Hi Using Basex 7.0.2 and the factbook.xml database, I observe the following:
declare variable $data:=db:open("factbook");
declare function local:myid1($id){ $data//*[@id=$id] }; (: get a 1000 ids to test :) let $ids:=subsequence($data//@province/string(.),1,1000)
for $s in $ids return local:myid1($s)
Takes 30 seconds!
Replacing the final line with
for $s in $ids return $data//*[@id=$s]
The time is 123ms.
/Andy
Hi Andy,
you can speed up the function by adding the data type of the $id argument:
declare function local:myid1($id as xs:string*) { ... };
Otherwise, the query compiler won't know if the incoming ids will be strings, numbers, or of any other type.
Hope this helps, Christian ___________________________
On Mon, Nov 21, 2011 at 11:39 PM, Andy Bunce bunce.andy@gmail.com wrote:
Hi Using Basex 7.0.2 and the factbook.xml database, I observe the following:
declare variable $data:=db:open("factbook");
declare function local:myid1($id){ $data//*[@id=$id] }; (: get a 1000 ids to test :) let $ids:=subsequence($data//@province/string(.),1,1000)
for $s in $ids return local:myid1($s)
Takes 30 seconds!
Replacing the final line with
for $s in $ids return $data//*[@id=$s]
The time is 123ms.
/Andy
BaseX-Talk mailing list BaseX-Talk@mailman.uni-konstanz.de https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk
Hi Christian,
Thanks, that reduces the difference in times to ~30ms. I was not expecting the lack of typing to have such a bad effect. I MUST remember to always declare types from now on :-)
/Andy
On Mon, Nov 21, 2011 at 10:50 PM, Christian Grün christian.gruen@gmail.comwrote:
Hi Andy,
you can speed up the function by adding the data type of the $id argument:
declare function local:myid1($id as xs:string*) { ... };
Otherwise, the query compiler won't know if the incoming ids will be strings, numbers, or of any other type.
Hope this helps, Christian ___________________________
On Mon, Nov 21, 2011 at 11:39 PM, Andy Bunce bunce.andy@gmail.com wrote:
Hi Using Basex 7.0.2 and the factbook.xml database, I observe the following:
declare variable $data:=db:open("factbook");
declare function local:myid1($id){ $data//*[@id=$id] }; (: get a 1000 ids to test :) let $ids:=subsequence($data//@province/string(.),1,1000)
for $s in $ids return local:myid1($s)
Takes 30 seconds!
Replacing the final line with
for $s in $ids return $data//*[@id=$s]
The time is 123ms.
/Andy
BaseX-Talk mailing list BaseX-Talk@mailman.uni-konstanz.de https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk
Thanks, that reduces the difference in times to ~30ms. I was not expecting the lack of typing to have such a bad effect. I MUST remember to always declare types from now on :-)
I agree it's not really obvious that typed variables are so much faster; indeed there are still some cases in which you might get slightly better performance with untyped values. In future, queries such as yours will be optimized at runtime (by generating more than one execution plan and choosing the cheapest at runtime) , but that's still on our todo list..
Your questions are welcome, Christian
basex-talk@mailman.uni-konstanz.de
-
Andy Bunce -
Christian Grün