In migration process from SharePoint 2007 to SharePoint 2013 content databases are growing enormously on size. I have encountered growth about 70% (And that is really big problem, when you have limited resources – for example the 10GB limit of Microsoft SQL Server 2008 Free Edition).

Because of differences between SharePoint 2007 and 2010 table design, the action UpgradeAllDocStreamsAndAllDocVersions is triggered in migration process. This is supposed to move binary content of files from table AllDocVersions to AllDocStreams and then will drop the column Content from AllDocVersions table.

But still, the size of database will not change. You need to clean tables and shrink database to gain back the reserved data with this process:

1. Backup Content database (really 🙂 )

2. Run following commands on content DB:

DBCC CLEANTABLE ('WSS_Content_YOUR_CONTENT_DB', 'DocStreams')
DBCC CLEANTABLE ('WSS_Content_YOUR_CONTENT_DB', 'AllDocVersions')

3. Shrink content databse (via Management Studio or with this query)

DBCC SHRINKDATABASE ('WSS_Content_YOUR_CONTENT_DB')

4. Check size of your Content DB