Tuesday, February 26, 2013


SQL Diagnostic Runner Updated

Thanks to Todd who reported a bug when connecting with username and password (I messed up the connection string).

I’ve uploaded an updated version (v1.0.4.13057) which you can download from the links below (or from any of the previous posts):



[Servername will now take a semi-colon separated list of servers to run against, but with the limitation of using the same credentials and diagnostic script.]

Sunday, February 24, 2013


Parsing Command Line Arguments

If you want a full blown Command Line Parser then there are several good options available:

[I used the Command Line Parser Library recently in the SQL Diagnostic Runner I wrote.]

If you just want a very basic parser, supporting simple options in the format  /argname:argvalue  then you could use this:

/// <summary>
/// Very basic Command Line Args extracter
/// <para>Parse command line args for args in the following format:</para>
/// <para> /argname:argvalue /argname:argvalue ...</para>
/// </summary>
public class CommandLineArgs
private const string Pattern = @"\/(?<argname>\w+):(?<argvalue>.+)";
private readonly Regex _regex = new Regex(Pattern, RegexOptions.IgnoreCase|RegexOptions.Compiled);
private readonly Dictionary<String, String> _args = new Dictionary<String, String>();

public CommandLineArgs()

public string this[string key]
get { return _args.ContainsKey(key) ? _args[key] : null; }

public bool ContainsKey(string key)
return _args.ContainsKey(key);

private void BuildArgDictionary()
var args = Environment.GetCommandLineArgs();
foreach (var match in args.Select(arg => _regex.Match(arg)).Where(m => m.Success))
_args.Add(match.Groups["argname"].Value, match.Groups["argvalue"].Value);
// Ignore any duplicate args
catch (Exception) {}

Monday, February 18, 2013


Largest .NET Object….

In .NET versions prior to .NET 4.5, the largest allocation for any single object is 2GB.

On 64-bit platforms, in .NET versions 4.5 and greater, it is possible to enable the allocation of arrays that are larger than 2 GB in total size (but NOTE this does not change other limits on object size or array size):

  • The maximum number of elements in an array is UInt32MaxValue.

  • The maximum index in any single dimension is 2,147,483,591 (0x7FFFFFC7) for byte arrays and arrays of single-byte structures, and 2,146,435,071 (0X7FEFFFFF) for other types.

  • The maximum size for strings and other non-array objects is unchanged.

The default setting is not enabled.

You can enable this feature by using the gcAllowVeryLargeObjects element in your application configuration file:

<gcAllowVeryLargeObjects enabled="true" />

Before enabling this feature, ensure that your application does not include unsafe code that assumes that all arrays are smaller than 2 GB in size. For example, unsafe code that uses arrays as buffers might be susceptible to buffer overruns if it is written on the assumption that arrays will not exceed 2 GB.


Sunday, February 17, 2013


Guide to Recognizing Popular Timestamp Formats

Bookmarking for future reference: Guide to recognizing popular timestamp formats

Thursday, February 07, 2013


SQL Diagnostic Runner Updated

David Vogelaar (and others) kindly reported a bug: I wasn’t converting invalid filename characters when using an SQL Server instance name for the auto-generated results filename. This has been fixed. You can download version 1.0.2 from the previous download links or the ones below.



There is a known issue:   

The results file is generated OK but sometimes when you open it in Excel a seemingly ‘nasty’ message is shown:

"Excel found unreadable content in ‘???.xlsx’. Do you want to recover the contents of this workbook?"

The file will open OK if you chose to recover: simply accept the prompts and save over the original. I will fix as soon as I can.

Tuesday, February 05, 2013


SQL Server: Differences between Temp Tables and Table Variables

I had been thinking of collating the differences between temp tables and table variables and posting it, but Martin Smith has already written a great summary over at DBA StackExchange:

What's the difference between a temp table and table variable in SQL Server?

It’s broken up into the following categories:

  • Storage Location
  • Logical Location
  • Visibility to different scopes
  • Lifetime
  • Transactions
  • Logging
  • Object Metadata
  • Cardinality
  • Column statistics
  • Recompiles
  • Locking
  • Indexes
  • Parallelism
  • Other Functional Differences
  • Memory Only?


    SQL Diagnostic Runner: Version 1.0

    Glenn Berry mentioned the runner for his diagnostic scripts I wrote a few weeks ago. He also mentioned it would be nice to have a UI version. I had already written a basic UI when I initially released the command line version. So here it is, warts and all! (along with a minor update to the command line version)



    Comments and feedback welcome.

    Monday, February 04, 2013


    List of Freely Available Programming Books

    One of the things I think StackOverflow has got wrong is hiding, closed, highly useful questions that are deemed in some way not to ‘fit’ the site’s philosophy (whatever that might be). If your rep is higher than 10K, you can view these hidden closed questions. The site has bigger problems such as the increasing amount of very, very poor quality questions that amount to nothing more than “I can’t be bothered doing/looking up X. Please do X for me”.
    Here’s an example: List of freely available programming-books
    Can’t see it? I’d obviously prefer to link to the entire question and answers, but assuming you can’t see it, here’s an excerpt from the answer begun by George Stocker (who ironically is one of the people who closed it), and then contributed to by many people as a community wiki:
    Language Agnostic
    NET (C# / VB / Visual Studio)
    SQL (implementation agnostic)


    Powered by Blogger