…for replication to continue. This prevents any node in the synchronous replication group from getting too far behind the…the cost of certification depends only the size of the transactions, which translates into number of unique key lookups into the certification index…
Post: Is Synchronous Replication right for your app?
May 14, 2013 By 18 Comments
…KEY index entry for that row). This means typically on a single Innodb node we can have all sorts modifications floating around as long…for the transaction, so by the time the original node gets acknowledgement of the transaction back from all the…used to the…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…the mysql.* tables, running mk-duplicate-key-checker to find redundant indexes, and so on. As with settings and status, these set the stage for…long time to finish. And it’s important to focus on ones that can give the greatest improvement for the…
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 28 Comments
…use for the statistics from which the ratio is derived (but not the ratio itself, which you should ignore). Read on for the…the indexes are on disk, and so on. Raise the key_buffer_size until, when the buffer is full, Key…
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
…For The Long Tail People talk about the long tail and how you can focus on optimizing the short head. It’s the…the indexes less than half the size. In real life this technique often makes the table+index much less than half the…
Post: MySQL Indexing Best Practices: Webinar Questions Followup
August 16, 2012 By 4 Comments
…for primary key which gets a lot of lookups is frequent reason to use something else as primary key. Q: How many indexes is too…the index on column using order by clause. A: If index is used for ORDER BY the same index must be used for selection for the same table, not other index…
Post: Heikki Tuuri answers to Innodb questions, Part II
November 4, 2007 By 13 Comments
… any table / index fragmentation, without having to run the OPTIMIZE? HT: Since OPTIMIZE rebuilds the whole table, it may last way too long for your 150… of table online. Q38: Seems that adaptive hash indexes are not used for primary key lookups or not showed up in “show innodb…
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
…use Scale Factor of 40 (InnoDB dataset size ~95G), because the query was taking far too long…the start of the post that traditional index lookup (for non-index-only columns) involves, reading an index record, and then using the PK column value in the index…
Post: A workaround for the performance problems of TEMPTABLE views
May 19, 2010 By 7 Comments
…the table is inserted too (see below) the connection_id() function will be used to generate the value for the connection_id column. Also notice the…
Post: Dynamic row format for MEMORY tables
September 6, 2011 By 5 Comments
…The key columns must come before any non-key variable-length columns. For performance reasons, the key columns are stored in a fixed-length block at the…use. This is a valid question because the MEMORY implementation has changed significantly with this patch–for the fixed-length records too…
