Bring back coalesce ```release-note NONE ``` --- store/sqlstore/thread_store.go | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/store/sqlstore/thread_store.go b/store/sqlstore/thread_store.go index 9592a1eee9..a12854e31c 100644 --- a/store/sqlstore/thread_store.go +++ b/store/sqlstore/thread_store.go @@ -200,12 +200,12 @@ func (s *SqlThreadStore) GetThreadsForUser(userId, teamId string, opts model.Get }() go func() { mentionsQuery, mentionsQueryArgs, _ := s.getQueryBuilder(). - Select("COALESCE(SUM(ThreadMemberships.UnreadMentions),0)"). - From("ThreadMemberships"). - LeftJoin("Threads ON Threads.PostId = ThreadMemberships.PostId"). - LeftJoin("Posts ON Posts.Id = ThreadMemberships.PostId"). - LeftJoin("Channels ON Threads.ChannelId = Channels.Id"). + Select("COALESCE(SUM(ThreadMemberships.UnreadMentions), 0)"). + From("ThreadMemberships, Posts, Channels"). + Where("Posts.Id = ThreadMemberships.PostId"). + Where("Posts.ChannelId = Channels.Id"). Where(fetchConditions).ToSql() + totalUnreadMentions, err := s.GetMaster().SelectInt(mentionsQuery, mentionsQueryArgs...) totalUnreadMentionsChan <- store.StoreResult{Data: totalUnreadMentions, NErr: err} close(totalUnreadMentionsChan)