more cleanup

Author: hschellman

_episodes/07-grid-job-submission.md

@@ -368,6 +368,29 @@ Since the workflow was causing a systemwide disruption we immediately held all o
 
 DUNE has also created a a global glideinWMS pool similar to the CMS Global Pool that is intended to serve as a single point through which multiple job submission systems (e.g. HTCondor schedulers at sites outside of Fermilab) can have access to the same resources. Jobs using the global pool still run in the exactly the same way as those that don't. We plan to move more and more work over to the global pool in 2023 and priority access to the FermiGrid quota will eventually be given to jobs submitted to the global pool. To switch to the global pool with jobsub, it's simply a matter of adding `--global-pool dune` as an option to your submission command. The only practical difference is that your jobs will come back with IDs of the form NNNNNNN.N@dunegpschedd0X.fnal.gov instead of NNNNNNN.N@jobsub0X.fnal.gov. Again, everything else is identical, so feel free to test it out.
 
+
+## Making subsets of metacat datasets
+
+Running across very large number of files puts you at risk of system issues.  It is often much nicer to run over several smaller subsets.
+Many official metacat definitions are large data collections defined only by their properties and not really suitable for a single job.
+
+You can do the following.  Submit your jobs using the skip and limit commands.  Here 'namespace:official_dataset' describes the official dataset. 
+
+See [the basics tutorial](https://dune.github.io/computing-basics/03-data-management/index.html#official-datasets-) for information on official datasets. 
+
+~~~
+query="files from namespace:official_dataset skip 0 limit 1000"
+query="files from namespace:official_dataset skip 1000 limit 1000"
+query="files from namespace:official_dataset skip 2000 limit 1000"
+....
+~~~
+{: ..language-bash}
+
+
+
+
+<!-- 
+
 ## Making subsets of sam definitions
 
 Running across very large number of files puts you at risk of system issues.  It is often much nicer to run over several smaller subsets.
@@ -399,7 +422,7 @@ samweb create-definition $USER-mydataset-part4 “defname:mydataset limit 2000 w
 
 
 
-More on samweb can be found [here]({{ site.baseurl }}/sam-by-schellman).
+More on samweb can be found [here]({{ site.baseurl }}/sam-by-schellman). -->
 
 ## Verify Your Learning: