If Crazy = Genius, I’m rebuilding one partition at a time!

We have had an index job that has been failing for a while.  This is one of those things you really don’t want to clean up because no one is complaining, but you know you should.  I had heard that I could rebuild one partition at a time, but where to start?  Today, I worked my way through it, so here it is so that you can do it too.

First you need to find the biggest indexes, there is a good chance those are the ones that live on partitions. I am removing Primary Keys.


SELECT i.[name] AS IndexName
,SUM(ps.[used_page_count]) * 8 AS IndexSizeKB
FROM sys.dm_db_partition_stats AS ps
INNER JOIN sys.indexes AS i ON ps.[object_id] = i.[object_id]
AND ps.[index_id] = i.[index_id]
WHERE i.name NOT LIKE 'PK%'
GROUP BY i.[name]
ORDER BY IndexSizeKB DESC

The top ones are most likely the ones you want to focus on.  Next, we need to track down the partition function.


SELECT * FROM sys.partition_functions

Next we are going to figure out which partition we want to rebuild.


SELECT sprv.value AS [Value], sprv.boundary_id AS [ID]
FROM sys.partition_functions AS spf
INNER JOIN sys.partition_range_values sprv ON sprv.function_id = spf.function_id
WHERE (spf.name = N'NameOfFunctionFromPartitionFunctions')
ORDER BY [ID] ASC

Pick the number of the partition you want to rebuild.

Next use your index name from earlier.  You will also need the table name and the partition number.


ALTER INDEX [IndexName]
ON [dbo].[TableName]
REBUILD PARTITION = 3

This will rebuild just the partition that you requested.

Strip it down and remove the bad query plan

Today I got to play with some really bad queries. But the queries weren’t necessarily bad, it was more they had bad plans. I thought I had already blogged about it and tried to find my code. Alas, it wasn’t there so let’s strip it down on how you would remove a bad query plan. I am leaving out the trouble shooting part of how to determine if it is a bad plan because so much of it “depends”.
First you have to find the bad query plan.  Get a unique line from your query and paste it in the query below.

USE master;
GO

SELECT usecounts, cacheobjtype, objtype, text, plan_handle
FROM sys.dm_exec_cached_plans
CROSS APPLY sys.dm_exec_sql_text(plan_handle)
WHERE usecounts > 1
AND TEXT LIKE '%Unique part of query%' --put the unique part of the query here.
ORDER BY usecounts DESC;

Now, copy the plan handle and paste it over the plan handle that I have listed here:

SELECT * FROM sys.dm_exec_query_plan (0x060001004DE4D526F0BEA28F05000);

If you click on the query_plan link, you can see what the plan looks like.  After you have reviewed it and determined the plan is bad then you can paste your plan handle over the one below to remove it from the proc cache.

DBCC FREEPROCCACHE (0x060001004DE4D526F0BEA28F05000)

There you have it. Best of luck with your bad plans.

For one good, naughty little girl found a diamond…Object Explorer Details

It’s Christmas time again and time to listen to my FAVORITE Christmas song called Joel The Lump of Coal.
Just before Thanksgiving we had our SQLSaturday\Big Mountain Data event and I spoke! This is my third time speaking at this event and every year I regret speaking and feel like everyone would have been better in another session, every year that is until this one! I loved my session and I will actually be submitting it to PASS Summit this year. Keep your fingers crossed with me. It was on SQL Server Management Studio Tips and Tricks.

One of the tips that I was super surprised that many people didn’t know is the Object Explorer Details. It allows you to delete multiple objects at once, script out multiple objects at once and just do some really cool stuff. How do I access this magic you are asking? When in management studio, click on View>>Object Explorer Details.

 

ObjectExplorerDetails

Now you can have a diamond that will help you too!

And you said you are unconsolable…clean up before you leave

Greetings,

I am approaching my last day at my current job. I love it here and will be really sad to leave, but have an awesome opportunity to grow my knowledge and career with a company on my “want to work for” list.

There are a lot of things to take care of before I leave.  I have been updating documentation (with meme’s) so that it is useful and fun.  I am trying to wrap up all my tickets and outstanding items and last night I woke up and realized, I was the owner of some databases.  This is how I fixed it:

I launched a query window on my Central Management Server to save time, but you can run this on one server at a time if you want.  I used the syntax from sp_helpdb to find out what I wanted to query:

select name, isnull(suser_sname(sid),'~~UNKNOWN~~') AS Owner, convert(nvarchar(11), crdate),dbid, cmptlevel
from master.dbo.sysdatabases
WHERE suser_sname(sid) = 'domain\MyUserName'

Some of the applications in my environment run under a special user and I didn’t want to interfere with those, I just wanted to fix the ones that use me.  Then I borrowed some code from Brent Ozar:

SELECT 'ALTER AUTHORIZATION ON DATABASE:: ['+ name +'] to sa;'
FROM master.dbo.sysdatabases
WHERE suser_sname(sid) = 'domain\MyUserName'

Here’s one I run on the CMS to find any SQL Agent Jobs that I own across my enterprise and then I can run the update scripts that are generated on the individual servers.


SELECT 'EXEC MSDB.dbo.sp_update_job ' + char(13) +
'@job_name = ' + char(39) + [Name] + char(39) + ',' + char(13) +
'@owner_login_name = ' + char(39) + 'sa' + char(39) + char(13) + char(13)+';'
FROM msdb.dbo.sysjobs
WHERE SUSER_SNAME(owner_sid) = 'domain\MyUserName'

What you gonna do? Memory, I’m coming for you!

Today I needed to quickly check 68 SQL Server Instances Min and Max memory settings. I didn’t have time to go through each one and I know I will need to do this again in the future. Thank goodness I have my Central Management Server configured with all those servers. I was able to connect to my main CMS server, and run this simple query that will tell me all my servers min and max memory setting:

SELECT ServerName, [Max], [Min]
FROM
(SELECT @@ServerName AS ServerName, LEFT(name,3) AS Memory, value
FROM sys.configurations
WHERE name like '%server memory%') AS SourceTable
PIVOT
(
MAX(Value)
FOR Memory IN ([Max], [Min])
) AS PivotTable;

Then, I also used this code from my last post but added a server name to it so I could see what memory was available on each server.

SELECT @@Servername,physical_memory_kb * 9.5367431640625E-7
FROM sys.dm_os_sys_info

Hey what’s that thing I can’t remember…determining RAM amounts

I frequently am trying to determine how much RAM I can give to SQL Server without starving the OS.  Since my servers usually only have SQL Server on them and no other applications, I can give them everything except 2-4gb for the OS. Depending on what that server is doing and if it still looks hungry, I will give the OS more or SQL Server more.  The question is, if I can’t remote on to the server, how do I know how much RAM is on the server? After much searching and calculating, I have come up with a T-SQL query to help. It will tell you how much RAM is on your instance.

SELECT physical_memory_kb * 9.5367431640625E-7
FROM sys.dm_os_sys_info

 

It uses the system views which I haven’t begun to scratch the surface of their awesomeness, but plan to learn more.

We could be immortals, just not for long when using a duplicate delete!

Sometimes awesome things just happen.  Today Rob Farley (@Rob_Farley) was helping me with a previous post about my dates table and just as a side note he said, “Oh, let me show you something else cool.” It was really cool and so I asked if I could add it to my blog since I never know when this problem will strike.

I have a table about Super Heroes and their cape colors.  I made a mistake and put Batman in there twice.  But since there is no primary key, how do I tell it which one to delete?  Hero Table

Since they are exactly the same, I can let SQL sort it out. This uses both a CTE (I hadn’t ever used it without some kind of join before today) and OVER which I am learning about.  So cool!

WITH SuperHeroDuplicates 
AS 
(SELECT *, ROW_NUMBER() over (partition by HeroName,CapeColor order by HeroName,CapeColor) as rownum 
FROM dbo.HeroCapeColor) 
DELETE 
FROM SuperHeroDuplicates 
where rownum > 1;

Thanks Rob!

—————UPDATE—————

Kenneth Fisher (@sqlstudent144) also wrote a blog post about another way you can accomplish this task if you only have a few of them to delete.

He has been a super big help to me.  He taught me how to display my code better in my blog so it is easier to read and copy. He also encourages me, builds my confidence and even included a link to one of my posts in an article. It made me feel special and like what I have to say matters to other people.  I love how he comments on my posts and gives me ideas on how to make them better. I feel so lucky to be a part of such a great community of people that are so thoughtful, selfless and giving.  Thanks Kenneth for being such a great example to me!