…shines. Compared to a deployment with no SSD cache whatsoever, FlashCache still does…requests=0 –percentile=95 \ –mysql-user=root –mysql-socket=/tmp/mysql.sock –mysql-table-engine=innodb \ –oltp-read…64M serverid = 101 key_buffer_size = 8M read_buffer_size = 1M read_rnd_buffer_size …
Post: More on MySQL transaction descriptors optimization
April 26, 2013 By Leave a Comment
…) vs. two-node (on the right) configuration. No surprises here, the general pattern is consistent… of read-only transactions become obvious. In the following test sysbench does 9 primary key SELECTs… –forced-shutdown=1 –max-time=120 –max-requests=0 –percentile=99 –mysql-user=root –mysql-…
Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark
March 11, 2013 By 7 Comments
…READ_REQUESTS | 3776369 | | INNODB_BUFFER_POOL_READS | 191571 | | INNODB_DATA_PENDING_READS | 0 | | INNODB_DATA_READ | 3140882432 | | INNODB_DATA_READS | 191581 | | INNODB_PAGES_READ | 191570 | | INNODB_ROWS_READ…
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 28 Comments
… “The ratio of key_reads to key_read_requests should be as low as possible, no more than 1:100″ or “your key cache hit ratio should… #1 has 23 Key_reads and 100 Key_read_requests (23% miss ratio). Server #2 has one trillion Key_reads, and one hundred quatrillion Key_read_requests (1/100th of…
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
…key_column, pk_column FROM tbl WHERE key_column=x ORDER BY key_column (Note that secondary keys in InnoDB contain primary key…read_requests 1361851 1264739 1235472 1263290 1235781 Innodb_buffer_pool_reads 120548 102948 76882 102672 76832 Innodb_data_read…do read_ahead, while in MySQL 5.5 no read_ahead…
Post: Find and remove duplicate indexes
June 20, 2012 By 9 Comments
… big difference in the number of Handler_read_next requests, so less data needs to be read. It’s also worth to mention that some people tends to create a UNIQUE(i) key on the primary key because… there is no duplicated. That’s not necessary because the PRIMARY KEY is indeed UNIQUE. How can I find all those keys? There…
Post: Heikki Tuuri answers to Innodb questions, Part II
November 4, 2007 By 13 Comments
… page read requests per a readahead. The InnoDB buffer is 256 page read requests for the aio read thread. … moves the contention to another place. Thus, no general rules can be established. I have…01 non-hash searches/s HT: Strange, primary key equality searches should work through the adaptive …
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 4 Comments
…read_requests 12947073 10228611 7816154 10251697 9319281 9393396 Innodb_buffer_pool_reads 327963 332092 12889 335080 14067 13384 Innodb_data_read…read_key‘, ‘Handler_read_next’ and ‘Handler_read_rnd_next’. MariaDB 5.5 with Hash Joins enabled is doing less Handler reads…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
… key constraint: ———————— LATEST FOREIGN KEY ERROR ———————— 060717 4:29:00 Transaction: TRANSACTION 0 336342767, ACTIVE 0 sec, process no …read” shows average size of read requests. For random IO these should be 16K – page size, for full table scan or index scan read…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…key_cache_age_thresholdblogpercona.commanual key_cache_block_sizeblogpercona.commanual key_cache_division_limitblogpercona.commanual Key_read_requestsblogpercona.commanual Key_readsblogpercona.commanual Key_write_requestsblogpercona.commanual Key…_sync_master_wait_no_slaveblogpercona.commanual Rpl_…
