…”flight”. I have labeled each query as Q{FLIGHT_NUMBER}.{QUERY_NUMBER}. In general, each flight…=/mnt/mysql56/data basedir=/usr/local/mysql socket=/var/lib/mysql/mysql.sock user=justin innodb_buffer_pool…_blocks_time=0 table_open_cache=2048 table_definition_cache=16384 innodb_flush_method=O_DIRECT key…
Post: Rotating MySQL slow logs safely
April 18, 2013 By 7 Comments
… a solution for keeping the caches of a MySQL standby server hot using MySQL slow logs with long_query_time set to 0. Here… also flushes tables in addition to logs. Flushing tables can impact running queries. Disable MySQL slow logs during rotation Flushing logs takes time. Meanwhile, queries are…
Post: MySQL and Percona Server in LinkBench benchmark
May 8, 2013 By 18 Comments
…. Percona Server 5.5 outperforms MySQL in about 2x times. Both MySQL 5.5.30 and MySQL 5.6.11 demonstrate notable drops…=5000 table_open_cache=5000 table-definition-cache=1000 query_cache_size=0 query_cache_type=0 performance_schema=0 #56only loose-innodb_flush_neighbors=0 loose-metadata_locks_hash_instances=256 innodb_buffer_pool_instances=16 # MySQL 5.5 and 5…
Post: More on MySQL transaction descriptors optimization
April 26, 2013 By Leave a Comment
…100M:autoextend innodb_flush_log_at_trx_commit = 2 innodb_flush_method = O_DIRECT… 2000 max_connections=5000 table_open_cache=5000 query_cache_type=OFF performance_schema=0 warmup…–percentile=99 –mysql-user=root –mysql-db=sbtest8t1M –mysql-table-engine=INNODB –mysql-socket=/tmp/mysql.sock –oltp-…
Post: Virident vCache vs. FlashCache: Part 2
May 17, 2013 By 3 Comments
…base HDD MySQL configuration for purposes of comparison. Given the apparent differences in time-based flushing in vCache and FlashCache, both cache devices…_cache_size = 16M max_heap_table_size = 64M sort_buffer_size = 4M join_buffer_size = 4M thread_cache_size = 1000 query_cache_size = 0 query_cache…
Post: Benchmarking Percona Server TokuDB vs InnoDB
May 7, 2013 By 32 Comments
….x86_64/lib/mysql/libjemalloc.so [mysqld] gdb datadir=/mnt/data/mysql #for SSD innodb_flush_neighbor_pages = none innodb_adaptive_flushing_method = keep…_cache_size = 16M max_heap_table_size = 64M sort_buffer_size = 4M join_buffer_size = 4M thread_cache_size = 1000 query_cache_size = 0 query_cache…
Post: MySQL Query Cache
July 27, 2006 By 70 Comments
…FLUSH QUERY CACHE command can be used for query cache defragmentation but it may block query cache for rather long time for large query caches…
Post: Beware large Query_Cache sizes
March 23, 2007 By 3 Comments
… had number of consulting projects with MySQL Query Cache being source of serious problems. One would see queries both for MyISAM and Innodb tables… if your query cache size is in Gigabytes. At the same time check how many queries do you have in cache – Qcache_queries_in_cache – if… rather than constant insertion. You can also check how long FLUSH QUERY CACHE takes – if it is in seconds this is about as…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…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…
Comment: What does Handler_read_rnd mean?
June 25, 2010 By 15 Comments
… row in set (0.00 sec) mysql> flush status; Query OK, 0 rows affected (0.00 sec) mysql> select * from t1; +——+ | n | +——+ | 1 | | 2… row in set (0.01 sec) mysql> flush query cache; Query OK, 0 rows affected (0.00 sec) mysql> show status like ‘Handler_read_rnd_next… second time you ran the query even if you flushed the query cache. However, if you did not flush the query cache, but flushed the tables, it did…
