• A Sql Query test can be both descriptor-based and non-descriptor based. For example, the following query returns a descriptor-based ouput. The query retrieves from a table named metatest the number of records that carry the same value in a field named info.

  select substr(info, 2), count(*) from metatest where info<>'+' group by info

  For a descriptor-based test, the first value of the results of the query must be a string. The other results should be integer or double values. If the first value of a query's result is not a string, the test is not descriptor-based and only the first row of the result set will be used.

  A Sql query can return multiple outputs. For example:

  select read_rate, write_rate from disktest where msmt_time=(select max(msmt_time) from disktest) and info='+/'

• Typically, large or complex processing that might require the execution of several SQL statements is moved into stored procedures. You might choose a stored procedure over a SQL query, if:

  • you want to execute multiple SQL queries, simultaneously
  • you not only want to query metrics from the database, but also intend to perform mathematical computations on the result set and display the net output in the eG monitor interface.

  Just like a sql query, a stored procedure can also be descriptor-based or non-descriptor-based. Given below is a sample 'info-based' stored procedure that will execute on an MS SQL server database; this stored procedure will take a HOST IP from the user, calculate the average CPU utilization of every processor on the given HOST, and report the computations to the eG manager.

  CREATE PROCEDURE avgCpuUtil @host varchar(30)

  as

  SELECT 'Processor_'+info, avg(cpu_util) Avg_cpu_util

  FROM systemtest

  WHERE trgt_host=@host

  GROUP BY info

  ORDER BY info

  Typically, the syntax for the command to be issued to execute a stored procedure is: StoredProcedurename. In our example however, the stored procedure accepts a Host IP from the user and retrieves the CPU usage statistics that correspond to the given IP address. To execute a stored procedure that supports input parameters/arguments (such as the one in our example), you should use the command: StoredProcedureName <<Argument>>. In the case of our example therefore, the command would be: avgCpuUtil <<TargetHost>>, where avgCpuUtil is the name of the stored procedure, and TargetHost is the name of the parameter that the procedure supports.

  Note:

  The arguments/parameters that are passed to a stored proocedure are case-sensitive, and should always be enclosed within angular brackets (<< >>).

  A stored procedure that is executed on an MS SQL database can take any number of arguments, and returns a result set. A result set with multiple columns, where the first column contains character values, is said to be 'info-based'. On the other hand, if a result set consists of multiple columns, and all columns support only numeric values, then such a result set is said to be a 'non-info-based'. An info based test will typically return multiple rows of output, with each row representing the metrics for a particular info. A non-info based test, on the contrary, will always have a single row of output.

  In case of a non-info-based test therefore:

  The total number of measures for the test = The total number of columns returned by the query

  In case of an info-based test:

  The total number of measures for the test = (The total number of columns in the query output) - 1

  The first column of an info-based result set represents the name of the info.

  When a stored procedure returns a result set comprising of multiple columns, all of which contain only numeric values, then this is a 'non-info-based' stored procedure. For example, assume that you need to create a stored procedure that computes the average CPU utilization of a host across processors (and not per processor). Such a stored procedure is 'non-info-based', and can be coded as follows:

  CREATE PROCEDURE avgCpuUtil @host varchar(30)

  as

  SELECT avg(cpu_util) Avg_cpu_util

  FROM systemtest

  WHERE trgt_host=@host

  To create a stored procedure on an Oracle database, you will have to create a package of type 'CURSOR', and then write a function that returns a cursor of that type. For instance, to write a stored procedure that returns the average CPU usage of every processor supported by a given host, you will first have to create a package of type CURSOR, as indicated below:

  CREATE OR REPLACE PACKAGE cpuUtilAvg_pack

  AS

  TYPE cpuUtilAvg_cursor IS REF CURSOR;

  END cpuUtilAvg_pack;

  As you can see, for the purpose of our example, a package named cpuUtilAvg_pack has been created as type, cpuUtilAvg_cursor.

  Next, you will have to write a function that returns a cursor of that type, as indicated below:

  CREATE OR REPLACE PROCEDURE cpuUtilAvg_procedure (host IN systemtest.trgt_host%TYPE, resultCursor OUT cpuUtilAvg_pack.cpuUtilAvg_cursor)

  AS

  BEGIN

  OPEN resultCursor

  FOR

  SELECT decode(info,'+','DEFAULT',info) as info, avg(cpu_util) from

  systemtest WHERE trgt_host = host GROUP BY info ORDER BY info;

  END cpuUtilAvg_procedure;

• After providing the SQL query/ command for executing the stored procedure in the Query text box, click on the Generate button to integrate the test's implementation into the eG system.

The Back button enables the administrator to go back to the previous screen.