It seems like this should be possible in SPARQL, but I think a SPARQL doesn't
have COUNT yet? When that's implemented it might also make sense to add an
XQuery accessor, maybe something like cts:remainder. Another approach might be
to make xdmp:estimate accurate for triples.
The fact that count(doc()//sem:triple) is faster than count(cts:triples()) may
be a bug, or at least a missing optimization. If it's an important use-case for
you, contact support.
If you don't mind a little imprecision you can sample. This assumes the count
of triples in the first triple document is representative of the rest of the
database.
count((//sem:triple)[1]/root()//sem:triple)
* xdmp:estimate(//sem:triple)
Of course you could sample more documents rather than just the first one, and
adjust accordingly.
-- Mike
On 21 Feb 2014, at 23:04 , David Ennis <[email protected]> wrote:
> Howdy.
>
> In trying to learn the details of the Triple Store in MarkLogic, I decided to
> keep kicking it until it dies. To really stress it, I am using a 1 CPU setup
> with 2 gig of memory and have loaded in ~42 million triples. It grumbled a
> bit in the process, but succeeded and the graph endpoint on the rest
> interface is happy enough for some tesing..
>
> But... I am stumped... How can I get the count of all of my triples?
>
> Documentation suggests fn:count( cts:triples() ) - but that is unrealistic
> when you have any real volume..
>
> After some thoughts, I came up with this silly approach:
>
> - Added range index on sem:triples
>
> With this, I get OK results(considering hardware) when counting in the
> following ways:
> - cts:count-aggregate(cts:element-reference(xs:QName("sem:triple")))
> - fn:count(doc()//sem:triple)
>
> This seems like a viable approach - because you can still play with the
> triples like they are any other document so I am getting the benefit of the
> index. But.. for this I added an index just for this purpose, which seems a
> bit silly.
>
> OK, maybe in production the question of how many triples I have is
> irrelevant, but for testing, it would be a nice thing to know..
>
> Does anyone else have any idea how to get a count of the number of triples in
> a system
>
> Regards,
> David
> David Ennis
> Content Engineer
>
> Mastering the value of content
> creative | technology | content
> Delftechpark 37i
> 2628 XJ Delft
> The Netherlands
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