SQL Server 2019 brings a very exciting new feature that, is long overdue. Resumable online index create is one of my favorite new things. This paired with the Resumable Index Rebuilds introduced with SQL Server 2017 really gives database administrators much more control over index processes. Have you ever started to build a new index on very large table only to have users call and complain their process is hung, not completing, or system is slow? That’s when you realize you’re the cause because you tried to sneak in a new index. I have many times, because creating a new index can impact performance and can be a problematic process…
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Did you know compression can gain you more than just space on a disk, it can allow you to fit more data into the buffer pool? That means queries have faster and more efficient reads which can help reduce I/O. It is a performance tool I highly recommend you consider for your environments. But how do you know how much compression savings you can gain? SQL Server gives you a handy system stored procedure sp_estimate_data_compression_savings that will help you calculate compression gains. It’s a great tool to use when trying to decide if compression is right for your environment and what type to use. This procedure allows you to estimate…
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Statistics are the magic ingredient that helps the query optimizer create its best guess for generating an execution plan. Keeping statistics as accurate as possible will give the optimizer the information it uses to calculate estimated costs and cardinality, which enables it to properly allocate resources such as memory grants. In this blog I am not going to go into what statistics are and how they are used. There are many great resources out there to read, I am however going to tell you about a trace flag that can help you with keeping your large table statistics up to date. I will also explain why your statistics may not…
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At the last few events I attended, I’ve gotten into conversations on how to begin as a speaker. So I thought I’d share some of my advice that I provided to them. First and foremost, get your first talk scheduled. Reach out to your local user group and ask to be “penciled” in for a meeting a few months out. Giving yourself a goal and deadline is essential to putting yourself out there to speak. Next, write down ten topics you may want to speak on. Narrow down that list to five by thinking about what you would be most comfortable speaking about. Next look at your five topics and…
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We all have the need to collect system and performance information regarding our SQL Servers. Some of us use third-party tools, SQL Trace, or a homegrown solution. Did you know Microsoft has a built-in tool to help you accomplish this? It’s called Data Collection and the data it collects (collection sets) is stored in a relational Management Data Warehouse. The data collected is used to generate reports giving us in with very readable and useful insights to our servers. Not only can you get performance information, but you can also use SQL Profiler to export trace definition and create custom collection sets. This is not a new SQL Server feature,…
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I saw this again recently and see it too often in environments so wanted to take a second to remind everyone to cycle their error logs on a regular basis. SQL Server keeps error logs and when you reboot or restart SQL Server services the logs are cycled and a new one is created. Depending on how many logs you have configured for SQL Server to have this may include removal of the oldest log as well. Since many of pride ourselves on keeping our SQL Servers up and running, reboots may be few and far between thus our logs get large in size. When they grow out of control…
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Quite often I see database administrators set SQL Server max server memory thinking everything related to SQL Server uses this shared memory pool. This is a mistake. There are many things that rely on memory that are not part of SQL Server. Best practices state that you should leave memory allotted for the operating system. However, did you know that if you are running services like SSIS, SSAS or SSRS on the same server as the database engine that it does not use the same memory you have allocated for SQL Server? If the Max Memory setting is not configured correctly, these other serves could incur memory pressure. While the…
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Nowadays security breaches happen way to frequently. As DBA’s we should all take extra care with sensitive data and ensure we are encrypting correctly. But some of us forget to take it a step farther and don’t encrypt our backups. For those working in an ultra data sensitive environment I highly recommend you go this extra step. As of SQL 2014, SQL Server now has the ability to encrypt your data during the backup process. Not only that but they have made the process simple. Prior to 2014, the only way to encrypt backups was Transparent Data Encryption (TDE), and that requires Enterprise Edition which made this out of reach for most. First…
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Microsoft has long given us DBA tools and suggestions to help tune databases, to fix queries with indexes, and many times they were of questionable merit. We have all seen the dreaded dta_index names in a database and rolled our eyes knowing that sometimes these indexes are not what is needed. While the Database Tuning Advisor, has gotten better over time it is still not a tool more senior DBAs use. Microsoft made big steps in helping DBAs with performance with the introduction of Query Store in both Azure SQL Database and SQL Server 2016. Query Store collects execution and run-time performance information. Microsoft has taken an additional leap with…
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Microsoft gives you two purchasing models for your Azure SQL Databases (SQL DB), a DTU and a vCore based model (logical CPU’s). Both options allow you to scale up or down based on your compute and storage requirements. Regardless of which model you choose performance tuning can save you money using SQL DB. DTU (s) (Database Transaction Units) measure “a blended measure of CPU, memory, and data I/O and transaction log I/O” that Microsoft uses to help estimate which DTU based Service Tier you should be using. By reducing your I/O, memory or CPU consumption you utilize less DTUs or cores and thus can step down service tiers. Stepping down service…
