May 25, 2012

Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5

… case of MySQL 5.5 and ~5 hours in case of MySQL 5.6 and MariaDB 5.5. Note that query cache is disabled… revenue, c_acctbal, n_name, c_address, c_phone, c_comment from customer, orders, lineitem, nation where c_custkey = o_custkey… when the correct query execution plan is not used, there is no difference in query times between MySQL 5.5 and MySQL 5.6…

Post: Should we give a MySQL Query Cache a second chance ?

MySQL Query Cache is most useful for complex expensive queries, for which tracking exact rows used from query syntax may be hard. Query Cache Storage Engines MySQL Query Cache

Post: MySQL Query Cache WhiteSpace and comments

Commenting on my previous post on MySQL Query Cache Gerry pokes me as I’m all wrong and both comments and whitespace are fixed in MySQLcomments Repeating queries from PHP instead we can learn the following about MySQL 5.0 Query Cache: Whitespace at the start of query does not block query

Post: MySQL Query Cache

MySQL Query Cache is – I’ve seen number of people being confused, thinking MySQL Query Cache is the same as Oracle Query Cache – meaning cache where execution plans are cached. MySQL Query Cache

Post: mk-query-digest, query comments and the query cache

…. You can enable query cache stripping in Percona Server at runtime: mysql> set global query_cache_strip_comments=’ON’; Query OK, 0 rows … query cache, but would like better instrumentation in your queries, consider using Percona Server and turning on the –strip-query-cache-comments feature. …

Post: Caching techinques

comments about Jays article. First – caching in files should be used with caution. It may be very efficient especially if number of cached… or remove objects in cache once underlying information is updated. This is how MySQL Query Cache works by removing all queries derived from the table…

Post: Ultimate MySQL variable and status reference list

MySQL manual, especially the option and…query_alloc_block_sizeblogpercona.commanual query_cache_limitblogpercona.commanual query_cache_min_res_unitblogpercona.commanual query_cache_sizeblogpercona.commanual query_cache_typeblogpercona.commanual query_cache_wlock_invalidateblogpercona.commanual query

Post: Shard-Query EC2 images available

COMMENT=’Contains all avaialble data from 1988 to 2010′; mysql> use ontime1; Database changed mysqlquery command, called pivot_results cd shard-query/ $ ./run_query < queries

Post: Recall of Percona Server 5.1.47-11.0

… if query is starting from SEL or comment. After Query is parsed and executed MySQL stores results for SELECT queries in Query Cache. There are cases when queries will not be considered as cachable query

Post: Aligning IO on a hard disk RAID – the Benchmarks

…IO alignment, not different MySQL configurations, I didn’t try out different MySQL versions or settings….cache = 2048 max_allowed_packet = 16M binlog_cache_size = 16M max_heap_table_size = 64M thread_cache_size = 32 query_cache… some numbers to share, please leave a comment. Next, I plan to look at IO…