Hi,

This is a follow up to the benchmarking work I presented at the user meeting in Prague.

I have made some changes to my BenchX application to allow the split option (-s) of xmgen to be used. http://www.xml-benchmark.org/faq.txt

I have compared the timings for databases created from sources with and without the -s option. In principle these should provide very similar results.

xmlgen /f 0.2 /o folder/auction

xmlgen /f 0.2 /o folder/auction /s 400

In the first case a single file auction is created. In the second 35 files (auction00000... auction00034) are created.

In both cases the file or files are loaded to a single database to query. In most cases the query performance is very similar.

The exception is q09.xq. This appears to be 2 or 3 orders of magnitude slower against the database created from the split sources.

The actual query result seems to be the same. I have seen the same performance effect for factors f= 0.2, 0.5, 1 but not the somewhat trival f=0.

Any idea what is happening here?

Regards

/Andy

--q09.xq---------

let $auction := collection("benchx-db") return
let $ca := $auction/site/closed_auctions/closed_auction return
let
    $ei := $auction/site/regions/europe/item
for $p in $auction/site/people/person
let $a :=
for $t in $ca
where $p/@id = $t/buyer/@person
return
    let $n := for $t2 in $ei where $t/itemref/@item = $t2/@id return $t2
    return <item>{$n/name/text()}</item>
return <person name="{$p/name/text()}">{$a}</person>