[Monetdb-developers] Fw: Re: Fw: Re: need help in monetdb xquery interface

anshul gangwar anshul1886 at yahoo.co.in
Sat Mar 6 14:57:09 CET 2010



how can we get the estimate of the size of result of query based on any two attributes with varying rangeAnshul


On Sat, Mar 06, 2010 at 11:32:03AM +0530, anshul gangwar wrote:
> 
> 
> --- On Fri, 5/3/10, Martin Kersten <Martin.Kersten at cwi.nl> wrote:
> 
> From: Martin Kersten <Martin.Kersten at cwi.nl>
> Subject: * Re: [Monetdb-developers] need help in monetdb xquery interface
> To: "anshul gangwar" <anshul1886 at yahoo.co.in>
> Date: Friday, 5 March, 2010, 11:26 PM
> 
> anshul gangwar wrote:
> > hello ,
> >           I want to know whether there is any expression or command or anything equivalent to explain sql construct. Also What is the way to 
> There is material for you to study on the website:
> http://monetdb.cwi.nl/SQL/Documentation/SQL-Runtime-Features.html
> http://monetdb.cwi.nl/SQL/Documentation/EXPLAIN-Statement.html#EXPLAIN-Statement
> > get histogram statistics i.e way to find that histogram exists on attribute or not through Xquery interface. not through sql .
> MonetDB does not rely on separate statistics tables.
> 
> >  Please reply as soon as possible.
> > 
> > thank you.
> 
> 
> Actually i want the xquery construct equivalent to sql explain construct and 

MonetDB/XQuery does not provide such feature.

To see the equivalent of the SQL EXPLAIN output, i.e., the MIL plan
generated from your XQuery query, you need to use the Pathfinder stand-alone
compiler "pf"; see
    `pf --help`
and/or
    `pf --fullhelp`
for details.

> so how it simulates histogram features i.e to get that percentage of query etc.

Like MonetDB/SQL also
 MonetDB/XQuery does not rely on separate statistics
such as histograms.

Stefan




       
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