How much free hard disk space is required?

Last modified: August 8, 2024

When working with large databases in Data Compare for SQL Server, you may encounter a message that you have run out of hard disk space.

For the comparison engine to work effectively, data from selected tables in the source and target databases needs to be loaded onto the computer’s temporary cache. Additionally, a separate cache is required for the script generation engine. It is necessary to have 2-4 times more free space on the local computer than the size of the database to accommodate these caching needs.

Similar databases

If your databases are rather similar, it is recommended to disable the Identical records in Display Options while configuring the data comparison. This way the same data from the two databases will not be saved during the comparison, thereby taking up less disk space.

Different databases

In case you are comparing two different databases, you might consider performing the comparison in parts.

In the Mapping window of the New Data Comparison wizard, you will be able to clear some of the selected objects. This way, less disk space will be required to process the comparison.

To split the tables vertically, select the columns to be compared either by double-clicking the table or by clicking … at the end of a row. A dialog box will be displayed with checkboxes to include or exclude the columns.

In the Column Mapping window indicate the comparison key column. The difference between the columns will be ignored during comparison if the checkboxes in the Compare column are clear. The column will be excluded from the UPDATE statement and will not be synchronized if the checkboxes in the Sync column are clear.

Temporary directory

If you are running out of space you can change the location that dbForge Data Compare uses for its temporary directory:

1. On the main toolbar, click Tools and select Options.
2. Go to Data Comparison > General.
3. Select Custom folder.
4. Choose the directory for the cache folder.
5. Click OK.

To improve the performance of you data comparisons, refer to Improve the comparison performance.

To learn how to organize the comparison and synchronization process for tables containing 1 million records, watch this video.