The blog title seems something crazy ?

Yes, by default your InnoDB transactions don’t have the Atomicity . But, you can control the atomicity of your InnoDB transaction with the variable innodb_rollback_on_timeout. We had a weird data inconsistency issue within the transaction . In this blog , I am going to explain “How it will happen?” and “How it can be fixed ?” .

Whats is Atomicity ?

From Wiki ,

Transactions are often composed of multiple statements. Atomicity guarantees that each transaction is treated as a single “unit”, which either succeeds completely, or fails completely: if any of the statements constituting a transaction fails to complete, the entire transaction fails and the database is left unchanged.

What is …

MySQL Connector in 8.0.19 includes the support of DNS SRV.

The following URL can be a good starting point to understand what this feature is about.


https://www.slideshare.net/Grypyrg/mysql-connectors-8019-dns-srv

https://dev.mysql.com/doc/connector-j/8.0/en/connector-j-reference-dns-srv.html

https://learn.hashicorp.com/consul/security-networking/forwarding


MySQL Router in MySQL InnoDB Cluster setup offers the transparent access to the backend database servers.   However, the application has to know the IP Address of the Router in order to get …

                Had an interesting requirement from one of our client to have the two MySQL partitions ( partition_full / partition_half ) for store the Names based on the user input.

Requirement :

• The table have two columns first_name and last_name. With the user input of both columns, it needs to be automatically compute the data for another column full_name . And, the status needs be consider as “FULL” .
• If the column last_name don’t have the input from the user, then the first_name data needs to be compute as the full_name . And, the status needs be considered as “HALF” .
• Need the separate partitions for both status HALF and FULL

We can achieve …

Sometimes, you may experience “ERROR 1034: Incorrect key file” while running the ALTER TABLE or CREATE INDEX command:

mysql> alter table ontime add key(FlightDate);
ERROR 1034 (HY000): Incorrect key file for table 'ontime'; try to repair it

As the error message mentions key file, it is reasonable to assume we’re dealing with the MyISAM storage engine (the legacy storage engine which used to have such a thing), but no, we can clearly see this table is InnoDB!

When the error message in MySQL is confusing or otherwise unhelpful, it is a good idea to check the MySQL error log:

2019-02-24T02:02:26.100600Z 9 [Warning] [MY-012637] [InnoDB] 1048576 bytes should have been written. Only 696320 bytes written. Retrying for the remaining bytes.
2019-02-24T02:02:26.100884Z 9 [Warning] [MY-012638] [InnoDB] Retry attempts for writing partial data failed.
2019-02-24T02:02:26.100894Z 9 [ERROR] [MY-012639] [InnoDB] Write to file (merge) …

In this blog I will go through a number of popular applications that use
NDB Cluster 8.0 and also how these applications have developed over the
years.

There is a presentation at slideshare.net accompanying this blog.

The first major NDB development project was to build a prototype of a
number portability application together with a swedish telecom provider.
The aim of this prototype was to show how one could build advanced
telecom applications and manage it through standardised interfaces.
The challenge here was that the telecom applications have stringent
requirement, both on uptime and on latency. If the database access
took too long time the telecom applications would suffer from
abandoned calls and other problems. Obviously the uptime of the …

It used to be the case where, in order to actually process data retrieved from the database using Connector/Node.js, you would have to resort to an API that required the use of both JavaScript callbacks and Promises. This was meant to provide more flexibility and control to the application developer and at the same time decrease the chance of buffering data unnecessarily. However this wasn’t useful for 99% of the use-cases and made simple tasks a little bit cumbersome. Also, the fact that it required using two different asynchronous constructs made it a little bit harder to grasp.

To make matters worse, in order to consume operational metadata about the columns in the result set, you would have to provide an …

Netherlands/Benelux | Full Time

Do you want to work at the forefront of technologies?

HeleCloud™ is a fast-growing technology consultancy and managed services business focused on the Cloud platforms. We take our clients on a complete journey into the Cloud and work closely with businesses to develop a Cloud roadmap, ensuring that their transition into the Cloud is smooth, secure, and adds value to the organisation. We don’t just stop at making technology work for our clients, we ensure that their teams also understand the Cloud as well as we do, and can make the most of it. We operate across EMEA with offices in the Netherlands, UK and Bulgaria.

For one of our key clients in Rotterdam, we are looking for a Junior MySQL Database administrator.

Responsibilities

• MySQL Database administration in an enterprise environment with key applications running on Java and …

In this post I’ll expand on the subject of my MySQL pre-FOSDEM talk: what dbadmins need to know and do, when upgrading from MySQL 5.7 to 8.0.

I’ve already published two posts on two specific issues; in this article, I’ll give the complete picture.

As usual, I’ll use this post to introduce tooling concepts that may be useful in generic system administration.

The presentation code is hosted on a GitHub repository (including the …

Recently one of our client approach Mydbops with Query slowness on a MySQL environment . They deployed the new code for generate the huge reports for the year end analytics data . After the deployment the queries were extremely slow and they struggled lot , then they approached us for the solution. After the analysis, their OLAP database as expected it was IO bound with 100% disk IOPS utilised during the report generation. So, the queries were starving for the Disk IO slows the process .

Problem statement :

• Reports are majorly focused on two larger log tables ( emp_Report_model , emp_details ) .
• The report generator (procedure) is using the count(*) statement to stimulate the aggregated data on each call. It is required for their business purpose .
• Count(*) is terribly slow in MySQL ( Using MySQL 5.7 ) as it …

Galera is the best solution for High Availability, It is being used by many peoples world wide . Galera is doing synchronous replication ( really it is Certification based replication ) to keep update the data on group nodes . In this blog I have explained about “How the Galera replication works?” . For the better understanding, I have made an architecture diagram to describe the replication flow . I have also provided the explanation for the key words which has used in the architecture diagram .

Architecture flow Diagram :

What is writeset ?

Writeset contains all changes made to the database by the transaction and append_key of the changed rows .

What is append_key ?

Append_key registers the key of the changed data by the transaction. The key for rows can be represented in three parts as DATABASE NAME, TABLE NAME, PRIMARY KEY . …