suspect mode: database

---once the database goes to suspect mode
--follow the steps to recover the database

--1. reset the database from suspect mode
--sp_resetstatus turns off the suspect flag on a database.
--This procedure updates the mode and status columns of the named database in sys.databases.
--Also note that only logins having sysadmin priveleges can perform this :


use master
GO
exec sp_resetstatus 'db1';
--2.set the database to emergency mode
--Once the database is set to EMERGENCY mode it becomes a READ_ONLY copy
--only members of sysadmin fixed server roles have privileges to access it.
--The basic purpose for this is to facilitate troubleshooting

alter database db1 set emergency;

--3.run the consistency test
dbcc checkdb(db1)

--4. Roll the databse to single user mode
use master
GO
ALTER DATABASE db1 SET SINGLE_USER
WITH ROLLBACK IMMEDIATE


--5. this query will attempt to repir all the reported loss. This query can cause some data loss
dbcc checkdb('db1',REPAIR_ALLOW_DATA_LOSS)

--6.finally bring the database ONLINE and set to multiuser mode
ALTER DATABASE db1 SET MULTI_USER
WITH ROLLBACK IMMEDIATE

Stored procedure with an OUTPUT parameter

CREATE procName1 (@intClientId int, @account varchar(50), @intCount int OUTPUT)
AS

SELECT @intCount = COUNT (*) FROM Clients where clientId = @intClientId

SELECT @intCount

GO


--procedure call
Declare @out int
EXECUTE procName1 999, 'ABCSDRF',@out OUTPUT
SELECT @out

Dynamic sql: executing stored procedure using a sp_executesql

I had a situation where the logic on finding the duplicate records( based on the account number match) was different on each client. I built a logic where each client had it's own stored procedure called proc_check_dup_logic and the stored procedure name used by each client was stored in a table in a central admin database. I had a wrapper stored procedure in the admin database that would find the duplicate logic stored procedure name from the table and execute that using sp_executesql.

I try to stay away from dynamic sql but this was pretty fun writing and I unerstood the parameters scope as well.



@procname is a storedrocedure variable where the name is assigned and it's a storeprocedure with an OUTPUT value.

SELECT @procname = procedurename from table1 WHERE clientId = 10

BEGIN
--call special dup check logic

DECLARE @sqlStr NVARCHAR(500)
DECLARE @ParmDefinition NVARCHAR(500)

--the follwing are the parameters in this scope

DECLARE @parmINAccount VARCHAR(30),@parmINHospId int , @ParmINpatType varchar(1),@paramINPtno int
DECLARE @parmRET1 int
--assigning the values to be passed to the storeprocedure on sp_executesql call
SET @parmINAccount = @strAccount
SET @parmINHospId = @intHospital
SET @ParmINpatType = @patType
SET @paramINPtno = @intPtno

SET @sqlStr = N'Exec ' + @procName + ' @intPtno,@strAccount,@intHospital,@patType, @outDupCheck OUTPUT'

--the following parameters name and datatype should be exactly the same as the parameters in the called storedprocedure (e.g. @procname in this case)

SET @ParmDefinition=N'@IntPtno int, @strAccount varchar(50),@intHospital int,@patType varchar(1), @outDupCheck int OUTPUT';

EXECUTE sp_executesql @sqlStr, @ParmDefinition, @IntPtno = @paramINPtno, @strAccount = @parmINAccount, @intHospital=@parmINHospId,@patType=@ParmINpatType,@outDupCheck = @parmRET1 OUTPUT
Select @outDupCheck = @parmRET1

END

Error handler: TRY CATCH

BEGIN TRANSACTION TRAN1

BEGIN TRY

INSERT INTO.....

UPDATE.....

END TRY

BEGIN CATCH

If @@TRANCOUNT > 0

--error happened

ROLLBACK TRANSACTION TRAN1

END CATCH

If @@TRANCOUNT > 0

COMMIT TRANSACTION TRAN1

GO

Script: Log file size to a user table

DECLARE @rowcnt INT
DECLARE @iterator INT
DECLARE @dbname VARCHAR(200)
DECLARE @exec_sql VARCHAR(500)
SET @rowcnt = 0
SET @iterator = 1
CREATE TABLE #db_file_info ( [Database_Name] SYSNAME NOT NULL, [File_ID] SMALLINT NOT NULL, [File_Type] VARCHAR(10) NOT NULL, [File_Name] SYSNAME NOT NULL, [File_Path] VARCHAR(500) NOT NULL, [File_Size_in_MB] INT NOT NULL, [Space_Used_in_MB] INT NOT NULL, [Space_Left_in_MB] INT NOT NULL, [Time_collected] smalldatetime )
CREATE TABLE #db ( dbid INT, name VARCHAR(200))
INSERT INTO #db
SELECT database_id, name FROM sys.databases
WHERE --database_id <> 11 AND [state] <> 6
SET @rowcnt = @@ROWCOUNT
WHILE @iterator <= @rowcnt
BEGIN
SELECT @dbname = '['+ name + ']' FROM #db
SET @exec_sql = ' USE ' + @dbname + ';
Insert into #DB_FILE_INFO Select db_name(),fileid,case when groupid = 0 then ''log file'' else ''data file'' end, name,filename, [file_size] = convert(int,round ((sysfiles.size*1.000)/128.000,0)), [space_used] = convert(int,round(fileproperty(sysfiles.name,''SpaceUsed'')/128.000,0)), [space_left] = convert(int,round((sysfiles.size-fileproperty(sysfiles.name,''SpaceUsed''))/128.000,0)), getdate() from dbo.sysfiles; '
EXEC( @exec_sql)
SET @iterator = @iterator + 1
END
INSERT INTO SQLAdmin_Monitor_db_file_info
SELECT * FROM #db_file_info
DROP TABLE #db
DROP TABLE #db_file_info

Modifying database file

All the database files are set to autogrowth to 10% from the initial sizes. But,the auto growth can happen any time during business hours causing the database slow down. Therefore I am taking the following approach -

1 I have set up a sql job ( calls a script listed here) that logs the current datafile and the log file size in a table in interval of 4 hours daily. I use that historical data to research when the data file needs to grow.
2. Then I run this script from the table to find which database file has more than 95% filled up and those are the candidate for me to manually resize ( expand) the data file.
3. I use the follwing script to resize the datafile
use db1
Go

---select * from sys.sysfiles

alter database client_343
modify file
(
name = client_343,
size = 1024MB
);

Script: To find the database file where the file space is used more than 94 % of the current file size

--The historic data is logged in a table in every 4 hours and the following query in run in the table to find the current grown rate of the databse file

SELECT Database_Name,Space_Used_in_MB,File_Size_in_MB,(cast(Space_Used_in_MB as float)/cast(File_Size_in_MB as float)) * 100 as newval
FROM Monitor_db..SQLAdmin_Monitor_db_file_info
WHERE FILE_ID = 1 AND (cast(Space_Used_in_MB as float)/cast(File_Size_in_MB as float)) * 100 >= 95 AND Time_collected IN (SELECT MAX(time_collected) FROM hCFS_SQLMonitor..SQLAdmin_Monitor_db_file_info )
ORDER BY File_Size_in_MB