…showing the impact of memory allocators on MySQL performance can be found in this blogpost. This …Bug fixed #1082406 (Alex Yurchenko). Dropping a non-existing temporary table would be replicated when TOI…(Raghavendra D Prabhu). In case CREATE TABLE AS SELECT statement was running in parallel with the …
Post: Scaling problems still exist in MySQL 5.5 and Percona Server 5.5
May 20, 2011 By 11 Comments
… look at the gain system shows from performance at 1 thread to the peak performance we see the number is 2.3…_range_next,QUICK_RANGE_SELECT::get _next,rr_quick,sub_select,do_select,JOIN::exec,mysql_select,handle_select,execute_sqlcom_select,mysql_execute_command,my…_range_next,QUICK_RANGE_SELECT::get_next,rr_quick,sub_select,do_select,JOIN::exec,mysql_select,handle_select,execu te_sqlcom_select,mysql_execute_command…
Post: Innodb performance gotcha w Larger queries.
August 28, 2009 By 7 Comments
… ago I was looking for a way to improve update performance for the application and I was replacing single value UPDATE… in the batch performance improved, especially for network tests, however going to batches of 100 and 1000 values performance started to degrade… of performance bug of 5.0. At row0sel.c:row_search_for_mysql() “PHASE 3:”, InnoDB judge whether the SQL is “SELECT…
Post: SELECT LOCK IN SHARE MODE and FOR UPDATE
August 6, 2006 By 51 Comments
… be able to set locks on rows which no more exist – would it do any good for you ? Not really – for…’re updating selected rows. As query results may chance you need to access how it affects your application and perform changes required… like because locks are taken on Innodb level before MySQL performs like matching, and row is not unlocked if it does…
Post: MySQL Partitioning - can save you or kill you
December 11, 2010 By 45 Comments
… leaf key to verify such value does not exist, which reduced performance for random selects by UUID from 400 to 20 per second… of selects the table could deliver was increasing and there seems to be a reasonable number which would allow replication to perform better when it is now, while selects still performed in the amount system needs. What…
Post: Goal driven performance optimization
December 22, 2008 By Leave a Comment
… your existing system, looking for consolidation or saving on infrastructure cost. If this is the goal you can perform general system performance evaluation… example: mysql> select date_format(logged,’%H’) h,count(*),avg(wtime),avg(sphinx_time/wtime) sphinx_ratio from performance_log_081221 where…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…at this stage. Is it the current performance, future performance, scalability, ability to recover from disasters?…there are InnoDB tables whose .frm files exist but have been dropped from InnoDB, for …, I run EXPLAIN if possible (rewriting non-SELECT queries if needed, and using careful judgment…
Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark
March 11, 2013 By 7 Comments
… report. In an OLTP system this can have very negative performance consequences. The plugin attempts to fix this problem by splitting…’ve tested performance of the query with the join in both directions. Explain for query Q1.1: mysql> select straight_join sum…_HolidayFl tinyint, D_WeekDayFl tinyint ); DROP TABLE IF EXISTS lineorder; CREATE TABLE IF NOT EXISTS lineorder ( LO_OrderKey bigint not null, LO…
Post: Shard-Query turbo charges Infobright community edition (ICE)
May 6, 2011 By 23 Comments
…=t2.Year); The performance of the following queries depends on the size of the date range: — Q8.0 SELECT dest.CityName, COUNT… servers, it performs about 6x better as the degree of parallelism is controlled by the number of shards. — Q9 select Year ,count… data. Shard-Query can be used with existing data sets easily, improving the performance of queries significantly if they use common query…
Post: PBXT benchmarks
April 8, 2007 By 14 Comments
… key and couple of extra indexes. CREATE TABLE IF NOT EXISTS `$tableName` ( `id` int(10) unsigned NOT NULL auto_increment, `name… %d LIMIT 50 READ_FTS Query: SELECT min(dob) FROM $tableName The hardest query performs a scan of all million rows. General… reach InnoDB results, but I hope PBXT team will improve performance to make the difference a bit better. Unfortunately InnoDB shows…
