Month: May 2020

In an ironic twist of fate I adapted my ‘Drop all temp-tables’ script, to drop all tables beginning with an underscore.

Yes, it is ironic, because it uses a temp-table to store the working list of tables to be deleted. Whilst my original script used a real table to store a list of temp-tables.

Well … ok then

-- DropAllTablesStartingWithAnUnderscore.sql

IF OBJECT_ID('tempdb..#tables') IS NOT NULL DROP TABLE #tables
SELECT [name] 
INTO #tables
FROM sys.tables
WHERE [name] LIKE '/_%' ESCAPE '/'

DECLARE @table VARCHAR(200), @cmd VARCHAR(500)
WHILE (SELECT COUNT(*) FROM #tables) > 0
BEGIN
	SET @table = (SELECT TOP(1) [name] FROM #tables)
	SET @cmd = 'drop table ' + @table
	EXEC(@cmd)
	DELETE FROM #tables WHERE [name] = @table
END

(In case you were wondering why I created these underscore-tables in the first place. I was refactoring a stored-procedure that took over an hour to run, and had a large number of temp-tables. I wanted to persist those temp-tables for another day, and not have to start from scratch.)

Faced with a barrage of tabbed T-SQL in SSMS it can sometimes be quite difficult to see the close bracket that signifies – for example – the end of a CTE.

TIP: swipe from the inside of the bracket outwards to highlight (in grey) the bracket itself, and also its partner. EG: swipe right-to-left across an open bracket.

Normally I would not bother, but when CHECKDB runs on TempDB it cannot use a snapshot so has to lock all the temp tables. This script will wait for exclusive access for up to a minute.

DECLARE @outcome VARCHAR(50) = 'TempDB is currently too busy for CHECHDB', 
	@endtime DATETIME = DATEADD(mi,1,GETDATE())
WHILE GETDATE() < @endtime
BEGIN
  IF NOT EXISTS (SELECT 1 FROM sys.dm_tran_locks WHERE request_mode = 'X' AND resource_database_id = 2)
  BEGIN
    DBCC CheckDB([tempdb]) WITH NO_INFOMSGS;
    SET @outcome = 'success'
    BREAK;
  END
  WAITFOR DELAY '00:00:01';
END
SELECT @outcome