Configure Change Data Capture (CDC) Parameters in SQL Server

After enabling CDC in SQL Server, We can modify the retention period and the number of transactions that to be handled in Change Data Capture table.

Before configureing one should understand the basic terms in CDC Configuration:

Polling interval – (Default 5 seconds) the amount of time to wait between log scans

Maxtrans – (Default 500) the number of transactions to grab with each scan

Maxscans – (Default 10) the number of scans performed between each polling interval

Retention – (Default 72 hours, 4320 mins, 3 days). 

The period for which the new/updated/deleted data have to be retrieved and displayed in CDC tables. 

Execute the below query to get the CDC configured values:

SELECT * from msdb.dbo.cdc_jobs

Execute the below query to change capture instances:

EXEC sys.sp_cdc_change_job @job_type = 'capture'

       ,@maxtrans = 501

       ,@maxscans = 10

       ,@continuous = 1

       ,@pollinginterval = 5

Execute the below query to change retention period:

EXEC sys.sp_cdc_change_job @job_type = 'cleanup'

                          ,@retention = 4320 -- Number of minutes to retain (72 hours)

                          ,@threshold = 5000

Using this method we can use CDC hold the required period of historical data, i.e., for last 1 month, last 1 year or last 10 days, etc. 

Convert the year, month and day column as date format

Below is the script to convert the year, month and day column as date format

SELECT
CAST(
CAST(year AS VARCHAR(4)) +
RIGHT('0' + CAST(month AS VARCHAR(2)),2) +
RIGHT('0' + CAST(day AS VARCHAR(2)),2)
AS DATE )
FROM [dbo].[SampleTable]

Finding NULL values from all the tables in a database using single script

Script to find NULL values from all the tables in Database


USE [NULLTest]  --database name
GO

create table #SuspectColumns (
    TABLE_SCHEMA sysname,
    TABLE_NAME sysname,
    COLUMN_NAME sysname
)

declare csrColumns cursor fast_forward for
    select TABLE_SCHEMA, TABLE_NAME, COLUMN_NAME
        from INFORMATION_SCHEMA.COLUMNS
        where IS_NULLABLE = 'YES'

declare @TABLE_SCHEMA sysname,
        @TABLE_NAME sysname,
        @COLUMN_NAME sysname,
        @sql nvarchar(max)

open csrColumns

while (1=1) begin
    fetch next
        from csrColumns
        into @TABLE_SCHEMA, @TABLE_NAME, @COLUMN_NAME

    if @@FETCH_STATUS<>0 break

    set @sql = N'if exists(select 1 from ' + QUOTENAME(@TABLE_SCHEMA) + N'.' + QUOTENAME(@TABLE_NAME) + N' where ' + QUOTENAME(@COLUMN_NAME) + N'is null)
                     insert into #SuspectColumns values (''' + @TABLE_SCHEMA + N''',''' + @TABLE_NAME + N''',''' + @COLUMN_NAME + N''')'

    exec sp_executesql @sql
end /* while */

close csrColumns
deallocate csrColumns

select * from #SuspectColumns

drop table #SuspectColumns

below are the example tables which contain NULLs

following is the result while run the above script