When restarting SQL Server during the middle of a large transaction (say committing 100k rows), the database needs to recover by rolling back the transactions. The may take a while and removes all access to the database.

SQL Management Studio is not very helpful in giving an time for recovery, however the following commands come in useful in estimating the ETA:

SQL Server 2008

DECLARE @DBName VARCHAR(64) = 'databasename'
 
DECLARE @ErrorLog AS TABLE([LogDate] CHAR(24), [ProcessInfo] VARCHAR(64), [TEXT] VARCHAR(MAX))
 
INSERT INTO @ErrorLog
EXEC sys.xp_readerrorlog 0, 1, 'Recovery of database', @DBName
 
SELECT TOP 5
	 [LogDate]
	,SUBSTRING([TEXT], CHARINDEX(') is ', [TEXT]) + 4,CHARINDEX(' complete (', [TEXT]) - CHARINDEX(') is ', [TEXT]) - 4) AS PercentComplete
	,CAST(SUBSTRING([TEXT], CHARINDEX('approximately', [TEXT]) + 13,CHARINDEX(' seconds remain', [TEXT]) - CHARINDEX('approximately', [TEXT]) - 13) AS FLOAT)/60.0 AS MinutesRemaining
	,CAST(SUBSTRING([TEXT], CHARINDEX('approximately', [TEXT]) + 13,CHARINDEX(' seconds remain', [TEXT]) - CHARINDEX('approximately', [TEXT]) - 13) AS FLOAT)/60.0/60.0 AS HoursRemaining
	,[TEXT]
 
FROM @ErrorLog ORDER BY [LogDate] DESC

SQL Server 2012/2014

DECLARE @DBName VARCHAR(64) = 'databasename'
 
DECLARE @ErrorLog AS TABLE([LogDate] CHAR(24), [ProcessInfo] VARCHAR(64), [TEXT] VARCHAR(MAX))
 
INSERT INTO @ErrorLog
EXEC master..sp_readerrorlog 0, 1, 'Recovery of database', @DBName
 
SELECT TOP 5
	 [LogDate]
	,SUBSTRING([TEXT], CHARINDEX(') is ', [TEXT]) + 4,CHARINDEX(' complete (', [TEXT]) - CHARINDEX(') is ', [TEXT]) - 4) AS PercentComplete
	,CAST(SUBSTRING([TEXT], CHARINDEX('approximately', [TEXT]) + 13,CHARINDEX(' seconds remain', [TEXT]) - CHARINDEX('approximately', [TEXT]) - 13) AS FLOAT)/60.0 AS MinutesRemaining
	,CAST(SUBSTRING([TEXT], CHARINDEX('approximately', [TEXT]) + 13,CHARINDEX(' seconds remain', [TEXT]) - CHARINDEX('approximately', [TEXT]) - 13) AS FLOAT)/60.0/60.0 AS HoursRemaining
	,[TEXT]
 
FROM @ErrorLog ORDER BY [LogDate] DESC

Thanks Tim Lagua for original post.

With a SQL query I’ve had to write, I’ve had to encode some text in Base64.

The following functions where extremely useful, this is based on this solution, but has been adapted to handle Unicode characters.

Convert to Base64

CREATE FUNCTION [dbo].[fn_str_TO_BASE64]
(
    @STRING NVARCHAR(MAX)
)
RETURNS NVARCHAR(MAX)
AS
BEGIN
    RETURN (
        SELECT
            CAST(N'' AS XML).value(
                  'xs:base64Binary(xs:hexBinary(sql:column("bin")))'
                , 'NVARCHAR(MAX)'
            )   Base64Encoding
        FROM (
            SELECT CAST(@STRING AS VARBINARY(MAX)) AS bin
        ) AS bin_sql_server_temp
    )
END

Convert from Base64

CREATE FUNCTION [dbo].[fn_str_FROM_BASE64]
(
    @BASE64_STRING NVARCHAR(MAX)
)
RETURNS NVARCHAR(MAX)
AS
BEGIN
    RETURN (
        SELECT 
            CAST(
                CAST(N'' AS XML).value('xs:base64Binary(sql:variable("@BASE64_STRING"))', 'VARBINARY(MAX)') 
            AS NVARCHAR(MAX)
            )   UTF8Encoding
    )
END

Here’s how you run the SQL queries:

SELECT dbo.fn_str_TO_BASE64('Hello World')

SELECT [dbo].[fn_str_from_base64](dbo.fn_str_TO_BASE64('Hello World'))

I’ve wrote many scripts over the years to selectively reindex indexes and update statistics on Microsoft SQL Server. However more recently I’ve been using Hallengren’s SQL reindex script as it’s very powerful and pretty easy to use and schedule via SQL Agent.

Hallengren’s SQL Reindex Script

I currently use the following script run daily as it reorganises indexes with fragmentation of between 5% and 20%, and performs an online rebuild if over 20%. Fragmentation under 5% is ignored (it’s not worth doing anything with these). It also updates statistics on records which have been modified.

EXECUTE dbo.IndexOptimize @Databases = 'USER_DATABASES',
@FragmentationLow = NULL,
@FragmentationMedium = 'INDEX_REORGANIZE,INDEX_REBUILD_ONLINE,INDEX_REBUILD_OFFLINE',
@FragmentationHigh = 'INDEX_REBUILD_ONLINE,INDEX_REBUILD_OFFLINE',
@FragmentationLevel1 = 5,
@FragmentationLevel2 = 20,
@SortInTempdb = 'Y',
@MaxDOP = 0,
@UpdateStatistics = 'ALL',
@OnlyModifiedStatistics = 'Y'