【发布时间】：2021-09-27 05:03:15
【问题描述】：
将大型数据库从 MySQL 8.0.13 数据迁移到 MariaDB 10.5.11 后遇到特定查询性能问题。
我通过 repo 安装 MariaDB：
[mariadb]
name = MariaDB 10.5 para CentOS 7
baseurl = http://yum.mariadb.org/10.5/centos7-amd64
gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB
gpgcheck=1
要导出我使用的数据库：mysqldump database > database.sql
导入后我还重新创建了索引。
新服务器：
- centos-release-7-9.2009.1.el7.centos.x86_64
- 16GB 内存
- 8 CPU
旧服务器：
- centos-release-6-10.el6.centos.12.3.x86_64
- 12 GB 内存
- 4 CPU
性能慢的 SQL 查询：
SELECT rep.unique_id AS report_id, rep.name AS report_title,
sir.slide_id, s.slide_order, st.tag_category_id, stc.txt as categoria,
st.tag_value_id, stv.txt as valor, count(sir2.slide_id) as Slides,
count(s2.media_id) as Medias
FROM er_reports rep
INNER JOIN er_slides_in_report sir ON sir.deleted_date IS NULL
AND rep.unique_id = sir.report_id
INNER JOIN er_slides_in_report sir2 ON sir.deleted_date IS NULL
AND rep.unique_id = sir2.report_id
INNER JOIN er_slides s ON s.deleted_date IS NULL
AND s.unique_id = sir.slide_id
LEFT JOIN er_slides s2 ON s2.deleted_date IS NULL
AND sir2.slide_id = s2.unique_id
LEFT JOIN er_media m ON m.deleted_date IS NULL
AND s2.media_id = m.unique_id
INNER JOIN er_slides_tags st ON st.deleted_date IS NULL
AND s.unique_id = st.slide_id
INNER JOIN er_slide_tags_categories stc ON st.tag_category_id = stc.id
INNER JOIN er_slide_tags_values stv ON st.tag_value_id = stv.id
WHERE rep.deleted_date IS NULL
AND s.slide_order < 0
AND rep.user_id = 1606741093465
GROUP BY rep.unique_id, sir.slide_id, st.tag_category_id,
st.tag_value_id;
解释 MariaDB：
+------+-------------+-------+---------------+-----------------------------------------------------+---------------------------+---------+----------------------------------+---------+---------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+------+-------------+-------+---------------+-----------------------------------------------------+---------------------------+---------+----------------------------------+---------+---------------------------------+
| 1 | SIMPLE | stc | index | PRIMARY | txt | 767 | NULL | 47 | Using index |
| 1 | SIMPLE | st | ref | slide_id,tag_value_id,slide_cat_val,tag_category_id | tag_category_id | 8 | cloud_discipline.stc.id | 376 | Using where |
| 1 | SIMPLE | stv | eq_ref | PRIMARY | PRIMARY | 8 | cloud_discipline.st.tag_value_id | 1 | |
| 1 | SIMPLE | sir | ref | report_id,slide_id,deleted_date,slide_in_report | slide_id | 194 | cloud_discipline.st.slide_id | 1 | Using where |
| 1 | SIMPLE | rep | eq_ref|filter | unique_index,user_id,deleted_date | unique_index|deleted_date | 194|6 | cloud_discipline.sir.report_id | 1 (49%) | Using where; Using rowid filter |
| 1 | SIMPLE | s | ref | unique_id,deleted_date | unique_id | 194 | cloud_discipline.st.slide_id | 1 | Using where |
| 1 | SIMPLE | sir2 | ref | report_id,slide_in_report | slide_in_report | 194 | cloud_discipline.sir.report_id | 17 | Using index |
| 1 | SIMPLE | s2 | ref | unique_id,deleted_date | unique_id | 194 | cloud_discipline.sir2.slide_id | 1 | Using where |
| 1 | SIMPLE | m | ref | unique_id,deleted_date | unique_id | 194 | cloud_discipline.s2.media_id | 1 | Using where |
+------+-------------+-------+---------------+-----------------------------------------------------+---------------------------+---------+----------------------------------+---------+---------------------------------+
解释MySql：
+----+-------------+-------+------------+--------+--------------------------------------------------------+-----------------+---------+---------------------------------+--------+----------+-----------------------+
| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+-------+------------+--------+--------------------------------------------------------+-----------------+---------+---------------------------------+--------+----------+-----------------------+
| 1 | SIMPLE | sir | NULL | ref | report_id,slide_id,deleted_date,slide_in_report | deleted_date | 6 | const | 192448 | 100.00 | Using index condition |
| 1 | SIMPLE | rep | NULL | eq_ref | unique_id,unique_id_2,unique_id_3,user_id,deleted_date | unique_id | 194 | cloud_soccer.sir.report_id | 1 | 5.00 | Using where |
| 1 | SIMPLE | s | NULL | ref | unique_id,deleted_date | unique_id | 194 | cloud_soccer.sir.slide_id | 1 | 16.66 | Using where |
| 1 | SIMPLE | st | NULL | ref | slide_id,tag_value_id,slide_cat_val,tag_category_id | slide_cat_val | 194 | cloud_soccer.sir.slide_id | 17 | 10.00 | Using where |
| 1 | SIMPLE | stc | NULL | eq_ref | PRIMARY | PRIMARY | 8 | cloud_soccer.st.tag_category_id | 1 | 100.00 | NULL |
| 1 | SIMPLE | stv | NULL | eq_ref | PRIMARY | PRIMARY | 8 | cloud_soccer.st.tag_value_id | 1 | 100.00 | NULL |
| 1 | SIMPLE | sir2 | NULL | ref | report_id,slide_in_report | slide_in_report | 194 | cloud_soccer.sir.report_id | 35 | 100.00 | Using index |
| 1 | SIMPLE | s2 | NULL | ref | unique_id,deleted_date | unique_id | 194 | cloud_soccer.sir2.slide_id | 1 | 100.00 | Using where |
| 1 | SIMPLE | m | NULL | ref | unique_id,unique_id_2,deleted_date | unique_id | 194 | cloud_soccer.s2.media_id | 1 | 100.00 | Using where |
+----+-------------+-------+------------+--------+--------------------------------------------------------+-----------------+---------+---------------------------------+--------+----------+-----------------------+
MariaDB: 2-3 min
MySQL: 1.59sec
MariaDB 的my.cfg
[mysqld]
bind-address = 0.0.0.0
port = 3306
collation_server=utf8_general_ci
character_set_server=utf8
skip_name_resolve
innodb_buffer_pool_size = 8600MB
innodb_log_file_size=2048MB
max_allowed_packet=64M
performance_schema = ON
table_definition_cache = -1
MySqlTuner：
>> MySQLTuner 1.8.1 - Major Hayden <major@mhtx.net>
>> Bug reports, feature requests, and downloads at http://mysqltuner.pl/
>> Run with '--help' for additional options and output filtering
[--] Skipped version check for MySQLTuner script
[!!] Successfully authenticated with no password - SECURITY RISK!
[OK] Currently running supported MySQL version 10.5.11-MariaDB
[OK] Operating on 64-bit architecture
-------- Log file Recommendations ------------------------------------------------------------------
[OK] Log file /var/log/mysqld.log exists
[--] Log file: /var/log/mysqld.log(0B)
[--] Log file /var/log/mysqld.log is empty. Assuming log-rotation. Use --server-log={file} for explicit file
-------- Storage Engine Statistics -----------------------------------------------------------------
[--] Status: +Aria +CSV +InnoDB +MEMORY +MRG_MyISAM +MyISAM +PERFORMANCE_SCHEMA +SEQUENCE
[--] Data in MyISAM tables: 13.0M (Tables: 11)
[--] Data in InnoDB tables: 13.0G (Tables: 208)
[OK] Total fragmented tables: 0
-------- Analysis Performance Metrics --------------------------------------------------------------
[--] innodb_stats_on_metadata: OFF
[OK] No stat updates during querying INFORMATION_SCHEMA.
-------- Security Recommendations ------------------------------------------------------------------
[OK] There are no anonymous accounts for any database users
[OK] All database users have passwords assigned
[!!] User 'webappuser'@% does not specify hostname restrictions.
[--] There are 620 basic passwords in the list.
-------- CVE Security Recommendations --------------------------------------------------------------
[OK] NO SECURITY CVE FOUND FOR YOUR VERSION
-------- Performance Metrics -----------------------------------------------------------------------
[--] Up for: 39m 49s (2K q [1.134 qps], 1K conn, TX: 771K, RX: 720K)
[--] Reads / Writes: 100% / 0%
[--] Binary logging is disabled
[--] Physical Memory : 15.5G
[--] Max MySQL memory : 18.6G
[--] Other process memory: 0B
[--] Total buffers: 8.8G global + 66.9M per thread (151 max threads)
[--] P_S Max memory usage: 72B
[--] Galera GCache Max memory usage: 0B
[OK] Maximum reached memory usage: 8.9G (57.46% of installed RAM)
[!!] Maximum possible memory usage: 18.6G (120.22% of installed RAM)
[!!] Overall possible memory usage with other process exceeded memory
[OK] Slow queries: 0% (0/2K)
[OK] Highest usage of available connections: 1% (2/151)
[OK] Aborted connections: 0.00% (0/1340)
[OK] Query cache is disabled by default due to mutex contention on multiprocessor machines.
[OK] Sorts requiring temporary tables: 0% (0 temp sorts / 4 sorts)
[OK] No joins without indexes
[OK] Temporary tables created on disk: 9% (6 on disk / 63 total)
[OK] Thread cache hit rate: 99% (4 created / 1K connections)
[OK] Table cache hit rate: 70% (3K hits / 5K requests)
[OK] table_definition_cache(2097152) is upper than number of tables(411)
[OK] Open file limit used: 0% (78/32K)
[OK] Table locks acquired immediately: 100% (1K immediate / 1K locks)
-------- Performance schema ------------------------------------------------------------------------
[--] Memory used by P_S: 72B
[--] Sys schema isn't installed.
-------- ThreadPool Metrics ------------------------------------------------------------------------
[--] ThreadPool stat is enabled.
[--] Thread Pool Size: 8 thread(s).
[--] Using default value is good enough for your version (10.5.11-MariaDB)
-------- MyISAM Metrics ----------------------------------------------------------------------------
[!!] Key buffer used: 18.2% (24M used / 134M cache)
[OK] Key buffer size / total MyISAM indexes: 128.0M/1.1M
-------- InnoDB Metrics ----------------------------------------------------------------------------
[--] InnoDB is enabled.
[--] InnoDB Thread Concurrency: 0
[OK] InnoDB File per table is activated
[!!] InnoDB buffer pool / data size: 8.5G/13.0G
[OK] Ratio InnoDB log file size / InnoDB Buffer pool size: 2.0G * 1/8.5G should be equal to 25%
[--] Number of InnoDB Buffer Pool Chunk : 68 for 1 Buffer Pool Instance(s)
[OK] Innodb_buffer_pool_size aligned with Innodb_buffer_pool_chunk_size & Innodb_buffer_pool_instances
[OK] InnoDB Read buffer efficiency: 96.99% (1575458 hits/ 1624411 total)
[OK] InnoDB Write log efficiency: 99.14% (279173 hits/ 281589 total)
[OK] InnoDB log waits: 0.00% (0 waits / 2416 writes)
-------- Aria Metrics ------------------------------------------------------------------------------
[--] Aria Storage Engine is enabled.
[OK] Aria pagecache size / total Aria indexes: 128.0M/336.0K
[OK] Aria pagecache hit rate: 99.3% (2K cached / 20 reads)
-------- TokuDB Metrics ----------------------------------------------------------------------------
[--] TokuDB is disabled.
-------- XtraDB Metrics ----------------------------------------------------------------------------
[--] XtraDB is disabled.
-------- Galera Metrics ----------------------------------------------------------------------------
[--] Galera is disabled.
-------- Replication Metrics -----------------------------------------------------------------------
[--] Galera Synchronous replication: NO
[--] No replication slave(s) for this server.
[--] Binlog format: MIXED
[--] XA support enabled: ON
[--] Semi synchronous replication Master: OFF
[--] Semi synchronous replication Slave: OFF
[--] This is a standalone server
-------- Recommendations ---------------------------------------------------------------------------
General recommendations:
Restrict Host for 'webappuser'@'%' to 'webappuser'@LimitedIPRangeOrLocalhost
RENAME USER 'webappuser'@'%' TO 'webappuser'@LimitedIPRangeOrLocalhost;
MySQL was started within the last 24 hours - recommendations may be inaccurate
Reduce your overall MySQL memory footprint for system stability
Dedicate this server to your database for highest performance.
Consider installing Sys schema from https://github.com/mysql/mysql-sys for MySQL
Consider installing Sys schema from https://github.com/FromDual/mariadb-sys for MariaDB
Variables to adjust:
*** MySQL's maximum memory usage is dangerously high ***
*** Add RAM before increasing MySQL buffer variables ***
innodb_buffer_pool_size (>= 13.0G) if possible.
【问题讨论】：
-
也许你应该使用 SELECT STRAIGHT_JOIN ....................
-
来自 MySQL 和 MariaDB 的附加信息请求。 MySQL 主机上是否有任何 SSD 或 NVME 设备？在 pastebin.com 上发布并分享链接。从您的 SSH 登录根目录运行查询 TWICE 后，文本结果为：B) SHOW GLOBAL STATUS； C) 显示全局变量； D) 显示完整的处理程序； E) 状态；不显示状态，只是状态； F) MySQLTuner 报告 G) SHOW ENGINE INNODB STATUS； htop 或 top 用于大多数活动应用程序，ulimit -a 用于 Linux/Unix 限制列表，iostat -xm 5 3 用于按设备和核心/cpu 计数的 IOPS，用于服务器工作负载调整分析以提供建议。
-
感谢@WilsonHauck，但我一直在测试 MySQL 8.0.26，它运行良好。现在我们将使用 MySQL。
-
当您准备好提高 MySQL 实例的性能时，请提供上面要求的信息，以便在正常运行 24 小时后进行工作负载调整分析。谢谢。
标签： mysql sql mariadb query-optimization