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Question : Store procedure xp_sqlagent_enum_jobs help
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Hi
I have this code from website. I want to understand it so here are few questions I have regarding this proces.
1- why is there a need of the function that converts hex to char the result from sysprocess and the xp procedure contains the same job id as in hex format and so join can be created on that with out using the function.
2-in the procedure there are these lines below that I don't understant mainly I am confused about 32,32 and 16
on substring(a.program_name,32,32)= b.job_id_char
select job_id, dba.dbo.fn_hex_to_char(job_id,16) from #enum_job
3-In the mailing process this line is confusing what are these parameter refering to 1,78
@query= 'select substring(c.name,1,78)
Thanks
--Code for fn_hex_to_char function:
CREATE function fn_hex_to_char (
@x varbinary(100), -- binary hex value
@l int -- number of bytes
) returns varchar(200)
as
-- Written by: Gregory A. Larsen
-- Date: May 25, 2004
-- Description: This function will take any binary value and return
-- the hex value as a character representation.
-- In order to use this function you need to pass the
-- binary hex value and the number of bytes you want to
-- convert.
begin
declare @i varbinary(10)
declare @digits char(16)
set @digits = '0123456789ABCDEF'
declare @s varchar(100)
declare @h varchar(100)
declare @j int
set @j = 0
set @h = ''
-- process all bytes
while @j < @l
begin
set @j= @j + 1
-- get first character of byte
set @i = substring(cast(@x as varbinary(100)),@j,1)
-- get the first character
set @s = cast(substring(@digits,@i%16+1,1) as char(1))
-- shift over one character
set @i = @i/16
-- get the second character
set @s = cast(substring(@digits,@i%16+1,1) as char(1)) + @s
-- build string of hex characters
set @h = @h + @s
end
return(@h)
end
Code for usp_log_running_jobs SP:
CREATE proc usp_long_running_jobs as
-- Written by: Gregory A. Larsen
-- Date: May 25, 2004
-- Description: This stored procedure will detect long running jobs.
-- A long running job is defined as a job that has
-- been running over 6 hours. If it detects any long
-- running job then an email is sent to the DBA's.
------------------
-- Begin Section 1
------------------
set nocount on
declare @c char(1000)
declare @cnt int
-- Create table to hold job information
create table #enum_job (
Job_ID uniqueidentifier,
Last_Run_Date int,
Last_Run_Time int,
Next_Run_Date int,
Next_Run_Time int,
Next_Run_Schedule_ID int,
Requested_To_Run int,
Request_Source int,
Request_Source_ID varchar(100),
Running int,
Current_Step int,
Current_Retry_Attempt int,
State int
)
------------------
-- Begin Section 2
------------------
-- create a table to hold job_id and the job_id in hex character format
create table ##jobs (job_id uniqueidentifier ,
job_id_char varchar(100))
-- Get a list of jobs
insert into #enum_job
execute master.dbo.xp_sqlagent_enum_jobs 1,
'garbage' -- doesn't seem to matter what you put here
------------------
-- Begin Section 3
------------------
-- calculate the #jobs table with job_id's
-- and their hex character representation
insert into ##jobs
select job_id, dba.dbo.fn_hex_to_char(job_id,16) from #enum_job
------------------
-- Begin Section 4
------------------
-- get a count or long running jobs
select @cnt = count(*)
from master.dbo.sysprocesses a
join ##jobs b
on substring(a.program_name,32,32)= b.job_id_char
join msdb.dbo.sysjobs c on b.job_id = c.job_id
-- check for jobs that have been running longer that 6 hours.
where login_time < dateadd(hh,-6,getdate())
------------------
-- Begin Section 5
------------------
if @cnt > 0
-- Here are the long running jobs
exec master.dbo.xp_sendmail
@recipients='Greg.Larsen@databasejournal.com',
@subject='Jobs Running Over 6 hours',
@query= 'select substring(c.name,1,78)
''These jobs have been running longer than 6 hours''
from master.dbo.sysprocesses a
join ##jobs b
on substring(a.program_name,32,32)= b.job_id_char
join msdb.dbo.sysjobs c on b.job_id = c.job_id
where login_time < dateadd(hh,-6,getdate())'
drop table #enum_job
drop table ##jobs
GO
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Answer : Store procedure xp_sqlagent_enum_jobs help
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1- why is there a need of the function that converts hex to char the result from sysprocess and the xp procedure contains the same job id as in hex format and so join can be created on that with out using the function.
**** Not sure. Maybe the answers to the other questions will help answer this question. ****
2-in the procedure there are these lines below that I don't understant mainly I am confused about 32,32 and 16
on substring(a.program_name,32,32)= b.job_id_char
**** substring extracts a portion of a string. This statement says take the column program_name and start at character 32 and extract 32 characters. The 32 characters extracted include character 32. ****
select job_id, dba.dbo.fn_hex_to_char(job_id,16) from #enum_job
**** Per the function definition, the 16 specifies that the first 16 bytes of job_id are to be converted to hex. Thus, the resulting hex string will be 32 characters long. ****
3-In the mailing process this line is confusing what are these parameter refering to 1,78
@query= 'select substring(c.name,1,78)
**** this extracts 78 characters from name beginning with character 1. Note, if name is less than 78 characters long, then characters 1 through the end of the name are extracted. ****
Hope this helps.
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