…(“uneven reads“, Re: #1); let me rephrase the use case — * The entire table …scanning the entire last two partitions, performance is not bad. (The last …) anywhere in any ‘free’ variant of MySQL. PARTITIONs are scanned one at a …-row (non-partitioned) table will, at worst, hit the disk only 5 times. (…
Comment: MySQL 5.6 - InnoDB Memcached Plugin as a caching layer
March 29, 2013 By 10 Comments
…apply into MySQL 5.6 memcached. e.g. if i want to store a cache object for only 12 hours…apply to the MySQL innodb memcache? i.e. will the cache being delete off innodb table after 12hours or …do a comparison between performance of 5.6 memcached innodb write/read vs 5.6 innodb write/read with no …
Post: Is there room for more MySQL IO Optimization?
January 3, 2013 By 11 Comments
… cached — system files, binary log, FRM files, MySQL MyISAM system tables etc. Starting MySQL 5.5 MySQL uses asynchronous IO which should allow it… read only workloads, if anything unbuffered performance should be better as it has less overhead with double buffering as well as more information MySQL…
Post: Performance Schema overhead
April 25, 2011 By 22 Comments
… in MySQL 5.6.2, and I am going to check that using PERFORMANCE …PERFORMANCE SCHEMA. So I am going to run the same benchmarks (sysbench read-only and read-write) as in previous post with different performance… PS There is table with ratios for read-only case: ThreadsPS onPS only globalPS all off …
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…Performance_schema_rwlock_classes_lostblogpercona.commanual Performance_schema_rwlock_instances_lostblogpercona.commanual Performance_schema_table_handles_lostblogpercona.commanual Performance_schema_table_instances_lostblogpercona.commanual Performance…
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
… cost of repairing huge MyISAM tables and taking downtime, I would not use MyISAM for anything but read-only tables when things get big. And even if it’s read-only, there’s still another reason to use InnoDB/XtraDB tables…, like star schemas. The problem is that MySQL doesn’t tend to perform well on a data warehousing workload. The…
Post: Performance Schema tables stats
May 2, 2011 By 2 Comments
… on Benchmark Wiki. If we look on performance overhead it appears rather big in read-only benchmark, and it is well explained in… able to get from performance schema tables. 1. table_io_waits_summary_by_table mysql> select * from table_io_waits_summary_by_table where OBJECT_NAME=’sbtest55…
Post: Scaling problems still exist in MySQL 5.5 and Percona Server 5.5
May 20, 2011 By 11 Comments
MySQL 5.5 and Percona Server 5.5 do not solve all scalability problems even for read only…only on one query but yet mimics real world values distribution. The query looks something like this: SELECT * FROM table…published. For read only workload we get 17x gain from 1 thread to peak performance on …
Post: Wow. My 6 year old MySQL Bug is finally fixed in MySQL 5.6
August 30, 2012 By 2 Comments
… with empty set MySQL truncates the constant, performs the lookup and only when discards results: CREATE TABLE `trunc` ( `i` int(11…” here Lets look at query execution: | Handler_read_next | 1305742982 | mysql> select count(*) from trunc where i=4147483647; +———-+ | count(*) | +———-+ …
Post: Is MySQL 5.6 slower than MySQL 5.5?
February 18, 2013 By 23 Comments
… –test=oltp –mysql-socket=/tmp/mysql_sandbox5610.sock –mysql-user=msandbox_rw –mysql-password=msandbox –oltp-table-size=1000000 –num-threads=1 –oltp-read-only=on –init… run For single thread MySQL 5.5 is 11% faster than MySQL 5.6. If you disable Performance Schema in MySQL 5.6 comes…
