Tag: Performance_Schema

Feed: Planet MySQL; Author: Mark Lewin; A really convenient feature in MySQL 8.0 is the ability to persist the values of global variables across server restarts, without writing them into an options file. This was developed primarily for the benefit of Cloud installations of MySQL, but is very handy for a DBA in on-premise installations too. To use this feature you need to have the SYSTEM_VARIABLES_ADMIN and PERSIST_RO_VARIABLES_ADMIN privileges. To demonstrate, we'll increase the value of the max_connections system variable from its default of 151 to 152 and then restart the MySQL server to check that MySQL remembers the new ... Read More

Feed: Planet MySQL; Author: Shree Nair; MariaDB came into being the day that Oracle announced the purchase of Sun in 2010.  In order to keep it free under the GNU GPL, Michael Widenius forked MySQL and took several MySQL developers with him in the process.  Since then, MariaDB has been a drop-in replacement for MySQL, albeit with more features and better performance.In the Improve MariaDB Performance using Query Profiling blog, we learned some useful techniques for tracking and analyzing slow queries using a couple of MariaDB server’s built-in tools: the Slow Query Log and the Performance Schema.   The Slow ... Read More

Feed: Planet MySQL; Author: Andrew Grimo; There are lots of new features in MySQL 8.0 that was recently released including our Document Store capability.  There are a few core capabilities related to InnoDB Cluster in 8.0 that I’d like to share but some will arrive in some coming blogs.  Primarily here I’ll point out some nice details with InnoDB Cluster 8.0 deployments, plus point out how our ability to SET PERSIST GLOBAL configurations allows us to see the beneficial impact of the new replication default configurations in 8.0. I use a set of scripts to build and rebuild my clustered test setups ... Read More

Feed: Planet MySQL; Author: Dimitri Kravtchuk; This post is following previously published OLTP_RO results for MySQL 8.0 (latin1 and utf8mb4 charsets), and now is focusing on Sysbench RW workloads, particularly "mixed" OLTP_RW and Update-NoKey : OLTP_RW : while this workload has writes, it's mainly driven by reads (OLTP_RO + 2 updates + delete + insert) Update-NoKey : aggressively bombarding UPDATE queries (but with no changes on indexed columns) The same 2S Skylake server was used as in previous tests :Server configuration : OS : Oracle Linux 7.4 CPU : 48cores-HT Intel Skylake 2.7Ghz (2CPU sockets (2S), Intel(R) Xeon(R) Platinum 8168 ... Read More

Feed: Planet MySQL; Author: MySQL Performance Blog; Alex Poritskiy | May 3, 2018 |  Posted In: High-availability, Insight for DBAs, MySQL, Replication PREVIOUS POST Recently I worked on one customer issue that I would describe as “slave performance too slow”. During a quick analysis, I’ve found that the replication slave SQL thread cannot keep up while processing row-based events from the master’s binary log. For example: mysql> SHOW SLAVE STATUSG *************************** 1. row *************************** ... Master_Log_File: binlog.0000185 Read_Master_Log_Pos: 86698585 ... Relay_Master_Log_File: binlog.0000185 Slave_IO_Running: Yes Slave_SQL_Running: Yes ... Exec_Master_Log_Pos: 380 Relay_Log_Space: 85699128 ... Master_UUID: 98974e7f-2fbc-18e9-72cd-07003817585c ... Retrieved_Gtid_Set: 98974e7f-2fbc-18e9-72cd-07003817585c:1055-1057 Executed_Gtid_Set: 7f42e2c5-3fbc-16e7-7fb8-05003715789a:1-2, 98974e7f-2fbc-18e9-72cd-07003817585c:1-1056 ... mysql> SHOW SLAVE ... Read More

Feed: Planet MySQL; Author: João Gramacho; MySQL 8.0.11 introduced a new performance schema table named log_status, which provides consistent information about MySQL server instance log positions from replication and transactional storage engines. Used in conjunction with other MySQL 8.0 feature (the backup lock), this new feature will allow backup tools to take backup with minimal impact in DML throughput, but ensuring consistent snapshot with respect to GTIDs, replication, binary logs and transactional storage engine logs. Backup with minimal impact in DML throughput MySQL 8.0.3 introduced a new type of backup lock that permits DML during an on-line backup while preventing ... Read More

Feed: Planet MySQL; Author: Shree Nair; Query profiling is a useful technique for analyzing the overall performance of a database. Considering that a single mid-to-large sized application can execute numerous queries each and every second, query profiling is an important part of database tuning, both as a proactive measure and in diagnosing problems.  In fact, it can become difficult to determine the exact sources and causes of bottlenecks and sluggish performance without employing some sort of query profiling techniques. This blog will present a few useful query profiling techniques that exploit MariaDB server’s own built-in tools: the Slow Query Log ... Read More

Feed: Planet MySQL; Author: MySQL Server Dev Team; MySQL InnoDB Cluster has proven with the first GA release its potential as the native out-of-the-box HA solution for MySQL. With the second GA release, usability, stability and flexibility were greatly improved as described in the previous blog post. This tutorial aims to show how does a typical InnoDB cluster setup look like and how that setup even became simpler and more effective as before. It’s a great starting point for those not familiar with InnoDB cluster and shall help you to get started. For that purpose, we will use the new MySQL ... Read More

Feed: Planet MySQL; Author: MySQL High Availability; It is with extreme delight and a big smile on our face that we share the news that a new major MySQL release has been declared Generally Available (GA). The road to MySQL 8 was pretty eventful, sometimes painful and sometimes hard, always challenging, but nonetheless a great ride and an extremely rewarding journey for the engineers that have worked on it. This is another awesome release and we want you, as a MySQL user, to fully realize the exciting new things all around, in particular in replication! And if you want to ... Read More

Feed: Planet MySQL; Author: Valeriy Kravchuk; I have some free time today, but I am still lazy enough to work on numerous planned and pending "ToDo" kind of posts, so why not to continue review of older MySQL bugs I am subscribed to. Today I am going to list 15 more bugs reported more than a year ago and still not fixed:Bug #85805 - "Incorrect ER_BAD_NULL_ERROR after LOAD DATA LOCAL INFILE". This detailed bug report by Tsubasa Tanaka stays "Verified" for more than a year already. It's a great example of gdb use for MySQL troubleshooting. Setting a couple of breakpoints ... Read More