Hi Marco,
Finally some feedback. As you may already have guessed, there is no
obvious answer to your question. A straightforward query could look as
follows..
let $docs-a := db:open('A1')[ ..condition.. ]
let $paths := $docs-a ! db:path(.)
let $docs-b := $paths ! db:open('A1', .)
return (
db:delete('A1', $paths),
db:add('A2', $docs-a),
db:delete('B1', $paths),
db:add('B2', $docs-b)
)
..but it probably leads to out of memory exceptions. An alternative
could be to serialize the documents to disk and try to add it in a
second step. If this doesn't work out neither, I would indeed propose
to move the documents in chunks. A BaseX command script for that could
be generated via XQuery.
I will think about the implications of db:copy-doc and db:move-doc
functions. It's right that such scripts may not be obvious candidates
for OOM errors, because we already have database representations for
the documents to be moved/copied. Another solution to avoid OOM would
be to write the data structures of copied documents to disk instead of
keeping them in main memory. Mostly a matter of when we find enough
time to make it happen..
Cheers,
Christian
> - 2 dbs (let's say A and B) with around 200K documents each
> - every document in B refers to exactly one document in A (many to one is
> possible)
>
> - I have to apply a filter on every document of A and depending on the
> boolean outcome "move" the document to anoter db A'.
> - According to this the correlated documents of B need to be "moved" to a
> database B'.
> - The solution should be made automatic in the mid term
>
> What is the best design pattern and tool (I use the GUI by now) for this
> finding the right compromise for limiting "Out of memory (huge PUL)", "too
> much time", "complexity introduced by chunking" and "absence of a
> _db:move-document_ operation for moving one document in one single
> operation?
>
> Every suggestion is more then warmly welcome!
>
> Thanks and best regards,
> Marco
