Disk space requirements for data comparison

When comparing large databases in dbForge Studio for SQL Server, you may encounter a message that you have run out of hard disk space.

Optimize data comparison performance

For the comparison engine to function efficiently, data from selected tables in both the source and target databases must be loaded into the computer temporary cache. A separate cache is also required for the script generation engine. To support these caching processes, ensure that your local computer has 2 to 4 times the database size available as free disk space.

Optimize data comparison performance for similar databases

When you compare similar databases, clear the Identical records checkbox under Display Options on the Options page of the New Data Comparison wizard. This prevents duplicate data from the source and target databases from being stored during the comparison process.

Optimize data comparison performance for different databases

When you compare two different databases, you can use the following methods to optimize data comparison performance:

  • On the Mapping page, use the checkboxes to exclude specific objects from the comparison.

Mapping

  • To compare specific columns, double-click the table or click the ellipsis (…) to open the settings dialog. From there, you can choose which columns to include or exclude in the comparison.

Mapping Columns

  • In the Column Mapping dialog, set the comparison key column. If the checkboxes in the Compare column are cleared, the difference between the columns will be ignored during the comparison.

  • To exclude columns from the UPDATE statement, clear the checkboxes for the corresponding columns in the Sync column.

Change the temporary directory

If you’re running low on disk space, you can change the location of the temporary directory used by dbForge Studio for SQL Server.

To change the temporary directory:

1. In the top menu, select Tools > Options.

2. Go to Data Comparison > General.

3. Select Custom Folder.

4. Specify the directory for the cache folder.

5. Click OK to save the changes.