Historically, Random I/O Reads were always a major PITA
for any OLTP workload.. If Random I/O Writes you could yet
"delay" via controller's caches (or any kind of other
battery-protected caches -- specially if Writes are coming in
bursts), there is no way to "predict" I/O Reads if they are fully
Random (so you cannot "cache" or "prefetch" them ahead and have
to deliver the data directly from storage, read by read.. --
which is hitting a huge "rotation penalty" on HDD).
Indeed, things changed dramatically since arriving of Flash
Storage. You don't need to spend any particular attention if your
I/O Reads are Random or Sequential. However, you still need to
keep in mind to not hit the overall throughout limit of your
Flash Device. As the result, reading by smaller I/O blocks
allowing you to do more I/O operations/sec than with bigger
blocks. And what about InnoDB ? -- InnoDB is using by default
16KB page size (so by default all Random I/O …
There are two simple ways to backup only the users and privileges in MySQL:
1- Using mysqlpump utility (as create user and grant statements):
[shell ~]$ mysqlpump -uUSER -p --exclude-databases=%
--add-drop-user --users >
/tmp/pump-all-users_privileges-timestamp.sql
Dump completed in 1364 milliseconds
Sample output:
[shell ~]$ head
/tmp/pump-all-users_privileges-timestamp.sql
-- Dump created by MySQL pump utility, version: 5.7.21-20, Linux
(x86_64)
-- Dump start time: Sun May 13 23:30:49 2018
-- Server version: 5.7.21
SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0;
SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS,
FOREIGN_KEY_CHECKS=0;
SET @OLD_SQL_MODE=@@SQL_MODE;
SET SQL_MODE="NO_AUTO_VALUE_ON_ZERO";
SET …
Hello marceloaltmann,
I am installing McAfee Audit Plugin 1.1.6 in my Centos 7 MySQL
version 5.6.40 followed by all installation instruction given on
Wiki . After all troubleshooting I’m not able to Load Plugin
either my.cnf or INSTALL PLUGIN.
Always getting fail to initialize AUDIT error. Observed in ,MySQL
error log and found “McAfee Audit Plugin: Couldn’t find proper
THD offsets for: 5.6.40”.
We have also extract offset and OFF checksum but not Loaded
plugin.
Please help me….
Most companies make a mistake at the very beginning. They set their system time zone to Eastern, Central, Mountain, or Pacific time. Then, they install their database on it. They use all manner of timestamp and date types and insert terabytes of data. After that, it becomes almost impossible (in terms of being worth the effort) to change it some months or years later when the company has a popular product or service. One of the unfortunate issues that may arise is illegal datetimes.
On Sunday, March 11, 2018, when US time zones switched To daylight savings time, there was no 2AM hour. When we switch back to normal time on Sunday November 4, there will be two 2AM hours.
Inevitably, out of many database servers and many different types of application servers, some data manages to get inserted into MySQL with an illegal datetime during the 2AM hour on the “spring forward” date. Each …
[Read more]Join Percona Chief Evangelist Colin Charles as he covers happenings, gives pointers and provides musings on the open source database community.
rootconf.in 2018 just ended, and it was very enjoyable to be in Bangalore for the conference. The audience was large, the conversations were great, and overall I think this is a rather important conference if you’re into the “DevOps” movement (or are a sysadmin!). From the data store world, Oracle MySQL was a sponsor, as was MyDBOPS (blog), and Elastic. There were plenty more, including Digital Ocean/GoJek/Walmart Labs — many MySQL users.
I took a handful of pictures with people, and here are some of the MyDBOPS team and myself. They have over 20 …
[Read more]How do MySQL tables get corrupted? There are many ways to spoil data files. Often, corruption is due to defects in the underlying platform, which MySQL relies on to store and retrieve data - disk subsystem, controllers, communication channels, drivers, firmware or other hardware faults. Data corruption can also occur if the MySQL server daemon restarts suddenly, or your server reboots due to a crash of other OS components. If the database instance was in the middle of writing data to disk, it could write the data partially which may end up with a page checksum that is different than expected. There have also been bugs in MySQL so even if the server hardware is ok, MySQL itself can cause corruption.
Usually when MySQL data gets corrupted the recommendation is to restore it from the last backup, switch to DR server or take down the affected node if you have Galera cluster to serve data immediately from other nodes. In some cases you can't - if …
[Read more]Encryption is a very important form of security and It’s becoming a standard from a compliance perspective to ensure PCI, PII and HIPPA compliances. Encryption needs to be performed for Data at Rest, Data over Wire.
Data At Rest:
- Until 5.6, To encrypt the MySQL data files, Only disk level encryption possible (Gazzang, Luks)
- From 5.7.11 MySQL added a feature for tablespace encryption. Which encrypts only the …
MySQL Cluster Manager 1.4.6 is now available for download from My
Oracle Support.
Overview
In MCM 1.4.6, the list backups command has been extended
with a new –agent option for listing agent backups
created with the backup agents command.
mcm> list backups --agent mysite; +------------+-------+---------+----------------------+---------+ | BackupId | Agent | Host | Timestamp | Comment | +------------+-------+---------+----------------------+---------+ | 1522914101 | 0 | tonfisk | 2018-04-05 07:41:41Z | | | 1522914105 | 0 | tonfisk | 2018-04-05 07:41:45Z | | | 1522914121 | 0 | tonfisk | 2018-04-05 07:42:01Z | | …[Read more]
Yes, it does! In this blog post, I am going to share my recent experiences with ProxySQL and how important the database software version number can be.
Migration
I was working on a migration to Percona XtraDB Cluster (PXC) with ProxySQL, fortunately on a staging environment first so we could catch any issues (like this one).
We installed Percona XtraDB Cluster and ProxySQL on the staging environment and repointed the staging application to ProxySQL. At first, everything looked great. We were able to do some application tests and everything looked good. I advised the customer to do more testing to make sure everything works well. …
[Read more]Percona Live Santa Clara, an annual event where open source database users, developers and enthusiasts come together, was held in April at the Santa-Clara convention centre. Pythian was well represented once more with no less than five presentations and a total of nine attendees.
This year the conference was condensed to two days of breakout sessions and one day of tutorials. Though it was shorter in length, the organizers broadened their horizons by including not only MySQL and MongoDB tracks, but this year they even put together a full PostgreSQL track. Moving from MySQL only to multiple technologies, inspired this year’s tagline: polyglot persistence conference. The increase in number of sessions allowed for a lot more options, but the condensed schedule made it much harder to choose which sessions to attend!
My observation from last year’s …
[Read more]