SELECT.SQL

Must contain (or reference) a connection string, in one of the following ways:

• Name of a Data Source
  This data source must contain a connection string. This can be defined using the SET command.
• Complete Connection string
  Provider=SQLOLEDB;server=localhost;UID=perfion;PWD=mypw;DATABASE=NAV2018
• Lookup from a named Connection defined in Perfion
  Go to Administration -> Remote Connections to see defined connections
  @REMOTECONNECTIONNAME=Dynamics NAV 2018 Production
• Reference to current Perfion database
  Just type a '.' (period) in the From field

The SQL script code used to query the database.

The script-code can also be defined dynamically by including parameter references. The parameter values are evaluated in the same way as the script method { 9.16 Method: FillTemplate ( … ) }.
Example 1:
SELECT * FROM Customers WHERE Name='{=$CustomerName}'
Example 2:
If you want to create the entire script dynamically simple just include a reference to the parameter containing the script such as:
{=$MyScript}

If unspecified the default value is 30 secs.
Recommendation: Do not set this value unless you really need to.

Setting this value to e.g. 10 does not mean that the query will time out after 10 secs if it is not completed. It may actually run for much longer. Only if the client has not received any feedback within the timeout period will it time-out.
For example, if the query simply returns a large result-set (that takes long to transfer) it will often be transferred in blocks, and as long as the query detects as being alive it will continue running without timing out.
This means that queries that time out will most likely be due to long response times from finding the desired data, e.g. due to complex criteria, or missing indexes on large amounts of data.