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Displaying posts with tag: innodb (reset)
Will IO Size Affect your RDS Performance?​

During our recent consulting with one of our client, We came across an interesting issue on RDS. The baseline is that “Low IO size on your RDS instance can affect your DB performance”.  Yes, It’s IO size, Not IOPS.

We had our production systems running on RDS MySQL with a single master, 3 replicas. All instances are of same type db.m4.4xlarge with same parameter group configuration and the disk size is 1.5 TB. According to the AWS user guide, each of these instances can support up to 4500 (sustained IOPS) guaranteed IOPS.

Find below the Write IOPS graph for all the instances.

It’s understood that Write IOPS / pattern on Master can vary when compared with Slave, due to a lot of factors like binlog row format, log writing etc. But it has to be almost similar for all the slaves given that it …

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Fun with Bugs #77 - On MySQL Bug Reports I am Subscribed to, Part XIV

Slides for my talk about MySQL bugs at FOSDEM 2019 MySQL, MariaDB and Friends Devroon are ready, support customers decided not to break anything badly on weekend, so I have some free time for blogging.  As usual, when I do not have any better idea or useful recent real life experience to share I write about MySQL bugs.

Today I'd like to continue my review of interesting MySQL bug reports added by Community members in December, 2018. I'll review them starting from the oldest:

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MariaDB JIRA for MySQL DBAs

These days several kinds and forks of MySQL are widely used, and while I promised not to write about MySQL bugs till the end of 2018, I think it makes sense to try to explain basic details about bug reporting for at least one of vendors that use JIRA instances as a public bug tracking systems. I work for MariaDB Corporation and it would be natural for me to write about MariaDB's JIRA that I use every day.

As a side note, Percona also switched to JIRA some time ago, and many of the JIRA-specific details described below (that are different comparing to good old https://bugs.mysql.com/) apply to Percona bugs …

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Fun with Bugs #75 - On MySQL Bug Reports I am Subscribed to, Part XII

From the lack of comments to my previous post it seems everything is clear with ERROR 1213 in different kinds and forks of MySQL. I may still write a post of two about MyRocks or TokuDB deadlocks one day, but let's get back to my main topic of MySQL bugs. Today I continue my series of posts about community bug reports I am subscribed to with a review of bugs reported in November, 2018, starting from the oldest and skipping those MySQL 8 regression ones I've already commented on. I also skip documentation bugs that should be a topic for a separate post one day (to give more illustration to …

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Percona XtraBackup 8.0.4 Is Now Available

Percona is glad to announce the release of Percona XtraBackup 8.0.4 on December 10, 2018. You can download it from our download site and apt and yum repositories.

Percona XtraBackup enables MySQL backups without blocking user queries, making it ideal for companies with large data sets and mission-critical applications that cannot tolerate …

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What May Cause MySQL ERROR 1213

Probably all of us, MySQL users, DBAs and developers had seen error 1213 more than once, in one context or the other:
mysql> select * from t1;
ERROR 1213 (40001): Deadlock found when trying to get lock; try restarting transactionThe first thing that comes to mind in this case is: "OK, we have InnoDB deadlock, let's check the details", followed by the SHOW ENGINE INNODB STATUS check, like this:
mysql> show engine innodb status\G
*************************** 1. row ***************************
  Type: InnoDB
  Name:
Status:
=====================================
2018-12-08 17:41:11 0x7f2f8b8db700 INNODB MONITOR OUTPUT
=====================================
Per second averages calculated from the last 12 seconds
-----------------
BACKGROUND THREAD

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MySQL 8 and The FRM Drop… How To Recover Table DDL

… or what I should keep in mind in case of disaster

To retrieve and maintain in SQL format the definition of all tables in a database, is a best practice that we all should adopt. To have that under version control is also another best practice to keep in mind.

While doing that may seem redundant, it can become a life saver in several situations. From the need to review what has historically changed in a table, to knowing who changed what and why… to when you need to recover your data and have your beloved MySQL instance not start…

But let’s be honest, only a few do the right thing, and even fewer keep that information up to date. Given that’s the case, what can we do when we have the need to discover/recover the table structure?

From the beginning, MySQL has used some external files to describe its internal structure.

For instance, if I have a schema named windmills and a table …

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MySQL Partition Manager (Yahoo!) in a nutshell

Partitioning is a way of splitting the actual data down into separate .ibd files (data compartments) in the file system based on the defined ranges using the partitioning key. It can help us with maintaining the enormous amount of data in different partitions without much hassle.

In this blog post, we are going to see how to manage table partitioning using yahoo partition manager.

Needs for partitioning:

  • Enhanced data retrieval ( reduced IO ) with smaller B+Tree.
  • Easy Archival or Purge by dropping or truncate  of partition
  • Lesser fragmentation, hence avoiding frequent table optimization.

Partitions management activity like adding/Dropping partition is made easy and automated by …

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Fun with Bugs #73 - On MySQL Bug Reports I am Subscribed to, Part X

It's time to continue my review of MySQL bug reports that I considered interesting for some reason recently. I had not got any notable reaction from Oracle engineers to my previous post about recent regression bugs in MySQL 8.0.13, so probably this topic is not really that hot. In this boring post I'll just review some bugs I've subscribed to since August that are still not closed, starting from the oldest.

Let me start with a couple of bug reports that remain "Open":

  • Bug #91959 - "UBSAN: signed integer overflow in lock_update_trx_age". It's really unusual to see bug reported by …
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Compression options in MySQL (part 1)

Over the last year, I have been pursuing a part time hobby project exploring ways to squeeze as much data as possible in MySQL. As you will see, there are quite a few different ways. Of course things like compression ratio matters a lot but, other items like performance of inserts, selects and updates, along with the total amount of bytes written are also important. When you start combining all the possibilities, you end up with a large set of compression options and, of course, I am surely missing a ton. This project has been a great learning opportunity and I hope you’ll enjoy reading about my results. Given the volume of results, I’ll have to write a series of posts. This post is the first of the series. I also have to mention that some of my work overlaps work done by one of my colleague, Yura Sorokin, in a …

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