MySQL Performance Tuning Variables

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MySQL Performance Tuning

DOAG 2013 Datenbank

14. Mai 2013, Düsseldorf

Oli SennhauserSenior MySQL Berater, FromDual GmbH

[email protected]

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Über FromDual GmbH

● FromDual bietet neutral und unabhängig:● Beratung für MySQL● Support für MySQL und Galera Cluster● Remote-DBA Dienstleistungen für MySQL● MySQL Schulungen

● Oracle Silver Partner (OPN)

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Inhalt

HA Solutions

➢ Read scale-out➢ Replication set-up for HA➢ Active/passive fail-over➢ MySQL Cluster➢ Replication Cluster➢ Storage-Engine-Replication

MySQL Performance Tuning mit System-Variablen

➢ Performance Tuning Hebel➢ MySQL System Variablen➢ MySQL Status Variablen➢ MySQL Architektur➢ Speicherbelegung➢ Session Variablen➢ Globale Variablen➢ MyISAM Variablen➢ InnoDB Variablen➢ Monitoring➢ Informationen

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Performance Tuning Hebel

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MySQL System Variablen

● Datenbank-Konfiguration

my.cnf

mysqld ­­help –verbose/etc/my.cnf /etc/mysql/my.cnf /usr/local/mysql/etc/my.cnf $basedir/my.cnf ~/.my.cnf

SHOW GLOBAL VARIABLES;

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MySQL Status Variablen

● Was wir damit anrichten sieht man mit:

SHOW /*!50001 GLOBAL */ STATUS;

SHOW ENGINE INNODB STATUS\G

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MySQL Architektur

mysqld

Application / Client

ThreadCache

ConnectionManager

User Au-thentication

CommandDispatcherLogging

Query CacheModule

QueryCache

Parser

Optimizer

Access Control

Table Manager

Table OpenCache (.frm, fh)

Table DefinitionCache (tbl def.)

Handler Interface

MyISAM Memory NDB PBXTInnoDB ...Aria XtraDB Tokutek

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Speicherbelegung

Storage Engines

MySQL Server (mysqld)

Client 2 Client N

Local Memory Areas

Client 1

read_buffersort_buffertmp_table

read_bufferread_buffersort_buffer

table_open_cachetable_definition_cachequery_cache_sizeetc...

Global Memory Area

key_buffer_sizeinnodb_buffer_pool_sizeinnodb_log_buffer_sizeetc...

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Thread Cache

● Konifguration: thread_cache_size

● Status: threads_created

+­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­+| Variable_name        | Value |+­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­+| Threads_cached       | 8     || Threads_connected    | 242   || Threads_created      | 15355 || Threads_running      | 16    |+­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­+

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Query Cache

● Konfiguration: query_cache_size● Status:

Com_select,Qcache_hits

● Hit ratio:

Qache_hits/(Com_select + Qcache_hits)

+­­­­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­­­­+| Variable_name           | Value    |+­­­­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­­­­+| Com_select              | 25712    || Qcache_free_memory      | 19553200 || Qcache_hits             | 65137    || Qcache_inserts          | 172167   |+­­­­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­­­­+

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Per Session Parameter

● Im „Executor“● Alloziert/Dealloziert „on Demand“● Per Session oder global einstellbar● Meisst Effekt gering oder gar kontraproduktiv!● Join Buffer

● join_buffer_size

● Read Buffer und Read Random Buffer● read_buffer_size, read_rnd_buffer_size

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Sort Buffer, temporäre Tabellen

● Temporäre Tabellen(MEMORY oder MyISAM)

● Konfiguration: tmp_table_size,(max_heap_table_size)

● Status: created_tmp_tables,created_tmp_disk_tables

● Sort Buffer● Konfiguration: sort_buffer_size

● Status: sort_merge_passes

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Table Definition Cache

● Ab v5.1● Enthält Info vom .frm File

● Konfiguration: table_definition_cache

● Status: open_table_definitions, opened_table_defintions

+­­­­­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­+| Variable_name            | Value |+­­­­­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­+| Open_table_definitions   | 100   || Opened_table_definitions | 100   |+­­­­­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­+

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Table (Open) Cache

● Ab v5.1● File-Descriptioren (1 pro Connection pro Table)● Früher table_cache

● Konfiguration: table_open_cache

● Status: open_tables, opened_tables

+­­­­­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­+| Variable_name            | Value |+­­­­­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­+| Open_tables              | 64    || Opened_tables            | 11812 |+­­­­­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­+

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MyISAM

● Bis MySQL 5.1 default Storage Engine

● Konfiguration: key_buffer_size

● Status: Key_blocks_used, Key_blocks_unused, Key_reads, Key_read_requests

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InnoDB Buffer Pool

● InnoDB seit 5.5 default Storage Engine● InnoDB Buffer Pool● Konfiguration:innodb_buffer_pool_size,innodb_buffer_pool_instances,innodb_io_capacity

mysqld

system table space: ibdata1

table table space table table spacetable table space

ib_l

ogfi

le1

ib_l

ogfi

le2

ib_l

ogfi

len

undo

double write area

tables/indexes

dd

OS file cache

sync

asy

nc

buffer pool

secondary index buffer

trx

log b

uff

er

data pages

index pages

adaptive hash idx

undo recordslock info table

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InnoDB Buffer Pool

● Status:innodb_buffer_pool_pages_%, Innodb_buffer_bytes_%,Innodb_data_%

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InnoDB Log File

● REDO Log, Transaction Log

● Konfiguration: innodb_log_file_size, innodb_flush_log_at_trx_commit

● Status: innodb%log%

mysqld

system table space: ibdata1

table table space table table spacetable table space

ib_l

og

file

1ib

_log

file

2ib

_log

file

n

undo

double write area

tables/indexes

dd

OS file cache

sync

asy

nc

buffer pool

secondary index buffer

trx

log b

uff

er

data pages

index pages

adaptive hash idx

undo records

lock info table

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Binary Log

Application ApplicationApplication

mysqld

bin-log.n

binlog_cache_sizebinlog_stmt_cache_size

sync_binlog

+­­­­­­­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­+| Variable_name              | Value |+­­­­­­­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­+| Binlog_cache_disk_use      | 3456  || Binlog_cache_use           | 12786 || Binlog_stmt_cache_disk_use | 0     || Binlog_stmt_cache_use      | 0     |+­­­­­­­­­­­­­­­­­­­­­­­­­­­­+­­­­­­­+

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Monitoring

● Von Hand:● SHOW GLOBAL STATUS;● SHOW ENGINE INNODB STATUS\G● Performance Schema (P_S, >= v5.5)

● Irgend ein graphisches Monitoring Tool...

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PERFORMANCE_SCHEMA

● In Diskussion seit mindestens 2006● Eingeführt in MySQL 5.5 (2010)

→ Einblick in die Datenbank● In v5.5 disabled, in v5.6 enabled per default

performance_schema = 1● Overhead 5% - 200%! → also Vorsicht!

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Beispiel: Table I/O waits

SELECT OBJECT_SCHEMA, OBJECT_NAME     , ROUND(SUM_TIMER_WAIT/1000000000, 3) AS SUM_TIMER_WAIT     , ROUND(SUM_TIMER_READ/1000000000, 3) AS SUM_TIMER_READ     , ROUND(SUM_TIMER_WRITE/1000000000, 3) AS SUM_TIMER_WRITE  FROM table_io_waits_summary_by_table ORDER BY SUM_TIMER_WAIT DESC LIMIT 10;+­­­­­­­­­­­­­­­+­­­­­­­­­­­­­­+­­­­­­­­­­­­­­­­+­­­­­­­­­­­­­­­­+­­­­­­­­­­­­­­­­­+| OBJECT_SCHEMA | OBJECT_NAME  | SUM_TIMER_WAIT | SUM_TIMER_READ | SUM_TIMER_WRITE |+­­­­­­­­­­­­­­­+­­­­­­­­­­­­­­+­­­­­­­­­­­­­­­­+­­­­­­­­­­­­­­­­+­­­­­­­­­­­­­­­­­+| zabbix        | items        |    1182496.258 |     616630.696 |      565865.562 || zabbix        | history_uint |     889884.116 |     370528.991 |      519355.125 || zabbix        | history_str  |     460411.155 |     246159.458 |      214251.697 || zabbix        | history      |     389815.659 |      86285.980 |      303529.679 || zabbix        | trends_uint  |     133955.560 |     107365.626 |       26589.934 || zabbix        | functions    |     128657.654 |     128657.654 |           0.000 || zabbix        | trends       |      43683.159 |      36314.732 |        7368.428 || mpm           | mpm_agent    |      27837.056 |      27837.056 |           0.000 || zabbix        | hosts        |      23820.284 |      14044.672 |        9775.612 || zabbix        | triggers     |      21052.459 |      20970.604 |          81.855 |+­­­­­­­­­­­­­­­+­­­­­­­­­­­­­­+­­­­­­­­­­­­­­­­+­­­­­­­­­­­­­­­­+­­­­­­­­­­­­­­­­­+

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Informationen

● MySQL System Variablen:

http://dev.mysql.com/doc/refman/5.5/en/server-system-variables.html● MySQL Status Variablen:

http://dev.mysql.com/doc/refman/5.5/en/server-status-variables.html● MySQL DB Health Check:

http://www.fromdual.com/mysql-database-health-check● MySQL Performance Monitor:

http://www.fromdual.com/mysql-performance-monitor

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Q & A

Fragen ?

Diskussion?

Wir haben Zeit für ein Performance Audit...!

● FromDual bietet neutral und unabhängig:● Beratung

● Remote-DBA

● Support für MySQL und Galera Cluster

● Schulung

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