For queries that return a large number of objects, you can configure the row fetch size in the query to improve performance by reducing the number of database trips required to satisfy the selection criteria. 

For general information on the importance of fetch size, check the JDBC fetch size - commonly forgotten setting external article.

Each JDBC driver sets their own default fetch size and this value may need to be adjusted until an optimal performance is reached. Incorrectly setting a fetch size too large or too small can decrease performance.

DbVisualizer 10.0.21 and later

In DbVisualizer 10.0.21 and later versions, open the connection Properties tab and select the database type category (e.g. Oracle, MySQL, H2, etc). In the right pane there is the JDBC Fetch Size settings, set it to for example 250, click Apply and re-connect.

DbVisualizer 10.0.20 and earlier

Setting fetch size in 10.0.20 and older versions requires a different step. Add the following driver property in the connection Properties tab and Driver Properties:

java.sql.statement.setFetchSize = 250

Click Apply and then re-connect to verify.