Author: MySQL Planet

Feed: Planet MySQL; Author: Percona Community; Francisco Miguel Biete Banon  | December 13, 2019 |  Posted In: Intermediate Level, MySQL, Percona Server for MySQLDatabase administrators are responsible for maintaining the privacy and integrity of data. When the data contains confidential information, your company has a legal obligation to ensure that privacy is maintained. Even so, being able to access the information contained in that dataset, for example for testing or reporting purposes, has great value so what to do? MySQL Enterprise Edition offers data masking and de-identification, so I decided to contribute similar functionality to Percona Server for MySQL. In this post, ... Read More

Feed: Planet MySQL; Author: Mikael Ronström; In this part we are going to analyze a bit more complex query than before. This query is a 6-way join.The query is: SELECT         supp_nation,         cust_nation,         l_year,         SUM(volume) AS revenue FROM         (                 SELECT                         n1.n_name AS supp_nation,                         n2.n_name AS cust_nation,       ... Read More

Feed: Planet MySQL; Author: Shlomi Noach; One of the benefits of MySQL GTIDs is that each server remembers all GTID entries ever executed. Normally these would be ranges, e.g. 0041e600-f1be-11e9-9759-a0369f9435dc:1-3772242 or multi-ranges, e.g. 24a83cd3-e30c-11e9-b43d-121b89fcdde6:1-103775793, 2efbcca6-7ee1-11e8-b2d2-0270c2ed2e5a:1-356487160, 46346470-6561-11e9-9ab7-12aaa4484802:1-26301153, 757fdf0d-740e-11e8-b3f2-0a474bcf1734:1-192371670, d2f5e585-62f5-11e9-82a5-a0369f0ed504:1-10047. One of the common problems in asynchronous replication is the issue of consistent reads. I've just written to the master. Is the data available on a replica yet? We have iterated on this, from reading on master, to heuristically finding up-to-date replicas based on heartbeats (see presentation and slides) via freno, and now settled, on some parts of our apps, to using ... Read More

Feed: Planet MySQL; Author: Mark Callaghan; I am excited to start a new job next week working on performance at MongoDB. I have been a fan of the people and product for years and I look forward to contributing from the inside. The reasons I have been a fan include the rate at which the product has improved, WiredTiger and their contribution to MongoRocks.I look forward to learning the modern performance analysis tool chain courtesy of Brendan Gregg. His BPF book should be ready soon and there is much content on his web site. When I had to understand off-cpu ... Read More

Feed: Planet MySQL; Author: Mark Callaghan; It all started for me with the Google patch for MySQL in April 2007. The Register summary of that included a Cringely story repeated by Nick Carr that Google might have shared the patch as part of a plan to dominate IT via cloud computing. I thought that was ridiculous. AWS said hold my beer and brought us Aurora.I donated to the Wayback Machine to offset my HW consumption for those links.A list of talks from the RocksDB team is here.This is an incomplete list of slide decks and videos from me:MySQL for High-Scale, MySQL Ignite ... Read More

Feed: Planet MySQL; Author: Mark Callaghan; This summarizes work we did on MySQL at Google. These posts used to be shared at code.google.com but it was shutdown. After reformatting most of these (it was a fun day for me, but sorry for the spam) I remembered that somone had already done that in 2015. Thank you.It all started for me with the Google patch for MySQL in April 2007. The Register summary of that included a Cringely story repeated by Nick Carr that Google might have shared the patch as part of a plan to dominate IT via cloud computing. I thought that was ridiculous. AWS said hold my ... Read More

Feed: Planet MySQL; Author: Mark Callaghan; This post was shared on code.google.com many years ago but code.google has been shutdown. It describes work done by my team at Google. I am interested in the history of technology and with some spare time have been enable to republish it.This is a collection from several posts about InnoDB IO performanceMax dirty pagesInnoDB provides a my.cnf variable, innodb_max_dirty_pages_pct, to set the maximum percentage of buffer pool pages that should be dirty. It then appears to ignores said variable for IO bound workloads (see this post from DimitriK). It doesn't really ignore the value. The ... Read More

Feed: Planet MySQL; Author: Mark Callaghan; This post was shared on code.google.com many years ago but code.google has been shutdown. It describes work done by my team at Google. I am interested in the history of technology and with some spare time have been enable to republish it.This describes the patch for MySQL 5.0 provided by my team at Google. The early patches from us were difficult for others because they tended to include too many diffs. I didn't have time to better. After I moved to FB Steaphan Greene undertook the heroic effort to do proper diff management and the ... Read More

Feed: Planet MySQL; Author: Mark Callaghan; This post was shared on code.google.com many years ago but code.google has been shutdown. It describes work done by my team at Google. I am interested in the history of technology and with some spare time have been enable to republish it.I added support to rate limit DBMS accounts that were too busy. It wasn't successful in production for the obvious reason that it just shifts the convoy from the database to the app server -- the problem still exists. The better solution is to fix the application or improve DBMS capacity but that takes ... Read More

Feed: Planet MySQL; Author: Mark Callaghan; This post was shared on code.google.com many years ago but code.google has been shutdown. It describes work done by my team at Google. I am interested in the history of technology and with some spare time have been enable to republish it.I added support for roles to MySQL circa 2008. They arrived upstream with MySQL 8 in 2018. I wasn't able to wait. I enjoyed the project more than expected. It wasn't hard in terms of algorithms or performance but I had to avoid mistakes to avoid security bugs and the upstream code was well written ... Read More