Dawid's Blog

Adding Quartz to your ASP.NET Core

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++;
            });
        }
    }

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

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();
        }

1

2

3

4

5

6

7

8

9

public static int Counter = 0;

public static void Main(string[] args)

{

var host = BuildWebHost(args);

YourJob.Start();

host.Run();

}

Is my code not working?

How to regain space after dropping columns in SQL Server

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

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

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

Transaction log is full due to LOG_BACKUP

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;

The ALTER TABLE statement conflicted with the FOREIGN KEY constrain

I've been trying to apply a new migration and I was getting the following error: The ALTER TABLE statement conflicted with the FOREIGN KEY constraint "FK_dbo.Parent_dbo.Childs_ChildId". The conflict occurred in database "parents_db", table "dbo.Childs", column 'ChildId'. In my case, the table contained data. Therefore, either you have to assign a default value, set it as

MediaElement Not Firing Events

Today, we encountered quite an interesting problem. MediaElement wasn't firing events. Using simple speech synthesis on Windows 8.1 using the speech synthesiser we tried:

using(SpeechSynthesizer synthesizer = new SpeechSynthesizer())
{
    SpeechSynthesisStream stream = await synthesizer.SynthesizeTextToStreamAsync("How are you feeling today?");
    MediaElement mediaElement = new MediaElement();
    mediaElement.IsMuted = false;
    mediaElement.SetSource(stream, stream.ContentType);
    mediaElement.MediaEnded += (a, b) => { System.Diagnostics.Debug.WriteLine("Steam has eneded."); };
    mediaElement.Play();
}

1

2

3

4

5

6

7

8

9

using(SpeechSynthesizer synthesizer = new SpeechSynthesizer())

{

SpeechSynthesisStream stream = await synthesizer.SynthesizeTextToStreamAsync("How are you feeling today?");

MediaElement mediaElement = new MediaElement();

mediaElement.IsMuted = false;

mediaElement.SetSource(stream, stream.ContentType);

mediaElement.MediaEnded += (a, b) => { System.Diagnostics.Debug.WriteLine("Steam has eneded."); };

mediaElement.Play();

}

None of the variations worked. The speech worked just the event wasn't getting fired. After a bit of digging it turned out that in order to fire events MediaElement must

Implementation Overview in FHIR

Paradigms In order to make FHIR interoperable, it was based on 4 paradigms: RESTful API Documents Messages Services This is what's called an exchange framework. REST FHIR was primary designed to be used with Restful services which handle all requests. Restful service implies that we have a choice between using JSON or XML and it

My Woes with Oracle Databases

I have been extensively working with the Oracle Database over the last couple of weeks. I thought I would share some of my experiences. The version I've been playing around isn't the newest, but, it roughly compares with the versions of MySQL and SQL Servers when I was learning databases. There is quite an interesting

Architectural Views

Architectural views represent a perspective of looking at a particular problem solution. There are different standards. And different versions of diagrams. That is because one diagram rarely would give you everything you'd want. So you sort of mix and match. We have to recognize that there are many stakeholders in the system: from architects themselves,

Databindings - small values treated as 0s

Today, I encountered an interesting problem with WinForms. In the application, NumericUpDowns (shown below) were used with small values e.g. 0.00001 etc. However, after we refreshed the panel, the value was being set to the default value. Digging further into the problem it turned out that the default Microsoft DataBinding converter was unable to convert

The Blog

Adding Quartz to your ASP.NET Core

Is my code not working?

How to regain space after dropping columns in SQL Server

Transaction log is full due to LOG_BACKUP

The ALTER TABLE statement conflicted with the FOREIGN KEY constrain

MediaElement Not Firing Events

Implementation Overview in FHIR

My Woes with Oracle Databases

Architectural Views

Databindings - small values treated as 0s

Search

Categories