What Happens When You Hit the SQL Server Express 4Gb/10Gb Limit

What happens when you hit the SQL Server Express 4GB / 10GB limit?

As I understand it you will start to see exception messages appear within your event log, such as:

Could not allocate space for object 'dbo.[table]' in database '[database]' because the
'PRIMARY' filegroup is full. Create disk space by deleting unneeded files,
dropping objects in the filegroup.

If you can then reduce the size of the database, you can then continue to add etc as before. Tools should carry on working regardless of the database size.

Hope this helps!

SQL Server Express 4GB Limit

The 4GB limit is on each database.

Can you bypass the size limit of SQL Server Express by stacking databases?

I realize this doesn't address your question exactly, but in my experience it's always more expensive to hack up a nasty kludge like this--think dollars per hour for development and maintenance, plus the time you've lost developing features that really matter--than to buy the right tools in the first place.

EDITED: And why Standard edition instead of Workgroup? If Express satisfies your feature requirements, so will Workgroup, and it's ~$3500 cheaper than Standard. Still, either is a bargain compared to saddling yourself as described above -- doubly so if you can license by CAL instead of by Processor. :-)

4GB limitation on these embedded/express DBs good enough? what's next if limitation is reached?

There is really no way to answer this question, other than to advise upgrading to a "real" database. That being said, if a single-user database is reaching 4GB without holding large blobs, then you're doing something out of the ordinary.


Edit

One thing that many people neglect to consider is the RAM and CPU restriction on the Express edition for SQL Server. While 2008 and prior have database size limits of 4GB (10GB for 2008 R2, as pointed out in the comments for this question), you're far more likely to be negatively impacted by the 1GB RAM and single CPU limitations, especially with data sets that large.


Archiving is (almost) never a simple solution, since that usually involves either breaking existing relationships or duplicating data. For example, consider I have a database of Customers and Orders.

                Order
Customer ----------
--------- OrderID
CustomerID <--- CustomerID
... ...

The natural choice here is to create a foreign hey between the two CustomerID columns, making it non-nullable in the Order table. But what happens when I want to archive the orders? Either I have to break the relationship in the archive database (allowing it to link to a CustomerID that doesn't exist in the archive database) or I have to duplicate the data (archive the linked Customer record, while still keeping it around in the live database). Neither option is particularly desirable from a maintenance perspective.

Is the SQL Server Express memory and CPU limit per instance?

If I have 8GB of RAM in a server and I run 4 instances of SQL Express,
will the total memory limit used by SQL Server be 1GB or 4GB?

Each instance can use up to 1GB of memory for the buffer pool. Each instance can use a bit more than 1GB in total because not all memory allocations go via the buffer pool. In your case, the maximum memory used by the four instances for buffer pool would be 4GB.

BOL extract

To confirm, I started two instances of the SQL Server 2008 Express Database Engine, performed some activity to load up the (separate) buffer pools, and then looked at per-instance memory utilization in a number of ways, for example using DBCC MEMORYSTATUS or by counting the number of buffers using the sys.dm_os_buffer_descriptors DMV.

The physical memory usage numbers below were obtained using simultaneous queries against the system DMV sys.dm_os_process_memory on each instance of the database engine:

SELECT 
dopm.physical_memory_in_use_kb
FROM sys.dm_os_process_memory AS dopm;

Output:

╔═══════════╦═══════════╗
║ Instance1 ║ Instance2 ║
╠═══════════╬═══════════╣
║ 1102872 ║ 1059812 ║
╚═══════════╩═══════════╝

Each of these is slightly in excess of 1GB as total physical memory usage includes more than just buffer pool usage, as mentioned previously.

Would it be advisable to run multiple instances like this to enable
each database to make better use of resources (assuming that the
server has plenty of resources)?

If the databases on each instance are functionally independent then it is at least workable to run multiple instances of Express in this way, though you would need to pay careful attention to configuration and maintenance may be made more complex.

You might be be better served using another edition, such as the fully-featured (and very cheap) Developer Edition, if the intended usage matches the licence). You would need to say much more about the circumstances to get a clear answer on this point.

How is the memory used greater than the SQL Server Express limitation?

According to this link

SQL Server 2014 Editions

Express Edition

Express edition is a free version of SQL Server that is limited in its
functionality and size. Is limited to one socket with a maximum of
four cores for CPU power, 1 GB of memory, and a database size. No
larger than 10 GB. If using the reporting features, The maximum memory
is raised to 4 GB.
Express edition is compatible with all other
editions of SQL Server. Express edition has a few different versions
that can be downloaded

And according to Features Supported by the Editions of SQL Server 2014, you will find that 4GB RAM limit is at Maximum memory utilized (per instance of Reporting Services) for Express with Advanced Services

Is SQL Server Express' 4GB limit affected by FILESTREAM enabled columns?

SQL Server Express supports
FILESTREAM. The 4-GB database size
limit does not include the FILESTREAM
data container.

From: http://msdn.microsoft.com/en-us/library/bb895334.aspx



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