… basing this on recent work I have been doing importing large amounts of data from a legacy schema to a completely re-structured one… it is. The only way to do it is to select out first and determine if it will be an insert or a select (and you must do those operations in bulk anyway to…
Comment: MySQL VIEW as performance troublemaker
April 19, 2011 By 57 Comments
… syntax of the CREATE VIEW command looks like this: CREATE [OR REPLACE] [ALGORITHM = UNDEFINED | MERGE | TEMPTABLE] VIEW name [(columnlist)] AS select command… usually more efficient. // ***Views have slow performance on tables with large amount of data http://bugs.mysql.com/bug.php?id=23135
Comment: MySQL VIEW as performance troublemaker
August 12, 2007 By 57 Comments
… syntax of the CREATE VIEW command looks like this: CREATE [OR REPLACE] [ALGORITHM = UNDEFINED | MERGE | TEMPTABLE] VIEW name [(columnlist)] AS select command… usually more efficient. // ***Views have slow performance on tables with large amount of datahttp://bugs.mysql.com/bug.php?id=23135
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
… see very large amount of spin waits and spin rounds significant CPU resources may be wasted. It should come to hundreds of thousands spin… MySQL thread id 8079, query id 728899 localhost root Sending data select sql_calc_found_rows * from b limit 5 Trx read… is executing certain operation. Number of pending operation is shown for each of helper threads – these are amount of operations queued for execution or…
Post: Using any general purpose computer as a special purpose SIMD computer
May 16, 2011 By 5 Comments
… a function on a large amount of input. Often times, the same function must be run on many pieces of input, and this is… add a small amount of serialization at the end. How does this work? Here is the most important part of the explain plan… of parallelism that this data set can achieve with my method. Likely current network technologies can not support such a degree. mysql> select…
Post: Choosing innodb_buffer_pool_size
November 3, 2007 By 39 Comments
…larger than your data (total size of Innodb TableSpaces) because it does not only contain data pages – …for it, especially in case you have large amount of tables). I could tell you some numbers,…Innodb Buffer Pool selection for dedicated Innodb system. If you have fair amount of MyISAM, Archive, PBXT…
Post: MySQL Query Cache
July 27, 2006 By 70 Comments
… stored procedure would simply preform select to retrieve data from table. Avoid comment (and space) in the start of the query – Query Cache… for rather long time for large query caches, which might be unsuitable for online applications. Limited amount of usable memory – Queries are constantly… number of queries in cache and memory used can’t grow forever even if your have very large amount of different queries being run. Of…
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 4 Comments
… is being used then, after the selected rows are read from table1, the values of indexed columns that will be used to… less no. of Innodb_buffer_pool_reads are done, and less amount of data is read from disk, in fact half the amount of data is read from disk 2.2G vs 5G. However, there is one number in MariaDB 5.5 that is quite large…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
… Server 5.5.11 with XtraDB. Requires m1.large or larger. ami-f65ea19f shard-query-infobright-demo … row store for queries which access a significant amount of data. One big reason for this is the excellent …dns” field is selected SSH to the public DNS entry of the node on the list of nodes. This node …
Comment: Database problems in MySQL/PHP Applications
August 11, 2006 By 13 Comments
… loosing data etc. Read more in my > Why MySQL Could be slow with Large Tables…SELECT * FROM articles WHERE user_id IN(23,545,654,34) > instead of: > SELECT * FROM articles WHERE user_id IN (SELECT… you PHP applications use test database with reasonable > amount of data in it. And do run EXPLAIN for…
