mysql manchester tt - performance tuning

1 Copyright © 2015, Oracle and/or its affiliates. All rights reserved. |

MySQL Server Performance Tuning 101

Ligaya Turmelle Principal Technical Support Engineer -‐ MySQL [email protected] @lig hKps://legacy.joind.in/16770

Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | 1


Safe Harbor Statement The following is intended to outline our general product direcTon. It is intended for informaTon purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or funcTonality, and should not be relied upon in making purchasing decisions. The development, release, and Tming of any features or funcTonality described for Oracle’s products remains at the sole discreTon of Oracle.

3 Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | Copyright © 2015, Oracle and/or its affiliates. All rights reserved. |

Laying the FoundaTon


Step 0

• General -‐ No easy answers -‐  Benchmark and test

-‐ Under allocate


Step 0

• The Server - OS

- Network

- Filesystem


Step 0

• MySQL Server -‐ OpTmize the queries

-‐  Database schema


MySQL and Memory

2

Global Per Connection

Server Start As Needed

Large Values Small Values

Allocated Once Allocated 0-N Times

Global Memory + (Max Connections * Per Connection Buffers)


Current Seangs

•  mysql> SHOW GLOBAL VARIABLES;

•  mysql> SELECT * FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES;

•  (5.7) mysql> SELECT * FROM PERFORMANCE_SCHEMA.GLOBAL_VARIABLES;

mysql> SHOW GLOBAL VARIABLES;+-----------------------------------------+------------------| Variable_name | Value +-----------------------------------------+------------------| auto_increment_increment | 1| auto_increment_offset | 1 | autocommit | ON | automatic_sp_privileges | ON | back_log | 80 | basedir | /Users/ligaya/mysql_installs/mysql-5.6.16-osx10.7-x86_64 | big_tables | OFF | bind_address | * | binlog_cache_size | 32768 | binlog_checksum | CRC32 | binlog_direct_non_transactional_updates | OFF | binlog_format | STATEMENT | binlog_max_flush_queue_time | 0 | binlog_order_commits | ON | binlog_row_image | FULL | binlog_rows_query_log_events | OFF | binlog_stmt_cache_size | 32768 | bulk_insert_buffer_size | 8388608 | character_set_client | latin1 | character_set_connection | latin1 | character_set_database | latin1 | character_set_filesystem | binary | character_set_results | latin1 | character_set_server | latin1 | character_set_system | utf8 | character_sets_dir | /Users/ligaya/mysql_installs/mysql-5.6.16-osx10.7-x86_64/share/charsets/ | collation_connection | latin1_swedish_ci

8


Current Seangs

• my.cnf / my.ini # The following options will be passed to all

MySQL clients[client]#password = your_passwordport = 5626socket

= /tmp/mysql.5.6.26.sock# The MySQL server[mysqld]##################### specific to this test instanceport = 5626socket = /tmp/mysql.5.6.26.socklog-error = /mysql-5.6.26/data/error.logbasedir = /mysql-5.6.26datadir = /mysql-5.6.26/datasafe-user-create

server-id = 1####################

9


Anything Else?

• RAM?

• Dedicated? • 32/64 bit OS/MySQL?

• Workload? •  Storage Engines?


Current Status

•  mysql> SHOW GLOBAL STATUS;

•  mysql> SELECT * FROM INFORMATION_SCHEMA.GLOBAL_STATUS;

•  (5.7) mysql> SELECT * FROM PERFORMANCE_SCHEMA.GLOBAL_STATUS;

mysql> SHOW GLOBAL STATUS; +--------------------------------------+---------------+

| Variable_name | Value |

+--------------------------------------+---------------+ | Aborted_clients | 9363 |

| Aborted_connects | 15925 |

| Binlog_cache_disk_use | 15684 | | Binlog_cache_use | 272758675 |

| Bytes_received | 1219816389366 |

| Bytes_sent | 5227022143540 | | Com_admin_commands | 12803263 |

| Com_assign_to_keycache | 0 |

| Com_alter_db | 0 | | Com_alter_db_upgrade | 0 |

| Com_alter_event | 0 |

| Com_alter_function | 0 |

| Com_alter_procedure | 0 | | Com_alter_server | 0 |

| Com_alter_table | 37 |

| Com_alter_tablespace | 0 | | Com_analyze | 0 |

| Com_begin | 33025640 |

| Com_binlog | 0 |

11


Time to Start

Copyright © 2015, Oracle and/or its affiliates. All rights reserved. |

Areas We Will Cover

•  General Info

•  InnoDB

•  MyISAM -‐ Older systems

1

2

3


Areas We Will Cover

•  Query Cache -‐ Older systems

•  Thread and Table Cache

•  Session Level

5

4

6


Areas We Will Cover

•  General Info

•  InnoDB

•  MyISAM -‐ Older systems

1

2

3


Et Al.

• ConnecTons and Max_used_connecTons

• Queries and QuesTons •  Slow_queries • Handler_read_*


max_connecTons

• Max permiKed concurrent connecTons. • Value affects memory usage • higher values (1000+) consider/invesTgate

-‐  thread pooling -‐  connecTon pooling


skip_name_resolve

• Do not resolve host name for client connecTons • Removes DNS lookups

-‐  faster connecTons -‐  no need to worry about slow DNS

• Drawback: Use only IP addresses


Areas We Will Cover

•  General Info

•  InnoDB

1

2

1

2


How is InnoDB doing?

•  Efficiency - Innodb_buffer_pool_reads_requests- Innodb_buffer_pool_reads

Formula: 1 - (Innodb_buffer_pool_read / Innodb_buffer_pool_read_requests)

= buffer pool hit ratio


innodb_buffer_pool_size

• Global • Dynamic (5.7.5) • Caches data and indexes •  Larger values reduces IO •  Self-‐contained • Max value -‐ Manual: 80% ; Personal: 60-‐70%


innodb_buffer_pool_instances

•  5.5+ • Problem: contenTon for the buffer pool resources •  For systems with large mulT-‐GB buffer pools •  Total buffer pool size divided between this many instances •  Each instance

-‐ Manages its own resources -‐  Has its own mutex


innodb_log_file_size

•  Size of file on disk •  Larger the file, the less checkpoint acTvity •  Size for each log file • Max combined log file size

-‐  4G < 5.5 -‐  5.6 = 512G

•  Larger the log file ➯ longer recovery Tme


innodb_log_buffer_size

• Global • Buffer for wriTng to log files on disk •  Large transacTons? Write heavy?

-‐  Yes -‐ increasing can help with IO • Default: 8M


innodb_file_per_table

•  .ibd files • Default: Off <= 5.6.5 > On •  Easier to reclaim space •  TRUNCATE for a table is faster • Can monitor table size on the file system • Can store specific tables on different storage devices •  (5.6) Transportable tablespaces

-‐  (5.7) ParTToned tables supported


innodb_flushlog_at_trx_commit

• Performance Vs Durability •  1 -‐ Default

-‐  ACID Compliant

•  2 -‐ Can lose up to 1 second of transacTons -‐  InnoDB log buffer wriKen to log file at each commit -‐  flushed to disk once per second

•  0 -‐ Can lose up to 1 second of transacTons -‐  InnoDB log buffer wriKen to log file once per second and then flushed to disk


innodb_flush_method

•  For Unix and Linux • Method used to flush data and log files to disk • Dependent on hardware • Default: fdatasync • O_DIRECT recommended if you use a hardware RAID controller


Areas We Will Cover

•  Threads and Table Cache


5

6


Gotchas!


Areas We Will Cover


•  Threads and Table Caches


5

4

6


Threads

•  Threads == ConnecTon •  Thread Cache

-‐  Threads_cached -‐  Threads_connected -‐  Threads_created

Formula: Threads_created / Connections = Thread cache miss rate


thread_cache_size

• Global but grows as needed • Number to be cached unTl needed • May increase performance with lots of new connecTons

-‐ Or may not

Formula: 100 - ((Threads_created / Connections) * 100) =

Thread cache efficiency


table_open_cache

•  table_cache <= 5.1.3 > table_open_cache • Global but expands as needed • Number of open tables for all connecTons

-‐  higher max_connecTons, more you need

• Watch Opened_tables


table_open_cache_instances

• Reduces contenTon between sessions • Default 1

-‐  Consider 8 or 16 on 16+ core systems

•  5.6+


table_definiTon_cache

• Global but expands as needed • Number of table definiTons (.frm file) to hold •  Large number of tables ➯large definiTon cache = speed up table opening •  InnoDB

-‐  Sow limit for open table instances in data dicTonary -‐  Sow limit for number of InnoDB file per table tablespaces open at 1 Tme

•  5.1+ • Autosizes >=5.6.8


Areas We Will Cover


•  Threads and Table Cache


5

4

6


Temporary Tables

max_heap_table_size

• Dynamic• Set maximum size of all

MEMORY tables

tmp_table_size

• Dynamic• In-memory - MEMORY table• max size of internal in-

memory temp tables• Becomes on-disk table


sort_buffer_size

• Dynamic • Doing a sort -‐ allocates a buffer this size • Helps with ORDER BY and/or GROUP BY •  256K is a decent starTng place • Watch Sort_merge_passes


join_buffer_size

• Use with care • Use for

-‐  Plain index scan -‐  Range index scan -‐  Joins that do not use indexes -‐ full table scan

• One buffer for each full join between tables


QuesTons?


MySQL Server Performance Tuning 101

Ligaya Turmelle Principal Technical Support Engineer -‐ MySQL [email protected] @lig hKps://legacy.joind.in/16770

Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | 41

mysql manchester tt - performance tuning

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