Why might Sql Server Agent's Next Run Time value not be what I expect? And is this definitely the next time my job will run?

At times, I'm seeing some inconsistencies with sql server agent's value in the sysjobschedules.next_run_date and time fields.

I have a web interface that interacts with the sql scheduling system.

I've created a test job that started on March 16th 2011 at 9:45am.
I've set it up to happen every 4 weeks on a Wednesday.

From today, this should put a next run date and time on January 18th at 9:45 but the Next Run Date/Time value for my job is saying January 4th.

The values in the job properties look good.

The start date says March 16th 2011.
The frequency values are all correct.
But it seems SQL is failing to land this occurrence properly.

Here is some relevant info for the job in question from the sp_help_jobschedule proc

freq_type 8

freq_interval 8

freq_subday_type 1

freq_subday_interval 1

freq_relative_interval 0

freq_recurrence_factor 4

active_start_date 20110316

active_end_date 99991231

active_start_time 154500

active_end_time 55959

date_created 2011-12-29 20:37:05.737

schedule_description Every 4 week(s) on Wednesday at 154500

next_run_date 20120104

next_run_time 154500

if the start date is March 16 2011 at 9:45, it doesn't make sense that the next run date would fall on January 4th 2012 based on the properties of the job.

I guess my question is, how much can I rely on this Next Run Date data?

When did you check this data? The msdb.dbo.sysjobschedules table refreshes every 20 minutes. So if you had it set and then changed it, then ran the sp_help_jobschedule stored procedure, the underlying data might not be updated yet.

What do you get for next_scheduled_run_date when you execute this query?

exec sp_help_jobactivity @job_name = 'YourJobScheduleName'

StackExchange Database Administrators Q#9925, answer score: 4