Extending INFORMIX-Universal Server: User-Defined Routines

Extending INFORMIX-Universal Server: User-Defined Routines
Chapter 4: Debugging User-Defined Routines

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Debugging a DataBlade Module

To debug your DataBlade module, use a debugger that can attach to the active server process and access the symbol tables of dynamically loaded shared object files. On Solaris, the debugger utility meets these criteria.

To attach to the server process, do the following:

Connect to the server from a client application, such as DB-Access.
Identify the server process that is executing the DataBlade module code.
Start the debugger on the server process.

The following sections describe these steps.

Connecting to the Server from a Client

To connect to Universal Server, choose a client tool that allows you to submit ad hoc queries. On Windows NT, you can use INFORMIX-SQL Editor. On UNIX, you can use DB-Access.

For example, from UNIX, execute the following command, where database is a database in which you registered the DataBlade module that you want to debug:

dbaccess database

Loading the DataBlade Module

Before you can attach to the server process with the debugger, you need to load the shared object file for your DataBlade modules into the server address space. With the shared object file loaded, you can set breakpoints on the entry points for the module and examine local storage provided by the module functions.

To load the DataBlade module into the server address space, execute one of its functions. One technique is to define a routine in the DataBlade module that you use to load the DataBlade module. The routine can be as simple as the following:

mi_integer mod_load_bld()
{
	return 0;
}

To prevent name conflicts, substitute the object prefix assigned to your DataBlade module in place of mod.

To load the DataBlade module shared object file, execute the following command in your client application:

select mod_load_bld()from informix.systables where tabid=1;

Identifying the Server Process

To find the CPU or EXT virtual process in which your DataBlade module is loaded, execute the onstat command, as follows:

onstat -g glo

Figure 4-2 shows the last section of the output of this onstat command.


Individual virtual processors:
 vp    pid       class       usercpu   syscpu    total   
 1     3544      cpu         3.75      0.96      4.71    
 2     3545      adm         0.05      0.03      0.08    
 3     3546      lio         0.04      0.07      0.11    
 4     3547      pio         0.05      0.03      0.08    
 5     3548      aio         0.04      0.04      0.08    
 6     3549      msc         0.39      0.19      0.58    
 7     3550      aio         0.09      0.10      0.19    
 8     3551      aio         0.03      0.07      0.10    
 9     3552      aio         0.02      0.07      0.09    
 10    3553      aio         0.04      0.04      0.08    
 11    3554      aio         0.03      0.05      0.08    
                 tot         4.53      1.65      6.18