Dawid, Author at Dawid's Blog

Fun C# Code #1 - Infinite Delay (until cancelled)

20th February 202018th February 2020 by Dawid

I came across this code when reading 'Concurrency in C# Cookbook' by Stephen Cleary. Did you know you can have an infinite Task.Delay without loops?

await Task.Delay(Timeout.InfiniteTimeSpan, ...)

1	await Task.Delay(Timeout.InfiniteTimeSpan, ...)

Obviously, there isn't much point in spinning a task that litterally will do nothing. You can use a CancellationToken to cancel the task.

using var cts = new CancellationTokenSource();
await Task.Delay(Timeout.InfiniteTimeSpan, cts.Token);

1 2	using var cts = new CancellationTokenSource(); await Task.Delay(Timeout.InfiniteTimeSpan, cts.Token);

No point. It's just one ... Read more Fun C# Code #1 - Infinite Delay (until cancelled)

Customise Semantic-UI

18th February 202018th February 2020 by Dawid

Semantic UI appears to be no longer under active development. However, thanks to the Open Source community it is still getting deveoped by under a different name - Fomantic UI. I never had the need customise Semantic-UI. I only ever used it within internal apps and it worked well. Recently, I decided to use it ... Read more Customise Semantic-UI

How to change time-zone on Ubuntu servers?

31st December 201831st December 2018 by Dawid

Servers US tend to be considerably cheaper in US than in Europe. This has its drawbacks, not least of all, your application will be reporting wired times for various events. However, this is something that can be easily fixed on Ubuntu servers. Our goal is to change date from EST to GMT:

#from
root@Polaris:~# date
Mon Dec 31 06:15:21 EST 2018
#to
root@Polaris:~# date
Mon Dec 31 11:18:36 GMT 2018

#from

root@Polaris:~# date

Mon Dec 31 06:15:21 EST 2018

#to

root@Polaris:~# date

Mon Dec 31 11:18:36 GMT 2018

How to select the active links using jQuery

23rd September 201823rd September 2018 by Dawid

There are numerous ways in which one can add active class to a link. One way is to use if statements to do so. Modern JS frameworks such as Angular, React and VueJS support route-link designed to manage routes in the application. The same effect can also be achieved with jQuery. It is certainly a ... Read more How to select the active links using jQuery

Maintaining user session on msdeploy in ASP.NET Core (in SQL Server)

2nd September 20182nd September 2018 by Dawid

Using TeamCity, Bitbucket and msdeploy, I have been able to develop a satisfactory CI process for my web apps. However, I found that whenever an application was deployed to production, the user sessions would expire. Initially, it was not a big issue, but as the number of users grew so did the issue. We want ... Read more Maintaining user session on msdeploy in ASP.NET Core (in SQL Server)

Dealing with SQL Server Space - Part 1

2nd July 20182nd July 2018 by Dawid

Recently, I have been building a large database for the new House-Buddy project. The site uses a huge collection of data to identify the sweet-spots around a particular location. The site is hosted on a shared hosting which in theory had unlimited DB storage, but after they noticed the size of the database has grown ... Read more Dealing with SQL Server Space - Part 1

Adding Quartz to your ASP.NET Core

23rd June 201823rd June 2018 by Dawid

This is a ready made example of how to add a scheduled job to your ASP.NET core web application:

    public class YourJob : IJob
    {

        public static async void Start() {
            IScheduler scheduler = await StdSchedulerFactory.GetDefaultScheduler();
            await scheduler.Start();

            IJobDetail job = JobBuilder.Create<YourJob>().Build();

            ITrigger trigger = TriggerBuilder.Create()
                .WithDailyTimeIntervalSchedule(s =>s.WithIntervalInSeconds(10))
                .StartNow()
                .Build();

            await scheduler.ScheduleJob(job, trigger);
        }

        Task IJob.Execute(IJobExecutionContext context) {
            return Task.Run(() => {
                Program.Counter++;
            });
        }
    }

public class YourJob : IJob

{

public static async void Start() {

IScheduler scheduler = await StdSchedulerFactory.GetDefaultScheduler();

await scheduler.Start();

IJobDetail job = JobBuilder.Create<YourJob>().Build();

ITrigger trigger = TriggerBuilder.Create()

.WithDailyTimeIntervalSchedule(s =>s.WithIntervalInSeconds(10))

.StartNow()

.Build();

await scheduler.ScheduleJob(job, trigger);

}

Task IJob.Execute(IJobExecutionContext context) {

return Task.Run(() => {

Program.Counter++;

});

}

In your Program.cs

        public static int Counter = 0;

        public static void Main(string[] args)
        {
            var host = BuildWebHost(args); 

            YourJob.Start();
            host.Run();
        }

public static int Counter = 0;

public static void Main(string[] args)

{

var host = BuildWebHost(args);

YourJob.Start();

host.Run();

}

Is my code not working?

22nd May 201826th April 2018 by Dawid

How to regain space after dropping columns in SQL Server

6th April 2018 by Dawid

I hit an annoying issue today. I wanted to regain space after I dropped several columns in a table. When I run the famous query from StackOverflow:

SELECT 
    t.NAME AS TableName,
    s.Name AS SchemaName,
    p.rows AS RowCounts,
    SUM(a.total_pages) * 8 AS TotalSpaceKB, 
    CAST(ROUND(((SUM(a.total_pages) * 8) / 1024.00 / 1024.00), 2) AS NUMERIC(36, 2)) AS TotalSpaceMB,
    SUM(a.used_pages) * 8 AS UsedSpaceKB, 
    CAST(ROUND(((SUM(a.used_pages) * 8) / 1024.00/ 1024.00), 2) AS NUMERIC(36, 2)) AS UsedSpaceMB, 
    (SUM(a.total_pages) - SUM(a.used_pages)) * 8 AS UnusedSpaceKB,
    CAST(ROUND(((SUM(a.total_pages) - SUM(a.used_pages)) * 8) / 1024.00, 2) AS NUMERIC(36, 2)) AS UnusedSpaceMB
FROM 
    sys.tables t
INNER JOIN      
    sys.indexes i ON t.OBJECT_ID = i.object_id
INNER JOIN 
    sys.partitions p ON i.object_id = p.OBJECT_ID AND i.index_id = p.index_id
INNER JOIN 
    sys.allocation_units a ON p.partition_id = a.container_id
LEFT OUTER JOIN 
    sys.schemas s ON t.schema_id = s.schema_id
WHERE 
    t.NAME NOT LIKE 'dt%' 
    AND t.is_ms_shipped = 0
    AND i.OBJECT_ID > 255 
GROUP BY 
    t.Name, s.Name, p.Rows
ORDER BY 
    t.Name

SELECT

t.NAME AS TableName,

s.Name AS SchemaName,

p.rows AS RowCounts,

SUM(a.total_pages) * 8 AS TotalSpaceKB,

CAST(ROUND(((SUM(a.total_pages) * 8) / 1024.00 / 1024.00), 2) AS NUMERIC(36, 2)) AS TotalSpaceMB,

SUM(a.used_pages) * 8 AS UsedSpaceKB,

CAST(ROUND(((SUM(a.used_pages) * 8) / 1024.00/ 1024.00), 2) AS NUMERIC(36, 2)) AS UsedSpaceMB,

(SUM(a.total_pages) - SUM(a.used_pages)) * 8 AS UnusedSpaceKB,

CAST(ROUND(((SUM(a.total_pages) - SUM(a.used_pages)) * 8) / 1024.00, 2) AS NUMERIC(36, 2)) AS UnusedSpaceMB

FROM

sys.tables t

INNER JOIN

sys.indexes i ON t.OBJECT_ID = i.object_id

INNER JOIN

sys.partitions p ON i.object_id = p.OBJECT_ID AND i.index_id = p.index_id

INNER JOIN

sys.allocation_units a ON p.partition_id = a.container_id

LEFT OUTER JOIN

sys.schemas s ON t.schema_id = s.schema_id

WHERE

t.NAME NOT LIKE 'dt%'

AND t.is_ms_shipped = 0

AND i.OBJECT_ID > 255

GROUP BY

t.Name, s.Name, p.Rows

ORDER BY

t.Name

I got a set of numbers which were the same before and after the removal has

DBCC CLEANTABLE('YOUR_DB', 'SCHEMA.TABLE');

1	DBCC CLEANTABLE('YOUR_DB', 'SCHEMA.TABLE');

There is, however, a potential issue with this approach if ... Read more How to regain space after dropping columns in SQL Server

Transaction log is full due to LOG_BACKUP

17th March 2018 by Dawid

Yesterday, when I was building a large DB from scratch I got an error saying:

Transaction Log for 'Database' is full due to LOG_BACKUP

1	Transaction Log for 'Database' is full due to LOG_BACKUP

Running this simple query solved the issue:

ALTER DATABASE MyDB SET RECOVERY SIMPLE;

1	ALTER DATABASE MyDB SET RECOVERY SIMPLE;