Tag: collation

Feed: Percona Database Performance Blog. Author: Sveta Smirnova. Sveta Smirnova  | September 11, 2017 |  Posted In: Database Monitoring, InnoDB, Insight for DBAs, Insight for Developers, MySQL PREVIOUS POST In this post, we will discuss how to fix cardinality for InnoDB tables manually. As a support engineer, I often see situations when the cardinality of a table is not correct. When InnoDB calculates the cardinality of an index, it does not scan the full table by default. Instead it looks at random pages, as determined by options innodb_stats_sample_pages, innodb_stats_transient_sample_pages and innodb_stats_persistent_sample_pages, or by the  CREATE TABLE option STATS_SAMPLE_PAGES. The default value for persistent statistics is 20 ... Read More

Feed: Planet MySQL; Author: Roberto V. Zicari; “To be competitive with non-open-source cloud deployment options, open source databases need to invest in “ease-of-use.” There is no tolerance for complexity in many development teams as we move to “ops-less” deployment models.” –Peter Zaitsev I have interviewed Peter Zaitsev, Co-Founder and CEO of Percona. In this interview, Peter talks about the Open Source Databases market; the Cloud; the scalability challenges at Facebook; compares MySQL, MariaDB, and MongoDB; and presents Percona’s contribution to the MySQL and MongoDB ecosystems. RVZ Q1. What are the main technical challenges in obtaining application scaling? Peter Zaitsev: When ... Read More

Feed: Planet MySQL; Author: Mark Callaghan; This post compares MyRocks, InnoDB and TokuDB on the time required to load and index a table for sysbench.tl;drMyRocks, InnoDB and TokuDB have similar load performance although there is a regression for InnoDB from 5.6 to 5.7 to 8.x InnoDB create index is much faster starting in 5.7 ConfigurationI used my sysbench helper scripts with my sysbench branch and configured it to create 1 table with 800M rows. The binlog was enabled but sync on commit was disabled for the binlog and database log. The sysbench client shared the host with mysqld. The host has ... Read More

Feed: Planet MySQL; Author: Mark Callaghan; I repeated the in-memory sysbench test on a small server and the results are similar to what I measured on the large server.tl;drMyRocks does worse than InnoDB and the difference is larger on read-heavy tests. InnoDB QPS tends to decrease after 5.6.35 InnoDB range scans are more efficient after 5.6.35 ConfigurationI used core i5 Intel NUC servers with an SSD, my sysbench helper scripts and sysbench branch. The test was run with 4 tables and 1M rows/table. Somewhat accurate my.cnf files are here. The test was run for MyRocks compiled on August 15 with git hash 0d76ae ... Read More

Feed: Planet MySQL; Author: Mark Callaghan; Today I share worst-case performance results for MyRocks -- in-memory sysbench and a small database. I like MyRocks because it reduces space and write amplification, but I don't show results for that here. Besides, there isn't much demand for better compression from such a small database. This is part 1 with results from a large server.tl;drMyRocks does worse than InnoDB 5.6.35 at low and mid concurrency for all tests except update-index. It suffers more on the read-heavy tests. MyRocks and TokuDB are more competitive at mid and high concurrency than at low InnoDB QPS ... Read More

Feed: Planet MySQL; Author: Mark Callaghan; This is part 3 of my performance report on IO-bound sysbench. In part 1 and part 2 I used a large server with 48 HW threads. Here I use a core i5 NUC with 4 HW threads.tl;drresults are similar to the first post MyRocks is competitive on the write-heavy tests MyRocks is slower on the read-heavy tests I don't attempt to show that MyRocks wins on space and write efficiency and that is why I like it ConfigurationI use my sysbench fork and helper scripts, release specific my.cnf files. The server is a core i5 NUC with 4 HW ... Read More

Feed: Planet MySQL; Author: Mark Callaghan; I have new performance results to share starting with modern sysbench, a large server, fast SSD and a database that is larger than RAM. Competitive read performance with much better space and write efficiency is why I like MyRocks and this is an example of that. However, we have work to do on read efficiency that will be apparent in future perf reports.tl;drFor write-heavy workloads MyRocks competes with InnoDB 5.7 and 8.0 and does better than 5.6 at all concurrency levels.  For read-heavy workloads MyRocks is usually within 10% of InnoDB 5.6. For write-heavy ... Read More

Feed: Planet MySQL; Author: Peter Gulutzan; MySQL has thrown away the mysql.proc table for version 8.0 Development Releases. The best explanation that I've seen is the one that Dmitry Lenev gave at a conference last October. To summarize it: mysql.proc and its ilk are non-transactional, redundancy is bad, and MySQL can fix some known bugs by moving over to information_schema tables backed by InnoDB. Of course I approve for a separate reason: mysql.proc is non-standard and therefore it is a mistake. On the other hand, programmers that have invested some time in using mysql.proc will have some trouble changing them ... Read More

Feed: Planet MySQL; Author: Oracle MySQL Group; It's our pleasure to announce that MySQL Community team is supporting multiple shows around the world. Please find a list of conferences & events where you can find us in August & September below: NA&LAD UbuCon LA,Lima, Peru, Aug 18-19, 2017 MySQL Community team is supporting this small Ubuntu conference in LAD as Platinum sponsor.   Pacific Northwest PHP, Seattle, US, Sep 9-11, 2017 You can find our team at the MySQL Community booth in the expo area. Madison PHP, Madison, US, Sep 22-23, 2017 MySQL Community team is supporting this PHP conference ... Read More

Feed: Planet MySQL; Author: Valeriy Kravchuk; I have to get back to the topic of checking user variables in gdb to clarify few more details. In his commentShane Bester kindly noted that calling functions defined in MySQL code is not going to work when core dump is studied. So, I ended up with a need to check what does the my_hash_element() function I've used really do, to be ready to repeat that step by step manually. Surely I could skip that and use Python and Shane himself did, but structures of HASH type are widely used in MySQL, so I'd ... Read More