The first release candidate of MySQL 8.0 is here, and I'm happy to share few performance stories about. This article will be about the "most simple" one -- our in-memory Read-Only performance ;-))
However, the used test workload was here for double reasons :

• 1) validate MySQL 8.0 performance
• 2) fully evaluate the "New" Sysbench developed by Alex (https://github.com/akopytov/sysbench)

Going ahead to the second point, the main worry about New Sysbench was about its LUA overhead (the previous version 0.5 was running slower than the old one 0.4 due LUA) -- a long story short, I can confirm now that the New Sysbench is running as fast as the oldest "most lightweight" Sysbench binary I have in use ! so, KUDOS Alex !!! ;-)) …

In my previous blog post, I talked about new general tablespaces in MySQL 8.0. Recently MySQL 8.0.3-rc was released, which includes a new data dictionary. My goal is to create one million tables in MySQL and test the performance.

Background questions

Q: Why million tables in MySQL? Is it even realistic? How does this happen?

Usually, millions of tables in MySQL is a result of “a schema per customer” Software as a Service (SaaS) approach. For the purposes of customer data isolation (security) and logical data partitioning (performance), each “customer” has a dedicated schema. You can think of a WordPress hosting service (or any CMS based hosting) where each …

In this blog post, we’ll look at how to avoid shared locks from subqueries.

I’m pretty sure most of you have seen an UPDATE statement matching rows returned from a SELECT query:

update ibreg set k=1 where id in (select id from ibcmp where id > 90000);

This query, when executed with

autocommit=1

, is normally harmless. However, this can have bad effects when combined with other statements in the same transaction that result in holding the shared locks from the SELECT query. But first, let me explain why the SELECT query would hold locks in the first place.

Due to InnoDB’s ACID properties, to make sure that the outer UPDATE statement has a consistent view of the matching rows from the SELECT query the server has to acquire a shared lock on those rows. No other thread should modify …

Welcome to the first day of the Percona Live Open Source Database Conference Europe 2017: Tutorials day! Technically the first day of the conference, this day focused on provided hands-on tutorials for people interested in learning directly how to use open source tools and technologies.

Today attendees went to training sessions taught by open source database experts and got first-hand experience configuring, working with, and experimenting with various open source technologies and software.

The first full day (which includes opening keynote speakers and breakout sessions) starts Tuesday 9/26 at 9:15 am.

Some of the tutorial topics covered today were:

…

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 default for MySQL server, InnoDB Engine is getting used widely due it’s ACID support, optimized read-write performance and for many other reasons which are great significance for the database server.

In this blog post, we are going to cover the InnoDB tablespace and its features like,

• InnoDB engine tablespaces
• Tablespace Data Encryption
• Tablespace related Configuration

InnoDB engine tablespaces System tablespace:  

Common tablespace for MySQL server operations. Apart from the table data storage, InnoDB’s functionality requires looking for table metadata, storing and retrieving MVCC info to support ACID compliance and Transaction Isolation. It contains several types of information for InnoDB objects.

• Contains:
  Table Data Pages
  Table Index Pages …

In MySQL 8.0, we will be introducing a new configuration parameter called innodb_dedicated_server=bool. When ON, this option will look at the system memory, and then automatically set the these configuration parameters using the following rules:

innodb_buffer_pool_size

server_memory < 1G ?

…

TL;DR: unless you know what you are doing, you should always have a primary key on your tables when replicating in RBR (and maybe even all the time).

TL;DR2: MariaDB 10.1 has an interesting way to protect against missing a primary key (innodb_force_primary_key) but it could be improved.

A few weeks ago, I was called off hours because replication delay on all the slaves from a replication chain

In one of my previous posts, I shared InnoDB table compression statistics for a read-only dataset using the default value of innodb_compression_level (6).  In it, I claimed, without giving much detail, that using the maximum value for the compression level (9) would not make a big difference.  In this post, I will share more details about this claim.

TL;DR: tuning innodb_compression_level is not

TL;DR: we still need MyISAM and myisampack because it uses less space on disk (half of compressed InnoDB) !

In the previous post, I shared my experience with InnoDB table compression on a read-only dataset.  In it, I claimed, without giving much detail, that using MyISAM and myisampack would result is a more compact storage on disk.  In this post, I will share more details about this claim.