…’s hard to make a general rule, because there are different types of subqueries (correlated, non-correlated, derived tables, scalar subqueries) and… be a problem if the keywords were returned in a different order from what you specify in the query? The tuple… that sometimes you find unexpected differences in performance like this, so it pays to test all different solutions, and measure the resulting…
Comment: How number of columns affects performance ?
May 25, 2013 By 12 Comments
… would it be more efficient to have multiple ( 7-10 ) different tables and minimize the record count in each table or… differentiate between my types of data and put them all in the same table. The only difference is the data type…all the… scenario and 16 if I had to add a data type column. We are probably looking at 2 million records total…
Post: The small improvements of MySQL 5.6: Duplicate Index Detection
May 31, 2013 By Leave a Comment
… for duplicate keys, but not redundant ones. What is the difference? Let’s see an example. If we execute: mysql> ALTER… and no errors in 5.6, as the indexes are different. But as you may know, we can use the second… definitions: # KEY `col2` (`col2`), # KEY `col2_2` (`col2`,`col3`) # Column types: # `col2` int(11) default null # `col3` varchar(200) default null…
Post: Experiences with the McAfee MySQL Audit Plugin
May 23, 2013 By 4 Comments
… VM I was working in and didn’t get significant differences between either output option, or between using the plugin or…”:”debian-sys-maint”,”host”:”localhost”,”cmd”:”Connect”,”query”:”Connect”} {“msg-type“:”activity”,”date”:”1369155747373″,”thread-id”:”6439″,”query-id”:”219309″,”user…”:”debian-sys-maint”,”host”:”localhost”,”cmd”:”Quit”,”query”:”Quit”} {“msg-type“:”activity”,”date”:”1369155747383″,”thread-id”:”6440″,”query-id”:”0″,”user…
Post: MySQL and the SSB - Part 2 - MyISAM vs InnoDB low concurrency
May 22, 2013 By Leave a Comment
…_NUMBER}. In general, each flight examines different time periods or different regions. The flights represent the type of investigations and drill-downs that… and is not ACID compliant. MyISAM and InnoDB may perform differently under concurrency, which this benchmark does not cover. I will…
Comment: Replication in MySQL 5.6: GTIDs benefits and limitations - Part 1
June 10, 2013 By 8 Comments
…. The same issue can arise if slave host is using different storage engine for the respective table on master databases. Also…. CREATE TABLE …. SELECT – It is not supported to perform such type of statements http://mysqlopt.blogspot.co.uk/2013/06/restrictions…
Comment: What Are Full, Incremental, and Differential Backups?
May 22, 2013 By 9 Comments
… please give examples of data usage with each of the types of backup e.g. A backup done once per week… for 7 weeks thereafter. Using 25MB on week1 then various differences for each of the weeks. Can you give an example…
Post: How to recover table structure from InnoDB dictionary
April 22, 2013 By 4 Comments
…successful recovery. Even an unnoticeable difference like NULL or NOT NULL…actor’; +————–+—–+——–+——+——–+———+————–+——-+ | NAME | ID | N_COLS | TYPE | MIX_ID | MIX_LEN | CLUSTER_NAME | SPACE | …
Post: More on MySQL transaction descriptors optimization
April 26, 2013 By Leave a Comment
… and MySQL 5.6. In order to understand more about differences between results we have rerun tests on several our boxes… then compared results across all 3 boxes to see if different hardware has any notable impact: Still no luck, everything is…-table-size=1000000 –rand-init=on –report-interval=1 –rand-type=uniform –forced-shutdown=1 –max-time=120 –max-requests=0…
Post: Benchmarking Percona Server TokuDB vs InnoDB
May 7, 2013 By 32 Comments
…: Kingston HyperX 3K 240 GB. Workload: I will use two different schemas. The first schema is from sysbench, and the table…. Now to see this point of intersection, let’s review different workload (which actually is closer to what I need). Tables… –report-interval=10 –max-requests=0 –num-threads=32 –rand-type=pareto run and InnoDB options are: [mysqld_safe] numa-interleave…
