…with optimizer hints like straight_join to have it look at tables in the right order and … say there are about 10 million rows in this orders table. Of the referenced columns there are 10 types of items, 5…not require indexes on FKs. The database designer should be able to choose what to do. Having …
Post: Read/Write Splitting with PHP Webinar Questions Followup
January 23, 2013 By 4 Comments
… the tolerance test, then the wrapper class executes the query against the master. Q: What are advantages/disadvantages of…are exception cases too, so we can’t make such a broad general statement. It depends on the types of…Join Percona and the MySQL community in Santa Clara, April 22-25 2013 for the…
Post: Percona XtraDB Cluster - installation and setup webinar follow up Q&A
October 28, 2012 By 4 Comments
… it can keep up with the writes and/or configure and rethink the retention of the raw data. Q: What are the steps to automatically restart a Percona Cluster after an outage? A: It depends of the type of failure… will join the cluster, but won’t store or serve data. Q: Is the configuration file my.cnf ? A: Yes. Q: If the cluster…
Post: Innodb row size limitation
April 7, 2011 By 12 Comments
…What‘s going on? Innodb gives you this error when it can’t store all of the…the type of data you’re inserting (hint: the more random your data is, the worse compression will work). Something important to note is that the…, precisely for the added join complexity. …Also, overflow pages are allocated 1…
Post: Picking datatype for STATUS fields
August 9, 2008 By 24 Comments
…the list of variants which can be used lets talk about two important types of these status fields. First is BOOLEAN or YES/NO type…the applications, just do not do it by randomly picked advice but think what kind of application do you have and what are the…
Post: XtraDB/InnoDB CPU bound benchmarks on 24cores server
December 29, 2008 By 6 Comments
…default_table_type=MYISAM…_threads = 16 join_buffer…are removed for additional checking) In the next run I tested sysbench oltp read-write load, and the results are: Here starting 16 threads the…of. We definitely we will look how to fix it as next step, read detailed investigation what is the reason of…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
…the minimum amount of drift for this type of MV is the amount of time it takes to execute the query on which the…what changed, even for MVs with aggregation and joins, is the value proposition for Flexviews. The flexviews.refresh() stored procedure The…
Post: ORDER BY ... LIMIT Performance Optimization
September 1, 2006 By 100 Comments
…is often the cause of MySQL Performance problems. Here is what you … LIMIT in the back end. In general this type of ORDER BY looks …networking and dating sites are perfect example of such queries SELECT FROM…the leading table. If ORDER BY is going by field from the table which is not first in the join…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 141 Comments
… there are few completely uncached workloads but 100+ times difference is quite frequent. Indexes What everyone knows about indexes is the fact they are… – For large data sets full table scans are often faster than range scans and other types of index lookups. Even if you look at 1% or rows or less full table scan may be faster. Avoid joins…
Post: How to find MySQL queries worth optimizing ?
September 11, 2012 By 6 Comments
… are no matches) but it had to examine 10Mil rows to produce result. What would be good scenario ? – query examining same amount of….00 sec) In this case we actually join 2 tables but because the access type to the tables is “const” MySQL does not count it as access to two tables. In case of “real” access to the…
