Database and Log Sizing

Since the database is a dynamic environment, allow plenty of space for the models you create. Tests have shown that models generate between 10 KB and 20 KB of data per entity during initial save times. Log overhead per object is approximately 15 KB to 21 KB per entity. Allocate 50 to 65 percent of the database size to the log to avoid running out of room in the log for a typical model save.

An average mart can range in size between 200 MB and 1 Gig. Size the transaction log accordingly. A 50 MB data device can store several large models (about 2,500 entities and 100,000 total objects), but keep in mind that the database becomes more flexible and has less storage space issues when the data device is large.

The following table shows the recommended database size and log size for small, medium, and large marts:

Database Size	Database Device	Transaction Log Device
Small	200 MB	100 MB
Medium	500 MB	200 MB
Large	1 GB	400 MB

How to Maintain an Efficient Database

To maintain an efficient database, perform the following maintenance tasks:

• Run UPDATE STATISTICS and execute sp_recompile frequently on every table in the database. This keeps the statistics up-to-date for the indexes, resulting in better overall performance.
• Periodically recreate the clustered indexes in the database to reduce fragmentation. Be sure to back up the database and transaction log daily.
• Run DBCC CheckDB(), DBCC CheckCatalog(), and DBCC CheckAlloc() or DBCC NewAlloc() on the database nightly, to check for corruption and inconsistencies in the database. Check the output of these queries and look for keywords like corrupt. Any problems detected by these commands are sent to the query output, so save the files and scan them regularly.

The following table shows maintenance tasks and the recommended frequency for performing these tasks:

Maintenance Task	Recommended Frequency	Reason
DBCC Checkdb	Nightly	Check for corruption in databases.
DBCC NewAlloc	Weekly	Check for allocation corruption (Microsoft SQL Server only).
DBCC CheckAlloc	Weekly	Check for allocation corruption (Microsoft SQL Server only).
DBCC CheckCatalog	Weekly	Check for system table inconsistencies.
UPDATE STATISTICS	Nightly	Recreates the statistics page for each index.
EXEC sp_recompile	Nightly	Tells which stored procedures have changed.
Backup Database	Weekly	Full backup of database should be done at least weekly, if not nightly.
Backup Transaction Log	Daily	Backing up the transaction log daily saves all committed transactions and clears the log.