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MySQL 5.5 and MySQL 5.6 default variable values differences

February 21, 2013 By Peter Zaitsev 8 Comments

As the part of analyzing surprising MySQL 5.5 vs MySQL 5.6 performance results I’ve been looking at changes to default variable values. To do that I’ve loaded the values from MySQL 5.5.30 and MySQL 5.6.10 to the different tables and ran the query:

mysql [localhost] {msandbox} (test) > select var55.variable_name,left(var55.variable_value,40) value55, left(var56.variable_value,40) var56  from var55 left join var56 on var55.variable_name=var56.variable_name where  var55.variable_value!=var56.variable_value;
+---------------------------------------------------+------------------------------------------+------------------------------------------+
| variable_name                                     | value55                                  | var56                                    |
+---------------------------------------------------+------------------------------------------+------------------------------------------+
| PERFORMANCE_SCHEMA                                | OFF                                      | ON                                       |
| PID_FILE                                          | /mnt/data/sandboxes/msb_5_5_30/data/mysq | /mnt/data/sandboxes/msb_5_6_10/data/mysq |
| CHARACTER_SETS_DIR                                | /mnt/nfs/dist/mysql-5.5.30-linux2.6-x86_ | /mnt/nfs/dist/mysql-5.6.10-linux-glibc2. |
| PERFORMANCE_SCHEMA_MAX_COND_INSTANCES             | 1000                                     | 836                                      |
| PERFORMANCE_SCHEMA_MAX_MUTEX_INSTANCES            | 1000000                                  | 3282                                     |
| OLD_PASSWORDS                                     | OFF                                      | 0                                        |
| INNODB_STATS_ON_METADATA                          | ON                                       | OFF                                      |
| PERFORMANCE_SCHEMA_EVENTS_WAITS_HISTORY_SIZE      | 10                                       | 5                                        |
| PERFORMANCE_SCHEMA_EVENTS_WAITS_HISTORY_LONG_SIZE | 10000                                    | 100                                      |
| PERFORMANCE_SCHEMA_MAX_RWLOCK_INSTANCES           | 1000000                                  | 1724                                     |
| PERFORMANCE_SCHEMA_MAX_TABLE_HANDLES              | 100000                                   | 2223                                     |
| INNODB_LOG_FILE_SIZE                              | 5242880                                  | 50331648                                 |
| BASEDIR                                           | /mnt/nfs/dist/5.5.30                     | /mnt/nfs/dist/5.6.10                     |
| BACK_LOG                                          | 50                                       | 80                                       |
| OPEN_FILES_LIMIT                                  | 1024                                     | 5000                                     |
| INNODB_AUTOEXTEND_INCREMENT                       | 8                                        | 64                                       |
| MAX_CONNECT_ERRORS                                | 10                                       | 100                                      |
| SORT_BUFFER_SIZE                                  | 2097152                                  | 262144                                   |
| LC_MESSAGES_DIR                                   | /mnt/nfs/dist/mysql-5.5.30-linux2.6-x86_ | /mnt/nfs/dist/mysql-5.6.10-linux-glibc2. |
| MAX_ALLOWED_PACKET                                | 1048576                                  | 4194304                                  |
| JOIN_BUFFER_SIZE                                  | 131072                                   | 262144                                   |
| TMPDIR                                            | /mnt/data/sandboxes/msb_5_5_30/tmp       | /mnt/data/sandboxes/msb_5_6_10/tmp       |
| TABLE_OPEN_CACHE                                  | 400                                      | 2000                                     |
| INNODB_VERSION                                    | 5.5.30                                   | 1.2.10                                   |
| INNODB_BUFFER_POOL_INSTANCES                      | 1                                        | 8                                        |
| QUERY_CACHE_SIZE                                  | 0                                        | 1048576                                  |
| SLOW_QUERY_LOG_FILE                               | /mnt/data/sandboxes/msb_5_5_30/data/dpe0 | /mnt/data/sandboxes/msb_5_6_10/data/dpe0 |
| TABLE_DEFINITION_CACHE                            | 400                                      | 1400                                     |
| PORT                                              | 5530                                     | 5610                                     |
| QUERY_CACHE_TYPE                                  | ON                                       | OFF                                      |
| REPORT_PORT                                       | 5530                                     | 5610                                     |
| PERFORMANCE_SCHEMA_MAX_FILE_INSTANCES             | 10000                                    | 1556                                     |
| SQL_MODE                                          |                                          | NO_ENGINE_SUBSTITUTION                   |
| INNODB_OLD_BLOCKS_TIME                            | 0                                        | 1000                                     |
| LOG_ERROR                                         | /mnt/data/sandboxes/msb_5_5_30/data/msan | /mnt/data/sandboxes/msb_5_6_10/data/msan |
| VERSION_COMPILE_OS                                | linux2.6                                 | linux-glibc2.5                           |
| THREAD_CACHE_SIZE                                 | 0                                        | 9                                        |
| PLUGIN_DIR                                        | /mnt/nfs/dist/5.5.30/lib/plugin/         | /mnt/nfs/dist/5.6.10/lib/plugin/         |
| SYNC_RELAY_LOG                                    | 0                                        | 10000                                    |
| GENERAL_LOG_FILE                                  | /mnt/data/sandboxes/msb_5_5_30/data/dpe0 | /mnt/data/sandboxes/msb_5_6_10/data/dpe0 |
| PERFORMANCE_SCHEMA_MAX_TABLE_INSTANCES            | 50000                                    | 445                                      |
| SYNC_RELAY_LOG_INFO                               | 0                                        | 10000                                    |
| SLAVE_LOAD_TMPDIR                                 | /mnt/data/sandboxes/msb_5_5_30/tmp       | /mnt/data/sandboxes/msb_5_6_10/tmp       |
| SECURE_AUTH                                       | OFF                                      | ON                                       |
| VERSION                                           | 5.5.30                                   | 5.6.10                                   |
| INNODB_CONCURRENCY_TICKETS                        | 500                                      | 5000                                     |
| INNODB_PURGE_THREADS                              | 0                                        | 1                                        |
| INNODB_OPEN_FILES                                 | 300                                      | 2000                                     |
| INNODB_DATA_FILE_PATH                             | ibdata1:10M:autoextend                   | ibdata1:12M:autoextend                   |
| INNODB_PURGE_BATCH_SIZE                           | 20                                       | 300                                      |
| PERFORMANCE_SCHEMA_MAX_THREAD_INSTANCES           | 1000                                     | 224                                      |
| SOCKET                                            | /tmp/mysql_sandbox5530.sock              | /tmp/mysql_sandbox5610.sock              |
| INNODB_FILE_PER_TABLE                             | OFF                                      | ON                                       |
| SYNC_MASTER_INFO                                  | 0                                        | 10000                                    |
| DATADIR                                           | /mnt/data/sandboxes/msb_5_5_30/data/     | /mnt/data/sandboxes/msb_5_6_10/data/     |
| OPTIMIZER_SWITCH                                  | index_merge=on,index_merge_union=on,inde | index_merge=on,index_merge_union=on,inde |
+---------------------------------------------------+------------------------------------------+------------------------------------------+
56 rows in set (0.05 sec)

mysql [localhost] {msandbox} (test) > select var55.variable_name,left(var55.variable_value,40) value55, left(var56.variable_value,40) var56 from var55 left join var56 on var55.variable_name=var56.variable_name where var55.variable_value!=var56.variable_value;

+---------------------------------------------------+------------------------------------------+------------------------------------------+

| variable_name | value55 | var56 |

+---------------------------------------------------+------------------------------------------+------------------------------------------+

| PERFORMANCE_SCHEMA | OFF | ON |

| PID_FILE | /mnt/data/sandboxes/msb_5_5_30/data/mysq | /mnt/data/sandboxes/msb_5_6_10/data/mysq |

| CHARACTER_SETS_DIR | /mnt/nfs/dist/mysql-5.5.30-linux2.6-x86_ | /mnt/nfs/dist/mysql-5.6.10-linux-glibc2. |

| PERFORMANCE_SCHEMA_MAX_COND_INSTANCES | 1000 | 836 |

| PERFORMANCE_SCHEMA_MAX_MUTEX_INSTANCES | 1000000 | 3282 |

| OLD_PASSWORDS | OFF | 0 |

| INNODB_STATS_ON_METADATA | ON | OFF |

| PERFORMANCE_SCHEMA_EVENTS_WAITS_HISTORY_SIZE | 10 | 5 |

| PERFORMANCE_SCHEMA_EVENTS_WAITS_HISTORY_LONG_SIZE | 10000 | 100 |

| PERFORMANCE_SCHEMA_MAX_RWLOCK_INSTANCES | 1000000 | 1724 |

| PERFORMANCE_SCHEMA_MAX_TABLE_HANDLES | 100000 | 2223 |

| INNODB_LOG_FILE_SIZE | 5242880 | 50331648 |

| BASEDIR | /mnt/nfs/dist/5.5.30 | /mnt/nfs/dist/5.6.10 |

| BACK_LOG | 50 | 80 |

| OPEN_FILES_LIMIT | 1024 | 5000 |

| INNODB_AUTOEXTEND_INCREMENT | 8 | 64 |

| MAX_CONNECT_ERRORS | 10 | 100 |

| SORT_BUFFER_SIZE | 2097152 | 262144 |

| LC_MESSAGES_DIR | /mnt/nfs/dist/mysql-5.5.30-linux2.6-x86_ | /mnt/nfs/dist/mysql-5.6.10-linux-glibc2. |

| MAX_ALLOWED_PACKET | 1048576 | 4194304 |

| JOIN_BUFFER_SIZE | 131072 | 262144 |

| TMPDIR | /mnt/data/sandboxes/msb_5_5_30/tmp | /mnt/data/sandboxes/msb_5_6_10/tmp |

| TABLE_OPEN_CACHE | 400 | 2000 |

| INNODB_VERSION | 5.5.30 | 1.2.10 |

| INNODB_BUFFER_POOL_INSTANCES | 1 | 8 |

| QUERY_CACHE_SIZE | 0 | 1048576 |

| SLOW_QUERY_LOG_FILE | /mnt/data/sandboxes/msb_5_5_30/data/dpe0 | /mnt/data/sandboxes/msb_5_6_10/data/dpe0 |

| TABLE_DEFINITION_CACHE | 400 | 1400 |

| PORT | 5530 | 5610 |

| QUERY_CACHE_TYPE | ON | OFF |

| REPORT_PORT | 5530 | 5610 |

| PERFORMANCE_SCHEMA_MAX_FILE_INSTANCES | 10000 | 1556 |

| SQL_MODE | | NO_ENGINE_SUBSTITUTION |

| INNODB_OLD_BLOCKS_TIME | 0 | 1000 |

| LOG_ERROR | /mnt/data/sandboxes/msb_5_5_30/data/msan | /mnt/data/sandboxes/msb_5_6_10/data/msan |

| VERSION_COMPILE_OS | linux2.6 | linux-glibc2.5 |

| THREAD_CACHE_SIZE | 0 | 9 |

| PLUGIN_DIR | /mnt/nfs/dist/5.5.30/lib/plugin/ | /mnt/nfs/dist/5.6.10/lib/plugin/ |

| SYNC_RELAY_LOG | 0 | 10000 |

| GENERAL_LOG_FILE | /mnt/data/sandboxes/msb_5_5_30/data/dpe0 | /mnt/data/sandboxes/msb_5_6_10/data/dpe0 |

| PERFORMANCE_SCHEMA_MAX_TABLE_INSTANCES | 50000 | 445 |

| SYNC_RELAY_LOG_INFO | 0 | 10000 |

| SLAVE_LOAD_TMPDIR | /mnt/data/sandboxes/msb_5_5_30/tmp | /mnt/data/sandboxes/msb_5_6_10/tmp |

| SECURE_AUTH | OFF | ON |

| VERSION | 5.5.30 | 5.6.10 |

| INNODB_CONCURRENCY_TICKETS | 500 | 5000 |

| INNODB_PURGE_THREADS | 0 | 1 |

| INNODB_OPEN_FILES | 300 | 2000 |

| INNODB_DATA_FILE_PATH | ibdata1:10M:autoextend | ibdata1:12M:autoextend |

| INNODB_PURGE_BATCH_SIZE | 20 | 300 |

| PERFORMANCE_SCHEMA_MAX_THREAD_INSTANCES | 1000 | 224 |

| SOCKET | /tmp/mysql_sandbox5530.sock | /tmp/mysql_sandbox5610.sock |

| INNODB_FILE_PER_TABLE | OFF | ON |

| SYNC_MASTER_INFO | 0 | 10000 |

| DATADIR | /mnt/data/sandboxes/msb_5_5_30/data/ | /mnt/data/sandboxes/msb_5_6_10/data/ |

| OPTIMIZER_SWITCH | index_merge=on,index_merge_union=on,inde | index_merge=on,index_merge_union=on,inde |

+---------------------------------------------------+------------------------------------------+------------------------------------------+

56 rows in set (0.05 sec)

Lets go over to see what are the most important changes [...]

Filed Under: Insight for DBAs, MySQL Tagged With: default variable values, MySQL 5.5, MySQL 5.6, Peter Zaitsev

MySQL 5.6: Improvements in the Nutshell

January 27, 2013 By Peter Zaitsev 16 Comments

Preparing for my talk for Percona MySQL University in Raleigh,NC, Tuesday 29th of January I have created the outline of improvements available in MySQL 5.6 which I thought was worth sharing to give a feel for how massive work have been done for this release in variety of areas. I’m sure the list is not [...]

Filed Under: Insight for DBAs, Insight for Developers, MySQL Tagged With: MySQL, MySQL 5.6, Peter Zaitsev

Write contentions on the query cache

September 5, 2012 By Stephane Combaudon 5 Comments

While doing a performance audit for a customer a few weeks ago, I tried to improve the response time of their top slow query according to pt-query-digest‘s report. This query was run very frequently and had very unstable performance: during the time data was collected, response time varied from 50µs to 1s. When I ran [...]

Filed Under: Insight for DBAs, MySQL

Improved InnoDB fast index creation

November 6, 2011 By Alexey Kopytov 4 Comments

One of the serious limitations in the fast index creation feature introduced in the InnoDB plugin is that it only works when indexes are explicitly created using ALTER TABLE or CREATE INDEX. Peter has already blogged about it before, here I’ll just briefly reiterate other cases that might benefit from that feature: when ALTER TABLE [...]

Filed Under: Benchmarks, Insight for DBAs, MySQL

Pretty-formatted index fragmentation with xtrabackup

March 15, 2011 By Baron Schwartz 4 Comments

The xtrabackup compiled C binary (as distinct from XtraBackup, which is the combination of the C binary and the Perl script) has support for printing out stats on InnoDB tables and indexes. This can be useful to examine whether you’d benefit from “defragmenting” your MySQL database with OPTIMIZE TABLE, although I have not determined firm [...]

Filed Under: MySQL, Percona Software

Moving from MyISAM to Innodb or XtraDB. Basics

November 22, 2010 By Peter Zaitsev 2 Comments

I do not know if it is because we’re hosting a free webinar on migrating MyISAM to Innodb or some other reason but recently I see a lot of questions about migration from MyISAM to Innodb. Webinar will cover the process in a lot more details though I would like to go over basics in [...]

Filed Under: Events and Announcements, MySQL Tagged With: InnoDB, MyISAM, XtraDB

InnoDB: look after fragmentation

November 5, 2009 By Vadim Tkachenko 12 Comments

One problem made me puzzled for couple hours, but it was really interesting to figure out what’s going on. So let me introduce problem at first. The table is

CREATE TABLE `c` (
  `tracker_id` int(10) unsigned NOT NULL,
  `username` char(20) character set latin1 collate latin1_bin NOT NULL,
  `time_id` date NOT NULL,
  `block_id` int(10) unsigned default NULL,
  PRIMARY KEY  (`tracker_id`,`username`,`time_id`),
  KEY `block_id` (`block_id`)
) ENGINE=InnoDB

CREATE TABLE `c` (

`tracker_id` int(10) unsigned NOT NULL,

`username` char(20) character set latin1 collate latin1_bin NOT NULL,

`time_id` date NOT NULL,

`block_id` int(10) unsigned default NULL,

PRIMARY KEY (`tracker_id`,`username`,`time_id`),

KEY `block_id` (`block_id`)

) ENGINE=InnoDB

Table has 11864696 rows and takes Data_length: 698,351,616 bytes on disk The problem is that after restoring table from mysqldump, the query that scans data [...]

Filed Under: Insight for DBAs, MySQL Tagged With: InnoDB

Just do the math!

July 6, 2009 By Peter Zaitsev 4 Comments

One of the most typical reasons for performance and scalability problems I encounter is simply failing to do the math. And these are typically bad one because it often leads to implementing architectures which are not up for job they are intended to solve. Let me start with example to make it clear. Lets say [...]

Filed Under: Insight for Developers Tagged With: Tips

MySQL Binaries Percona build10

December 11, 2008 By Vadim Tkachenko 12 Comments

We made new binaries for MySQL 5.0.67 build 10 which include next fixes: We addressed concerns about potential logging and statistics overhead, so now you can fully turn on / off query statistics for microslow patch and user statistics in runtime. Next variables were added:

| slow_query_log                  | ON                                           |
| slow_query_log_file             | /var/lib/mysql/slow_query.log                |
for compatibility with MySQL 5.1
and
| userstat_running                | OFF                                          |
to control gathering of user statistics.

| slow_query_log | ON |

| slow_query_log_file | /var/lib/mysql/slow_query.log |

for compatibility with MySQL 5.1

and

| userstat_running | OFF |

to control gathering of user statistics.

With both slow_query_log = OFF and userstat_running = OFF [...]

Filed Under: Percona Software Tagged With: Patches, Percona

Percona build7 with latest patches

November 14, 2008 By Vadim Tkachenko 26 Comments

We made new binaries for MySQL 5.0.67 build 7 which include patches we recently announced. The -percona release includes:

| innodb_check_defrag.patch                        | Session status to check fragmentation of the last InnoDB scan                            | 1.0     | Percona <info@percona.com>       | GPL     | The names are Innodb_scan_*                                                                      |
| userstatsv2.patch                                | SHOW USER/TABLE/INDEX statistics                                                         | V2      | Google                           | GPL     | Added INFORMATION_SCHEMA.*_STATISTICS                                                            |
| show_patches.patch                               | SHOW PATCHES                                                                             | 1.0     | Jeremy Cole                      | N/A     |                                                                                                  |
| innodb_io_patches.patch                          | Cluster of past InnoDB IO patches                                                        | 1.0     | Percona                          | GPL     | This patch contains fixed (control_flush_and_merge_and_read, control_io-threads, adaptive_flush) |
| innodb_show_hashed_memory.patch                  | Adds additional information of InnoDB internal hash table memories in SHOW INNODB STATUS | 1.0     | Percona <info@percona.com>       | GPL     |                                                                                                  |
| innodb_io_pattern.patch                          | Information schema table of InnoDB IO counts for each datafile pages                     | 1.0     | Percona <info@percona.com>       | GPL     | INFORMATION_SCHEMA.INNODB_IO_PATTERN                                                             |
| microsec_process.patch                           | Adds INFOMATION_SCHEMA.PROCESSLIST with TIME_MS column                                   | 1.0     | Percona <info@percona.com>       | GPL     |                                                                                                  |
| innodb_locks_held.patch                          | Add locks held, remove locked records in SHOW INNODB STATUS                              | 1.0     | Baron Schwartz <baron@xaprb.com> | GPL     | Bug #29126 fix                                                                                   |
| microslow_innodb.patch                           | Extended statistics in slow.log                                                          | 1.1     | Percona <info@percona.com>       | GPL     |                                                                                                  |
| mysqld_safe_syslog.patch                         | Patch allows redirect output of error.log to syslog-ng                                   | 1.0     | Percona <info@percona.com>       | GPL     | Ported from Debian                                                                               |
| innodb_fsync_source.patch                        | Information of fsync callers in InnoDB                                                   | 1.0     | Google                           | GPL     |                                                                                                  |
| innodb_show_bp.patch                             | show innodb buffer pool content                                                          | 1.0     | Percona <info@percona.com>       | GPL     |                                                                                                  |

and -percona-highperf release additionaly includes

| split_buf_pool_mutex_fixed_optimistic_safe.patch | InnoDB patch to fix buffer pool scalability                                              | 1.0     | Yasufumi Kinoshita               | BSD     |                                                                                                  |
| innodb_rw_lock.patch                             | Fix of InnoDB rw_locks                                                                   | 1.0     | Yasufumi Kinoshita               | BSD     |

1 2	\| split_buf_pool_mutex_fixed_optimistic_safe.patch \| InnoDB patch to fix buffer pool scalability \| 1.0 \| Yasufumi Kinoshita \| BSD \| \| \| innodb_rw_lock.patch \| Fix of InnoDB rw_locks \| 1.0 \| Yasufumi Kinoshita \| BSD \|

You can download RPMs for RedHat / CentOS 4.x and 5.x for x86_64, binaries, sources and patches there

Filed Under: Percona Software Tagged With: Patches, Percona, Release

MySQL 5.5 and MySQL 5.6 default variable values differences

MySQL 5.6: Improvements in the Nutshell

Write contentions on the query cache

Improved InnoDB fast index creation

Pretty-formatted index fragmentation with xtrabackup

Moving from MyISAM to Innodb or XtraDB. Basics

InnoDB: look after fragmentation

Just do the math!

MySQL Binaries Percona build10

Percona build7 with latest patches

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