[Jdbm-general] Where is value in BTree located?

[<ri...@dr...>]

Hi!

I was looking at BTree from a scalability point of view, especially what=20
happens if the objects being stored are larged. First I thought that the=20
objects were stored in one place and that the BTree only contained=20
pointers to them, but it seems as though the BTree is actually holding=20
the values directly in the BPages. The way I understand the code=20
currently is that if a value is updated the entire BPage is reserialized=20
to the database. Is this correct? If so, what happens if the values are=20
about 1MB each? Wouldn't that mean that each update of a value resulted=20
in 16Mb being written to disk? (if each BPage contains 16 values)

If the above is correct, then why not store the objects in the database=20
directly, and only put the rowid's in the BTree?

/Rickard

--=20
Rickard =C3=96berg
ri...@dr...
Senselogic

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