[MonetDB-users] XQuery: Schema import, Indexing
Hi,
we're trying to benchmark different XML-DBs, one of them is MonetDB/Xquery. Two questions came up: 1) How is schema import done in MonetDB/XQuery? Does it affect execution time for queries? We imported it in the XML file and also in the query, but did not have any effect on execution time. Also, a lot of schema items such as xs:enumeration or xs:dateTime seem not to be supported. 2) Is indexing possible?
Regards, Silvio
Hello Silvio,
First of all, thank you very much for trying MonetDB/XQuery!
To find (some) answers of your questions, I would like to refer you to the monetdb site: http://monetdb.cwi.nl Especially this page:
http://monetdb.cwi.nl/projects/monetdb/XQuery/Documentation/Supported-Functi...
As the name of the page suggests, there, you can find a list of supported XQuery features.
A list of XQuery built-in functions that have been / will be / won't be implemented can be found here:
http://monetdb.cwi.nl/projects/monetdb/XQuery/Documentation/XQuery-Functions...
Hoop this helps a bit.
Kind regards,
Jennie
On Tue, Nov 06, 2007 at 05:13:11PM +0100, Silvio Kohler wrote:
Hi,
we're trying to benchmark different XML-DBs, one of them is MonetDB/Xquery. Two questions came up:
- How is schema import done in MonetDB/XQuery? Does it affect execution
time for queries? We imported it in the XML file and also in the query, but did not have any effect on execution time. Also, a lot of schema items such as xs:enumeration or xs:dateTime seem not to be supported. 2) Is indexing possible?
Regards, Silvio
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Hi Jennie
thanks for your answer.
We have already visited the links you provided. But we still don't know how the import of the schema works (do we need to import it in the XML file or in the query? We tried both as mentioned on the monetdb-page, but did not make a difference in execution time), and if it has any effect. We also could not find any information on indexing and would be pleased to get information about that. On the "supported functions" page, a lot of for example dateTime functions are listed not to be supported. The schema type xs:dateTime is not listed, but seems not to be supported. Is this right? As we are planning to publicate the results, we want to be sure to get the best performance from MonetDB.
Silvio
Ying Zhang wrote:
Hello Silvio,
First of all, thank you very much for trying MonetDB/XQuery!
To find (some) answers of your questions, I would like to refer you to the monetdb site: http://monetdb.cwi.nl Especially this page:
http://monetdb.cwi.nl/projects/monetdb/XQuery/Documentation/Supported-Functi...
As the name of the page suggests, there, you can find a list of supported XQuery features.
A list of XQuery built-in functions that have been / will be / won't be implemented can be found here:
http://monetdb.cwi.nl/projects/monetdb/XQuery/Documentation/XQuery-Functions...
Hoop this helps a bit.
Kind regards,
Jennie
On Tue, Nov 06, 2007 at 05:13:11PM +0100, Silvio Kohler wrote:
Hi,
we're trying to benchmark different XML-DBs, one of them is MonetDB/Xquery. Two questions came up:
- How is schema import done in MonetDB/XQuery? Does it affect execution
time for queries? We imported it in the XML file and also in the query, but did not have any effect on execution time. Also, a lot of schema items such as xs:enumeration or xs:dateTime seem not to be supported. 2) Is indexing possible?
Regards, Silvio
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On Tue, Nov 06, 2007 at 05:53:27PM +0100, Silvio Kohler wrote:
Hi Jennie
thanks for your answer.
We have already visited the links you provided. But we still don't know how the import of the schema works (do we need to import it in the XML file or in the query? We tried both as mentioned on the monetdb-page, but did not make a difference in execution time), and if it has any effect. We also could not find any information on indexing and would be pleased to get information about that. On the "supported functions" page, a lot of for example dateTime functions are listed not to be supported. The schema type xs:dateTime is not listed, but seems not to be supported. Is this right? As we are planning to publicate the results, we want to be sure to get the best performance from MonetDB.
Indeed currently the temporal types and functions aren't supported.
Niels
Silvio
Ying Zhang wrote:
Hello Silvio,
First of all, thank you very much for trying MonetDB/XQuery!
To find (some) answers of your questions, I would like to refer you to the monetdb site: http://monetdb.cwi.nl Especially this page:
http://monetdb.cwi.nl/projects/monetdb/XQuery/Documentation/Supported-Functi...
As the name of the page suggests, there, you can find a list of supported XQuery features.
A list of XQuery built-in functions that have been / will be / won't be implemented can be found here:
http://monetdb.cwi.nl/projects/monetdb/XQuery/Documentation/XQuery-Functions...
Hoop this helps a bit.
Kind regards,
Jennie
On Tue, Nov 06, 2007 at 05:13:11PM +0100, Silvio Kohler wrote:
Hi,
we're trying to benchmark different XML-DBs, one of them is MonetDB/Xquery. Two questions came up:
- How is schema import done in MonetDB/XQuery? Does it affect execution
time for queries? We imported it in the XML file and also in the query, but did not have any effect on execution time. Also, a lot of schema items such as xs:enumeration or xs:dateTime seem not to be supported. 2) Is indexing possible?
Regards, Silvio
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Hi Silvio,
sorry for the delayed answer.
Quite some time ago we added an XML Schema import in pathfinder (MonetDB/XQuerys XQuery compiler). This import however did only read in the types but did not make use the gathered information. Furthermore is has not be maintained in the last years and thus is now disabled by default. -- So I think nothing useful for you on the query side.
The other alternative you asked for was whether we make use of it if a reference to an XML Schema is stored in a document. As far as I know we only use DTD (and perhaps also Schema) information during shredding the XML documents to find out which attributes represent IDs and IDREFs. The type information is almost certainly ignored. -- So here also nothing useful...
To answer your second question: Is indexing possible? -- yes and no. No because a user cannot create himself an own specialized index and yes because in some scenarios we have candidate list (e.g., based on node name or their kinds) that are used during the evaluation of path steps.
Cheers, Jan
On 11/06/2007 05:13 PM, Silvio Kohler wrote with possible deletions:
Hi,
we're trying to benchmark different XML-DBs, one of them is MonetDB/Xquery. Two questions came up:
- How is schema import done in MonetDB/XQuery? Does it affect execution
time for queries? We imported it in the XML file and also in the query, but did not have any effect on execution time. Also, a lot of schema items such as xs:enumeration or xs:dateTime seem not to be supported. 2) Is indexing possible?
Regards, Silvio
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participants (4)
-
Jan Rittinger -
Niels Nes -
Silvio Kohler -
Ying Zhang