Currently, the function C4::AuthoritiesMarc::merge calls ModBiblio for
all bibliographic records linked to the modified authority record. It
could seem a just behavior but we know that this could lead to
performance problems. This is why AuthorityMergeLimit
systempreference with merge_authorities.pl was introduced (earlier:
dontmerge).
Although this partially solves the performance problems, for
moderately large and large catalogs (500+ K) and authority records
linked with a large number of bibliographic records, performance
problems still occur, even with overnight processing with
merge_authorities.pl. This problem is particularly apparent when
updating authority records from central databases, whose modifications
are beyond our control.
It turns out, however, that many such modifications to authority
records involve fields other than the heading field (1XX in MARC 21),
so these updates in fact do not modify bibliographic records.
However, with the current merge function, every touch on an
authority record forces a call to the ModBiblio function. The
number of relatively expensive ModBiblio calls could be
reduced by checking whether there has been an actual change in
the field associated with the authority record.
However, with IncludeSeeFromInSearches or IncludeSeeAlsoFromInSearches
preferences enabled, the record should be refreshed in the search
engine just in case (should the 4XX, 5XX fields have changed, which we
don't know at this point).
Test plan:
==========
1. Make sure to have CataloguingLog set to Log and
IncludeSeeFromInSearches set to Include.
2. Have a bibliographic record with an authority record linked. Open
the authority record in a separate tab, open it in the editor and
save, without modifying it. Repeat this 2-3 times. In the
bibliographic record tab open the Modification log and see a number of
entries - for each “empty” modification of the linked authority
record.
3. Apply the patch ; restart_all.
4. Repat p. 2. Note that there are no new entries in the log.
5. Edit the authority record again, this time putting in one of the
proper 4XX $a subfield an uncommon word (but do not touch the 1XX
field). Save the authority record. In the bibliographic record
tab control that there are no new entries in the modification log.
Make a search for the word put in 4XX field. You should get the
bibliographic record(s) linked to the edited authority record, even
though the bibliographic record itself has not been modified.
6. Edit the authority record again, this time changing the 1XX field.
Save the authority record. In the bibliographic record tab control
that there are is new entry in the modification log.
Sponsored-by: Ignatianum University in Cracow
Signed-off-by: Roman Dolny <roman.dolny@jezuici.pl>
Signed-off-by: Thomas Klausner <domm@plix.at>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
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