Affect of Shrinking Database before Transaction log backup I am newbie in the world of Database administration, so excuse my stupid question :)

I have the following maintenance jobs scheduled through SQL Server Management Studio :


Full DB Backup at 2 am, 10 am &amp; 6 Pm daily (after every 8 hours).
Transactional log backup at 2:30 am daily.
Shrink job at 9:30 am &amp; 9:30 pm daily.


I have run the Shrink job at about 1 AM manually, after that the scheduled Transaction Log Backup got failed with following error


  Code: 0xC002F210     Source: Back Up Database (Transaction Log)
  Execute SQL Task     Description: Executing the query "BACKUP LOG
  [PRODDB] TO  DISK = N'S:\CAS Backup\Log..." failed with the following
  error: "BACKUP LOG cannot be performed because there is no current
  database backup.  BACKUP LOG is terminating abnormally.". Possible
  failure reasons: Problems with the query "ResultSet" property not
  set correctly parameters not set correctly or connection not
  established correctly.  End Error  DTExec: The package execution
  returned DTSER_FAILURE (1).  Started:  03:01:12  Finished: 03:01:12 
  Elapsed:  0.359 seconds.  The package execution failed.  The step
  failed.,00:00:00,0,0,,,,0


I need to understand was manually running Shrink Job before transaction log backup failed the later at 2:30 AM??
Your maintenance plan should not contain any shrink tasks anyway. These cause fragmentation by moving pages around the file and likely the database will just need to grow back to its original size shortly anyway.

But this isn't causing your error. 


  BACKUP LOG cannot be performed because there is no current database
  backup.


The transaction logs would need to be restored after a compatible backup has been restored. This is telling you that there is no such backup as one has never been taken since the database has been in full or bulk logged recovery mode.

It doesn't look like step 1 was run successfully for that database, or possibly someone temporarily changed the recovery mode for that database to simple and broke the log chain so you must take another full backup.