Hi guys,
I'm trying to implement this control for 1.5.5, and I'm a bit stuck in
the way we should handle it in the core server. Right now, the control
is decoded (the ASN.1 decoder has been written and tested, it works
fine). The SearchHandler has been modified so that we can implement the
control in only one case : the doSimpleSearch() method.
The problem I have is the following : we have to remember the pointer to
the last entry we have sent back to the client
How should we do ? My first approach was pretty naive : we are using a
cursor, so it's easy, we simply store the cursor into the session, and
the next request will just have to get back this cursor from the
session, and get the N next elements from this cursor.
This has the advantage of being simple, but there are some very
important cons :
- it's memory consuming, as we may keep those cursor in the session for
a very long time
- we will have to close all the cursors when the session is closed (for
whatever reason)
- if some data has been modified since the cursor creation, it may
contain invalid data
- if the user don't send and abandon search request, those cursors will
remain in the session until it's closed (this is very likely to happen)
So I'm considering an alternative - though more expensive and less
performant - approach :
- we build a new cursor for each request,
- we move forward the Nth entry in the newly created cursor, and return
back the M requested elements
- and when done, we discard the cursor.
The pros are
- we don't have to keep n cursors in memory for ever.
- from the client POV, it respects the PagedSeach contract
- it's easier to implement as we have less information to keep in the
session, and to restore back
The cons are :
- it's time consuming, as if we have N entry to return, with a P page
size, we will construct N/P cursors.
Do you see a better way to implement this control, and if not, which one
do you think is the best ?
Thanks !
--
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cordialement, regards,
Emmanuel Lécharny
www.iktek.com
directory.apache.org
