Author: SSUGE.org

Find a schema in all databases

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So what is a Schema?
A SQL Server database contains multiple objects: tables, views, stored procedures, functions, indexes, triggers.

SQL Server Schemas are a logical collection of database objects. A user that owns a schema in the database are known as Schema owners. There is no restrictions on the number of objects can be in a schema.

If you need to find that default schema for a user – you need to be logged into SSMS with that user and then run the following query:

SELECT SCHEMA_NAME();

If you need to retrieve all the schema and their owners in a database, use this SQL query:

SELECT s.name AS schema_name, 
       s.schema_id, 
       u.name AS schema_owner
FROM sys.schemas s
     INNER JOIN sys.sysusers u ON u.uid = s.principal_id
ORDER BY s.name;

On some occasion, a business user will give me a sql script to run on a database that does not have a USE clause in the script and they have no idea on which database it needs to be run on. And in most cases there are 50+ databases on the sql instance.

Here is an example of a script:

Select * from schema_name.table_name

Now usually the schema name is dbo but in some rare occasions they have a unique name for the schema. Since the user does now know which database the sql script on I use msforeachdb to find the schema name in all the databases and then I can find out in which database the schema resides on and then I can run the script the business user gave me on that database and provide the user the information they requested.

Here is the sql script to find a schema in all databases:

--This query will return a listing of all tables that matches a schema name on a SQL instance: 
DECLARE @command varchar(1000) 
SELECT @command = 'USE ? SELECT *
FROM INFORMATION_SCHEMA.COLUMNS
WHERE COLUMN_NAME LIKE "%prdobj%"' 
EXEC sp_MSforeachdb @command

This has helped me tremendously in numerous occasion of tedious work on finding on which database the schema resides on. Hope this helps.

Email Alert when SQL Server is restarted

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As a DBA we need to be notified when a SQL Server is restarted so that we can take a proactive reaction to identify the cause of the restart which could be an indication of underlining issues with the Server OS or the SQL Server Engine.

I have used this several years now and it has helped me avoid Severity 1 outages a few cases.

Just put this code in a sql job and make sure you change the db mail portion that pertains to your environment.

Declare @Title varchar(max)
Declare @Ebody varchar(max)
Declare @TableHead varchar(max)
Declare @TableTail varchar(max)

Select @Title = 'SQL Server Restarted - ' + @@SERVERNAME
Set NoCount On;
Set @TableTail= '</body></html>';

---HTML Layout--

Set @TableHead = '<html><head>' +
'<H4 style="color: #000000">**********This is an informational message only**********</H4>' +
 '</head>' +
 '<body>' + 'SQL Server Services have been RESTARTED : '+ '<strong>' + @@SERVERNAME + '</strong>' +
 '<p>' + ' If this was not planned, check the Server' + '</p>'

select @TableHead = @TableHead + @TableTail

WAITFOR DELAY '00:00:30'
EXEC msdb.dbo.sp_send_dbmail
@profile_name = 'DB_Admins',
@recipients = 'db_admins@yourdomain.com',
@body = @TableHead,
@body_format = HTML,
@subject = @Title;

Hope this helps you avoid any outages as it has helped me.

Get hard drive brand, size and serial number on a Windows Machine

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A few occasions I came across a request to find the hard drive brand, size and serial number installed on a Windows OS machine.

To get the basic hard drive info and to determine some basic info about the hard drive installed on your machine, follow these steps:

Click on the Search icon on your Task Bar:

Search for Command Prompt

Item 1: Your Search Text

Item 2: Will be the search results, right click on it and click on Run as administrator

The Command Shell will open, at the prompt type in:

wmic diskdrive get model,serialNumber,size,mediaType

You will see the following info:

If you have multiple hard drives on your machine then it might take a few seconds before the results are shown.

Find Missing Index

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As part of SQL Server’s processing algorithm for a query, SQL will recommend creating an index which it believes will help the query run faster – hence called Missing Index. You have to take this recommendation with a grain of salt. although SQL Server is very good at determining when an index is needed but sometimes it is not so good on the index recommendation.

I have been using this script for a few years now, donot remember where I got it from but I think it may be based off Glenn Berry’s Diagnostic Script.
The query below will show suggested missing index for a specified database. You can run it for a specified table by uncommenting the AND clause and specifying the table name.
Keep in mind that these missing index gets reset every time SQL Server is restarted, therefore if you have rebooted the server or restarted sql server recently you may not have the index stats updated yet.

USE DatabaseName
GO
 
SELECT db.[name] AS [DatabaseName]
    ,id.[object_id] AS [ObjectID]
	,OBJECT_NAME(id.[object_id], db.[database_id]) AS [ObjectName]
    ,id.[statement] AS [FullyQualifiedObjectName]
    ,id.[equality_columns] AS [EqualityColumns]
    ,id.[inequality_columns] AS [InEqualityColumns]
    ,id.[included_columns] AS [IncludedColumns]
    ,gs.[unique_compiles] AS [UniqueCompiles]
    ,gs.[user_seeks] AS [UserSeeks]
    ,gs.[user_scans] AS [UserScans]
    ,gs.[last_user_seek] AS [LastUserSeekTime]
    ,gs.[last_user_scan] AS [LastUserScanTime]
    ,gs.[avg_total_user_cost] AS [AvgTotalUserCost]  -- Average cost of the user queries that could be reduced by the index in the group.
    ,gs.[avg_user_impact] AS [AvgUserImpact]  -- The value means that the query cost would on average drop by this percentage if this missing index group was implemented.
    ,gs.[system_seeks] AS [SystemSeeks]
    ,gs.[system_scans] AS [SystemScans]
    ,gs.[last_system_seek] AS [LastSystemSeekTime]
    ,gs.[last_system_scan] AS [LastSystemScanTime]
    ,gs.[avg_total_system_cost] AS [AvgTotalSystemCost]
    ,gs.[avg_system_impact] AS [AvgSystemImpact]  -- Average percentage benefit that system queries could experience if this missing index group was implemented.
    ,gs.[user_seeks] * gs.[avg_total_user_cost] * (gs.[avg_user_impact] * 0.01) AS [IndexAdvantage]
    ,'CREATE INDEX [IX_' + OBJECT_NAME(id.[object_id], db.[database_id]) + '_' + REPLACE(REPLACE(REPLACE(ISNULL(id.[equality_columns], ''), ', ', '_'), '[', ''), ']', '') + CASE
        WHEN id.[equality_columns] IS NOT NULL
            AND id.[inequality_columns] IS NOT NULL
            THEN '_'
        ELSE ''
        END + REPLACE(REPLACE(REPLACE(ISNULL(id.[inequality_columns], ''), ', ', '_'), '[', ''), ']', '') + '_' + LEFT(CAST(NEWID() AS [nvarchar](64)), 5) + ']' + ' ON ' + id.[statement] + ' (' + ISNULL(id.[equality_columns], '') + CASE
        WHEN id.[equality_columns] IS NOT NULL
            AND id.[inequality_columns] IS NOT NULL
            THEN ','
        ELSE ''
        END + ISNULL(id.[inequality_columns], '') + ')' + ISNULL(' INCLUDE (' + id.[included_columns] + ')', '') AS [ProposedIndex]
    ,CAST(CURRENT_TIMESTAMP AS [smalldatetime]) AS [CollectionDate]
FROM [sys].[dm_db_missing_index_group_stats] gs WITH (NOLOCK)
INNER JOIN [sys].[dm_db_missing_index_groups] ig WITH (NOLOCK) ON gs.[group_handle] = ig.[index_group_handle]
INNER JOIN [sys].[dm_db_missing_index_details] id WITH (NOLOCK) ON ig.[index_handle] = id.[index_handle]
INNER JOIN [sys].[databases] db WITH (NOLOCK) ON db.[database_id] = id.[database_id]
WHERE  db.[database_id] = DB_ID()
--AND OBJECT_NAME(id.[object_id], db.[database_id]) = 'YourTableName'
ORDER BY ObjectName, [IndexAdvantage] DESC
OPTION (RECOMPILE);

Hope this helps in resolving index issues in your database environment.

Get list of table record count

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This SQL query will provide a list of tables in a database with the number of rows

select schema_name(tab.schema_id) + '.' + tab.name as [tablename],
       sum(part.rows) as [rowcount]
   from sys.tables as tab
        inner join sys.partitions as part
            on tab.object_id = part.object_id
where part.index_id IN (1, 0) -- 0 - table without PK, 1 table with PK
group by schema_name(tab.schema_id) + '.' + tab.name
order by sum(part.rows) desc

Each row represents each table. This will also include all the tables in the a database even the empty ones.

Get List of Table by size in Azure SQL Database

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Here is a handy sql script to get a list of tables by their size in Azure SQL Database

select schema_name(tab.schema_id) + '.' + tab.name as [tablename],

    cast(sum(spc.used_pages * 8)/1024.00 as numeric(36, 2)) as used_spacemb,

    cast(sum(spc.total_pages * 8)/1024.00 as numeric(36, 2)) as allocated_spacemb

from sys.tables tab

    inner join sys.indexes ind

        on tab.object_id = ind.object_id

    inner join sys.partitions part

        on ind.object_id = part.object_id and ind.index_id = part.index_id

    inner join sys.allocation_units spc

        on part.partition_id = spc.container_id

group by schema_name(tab.schema_id) + '.' + tab.name

order by sum(spc.used_pages) desc

The columns you will get from this script:

tablename

size_mb

allocated_spacemb