…were questions raised about Index Merge on Multiple Indexes vs Two Column Index efficiency. I …Merge technique for low cardinality table but instead pick to do single index scan. I’m…table using index. Also Full Table Scan is preferred for Q4 in all cases but in case of high cardinality multiple…
Post: Multi Column indexes vs Index Merge
September 19, 2009 By 31 Comments
… single index only and simply filter out rows we do not need after lookup. Lets look at some examples now: CREATE TABLE… mention the case when Index merge works much better than multiple column indexes. This is in case you’re using OR… doing full table scan or doing the Union (instead of intersection) on values it gets from the single table. I have reverted table to…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 19 Comments
… current state of Innodb scalability with multiple threads and multiple concurrent transactions ? HT: The scalability in … boost and it would write at 100MBps vs 33MBps. Any plans to enable tuning of … example, if ORDER and ORDERLINE tables are joined to form a single table), it might make sense for …
Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark
March 11, 2013 By 7 Comments
…_13599″ align=”alignright” width=”210″] MySQL 5.6 vs MySQL 5.5 & the Star Schema Benchmark[/caption] …=1000 on MySQL 5.5.30 and testing multiple buffer pools on MySQL 5.5.30. Finally, … mostly in one table (lineorder). Each of the 13 queries were executed serially in a single connection I modified …
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 141 Comments
…table has 10000 distinct value, so range 1..100 selects about 1% of the table. The times for full table scan vs… data sets. In MySQL single query runs as single thread (with exeption of…multiple servers to host portions of data set. Store portion of data you’re going to work with in temporary table…
Post: The Doom of Multiple Storage Engines
May 8, 2010 By 22 Comments
…you look at In Memory storage engines vs Distributed ones. Trying to handle all …multiple storage engines in the query you need to test all kinds of combination such as running multi-table…”FLUSH TABLE WITH READLOCK” and hoping nobody is touching “mysql” database any more. Single Storage Engine…
Post: Read/Write Splitting with PHP Webinar Questions Followup
January 23, 2013 By 4 Comments
…. Q: What are advantages/disadvantages of filtering-out tables from replication in master side vs slave side? A: You can configure filtering… high for a single database instance, and you need to scale out to multiple database instances. Q: Isn’t opening multiple database connections…
Post: Goal driven performance optimization
December 22, 2008 By Leave a Comment
…which are requested for real humans vs search engine bots (which are …can log all requests to MySQL table for larger ones you can log…components (like sphinx and MySQL) or multiple MySQL Servers because in these cases…attention. Though even for less complicated single MySQL server application there is …
Post: Innodb performance gotcha w Larger queries.
August 28, 2009 By 7 Comments
… update performance for the application and I was replacing single value UPDATE with multiple value REPLACE (though I also saw the same… degrade badly – the process which was taking 45 seconds with single value statements was taking over 12 minutes with 1000 values… tables instead. The process completed in 12 seconds for 1000 rows in a batch vs 40 seconds for single row statements. So with single…
Post: Full Text Search Webinar Questions Followup
August 24, 2012 By 5 Comments
… solution. David S. asked: Q: If searching on multiple terms, can you get Sphinx to report which matched… necessarily do table-scans. Jessy B. also asked: Q: Were these tests performed on a single machine and … where I announced the webinar: We evaluated MySQL vs Solr. I was able to index all the …
