There are a few tables that can become really big in Dynamics NAV. It is expected for our Ledger Entries to grow as time passes, but, quite often I hear people saying about Change Log Entries table is growing out of proportion.
And, not everybody knows, that you can actually delete Change Log Entries to recover the lost space (Here, I am making assumption, that you do not have any modifications which would be built on top of the change log, to track the document changes, etc. Otherwise, you might not want to delete the Change Log!). There is even default report in Dynamics NAV to do just that – to delete Change Log Entries.
Administration > IT Administration > Data Deletion > Delete Change Log Entries…
The biggest advantage of this report is – that you can apply filters and delete only the entries that you want (either by date, or by table number). The disadvantage – it is deleting one Change Log Entry at a time. Therefore, if you have a lot of data in the table (and here we are talking Gigabytes), deleting the table might be resource and time consuming.
In this case (if delete change log entries with default report is taking ages), you might want to have a look at the possibility of using TRUNCATE TABLE function for Change Log Entry table from SQL Server Management Studio.