…really really matters. High-Memory Quadruple Extra Large Instance 68.4 GB of memory …log_file_size = 1G innodb_log_files_in_group = 4 innodb_buffer_pool_instances = 4 innodb_adaptive…data-set on the insert rate. We can see that adding the secondary indexes to the table has decreased the insert rate by…
Post: Using any general purpose computer as a special purpose SIMD computer
May 16, 2011 By 5 Comments
…large. I inflated the document size significantly to over 3 million “words” by duplicating the entire set multiple times. mysql> load data…data set agnostic, operating only on sets, not relations. If it were smarter it would ask the data…_tmp_39323566` GROUP BY 1,2 ORDER BY 1 ASC ON DUPLICATE KEY …
Comment: Database problems in MySQL/PHP Applications
August 11, 2006 By 13 Comments
…group tables by certain logic, such as > you do with directories to group files. I think this makes a lot of > sense. Sometimes grouping…data sets helps document relationships of data. There is no reason why a query can’t reference data…data etc. Read more in my > Why MySQL Could be slow with Large… On…
Post: Percona XtraDB Cluster - installation and setup webinar follow up Q&A
October 28, 2012 By 4 Comments
…For the record, when I set the clock on my vms, they were almost off by 90s compared to the…end up having 2 different clusters serving data to different groups of clients. So, the last gcomm:// …a traditional Master Slave scenario when the data set is very large? Can you swap in Binaries ? A: Check…
Post: Make your file system error resilient
August 24, 2011 By 8 Comments
…on errors. By default these filesystems are configured to Continue when error (such as IO error or meta data…large…group: 32768 Fragments per group: 32768 Inodes per group: 2048 Inode blocks per group: 128 RAID stride: 8 RAID stripe width: 80 Flex block group…
Post: Shard-Query adds parallelism to queries
November 15, 2010 By 18 Comments
…queries which each examine large amounts of data. Since a single …data. What is Shard-Query? Shard-Query was initially conceived as a utility to add parallelism to horizontally partitioned data sets by…on Vadim’s list. The purpose of this test is to demonstrate that Shard-Query works with GROUP BY…
Post: Quickly finding unused indexes (and estimating their size)
December 5, 2012 By 2 Comments
…index workload on these two sets …_schema like ‘sakila%’ group by t.table_schema,… with test data): mysql> select * from droppable_indexes; …by simply doing: mysql> alter table mytable ENGINE=Innodb; However, this blocks and on a large…
Post: MySQL Indexing Best Practices: Webinar Questions Followup
August 16, 2012 By 4 Comments
…to be used, which can be important for large, heavily written tables. Q: in trick #1 will…. The size of this “working set” can greatly depend on application and can range from 5% …on the column MySQL can avoid temporary table or filesort for group by by this column. This works because by scanning data…
Post: Talking MySQL to Sphinx
April 19, 2009 By 4 Comments
…result set even if you have not asked it. Another thing to try is GROUP BY – Sphinx executes GROUP BY in…to quickly throw away large blocks of attributes if they do not contain any data: Sphinx select max…to “break” MySQL making it to do group by with on disk temporary table which will make Sphinx …
Post: Goal driven performance optimization
December 22, 2008 By Leave a Comment
… focus on hard data …16651488365119 | +———-+—————–+——————+——————+——————+——————+ 1 row in set (2…. for. Large portion…wtime>1 group by h; +——+———-+—————–+——————+ | h | count(*) | avg(wtime) | sphinx…
