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Bug #19856

closed

Redmine query is very slow after upgrading from MySql 5.7 to 8

Added by Anonymous over 1 year ago. Updated over 1 year ago.

Status:
Rejected
Assignee:
-
Target version:
-
ruby -v:
4.1.1.stable, 5.0.5
Backport:
3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN
[ruby-core:114576]

Description

Recently we upgraded the MySql version for Redmine from 5.7 to 8.0.32. After the upgrade the MyPage query is taking a very long time to execute (Around 1 minute). Previously in version 5.7 it used to execute within a few seconds. This is resulting in our CPU usage to reach 99% very quickly.

On initial research looks like MySql 8 uses derived query optimization concept due to which the logic that the query is interpreted in 5.7 and 8 is different.

Redmine Version: 4.1.1.stable (Tried this on latest redmine version 5.0.5 but faced the same issue. Also all the appropriate index have been done as well)

My Page Query:

SELECT
  issues.id AS t0_r0,
  issues.tracker_id AS t0_r1,
  issues.project_id AS t0_r2,
  issues.subject AS t0_r3,
  issues.description AS t0_r4,
  issues.due_date AS t0_r5,
  issues.category_id AS t0_r6,
  issues.status_id AS t0_r7,
  issues.assigned_to_id AS t0_r8,
  issues.priority_id AS t0_r9,
  issues.fixed_version_id AS t0_r10,
  issues.author_id AS t0_r11,
  issues.lock_version AS t0_r12,
  issues.created_on AS t0_r13,
  issues.updated_on AS t0_r14,
  issues.start_date AS t0_r15,
  issues.done_ratio AS t0_r16,
  issues.estimated_hours AS t0_r17,
  issues.parent_id AS t0_r18,
  issues.root_id AS t0_r19,
  issues.lft AS t0_r20,
  issues.rgt AS t0_r21,
  issues.is_private AS t0_r22,
  issues.position AS t0_r23,
  issues.remaining_hours AS t0_r24,
  issues.story_points AS t0_r25,
  issues.closed_on AS t0_r26,
  issue_statuses.id AS t1_r0,
  issue_statuses.name AS t1_r1,
  issue_statuses.is_closed AS t1_r2,
  issue_statuses.position AS t1_r3,
  issue_statuses.default_done_ratio AS t1_r4,
  projects.id AS t2_r0,
  projects.name AS t2_r1,
  projects.description AS t2_r2,
  projects.homepage AS t2_r3,
  projects.is_public AS t2_r4,
  projects.parent_id AS t2_r5,
  projects.created_on AS t2_r6,
  projects.updated_on AS t2_r7,
  projects.identifier AS t2_r8,
  projects.status AS t2_r9,
  projects.lft AS t2_r10,
  projects.rgt AS t2_r11,
  projects.inherit_members AS t2_r12,
  projects.default_version_id AS t2_r13,
  projects.default_assigned_to_id AS t2_r14
FROM
  issues
  INNER JOIN projects ON projects.id = issues.project_id
  INNER JOIN issue_statuses ON issue_statuses.id = issues.status_id
  LEFT OUTER JOIN enumerations ON enumerations.id = issues.priority_id
WHERE
  (projects.status <> 9
  AND EXISTS (
    SELECT 1
    FROM enabled_modules em
    WHERE em.project_id = projects.id AND em.name='issue_tracking'
  ))
  AND (
    issues.status_id IN (SELECT id FROM issue_statuses WHERE is_closed=FALSE)
    AND issues.assigned_to_id IN ('1051', '2643')
    AND projects.status IN ('1')
  )
ORDER BY
  enumerations.position DESC,
  issues.updated_on DESC,
  issues.id DESC
LIMIT 10;

Explain for MySQL 8.0.32

id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE issue_statuses ALL PRIMARY 19 100 Using temporary; Using filesort
1 SIMPLE issue_statuses eq_ref PRIMARY,index_issue_statuses_on_is_closed PRIMARY 4 deermine.issue_statuses.id 1 89.47 Using where
1 SIMPLE ALL 100 Using where; Using join buffer (hash join)
1 SIMPLE projects eq_ref PRIMARY PRIMARY 4 .project_id 1 9 Using where
1 SIMPLE issues ref issues_project_id,index_issues_on_status_id,index_issues_on_assigned_to_id issues_project_id 4 .project_id 1917 0.03 Using where
1 SIMPLE enumerations eq_ref PRIMARY,index_enumerations_on_id_and_type PRIMARY 4 deermine.issues.priority_id 1 100
2 MATERIALIZED em ALL enabled_modules_project_id 3545 10 Using where

Explain for MySQL 5.7

id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 PRIMARY issues range issues_project_id,index_issues_on_status_id,index_issues_on_assigned_to_id index_issues_on_assigned_to_id 5 2560 100 Using index condition; Using temporary; Using filesort
1 PRIMARY issue_statuses eq_ref PRIMARY,index_issue_statuses_on_is_closed PRIMARY 4 deermine.issues.status_id 1 89.47 Using where
1 PRIMARY issue_statuses eq_ref PRIMARY PRIMARY 4 deermine.issues.status_id 1 100
1 PRIMARY enumerations eq_ref PRIMARY,index_enumerations_on_id_and_type PRIMARY 4 deermine.issues.priority_id 1 100
1 PRIMARY projects eq_ref PRIMARY PRIMARY 4 deermine.issues.project_id 1 9 Using where
2 DEPENDENT SUBQUERY em ref enabled_modules_project_id enabled_modules_project_id 5 deermine.projects.id 5 10 Using where

As you can see, in 5.7 all the rows are being pulled in single query where as for 8.0.32 it is being pulled in multiple query.

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