On 30/01/12 8:21 PM, Andrus Adamchik wrote:
On Jan 30, 2012, at 12:13 PM, Aristedes Maniatis wrote:
Isn't this just a bug in the old DISJOINT approach rather than a new type of
prefetch? What is the use-case for fetching all related records in the database
when you have a fetch limit?
This is not a bug, rather a limitation of the algorithm. DISJOINT approach is
based on the root query qualifier transposed for the related entity. It has no
way of knowing which root objects will get below the fetch limit.
Root:
SELECT * FROM ARTIST WHERE ARTIST_NAME LIKE 'X%' FETCH LIMIT 10;
Prefetch
SELECT PAINTING.* FROM PAINTING JOIN ARTIST ON (..) WHERE ARTIST.ARTIST_NAME
LIKE 'X%' FETCH LIMIT ????
Andrus
And does DISJOINT map to:
SELECT * FROM ARTIST WHERE ARTIST_NAME LIKE 'X%' FETCH LIMIT 10;
SELECT * FROM PAINTING WHERE true;
Are you proposing this new join type be:
SELECT * FROM ARTIST WHERE ARTIST_NAME LIKE 'X%' FETCH LIMIT 10;
SELECT * FROM PAINTING WHERE ARTIST_ID IN (123, 124, ....)
Ari
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Aristedes Maniatis
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