full backups occasionally skipping certain databases - sql

Question

We have a job set up to run a script every night to do a full backup on all of our databases. Recently, we noticed that sometimes the last two databases are skipped, but not all of the time. We have a tracking table that we are inserting the state of each database in when we do the backups. On the nights that the last two databases are skipped, the state for those databases doesn't get recorded in the tracking table either. We can't figure out why those databases are being skipped. This is the backup script we are using:
DECLARE #dbname VARCHAR(100),
#dbid INT,
#rcmodel VARCHAR(50),
#state VARCHAR(60),
#date VARCHAR(50),
#time VARCHAR(50),
#sql VARCHAR(3000),
#dir VARCHAR(1000),
#path VARCHAR(100),
#type VARCHAR(10)
SET #path = 'E:\Backups\'
SET #type = 'Full'
SET #date = REPLACE(CONVERT(date,GETDATE(),101),'-','_')
SET #time = REPLACE(CONVERT(TIME(0), GETDATE()),':','_')
SET #path = #path + CONVERT(VARCHAR(30),##SERVERNAME) + '\' + #type + '\'
DECLARE BackupCur CURSOR FOR
SELECT NAME, database_id, recovery_model_desc, state_desc
FROM sys.databases
WHERE NAME <> 'tempdb'
OPEN BackupCur
FETCH NEXT FROM BackupCur INTO #dbname, #dbid, #rcmodel, #state
WHILE ##FETCH_STATUS = 0
BEGIN
INSERT INTO backuptrackingtable (db, statedesc, datecreated)
values (#dbname, #state, GETDATE())
IF #type = 'Full' AND #state = 'ONLINE'
BEGIN
SET #dir = 'EXECUTE master.dbo.xp_create_subdir N'''+#path+#dbname+''''
SET #sql = 'BACKUP DATABASE '+#dbname+' TO DISK = N'''+#path+#dbname+'\'+#dbname+'_'+#date+'.bak'' WITH NOFORMAT, INIT, SKIP, REWIND, NOUNLOAD, COMPRESSION'
PRINT 'Backing up ' + #dbname
EXEC (#dir)
EXEC (#sql)
END
IF #type = 'Log' AND #dbid > 4 AND #rcmodel = 'FULL' AND #state = 'ONLINE'
BEGIN
SET #dir = 'EXECUTE master.dbo.xp_create_subdir N'''+#path+#dbname+''''
SET #sql = 'BACKUP LOG '+#dbname+' TO DISK = N'''+#path+#dbname+'\'+#dbname+'_'+#date+'__'+#time+'.bak'' WITH NOFORMAT, INIT, SKIP, REWIND, NOUNLOAD, COMPRESSION'
PRINT 'Backing up ' + #dbname
EXEC (#dir)
EXEC (#sql)
END
FETCH NEXT FROM BackupCur INTO #dbname, #dbid, #rcmodel, #state
END
CLOSE BackupCur
DEALLOCATE BackupCur

Answer 1

Can think of three possible explanations.
They aren't being returned from the query against sys.databases because they don't exist or the user running the query doesn't have permissions on them.
An unhandled error means that the script aborts before processing them.
##FETCH_STATUS returns -2 at some point because a database has been dropped since the keyset cursor opened.
You would need to put more logging in to investigate further. But you might want to consider using a maintenance plan (dependant on edition) or Ola Hallengren's DB maintenance scripts rather than re-inventing the wheel anyway.