Re: [xsl] Question on streaming and grouping with nested keys

Subject: Re: [xsl] Question on streaming and grouping with nested keys
From: "Felix Sasaki felix@xxxxxxxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>
Date: Fri, 14 Jul 2017 12:04:54 -0000
Thank you for your feedback, Martin and David.


I tried the example from Martin with

<xsl:template match="TRANSACTION-LIST">
     <xsl:copy>
        <xsl:for-each-group select="copy-of(TRANSACTION)"
group-by="ITEM2/SUBITEM2/GROUPING-KEY">
           <xsl:copy>
              <item1-sum><xsl:value-of
select="sum(current-group()/ITEM2/SUBITEM2.1)"/></item1-count>

...

It gives me an of memory error. The input file is 160MB, but the individual
transactions are rather small (around 20+ elements). The error also appears
if I remove "<xsl:copy>".


I have a working solution using an accumulator and maps, see below, but
here I did not manage to use streaming. If I set the accumulator to
 streamable="yes", Saxon EE tells me


"The xsl:accumulator-rule/@select expression for a streaming accumulator
must be motionless"


Although I am using xsl-copy() as in Martin's example.


 <xsl:accumulator name="gather-values" as="map(xs:anyAtomicType, node())"
initial-value="map{}">
    <xsl:accumulator-rule match="TRANSACTION">
      <xsl:variable name="current" select="copy-of()"/>
      <xsl:variable name="currentKey"
select="$current/ITEM2/SUBITEM2/GROUPING-KEY"/>
      <xsl:choose>
        <xsl:when test="map:contains($value, $currentKey)">
          <xsl:variable name="amount">
            <amount>
              <xsl:value-of
                select="map:get($value, $currentKey)/amount +
xs:decimal($current/ITEM2/SUBITEM2.1)"
              />
            </amount>
          </xsl:variable>
          <xsl:sequence
            select="
              map:put($value, $currentKey,
              $amount)"/>
        </xsl:when>
        <xsl:otherwise>
          <xsl:variable name="amount">
            <amount>
              <xsl:value-of select="xs:decimal($current/ITEM2/SUBITEM2.1)"/>
            </amount>
          </xsl:variable>
          <xsl:sequence select="map:put($value, $currentKey, $amount)"/>
        </xsl:otherwise>
      </xsl:choose>
    </xsl:accumulator-rule>
  </xsl:accumulator>


- Felix







2017-07-14 10:17 GMT+02:00 Martin Honnen martin.honnen@xxxxxx <
xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>:

>
>
> Am 14.07.2017 um 09:09 schrieb Felix Sasaki felix@xxxxxxxxxxxxxx:
>
> I want to analyse a list of transactions in XSLT 3.0 streaming mode.
> Transactions should be grouped by a key which is nested inside each
> transaction (see SUBITEM2.2/GROUPING-KEY below). For the grouped
> transactions, there are items to count or items with numeric values to some
> up, see ITEM1 and ITEM2/SUBITEM2.1.
>
>
> <TRANSACTION-LIST>
>   <TRANSACTION>
>     <ITEM1> something to count </ITEM1>
>     <ITEM2>
>       <SUBITEM2.1> something to sum up</SUBITEM2.1>
>       <SUBITEM2.2> ...
>         <GROUPING-KEY>some-key</GROUPING-KEY>
>       </SUBITEM2.2>
>     </ITEM2>
>   </TRANSACTION> ...
> </TRANSACTION-LIST>
>
>   The output should be a list as follows:
> - Transaction following grouping key value 1:
>     Numbers of ITEM1
>     Sum of ITEM 2
> - Transactions following grouping key value 2, 3, ...n: the same list with
> other values.
>
> See also https://stackoverflow.com/questions/44287959/xslt-3-0-
> streaming-with-grouping-and-sum-accumulator/44291127#44291127 for a
> similar problem and some worked out code samples trying to tackle the
> problem.
> XSL-List info and archive <http://www.mulberrytech.com/xsl/xsl-list>
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