I have a database running under the simple recovery model. The database contains three narrow tables. For two of the tables, data is populated by insert statements. The third table is initially populated by an insert statement, and then the record is completed by an update statement. On average, the database sees 4000 inserts per minute and 2000 updates per minute. It's active, but not exceedingly so.
The database has 10GB of space allocated to the transaction log. According to the Disk Usage report / DBCC SQLPERF(LOGSPACE), the log space usage is steadily increasing. Yesterday, usage was at 33% and growing. Overnight, it has increased to 48% and continues to rise. DBCC OPENTRAN returns no open transactions on the database. Nothing stands out to me when I run sp_whoisactive.
Another database on the same server, with similar activity, a slightly larger transaction log size, and simple recovery model, is cycling between 0% and 10% usage, which is the behavior that I am used to seeing for the first database. What other steps can I take to determine the cause of this behavior and ensure that the transaction log will not fill up entirely?
*Given that I cannot justify the growth in log usage, please assume that "allocating more space to the transaction log" is not a viable solution.