[Koha-devel] Contents of more_subfields_xml

[Paul]

I have recently done some "house-keeping" looking for consistency in the 
MySQL db (5.5.24 in 3.8.5), and while some tidying up has been 
straight-forward I am having problems with more_subfields_xml in items.

Only about 90% of 'items' have any xml attached to them. Within those that 
do have an xml entry, only the following subfields appear:

<subfield code="f">   entries < 1%
<subfield code="i">   entries ~ 20%
<subfield code="k">   entries ~ 1.5%
<subfield code="x">   entries ~ 95%

and they are mostly filled with random values from 2xx, 6xx and 9xx, 
although the 'code="x"' values appear to be valid from the 952$x. code="f" 
contains values from 952$v; code="i" has some 952$i valid entries but 
mostly 650$a,x,y,z; code="k" has random authors, titles, etc - and I can't 
find where we might use 952$k in our frameworks.

Can someone please tell me how these blobs are mapped/created and used by 
koha?  Our odd-ball results/entries don't appear to be having much, if any, 
influence on cataloguing and search functions.

Also, if there is any way to "rebuild" more_subfields_xml -- it's way too 
big a problem to manage manually.

Many thanks - Paul

P.S.  For completeness, after de-duping all the entries obtained from " 
SELECT more_subfields_xml FROM items; " (249,636 text lines), the only data 
left (apart from the subfields above) are "empty containers" using:

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://www.loc.gov/MARC21/slim">
xsi:schemaLocation="http://www.loc.gov/MARC21/slim 
http://www.loc.gov/standards/marcxml/schema/MARC21slim.xsd"
<?xml version="1.0" encoding="UTF-8"?>
<collection
</collection>
<datafield tag="999" ind1=" " ind2=" ">
</datafield>
<leader>         a              </leader>
<record>
</record>