Posts by Phil Grayson

Data & Infrastructure Generalist @xTENLtd | Co-Founder @Aireforge | Volunteer @LeedsData, @DataAndGravy & @SQLBits | Friend of Redgate | Surfer, Biker, Boarder

Why you should love your connection strings

Who is responsible for configuring and maintaining connection strings within your organization? Developers, operations, the database team? For me, the correct answer should be everyone – each team has an important part to play in configuring optimal connection strings. Unfortunately in most organizations, once they’re configured that’s it – but there’s so much to gain from giving them a bit of love.

Connection strings are essential to every application – without them we can’t connect and nothing works. So it’s pretty obvious when they are wrong, but what about when they’re just not quite right? Optimizing your connection strings can improve the performance of your application and databases. Using the correct options will make them more secure, faster, require fewer resources, simplify maintenance and reduce the time it takes to diagnose issues.


Basic Settings

There’s an evergrowing list of options available to tune connection strings to suit your application, but it’s difficult to know what does what. This is made worse by most settings having 2 or 3 synonyms, just to keep you on your toes! To help with this, we created an online Connection String Generator which reduces some of the complexity and builds your connection string for you.

You don’t need much to get a connection string working. Most settings have a default if you don’t explicitly set them. Therefore, the minimal amount you need is simply the server name and how you wish to authenticate.

Data Source=database_server;Integrated Security=false;User ID=sql_user;Password=password123

Another setting that I’d like to class as a basic one is Application Name. It won’t improve the performance of your application but you’ll be glad you set it when you’re diagnosing server issues. Application name simply populates the program_name field in sys.dm_exec_sessions. So the next time your application is overloaded or having issues, you’ll know exactly what program on the host is causing it.

Application Name=Steves Test App;

Network and Security

Most people connect to SQL Server using SQL authentication purely through habit. Instead, try running your applications under service accounts, then connecting to SQL Server using integrated security. Here’s why.

Connecting via integrated security removes the requirement of storing passwords in plain text web.config files. Although these can be encrypted, you don’t have the same level of control over these. For example, web.config files may also be stored in source control or emailed around in zipped up folders of the application, which enables more people to gain control to your production systems.

Using Windows authentication over SQL authentication also removes the requirement of synchronizing security ids (SID) between availability group nodes. If you’re not aware of this issue, here’s a blog on synchronizing AG nodes, but if your SIDs are not synchronized, you won’t be able to authenticate after a failover.

Integrated security is simple to implement and much easier after the first time, so please have a good stab at it. Most applications can be updated using the same method when altering the service account for SQL Server and SQL Server Agent. You could go one step further by adding the service accounts that require similar access into AD groups, which will make maintenance and administration easier.

Data Source=database_server;Integrated Security=sspi

Network settings are an area you can get lost in and cause some interesting application problems, but there are few that should be considered when building connection strings.

Setting connection timeout is one. You may not want to wait for the default 15 seconds for new connections if your application tries to log thousands of requests a minute. On the other hand, you may want to allow 60 seconds to connect to a server on the other side of the world.

Connection Timeout=60;

Once the connection is established, subsequent queries will be quicker as the application will reuse the connection. This is where connection pooling comes in.

Connection pooling is a blog in itself but there are three main settings you should consider. Min pool size and max pool size control the size of the connection pool, so how many connections you want to keep open and how many connections you’re likely to use. The main gotcha here is that max pool size has a default of 100, so if you don’t set it, this is what you get. If you’re happy with 100 then actively set that, so you can see what it is rather than relying on secret knowledge.

Creating connections to a database can be expensive. Imagine that person on the phone in videos of the stock exchange. Instead of keeping their colleague on the phone and relaying commands, they dial the phone number of the other person every time, say hello, give them the command to sell (or order pizza? I’m not actually sure what they do) and then say goodbye.

So, we want to keep them open, but there’s a balance. Too few connections will starve your application, but too many can consume precious resources – from using memory in SQL Server, to playing havoc with your load balancer by exhausting the number of concurrent connections allowed and causing issues with load distribution (covered next).

Min Pool Size=10;Max Pool Size=100;

The third option I think you should consider is Connection Lifetime. Its synonym, Load Balance Timeout, gives us a pretty good clue to why you should set it. With pooling, we create a connection and leave it open so it can be reused. This is great until we need to add a new server in a distribute the load. Let’s say we have a hundred connections to servers 1, 2 and 3 but none to 4 as it’s just been restarted. Once this server comes back online it won’t get a new connection until the application needs to create one, and if we’ve set our pools correctly, it won’t.

Setting the connection lifetime tells the application to kill a connection after a certain length of time, giving the load balancer the opportunity to evenly distribute the database connections and therefore load.

Connection Lifetime=300

Complete Connection String

There are so many options that can be set and I haven’t gone into enough detail (more blogs to come) but if we use the Connection String Generator and set the options we’ve discussed in this thread, we’ll end up with the following:

Data Source=database_server;Application Name=Steves Test App;Connection Timeout=60;Integrated Security=sspi;Min Pool Size=10;Max Pool Size=100;Load Balance Timeout=300

Aireforge Studio 1.1.9

A lot of work has gone into this release but many of the changes won’t be immediately obvious as we’ve;

  • Changed and standardized every button.
  • Relaxed the server limits for Pro versions.
  • Improved the handling of licensing issues.

A good example of the changes can been seen in the splash screen. Not huge changes but they’ve been made everywhere. Another example is the comparison configuration screen.

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Improvements to Advise

  • Added partial support for column store indexes.
  • Ignore fragmented indexes now based on pages rather than rows. Defaults to Microsoft recommended value of 1,000 pages.

New Checks

  • Database owner does not exist.
  • Auto update statistics is disabled.
  • Data files larger than 10GB with more than 90% free.

Improved Checks

  • Cost threshold for parallelism alerts if set to < 15, but suggests setting it to 30.

New Scripts

  • If page verify is NONE or TORN_PAGE, suggest setting to CHECKSUM.
  • If auto shrink is enabled, suggest setting to disabled.
  • If auto create statistics is disabled, suggest setting to enabled.
  • If auto update statistics is disabled, suggest setting to enabled.
  • If auto close is enabled, suggest setting to disabled.
  • If the compatibility level isn’t the latest, suggest setting to the latest but with a warning.

Improved Scripts

  • The suggested size for new tempdb data files are now set to the total space / existing files * number of suggested files.

Multi-server scripting with Aireforge Studio

We’ll keep this short, but we’ve created a scripting tool for running queries against multiple SQL instances via Aireforge Studio. Oh, and it’s FREE.

Script.png

The Microsoft Central Management Servers (CMS) are great (link), but they’re lacking functionality and haven’t had much attention in recent years. So, given that Aireforge users already have their estates loaded into their profiles, we thought it made sense to build a scripting module into Aireforge Studio. You can use the same servers and groups from the estate manager or select individual servers; giving you more control over which scripts are run and where. You can also export to CSV, validate your queries before running them and change how the results are displayed or grouped.

We have a healthy backlog in JIRA for Script, but any feedback is always appreciated. If you think that we’re missing something, please let us know (via Wantoo) and we’ll do our best to implement it.

Enjoy.

New Advise module and Aireforge Studio v1.0.7

What’s new at Aireforge?

We’re pleased to announce that Aireforge Studio is now officially live and supported. Version 1.0.7 ships with hundreds of improvements with a new UI, simpler comparisons with advanced options, 2017 support and our new tuning / best practices module; Advise.
Depending on your version, the application should prompt to update after starting. If not, please download the latest version using the link below.

Introducing Advise

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The new Advise module within Aireforge Studio analyses instances, databases, tables and indexes, before providing recommendations. The growing list of checks vary from best practices and naming convention violations to orphaned users and missing, duplicate or overlapping indexes.

Read more…

Compare v1 & Custom Comparisons

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The Compare module within Aireforge Studio performs a growing list of comparisons, which can be restricted if certain values are known to differ, such as core count or edition (e.g. Enterprise vs Developer).

Common use cases for Aireforge Studio Compare are checking production databases against staging and / or staging against test, auditing the SQL Server estate, sharing configurations with colleagues / support teams.

Read more…

Viewing configuration settings without access to SQL Server

Have you ever been asked to help with a database issue but you can’t get access? Maybe you’re helping out a colleague over Skype, responding to a #sqlhelp request or asking for help yourself and want to provide more information. Quite often, there’s a simple configuration setting that may not be optimal but checking every setting could be time consuming and something could be missed (there’s a lot of settings).

You could start by running some scripts like sp_blitz (really useful) but they don’t always give you the complete picture or you need to extract all settings to store, share or compare them. Aireforge Studio can take an in-depth snapshot of a single instance or the entire estate. This can be really useful to do before or after carrying out any changes or if you need to share your configuration with someone else. You could also attach the saved comparison file to the ticket you’re working on, so you know exactly how it looked before and after any changes were made.

Here’s a quick tutorial on how you could share configuration information about your SQL Server instance or instance(s) with another person or organisation.

Taking a configuration snapshot

If you’re new to Aireforge Studio check out the getting started pages, although it’s a quite simple application. Once downloaded, create a profile and add the server(s) in question.

Go to the Compare tab and select the comparisons you wish to run or select Full to run them all. A full comparison should finish in a few seconds and won’t display any results if you only compared one server or if all of your servers are identical. Now save the results as an .afd (Aireforge Data) file and send it to the other party.

save

Viewing the results

The receiver will also need to have Aireforge Studio installed. Once installed you can either double click on the .afd file to open, or load the file from within the application. To view the results change Differences to All Rows and the View to Grid. If information has been collected from more than one server, you could also use the summary view to quickly see any differences.

results

Aireforge Studio performs a lot of preconfigured checks but if it doesn’t gather the information you require, you can create your own custom comparisons.

Any problems, however small, please contact Aireforge support.

You can also use our Wantoo board to request new features or improvements?

Custom comparisons in Aireforge Studio

The Compare module in Aireforge Studio can compare the instance, database, security and host configurations across hundreds of SQL Server and Azure SQL Database instances but sometimes you need something custom to your environment. This is where custom comparisons can help out.

Custom comparisons enable you to check values that are specific to your setup, such as the last update time in a table, row counts from replicated tables that should be in sync or you could make use of a brand new DMV, by creating your own query rather than waiting for the comparison definition updates from Aireforge.

Creating a custom comparison

Open Aireforge Studio and navigate to the Compare tab, select Configure from the toolbar and then Add Comparison.

compare_customcomparison

From this dialog you can create your own custom comparison. Lets create one to check if lock pages in memory is set.

Name: Lock Pages in Memory

Author: You

Category: Create a new one or put it in Instance \ Hardware

Description: Returns sql_memory_model_desc which is either CONVENTIONAL, LOCK_PAGES or LARGE_PAGES (EE Only)

Query: As this only applies to SQL Server 2016 SP1, we only need a single query but it’s possible to create different queries, for different versions of SQL Server. This is useful if you want to convert values so that they match between versions (KB to MB etc.).

SELECT  sql_memory_model_desc
FROM    sys.dm_os_sys_info;

Applies to: Select SQL Server 2016.

Note: This example query will only work for SQL Server 2016 SP1 or newer and will fail on 2016 or below. You could put your own version check in the script for now but we’ll be making the version selection more granular.

Columns: Select how Aireforge Studio should compare the column(s) and match the rows. We should choose Normal Compare for this example but the other options are:

  • Primary Key: Used to match rows in the result sets
  • Ignore: Ignored from the result set and not displayed
  • Normal Compare: Should be equal across all servers
  • No Compare: Displayed in results but not compared between servers
  • Unique: Should be unique amongst servers

Now save the custom comparison and perform an Aireforge Studio compare. If you create a useful script and you think we should include it, please email us or create a support ticket.

OmniCompare becomes Aireforge Studio

We created OmniCompare over a year ago now and it has evolved quite a bit since the early days of merely comparing the results from a small number of queries; mainly sys.configurations. The application is getting more powerful with each release and we’re also making good progress on OmniGuard, which protects SQL Server estates from unauthorised access, and OmniTune, which provides powerful tuning information for single or multiple databases.

With these new applications nearing beta release and OmniCompare nearing it’s official release, we had to make the decision to either continue with OmniCompare and create separate applications for our others tools or create a single application which contains our growing suite of tools. We opted for the later, and created Aireforge Studio.

A single application enables us to remain lean in terms of development and marketing but it will provide a better experience for the user. Again, this consumed a large amount of our development time and pushed us back a few month, but we’re keen to create the best foundation for our products before the official release(s).

The beta of Aireforge Studio 0.9.5 is now available to download either by updating OmniCompare or downloading OmniCompare from the website.