Rowcount for SQL Server and Sybase

We recommend that you allow AQT to manage the rowcount (see below), as there are a number of considerations for using it from within AQT.

For Sybase and SQL Server, you can use the set rowcount n statement to restrict queries to return (a maximum of) n rows. Using this clause can give significant performance benefits when dealing with large tables, however

• When you use set rowcount n, this rowcount will stay in effect for the remainder of your AQT session (for this database) (for Sybase, see note below). It will only change when you use another set rowcount statement.
• AQT itself runs a number of queries to populate the Database Explorer. It also runs queries to get column information for your tables in the GUI Query builder and other places. If you have set the rowcount, the rowcount will affect these internal AQT queries also. This can lead to "unexpected results", such as the Database Explorer not showing you all information, and the GUI Query Builder or Run SQL window not showing you all the columns in your tables.

Note for Sybase

The set rowcount will only stay in effect for the duration of your session if your ODBC Driver has been configured to use a Select Method of 1-Direct. We recommend using this setting in conjunction the the rowcount option (see next section).

Allow AQT to manage the ROWCOUNT

AQT can automatically set the rowcount for you. To enable this feature, go Options > Technical Parameters then check For Sybase and SQL Server, use SET ROWCOUNT. When this feature is enabled, AQT will periodically run a set rowcount n statement, where n is:

• for normal queries, the value specified in Options > Display Limits > Max Rows Displayed
• for internal AQT queries, 0 (which means no limit)
• for Table contents (first 30 rows) (this is a display in the Database Explorer), 30

AQT doesn't set the rowcount every time you run a query; instead it will do that whenever the rows-to-be-displayed are changed. This will happen, for instance, when you go from running queries to using the Database Explorer. If you manually set the rowcount, it will stay into effect for a while, but will at some point be reset by AQT

Get More Rows feature

If the Get More Rows feature is used, the Rowcount will be set to 0 (no limit).