2008/6/20 Bill Ott <[EMAIL PROTECTED]>:
> Last question of the week:
>
> If importing a small batch of records into a database with a few hundred
> thousand existing records, is there a good alternative to running
> quick_metarecord_map.sql? ...it can get a bit time consuming.
Untested, but theoretically running the two INSERT statements within a
transaction limiting to the biblio.record_entry IDs (WHERE id >
somenumber) rather than rebuilding the whole thing from scratch would
avoid the full overhead:
BEGIN;
INSERT INTO metabib.metarecord (fingerprint,master_record)
SELECT fingerprint,id
FROM (SELECT DISTINCT ON (fingerprint)
fingerprint, id, quality
FROM biblio.record_entry
WHERE id > somenumber
ORDER BY fingerprint, quality desc) AS x
WHERE fingerprint IS NOT NULL;
INSERT INTO metabib.metarecord_source_map (metarecord,source)
SELECT m.id, b.id
FROM biblio.record_entry b
JOIN metabib.metarecord m ON (m.fingerprint = b.fingerprint)
WHERE b.id > somenumber;
COMMIT;
Alternately, Jason just pointed me to the (slightly different) version
of this same idea at the very bottom of
http://open-ils.org/dokuwiki/doku.php?id=scratchpad:random_magic_spells
- it's more likely that that's tested, and the AND NOT EXISTS clause,
upon reflection, is an intelligent addition :)
One more update: Mike states that the "magic spell" has been used many
times. So go with that.
--
Dan Scott
Laurentian University
