XSLT - How to speed up a complex for-each - performance

Question

I am new to XSLT and i'm having a few speed issues with the following for-each statement. I was hoping someone could give me some pointers as how to optimise this please?
The for-each below is looping through about 4mb of XML. It is testing to ensure that each hotel node has a description and a destination. It is also testing that each hotel has a rating greater than 2 but not 6. The possible values for the rating in the XML are 0, 1, 2, 3, 4, 5 or 6. Ideally i would like it to only select ratings 3, 4 or 5 and ignore the others.
<for-each select="response/results/hotel[
not(#description = '') and
#rating > '2' and
not(#rating = '6') and
not(#destination = '') ]">
<call-template name="hotelparams"/>
<call-template name="upropdata"/>
<call-template name="request"/>
<call-template name="Newline"/>
</for-each>
As request I have added the templates that are being called below. The output is creating tab delimited text files which are then imported in mySQL. By the way please ignore the upropdata template, it will be removed shortly...
<xsl:template name="hotelparams">
<xsl:value-of select="#itemcode"/><xsl:value-of select="$tab"/>
<xsl:value-of select="#cheapestcurrency"/><xsl:value-of select="$tab"/>
<xsl:value-of select="#cheapestprice"/><xsl:value-of select="$tab"/>
<xsl:value-of select="#checkin"/><xsl:value-of select="$tab"/>
<xsl:value-of select="#checkout"/><xsl:value-of select="$tab"/>
<xsl:value-of select="#description"/><xsl:value-of select="$tab"/>
<xsl:value-of select="#destair"/><xsl:value-of select="$tab"/>
<xsl:value-of select="#destination"/><xsl:value-of select="$tab"/>
<xsl:value-of select="#destinationid"/><xsl:value-of select="$tab"/>
<xsl:value-of select="#engine"/><xsl:value-of select="$tab"/>
<xsl:value-of select="#hotelname"/><xsl:value-of select="$tab"/>
<xsl:value-of select="#image"/><xsl:value-of select="$tab"/>
<xsl:value-of select="#nights"/><xsl:value-of select="$tab"/>
<xsl:value-of select="#rating"/><xsl:value-of select="$tab"/>
<xsl:value-of select="#resultkey"/><xsl:value-of select="$tab"/>
<xsl:value-of select="#resultno"/><xsl:value-of select="$tab"/>
<xsl:value-of select="#supplierdestination"/><xsl:value-of select="$tab"/>
<xsl:value-of select="#type"/></xsl:template>
<xsl:template name="upropdata">
<xsl:value-of select="$tab"/>\N<xsl:value-of select="$tab"/>\N<xsl:value-of select="$tab"/>\N<xsl:value-of select="$tab"/>\N<xsl:value-of select="$tab"/>\N<xsl:value-of select="$tab"/>2011-01-01</xsl:template>
<xsl:template name="request">
<xsl:for-each select="/response/request/method"><xsl:value-of select="$tab"/><xsl:value-of select="./#sessionkey"/></xsl:for-each></xsl:template>
<xsl:template name="Newline">
<xsl:text>
</xsl:text></xsl:template>

Answer 1

How about ...
<xsl:for-each select="response/results/hotel
[not(#description = '')]
[#rating = (3,4,5)]">
<xsl:call-template name="hotelparams"/>
<xsl:call-template name="upropdata"/>
<xsl:call-template name="request"/>
<xsl:call-template name="Newline"/>
</xsl:for-each>
Note: I have not included a check for destination, because you did not specify its node name.
Also, if you can eliminate the possibility of empty description attributes (that is to say hotels will have a non empty description or no description attribute at all), then you can use this slightly abbreviated form...
<xsl:for-each select="response/results/hotel
[not(#description)]
[#rating = (3,4,5)]">
<xsl:call-template name="hotelparams"/>
etc...
</xsl:for-each>
Also note, an alternate form for the second predicate would be...
[#rating = (3 to 5)]
One could write...
[(#rating > 2) and (#rating < 6)]
or
[#rating > 2][#rating < 6]
... but I suspect that this would be less efficient, because #rating would have to be fetched twice.

Answer 2

The for-each below is looping through about 4mb of XML. It is testing
to ensure that each hotel node has a description and a destination. It
is also testing that each hotel has a rating greater than 2 but not 6.
The possible values for the rating in the XML are 0, 1, 2, 3, 4, 5 or
6. Ideally i would like it to only select ratings 3, 4 or 5 and ignore the others.
<for-each select="response/results/hotel[
not(#description = '') and
#rating > '2' and
not(#rating = '6') and
not(#destination = '') ]">
<call-template name="hotelparams"/>
<call-template name="upropdata"/>
<call-template name="request"/>
<call-template name="Newline"/>
</for-each>
I believe that the reason for the performance problem is in the templates that are being called (and not provided in the question) -- not in the xsl:for-each itself.
It can be re-written in different alternative ways, but the performance gains would be minimal (milliseconds), if any at all.
Do note, that the provided code doesn't check for the existence of a #destination attribute at all. Any hotel element that satisfies the other conditions, but has no destination attribute is selected.
Exactly the same is true for the description attribute.
One correct way of specifying the xsl:for-each is:
<xsl:for-each select="response/results/hotel[
string(#description)
and
#rating > 2
and
not(#rating > 5)
and
string(#destination)
]">
<xsl:call-template name="hotelparams"/>
<xsl:call-template name="upropdata"/>
<xsl:call-template name="request"/>
<xsl:call-template name="Newline"/>
</xsl:for-each>
Update:
The OP has now provided the code of the called templates.
I will use the following for the hotelparams template:
<xsl:sequence select=
"string-join
(
(#itemcode,
#cheapestcurrency,
#cheapestprice,
#checkin,
#checkout,
#description,
#destair,
#destination,
#destinationid,
#engine,
#hotelname,
#image,
#nights,
#rating,
#resultkey,
#resultno,
#supplierdestination,
#type),
$tab
)
"/>
I would replace the template upropdata with:
this code:
<xsl:sequence select="' \N \N \N \N \N2011-01-01'"/>
Or, if $tab really can be something different than , I will calculate this only once and place the result in a global variable:
<xsl:variable name="vUPropData" select=
"concat($tab,'\N',$tab,'\N',$tab,'\N'$tab,'\N',$tab,'\N2011-01-01')"/>
and then just have:
<xsl:sequence select="$vUPropData"/>
I would replace the request template with:
this code:
<xsl:sequence select=
"concat($tab,string-join(/response/request/method/#sessionkey, $tab))"/>
As this doesn't depend on any context node (is an absolute expression), I would calculate this only once and put it in a global variable (as in the previous case) and only reference this global variable.
Finally, it is not meaningful to generate the same single character in a named template. I will replace the Newline template with a global variable or with a global parameter.
I believe that after this refactoring, the code might execute significantly faster.