[elephant-devel] get-instances-by-range oddity

[Ian Eslick]

I don't have time to dive into the details of 'why' this is failing,  
but here is a workaround in the meantime.

(defmethod cursor-set-range :around ((cursor bdb-cursor) key)
   (multiple-value-bind (valid? k v)
       (cursor-set cursor key)
     (if valid?
	(values valid? k v)
	(cursor-next cursor))))

This is in the db-bdb package.

For some reason cursor-next does the comparison properly while cursor- 
set-range does not.  Something about the types returned by (get- 
universal-time) cause the serializer to do something unexpected and it  
will take some time to track it down due to issues of visibility in  
the serializer buffer streams.

Let me know if this gets you unstuck.

Ian

On Nov 6, 2008, at 11:14 PM, Kevin Raison wrote:

> Given this class defined with elephant-unstable in sbcl 10.22 using
> berkeleydb 4.6:
>
> (defpclass test-class ()
>   ((host :accessor host :initarg :host :type string :initform  
> "" :index t)
>    (timestamp :accessor timestamp :initarg :timestamp :initform
> (get-universal-time)
>               :type integer :index t))
>   (:index t))
>
> Can someone help me understand why this works:
>
> CL-USER> (make-instance 'test-class :host "test1" :timestamp  
> 10000000000)
> #<TEST-CLASS oid:791>
> CL-USER> (get-instances-by-range 'test-class 'timestamp 0 10000000001)
> (#<TEST-CLASS oid:791>)
>
> But this does not:
> CL-USER> (make-instance 'test-class :host "test1" :timestamp
> (get-universal-time))
> #<TEST-CLASS oid:795>
> CL-USER> (get-instances-by-range 'test-class 'timestamp 0
> (get-universal-time))
> NIL
> CL-USER> (get-instances-by-range 'test-class 'timestamp 0 10000000001)
> NIL
>
> When (type-of (get-universal-time)) is (INTEGER 0 1152921504606846975)
>
>
> If I do not drop all instances between the above two command sets, I  
> get
> this:
> CL-USER> (make-instance 'test-class :host "test1" :timestamp  
> 10000000000)
> #<TEST-CLASS oid:798>
> CL-USER> (get-instances-by-range 'test-class 'timestamp 0 10000000001)
> (#<TEST-CLASS oid:798>)
> CL-USER> (make-instance 'test-class :host "test1" :timestamp
> (get-universal-time))
> #<TEST-CLASS oid:799>
> CL-USER> (get-instances-by-range 'test-class 'timestamp 0
> (get-universal-time))
> (#<TEST-CLASS oid:798>)
> CL-USER> (get-instances-by-range 'test-class 'timestamp 0 10000000001)
> (#<TEST-CLASS oid:798>)
>
>
> I have tried a number of variations, including not specifying types in
> the class definition, specifying "number" as the type of timestamp,
> coercing (get-universal-time) to an integer.  Nothing has worked.  Can
> anyone shed light on this for me?  Am I missing something obvious?   
> The
> hyperspec specifies that universal time "is an absolute time  
> represented
> as a single non-negative integer."  So why would it not be indexed  
> like
> any other integer?
>
> Thanks in advance.
>
> Kevin Raison
>
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