While implementing ClickHouse for query executions statistics storage in Percona Monitoring and Management (PMM),  we were faced with a question of choosing the data type for metrics we store. It came down to this question: what is the difference in performance and space usage between Uint32, Uint64, Float32, and Float64 column types?

To test this, I created a test table with an abbreviated and simplified version of the main table in our ClickHouse Schema.

The “number of queries” is stored four times in four different columns to be able to benchmark queries referencing different columns.  We can do this with ClickHouse because it is a column store and it works only with columns referenced by the query. This method would not be appropriate for testing on …

Since the concept of cloud was born, there has been strong growth in the number of migrations to this environment. However, not everything that shines is gold.

As the demand grows, so does the costs. We can find ourselves in a situation where our monthly cloud expenses are very high and, in this case, it may make sense to migrate back to an on-prem environment.

The costs may not be the only reason. There might be security or compliance requirements, or we may need to have more control of our systems. Knowing what happens at a lower level can help us better optimize things.

AWS not only give us the environment, it also provides us with monitoring and management tools to run our system in the cloud. So, it can be really hard to migrate to an on-prem environment and recreate all these tools to …

Mydbops database meetup was held on 26-01-2019 and 48 members from open source database community has attended this event. We had talks on MySQL and MongoDB databases.

Open source database enthusiastic from companies like OLA Cabs, Searce Inc, PayTm, Quikr, Zensar, Grab, SAP labs, Travel Yarri, Meddiff and a few has travelled from other cities of India like Hyderabad and Chennai.

The Welcome talk was given my Selva venkatesh of Mydbops. He spoke about the open source database community and welcomed all the participants and speakers.

Followed by it Karthik P R , CEO/ Founder, Mydbops made his presentation on “InnoDB Performance Optimisation” . InnoDB is the prime engine in MySQL.This talk focuses on the InnoDB Architecture in MySQL 8.0 and its fine tuning. He also answered the various questions raised …

For those not familiar with it, FOSDEM is an amazing, free entry, full on celebration of open source that takes place in Brussels, Belgium every year. This year the event was held over the first weekend of February. Fringe events, such as the Pre-FOSDEM MySQL day hosted by Oracle MySQL, and the community dinner that follows, provide an opportunity to network.

In case you didn’t make it to FOSDEM this year, here are links to Percona’s presentations from the event. Organizers video and share online every talk from every dev room, a phenomenal achievement in itself. All credit to the volunteers who run this show.

Database Dev Room: Hugepages and databases presented by Fernando Laudares …

How to Monitor MySQL Databases?

Operational visibility is a must in any production environment. It is crucial to be able to identify any issues as soon as possible, otherwise you may end up in serious troubles as an undetected issue can cause serious service disruption or downtime. MySQL Enterprise Monitor is one of the oldest monitoring products for MySQL on the market, and is available as part of an commercial enterprise subscription agreement from Oracle.In this blog post we will take a look at MySQL Enterprise Monitor and the kind of insight it provides into MySQL.

Installation

First of all, MySQL Enterprise Monitor is part of MySQL Enterprise Edition, a …

Vitess is a sharding and scaling solution for MySQL that can make thousands of databases appear to be a single monolithic database. Vitess is interesting, and promising, in a number of ways. It’s addressing an extremely hard set of problems that’s been tried many times before with mixed results, but evidence points to Vitess succeeding where others have thus far failed.

Vitess solves three fundamental, hard problems for its target user base:

• Sharding. Sharding is essential for scaling traditional relational databases that weren’t built natively to operate as a distributed cluster of many nodes forming a single database. Every large-scale MySQL deployment—and there are thousands—uses sharding, bar none.
• Kubernetes deployment. You can’t just run a database like MySQL on Kubernetes without a robust suite of operational tooling for high availability. MySQL …

The introduction of DevOps in organizations has changed the development process and also introduced some new challenges. In addition, developers and DevOps teams, along with their own chosen programming languages, also have their favorite database systems.

The product life cycle is getting shorter each year so developers want to be able to develop fast, using technologies they know best.

Having multiple RDBMS database backends means your organization will become more agile on the development side, but it also imposes additional knowledge on the operation teams.

Extending your infrastructure from one to many databases implies you have to also monitor, manage and scale them.

As every storage backend excels at different use cases, this also means you have to reinvent the wheel for every one of them.

Working with Aurora MySQL I thought would be a breeze, but its subtle differences make me scratch my head. Thus I need to find out more about this and write a post :)

What is Aurora?

It's a mySQL wire protocol compatible storage management system that sits on top of mySQL and modifies some innodb internals. You can read about more of the architecture here: I think of it as a Proxy Storage Engine System


The differences start from just starting the server.  Aurora MySQL has Huge Page support turned on by default since AWS launches Aurora MySQL server with their custom flag for innodb large page support:

innodb_shared_buffer_pool_uses_huge_pages

This is not an open source setting documented by MySQL official  …

Recently, I had to work on an emergency for a customer who was having a problem restarting a MariaDB Galera Cluster. After a failure in the cluster they decided to restart the cluster entirely following the right path: bootstrapping the first node, and then adding the rest of the members, one by one. Everything went fine until one of the nodes rejected the request to join the cluster.

Given this problem, the customer decided to ask us to help with the problematic node because none of the tests they did worked, and the same symptom repeated over and over: SST started, copied few gigs of data and then it just hanged (apparently) while the node remained out of the cluster.

Identifying the issue…

Once onboard with the issue, initially I just checked that the cluster was trying a SST: given the whole dataset was about 31GB I decided to go directly to a healthy solution: to clean up the whole datadir and start afresh. No luck …

In a previous blog post, we discussed how the initialization and restart of the MySQL server has changed between versions 5.6, 5.7 and 8.0. Now, we will take a closer look at MySQL 8.0 to explain in more detail how the transactional data dictionary is bootstrapped.…

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