This is part 2 in a 3 part series. In part 1, we took a quick look at some initial configuration of InnoDB full-text search and discovered a little bit of quirky behavior; here, we are going to run some queries and compare the result sets. Our hope is that the one of two things [...]
MySQL 5.5 and MySQL 5.6 default variable values differences
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:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 | 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 [...]
Edge-case behavior of INSERT…ODKU
A few weeks back, I was working on a customer issue wherein they were observing database performance that dropped through the floor (to the point of an outage) roughly every 4 weeks or so. Nothing special about the environment, the hardware, or the queries; really, the majority of the database was a single table with [...]
Full Text Search Webinar Questions Followup
I presented a webinar this week to give an overview of several Full Text Search solutions and compare their performance. Even if you missed the webinar, you can register for it, and you’ll be emailed a link to the recording. During my webinar, a number of attendees asked some good questions. Here are their questions and my [...]
Percona XtraDB Cluster: Failure Scenarios with only 2 nodes
During the design period of a new cluster, it is always advised to have at least 3 nodes (this is the case with PXC but it’s also the same with PRM). But why and what are the risks ? The goal of having more than 2 nodes, in fact an odd number is recommended in [...]
Air traffic queries in InfiniDB: early alpha
As Calpont announced availability of InfiniDB I surely couldn’t miss a chance to compare it with previously tested databases in the same environment. See my previous posts on this topic: Analyzing air traffic performance with InfoBright and MonetDB Air traffic queries in LucidDB I could not run all queries against InfiniDB and I met some [...]
Gathering queries from a server with Maatkit and tcpdump
For the last couple of months, we’ve been quietly developing a MySQL protocol parser for Maatkit. It isn’t an implementation of the protocol: it’s an observer of the protocol. This lets us gather queries from servers that don’t have a slow query log enabled, at very high time resolution. With this new functionality, it becomes [...]
Beware of MySQL Data Truncation
Here is nice gotcha which I’ve seen many times and which can cause just a minefield for many reasons. Lets say you had a system storing articles and you use article_id as unsigned int. As the time goes and you see you may get over 4 billions of articles you change the type for article_id [...]
MySQL for Hosting Providers – how do they manage ?
Working with number of hosting providers I always wonder how do they manage to keep things up given MySQL gives you so little ways to really restrict how much resources single user can consume. I have written over a year ago about 10+ ways to crash or overload MySQL and since that people have come [...]
How Percona does a MySQL Performance Audit
Our customers or prospective customers often ask us how we do a performance audit (it’s our most popular service). I thought I should write a blog post that will both answer their question, so I can just reply “read all about it at this URL” and share our methodology with readers a little bit. This [...]

