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.

They’ll never take my body from your side, Love don’t die from partitioning…

New dress for Christmas

New dress for Christmas

So this week there was this small fire around running out of partitions.  Because I had to learn how all of it works really fast, I need to write it down before I forget.  I was getting a range doesn’t exist error so here is what I did:

I already had my file groups created.  If you don’t do that before you move on.

Find what partition schemes and functions you have in your database:

SELECT * FROM sys.partition_schemes

SELECT * FROM sys.partition_functions

(Hint: the fanout is the last range so that can help you identify which one is failing.)

Next, see what your current ranges look like:

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'PartitionFunctionName')
ORDER BY [ID] ASC

Now we are going to split out our partitions one at a time.  Even if you need to add 5 or more ranges, this is an easy step to do one at a time.  Also, you can only split a range into to pieces at a time, so just run the whole query for each range you want to add.

ALTER PARTITION SCHEME [PartitionScheme] NEXT USED [YourFileGroup]

ALTER PARTITION FUNCTION [PartitionFunction]() SPLIT RANGE (N'NewRange')

This should get you back on track.

Happy Trails!