Compute model: results

A result describes an instance of a computation, either to be performed, in progress, or completed. Results are stored in the result table of the BOINC DB. The attributes of a result include:

• The name of the result (unique across all results in the project).
• The name of the associated workunit.
• An XML document listing the names of its output files; see below.
• An XML document giving the sizes and checksums of its output files (this is filled in after the result is completed).
• The stderr output of the result.
• The host that computed the result.
• The times when the result was dispatched and received.
• The exit status of the application.
• The reported CPU time.
• Its state. Values include:
  • Inactive (not ready to dispatch)
  • Unsent (ready to dispatch, but not dispatched)
  • In progress (dispatched, not done)
  • Done successfully
  • Timed out
  • Done with error

<file_info>...</file_info>
[ ... ]
<result>
    <name>foobar</name>
    <wu_name>blah</wu_name>
    <file_ref>...</file_ref>
    [ ... ]
</result>

• The <name> element is the result name.
• The <wu_name> element is the workunit name.
• Each <file_ref> element is an association to an output file, described by a corresponding <file_info> element.

The XML document describing the sizes and checksums of the output files is just a list of <file_info> elements, with the nbytes and md5_cksum fields present. The project back end must parse this field to find the locations and checksums of output files.

Several results may be associated with a single workunit. Results may be generated in either of two ways (selected as part of the application):

• Advance generation of results. One or more result records are stored in the database when the workunit is produced. The scheduling server dispatches each result to a single participant host. When all result records have been dispatched, participants hosts are "turned away".
• On-demand generation of results. The application specifies a "result template", which has place-holder tokens for the output filenames. The scheduling server, in response to a host request, generates a new result record and sends the result template. The host generates unique output filenames, and returns them along when it the computation is done.