Tuesday, November 16, 2010

What "pureXMLness" do you have...?

The longer and the more intense the work with XML in a database system of your choice (this is DB2, right?), the more often comes the question: What pureXMLness do I have?

To what degree am I using pureXML? How much XML does my system have? Is our system mostly relational or XML (remember DB2 is hybrid)? How do we measure how XML is used? Give me some numbers for our CIO, it's Q4.

To give a scientifically-proven, valuable answer, something that stands the test of time and holds up to all questions from the business side, I came up with THE pureXMLness factor. How is it computed? The following is the simple query that needs to be run against the DB2 database in question. It's an XQuery of course.

let $i:=db2-fn:sqlquery("select xmlcast(count(*) as xml) from sysibm.sysindexxmlpatterns"),
$j:=db2-fn:sqlquery("select xmlcast(count(*) as xml) from sysibm.syscolumns where coltype='XML'"),
$k:=db2-fn:sqlquery("select xmlcast(count(*) as xml) from sysibm.sysxmlstrings"),
$l:=db2-fn:sqlquery("select xmlcast(count(*) as xml) from sysibm.sysxmlpaths"),
$m:=db2-fn:sqlquery("select xmlcast(count(*) as xml) from sysibm.sysxsrobjects"),
$n:=db2-fn:sqlquery("select xmlcast(cast (avg(xda_hit_ratio_percent) as float) as xml) from sysibmadm.bp_hitratio")
return <pureXMLness>{avg((($i+$j+$m) div 20,($k+$l) div 300,$n))}</pureXMLness>;

Let me know what pureXMLness you have or if you think you have a better formula...