John McCormack DBA

SQL Server Databases and Cloud

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How to change the slow query log threshold on RDS

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turtles on a log

What is the slow query log

Before we discuss how to change the slow query log threshold on RDS, let’s quickly establish what the slow query log is.

The slow query log will record all queries which are above the threshold level. The default value is 10 (seconds) but you can set it higher or lower depending on your requirements. It is useful for finding slow queries and allows you to pick out candidates for tuning.

If you set the threshold too low, it can increase I/O overhead on your instance and use a lot of valuable disk space. If you set it too high, it might not capture enough useful information.

AWS Web console

If you are doing this change as a one off, it might be simpler to just use the AWS web console.

  1. Log into AWS
  2. Select RDS
  3. Find out which parameter group your instance is in
    1. Select instance then click configuration.
    2. Scroll down to see the parameter group
    3. It will be a hyperlink so just click on it
  4. In the parameter group page, use the search box and search for slow_query_log
    1. Ensure it is set to 1
    2. If not, click edit parameters and change the value to 1.
  5. Change search box to long_query_time
    1. Set it to any value between 1 and 31536000
    2. Save changes
AWS CLI
aws rds modify-db-parameter-group --db-parameter-group-name "primary-mysql-5point7" --parameters "ParameterName='long_query_time',ParameterValue=1,ApplyMethod=immediate" --profile dev
# If you don't have multiple profiles set, leave out --profile dev.
AWS PowerShell
$HashArguments = @{
    DBParameterGroupName = "mysql5point7-monster-param-grp-ci"
    Parameter=@{ParameterName="long_query_time";ParameterValue="10";ApplyMethod="Immediate"}
    Profilename = "Dev"
    }
Edit-RDSDBParameterGroup @HashArguments

No restart needed

Changing either slow_query_log or long_query_time parameters can both be safely done without the need to restart your instance. This is because RDS defines them as Dynamic parameters. Take note when changing parameters that are defined as Static as they will require a restart. This either means short but immediate downtime or waiting until your next maintenance window.

rds parameters slow_query_log
rds parameters long_query_time

Further reading

I used some of these links to help me gather the information I needed to write this blog post.

  1. https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_WorkingWithParamGroups.html#USER_WorkingWithParamGroups.Modifying
  2. https://docs.aws.amazon.com/cli/latest/reference/rds/modify-db-parameter-group.html
  3. https://docs.aws.amazon.com/powershell/latest/reference/items/Edit-RDSDBParameterGroup.html
Featured image by icsilviu from Pixabay

Balancing work and life – The COVID years – tsql2sday

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t-sql tuesday logo

For this month’s T-SQL Tuesday, Tjay Belt (b|t) asks about balancing work and life. He lists some options and I decided to write about What rules have you implemented that made it easier to balance?

Balancing work and life

The initial shift to working from home didn’t phase me. I thought it was just a short term measure to keep people safe. I found that my team became more productive and there were high spirits initially. I was happy to work overtime and spend time on community work. (Looking back, I spent far too long at my desk)

The period up to July/August I was very productive with blogging and creating content for online presentations and YouTube videos. I then felt a little flat and my productivity dropped off a cliff. Similarly I had a small boost in February when I felt motivated. So I had to come up with some rules.

Striking the balance – The rules

I have adopted a few rules and try to stick to them but I don’t stress out about it. If I need to work on, or I don’t want to go outdoors, it’s not a big deal.

  1. Try to finish work at 5:30
  2. Spend 30 minutes outdoors every day
  3. Have some fun

Try to finish work at 5:30

Honestly: finish at finishing time. Don’t work for free. It’s my number one tip for balancing work and life. The work will always wait for you. Now I’m not saying this is possible 100% of the time but it should be your aim. For example, I’ve had to deal with production issues that can’t wait but on the whole, I’m referring to the ticket queue and requests from end users. I’ll also take time back if I’ve had to work on at a time that suits me and my company.

My employer also introduced a new perk called Summer Hours where all employees get every Friday afternoon off during July and August. It’s such a fantastic employee benefit which is worth 4 extra paid days off per year.

Spend 30 minutes outdoors

I attended an online seminar at my work (Monster.com) talking about mental health. I was inspired by one of the speakers who had set up a podcast and blog called humansoutside. She described that simply spending 30 minutes outdoors every day had had a profound effect on her’s and her husband’s mental health. You should give the podcast a listen.

So now I try to spend some time outside each day. Whether is working in the garden, going a walk or just taking refuge from the rain under my Gazebo to drink a coffee, it is a refreshing habit.

Have some fun

I mentioned on a previous post that I had got a pool table at home. I’m lucky to have the space and I really use it all the time. I aim to clear the balls once a day. If I can play more and get my kids involved, even better.

John playing pool to avoid burnout in IT
John playing pool

I’m also a bit of a telly addict. During lockdown, I re-watched the series Curb you enthusiasm. It’s cringe comedy but I love the pedantry. I also re-watched Mad Men which is one of the all time greatest box sets (imho).

I try to have a box set on the go with my wife as well that we only watch at the pace where we can both manage it. (No sneaking ahead, even although sometimes it is tempting)

I hope this helps. Do whatever works for you but do try to do something actively to ensure you strike a work/life balance that works for you.

Why I certified to become more than a SQL DBA

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t-sql tuesday logo

For this month’s T-SQL Tuesday, Andy Leonard (b|t) asks How Do You Respond When Technology Changes Under You?

It’s a great topic and inspired me to write a T-SQL Tuesday post this month. I’ve missed the last couple due to a combination of just not feeling like it, and the previous topics weren’t best suited to me. Hopefully this can inspire me to get writing again.

Hey, I thought I was the SQL DBA!

When I got my start with SQL Server, I was just that –  A SQL DBA. I worked as a junior member of a big team, we had a large SQL Server estate and I just wanted to learn to become as experienced as the senior folk. I was able to learn and be mentored and was enjoying making progress. Then I heard we were going to start using “The Cloud”. Not only that but I was going to be responsible for the operation of our Kafka clusters, EMR and ElasticSearch.

A lot of these technologies were developer led, they knew why they wanted to use them and from an operations perspective, it was about making sure things didn’t fail, and errors were handled. I had no background in them, and didn’t really understand them well. Simply learning to use PuTTY to log into a linux VM was one of my early successes.

AWS Certifications FTW

The move to the cloud, in this case AWS was going ahead with or without me so I had to embrace it. Of course, I learned and collaborated with colleagues and got to an acceptable standard but it was only when I decided to do AWS certifications that things really took off. I found that by studying for the AWS Cloud Solutions Architect certification that I got an appreciation for all cloud services, not just the data ones like RDS. Studying for the AWS certifications improved my networking skills; I learned about object vs block storage and of course I learned all of the different data products (often managed services but not always).

I approached the certification process from a genuine perspective of learning the technology well, rather than just passing the exam. Simply passing the exam does not do much for you. Even if it gets you a job, you will likely be found out pretty quickly.

A further benefit to learning one cloud technology well is that when we started using Azure, I found the concepts were the same. I understood the networking, the security groups and PaaS vs IaaS. It made this transition much easier and meant that when I moved to a job that was predominantly based in Azure, I didn’t have the huge knowledge gap that I would have had, if I had not done my AWS certifications.

So for me, a structured learning approach is best. It’s not for everyone but I am certainly glad that my job is no longer just “SQL DBA”.

You don’t need to run CHECKDB on Azure SQL DB

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right or wrong sign for dbcc checkdb
Featured image by Tumisu from Pixabay

CHECKDB on Azure SQL DB?

This is a selfish post because I’ll probably forget and go googling for info on this topic, so I though I would link to an authoritative answer on the question, do you need to run DBCC CHECKDB on Azure SQL DB?

https://azure.microsoft.com/en-gb/blog/data-integrity-in-azure-sql-database/

Microsoft distinguished engineer Peter Carlin says you don’t need to, it is monitored by Azure on your behalf. And if something was to go wrong, they will also work with you to put things right.

Although Peter says you can run them if you want, his post gives me enough peace of mind to stop running these on my Azure SQL DB instances. Let me know if you agree in the comments.

For more Azure content, check out my Azure tag.

How to find out Azure SQL DB Startup time

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Alarm clock and cup of tea
Wakey Wakey SQL DB

Azure SQL DB Startup time

The query

SELECT sqlserver_start_time FROM sys.dm_os_sys_info;

Why write a post about this?

The traditional methods used for to find the start up time for SQL Server don’t work in Azure SQL DB.

I searched high and low to find this and thought I’ve got to share, and hopefully make it search engine friendly. A traditional google or bing search wasn’t bringing up the best way to find this out. I saw a lot of complicated queries to pull data, convert it and estimate start up time using functions and all kinds of magic. Actually, it turns out that the start up time is provided for you in sys.dm_os_sys_info (which works in Azure SQL DB). It also work in SQL Server which is a bonus.

Permissions to check Azure SQL DB Startup time

The permissions you need to run this query vary depending on the pricing tier of your Azure SQL DB. I ran this successfully on a P2 and a basic tier database.

On SQL Server, requires VIEW SERVER STATE permission.
On SQL Database Basic, S0, and S1 service objectives, and for databases in elastic pools, the Server admin or an Azure Active Directory admin account is required. On all other SQL Database service objectives, the VIEW DATABASE STATE permission is required in the database.

https://docs.microsoft.com/en-us/sql/relational-databases/system-dynamic-management-views/sys-dm-os-sys-info-transact-sql?view=sql-server-ver15

I hope this one liner t-sql script was useful. Please let me know in the comments if you know a better way to get the start up time of Azure SQL DB, using T-SQL.

While you’re on my site, why not take a look to see if you can save money on your Azure SQL DBs, and other Azure resources by looking at my guide: 7 ways for data teams to save money in Azure.

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