You are viewing a plain text version of this content. The canonical link for it is here.
Posted to dev@xalan.apache.org by bu...@apache.org on 2001/09/05 00:35:16 UTC
[DO NOT REPLY: Bug 3424] New:
Memory Retention problem (diagnosis and patch)
PLEASE DO NOT REPLY TO THIS MESSAGE. TO FURTHER COMMENT
ON THE STATUS OF THIS BUG PLEASE FOLLOW THE LINK BELOW
AND USE THE ON-LINE APPLICATION. REPLYING TO THIS MESSAGE
DOES NOT UPDATE THE DATABASE, AND SO YOUR COMMENT WILL
BE LOST SOMEWHERE.
http://nagoya.apache.org/bugzilla/show_bug.cgi?id=3424
*** shadow/3424 Tue Sep 4 15:35:16 2001
--- shadow/3424.tmp.29625 Tue Sep 4 15:35:16 2001
***************
*** 0 ****
--- 1,281 ----
+ +============================================================================+
+ | Memory Retention problem (diagnosis and patch) |
+ +----------------------------------------------------------------------------+
+ | Bug #: 3424 Product: XalanJ2 |
+ | Status: NEW Version: CurrentCVS |
+ | Resolution: Platform: PC |
+ | Severity: Major OS/Version: Windows NT/2K |
+ | Priority: Other Component: org.apache.xalan.xsltc |
+ +----------------------------------------------------------------------------+
+ | Assigned To: xalan-dev@xml.apache.org |
+ | Reported By: johnh@schemasoft.com |
+ | CC list: Cc: |
+ +----------------------------------------------------------------------------+
+ | URL: |
+ +============================================================================+
+ | DESCRIPTION |
+ It can be noticed that highly recursive stylesheets exhibit memory retention
+ problems that verge on the asymtotic. Much of this problem appears to be caused
+ by use of the Vector class insertElementAt(...) api (for runtime parameters and
+ stack variables) without the proper deletion of the inserted objects. Without
+ deletion there are also Vector induced performance penalities.
+
+ XSL
+ ---
+
+ <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
+ <xsl:output method="text" />
+
+ <!-- FileName: log10.xsl -->
+ <!-- Author: Darryl Fuller, SchemaSoft -->
+ <!-- Purpose: Torture test, compute log10 recursivly for the a bunch of
+ numbers -->
+
+
+ <xsl:template match="/">
+ <xsl:for-each select="./*/*/*/*">
+ <xsl:variable name="val" select="position()"/>
+ <xsl:variable name="logval">
+ <xsl:call-template name="log10">
+ <xsl:with-param name="x" select="$val"/>
+ </xsl:call-template>
+ </xsl:variable>
+ Value: <xsl:value-of select="$val"/> Log10: <xsl:value-of select="$logval"/>
+ </xsl:for-each>
+ </xsl:template>
+
+ <xsl:template name="ln" >
+ <xsl:param name="x"/>
+ <xsl:variable name="e">2.71828182845904</xsl:variable>
+ <xsl:choose>
+ <xsl:when test="$x = 0">0</xsl:when>
+ <!-- technically, a negative number should be NaN, but
+ we will
+ instead pretend we're just scaling a negative number
+ with the ln function -->
+ <xsl:when test="$x < 0">
+ <xsl:variable name="scaled_answer">
+ <xsl:call-template name="ln">
+ <xsl:with-param name="x"
+ select="$x * -1"/>
+ </xsl:call-template>
+ </xsl:variable>
+ <xsl:value-of select="$scaled_answer * -1"/>
+ </xsl:when>
+ <!-- A table of some common values -->
+ <xsl:when test="$x = 10">2.3025850929940</xsl:when>
+ <xsl:when test="$x = 20">2.9957322735539</xsl:when>
+ <xsl:when test="$x = 30">3.4011973816621</xsl:when>
+ <xsl:when test="$x = 40">3.6888794541139</xsl:when>
+ <xsl:when test="$x = 50">3.9120230054281</xsl:when>
+ <xsl:when test="$x = 60">4.0943445622221</xsl:when>
+ <xsl:when test="$x = 70">4.2484952420493</xsl:when>
+ <xsl:when test="$x = 80">4.3820266346738</xsl:when>
+ <xsl:when test="$x = 90">4.4998096703302</xsl:when>
+ <xsl:when test="$x = 100">4.6051701859881</xsl:when>
+ <xsl:when test="$x = 200">5.2983173665480</xsl:when>
+ <xsl:when test="$x = 300">5.7037824746562</xsl:when>
+ <xsl:when test="$x = 400">5.9914645471079</xsl:when>
+ <xsl:when test="$x = 500">6.2146080984222</xsl:when>
+ <xsl:when test="$x = 600">6.3969296552161</xsl:when>
+ <xsl:when test="$x = 700">6.5510803350434</xsl:when>
+ <xsl:when test="$x = 800">6.6846117276679</xsl:when>
+ <xsl:when test="$x = 900">6.8023947633243</xsl:when>
+ <xsl:when test="$x = 1000">6.90775527898213</xsl:when>
+ <!-- scale the answer -->
+ <xsl:when test="$x > 20">
+ <xsl:variable name="scaled_answer">
+ <xsl:call-template name="ln">
+ <xsl:with-param name="x"
+ select="$x div $e"/>
+ </xsl:call-template>
+ </xsl:variable>
+ <xsl:value-of select="$scaled_answer + 1"/>
+ </xsl:when>
+ <!-- scale the answer -->
+ <xsl:when test="$x < 0.005">
+ <xsl:variable name="scaled_answer">
+ <xsl:call-template name="ln">
+ <xsl:with-param name="x"
+ select="$x * $e"/>
+ </xsl:call-template>
+ </xsl:variable>
+ <xsl:value-of select="$scaled_answer - 1"/>
+ </xsl:when>
+ <!-- The straight goods -->
+ <xsl:otherwise>
+ <xsl:variable name="z">
+ <xsl:call-template name="z_value">
+ <xsl:with-param name="x"
+ select="$x"/>
+ </xsl:call-template>
+ </xsl:variable>
+ <xsl:variable name="interim_answer">
+ <xsl:call-template name="ln_recurse">
+ <xsl:with-param name="z"
+ select="$z"/>
+ <xsl:with-param name="current"
+ select="0"/>
+ <xsl:with-param name="term"
+ select="1"/>
+ </xsl:call-template>
+ </xsl:variable>
+ <xsl:value-of select="$interim_answer * 2"/>
+ </xsl:otherwise>
+ </xsl:choose>
+ </xsl:template>
+ <xsl:template name="z_value">
+ <xsl:param name="x"/>
+ <xsl:value-of select="($x - 1) div ($x + 1)"/>
+ </xsl:template>
+ <xsl:template name="ln_recurse">
+ <xsl:param name="z"/>
+ <xsl:param name="current"/>
+ <xsl:param name="term"/>
+ <xsl:variable name="term_value">
+ <xsl:call-template name="ln_term">
+ <xsl:with-param name="z" select="$z"/>
+ <xsl:with-param name="n" select="$term"/>
+ </xsl:call-template>
+ </xsl:variable>
+ <xsl:variable name="val" select="$current + $term_value"/>
+ <xsl:choose>
+ <xsl:when test="$val = $current">
+ <xsl:value-of select="$current"/>
+ </xsl:when>
+ <!-- Limiting the number of terms we calculate to is a
+ trade
+ off of accuracy v.s. speed. I'm currently sacrificing
+ accuracy for a bit o' speed to make this less painfully
+ slow -->
+ <xsl:when test="$term > 100">
+ <xsl:value-of select="$current"/>
+ </xsl:when>
+ <xsl:otherwise>
+ <xsl:call-template name="ln_recurse">
+ <xsl:with-param name="z" select="$z"/>
+ <xsl:with-param name="current"
+ select="$val"/>
+ <xsl:with-param name="term"
+ select="$term + 2"/>
+ </xsl:call-template>
+ </xsl:otherwise>
+ </xsl:choose>
+ </xsl:template>
+ <xsl:template name="ln_term">
+ <xsl:param name="z"/>
+ <xsl:param name="n"/>
+ <xsl:variable name="numerator">
+ <xsl:call-template name="pow_function">
+ <xsl:with-param name="number" select="$z"/>
+ <xsl:with-param name="power" select="$n"/>
+ </xsl:call-template>
+ </xsl:variable>
+ <xsl:value-of select="$numerator div $n"/>
+ </xsl:template>
+ <xsl:template name="pow_function" ><!-- Power function.
+ Calculates number ^ power where power is an
+ integer. -->
+ <xsl:param name="number"/>
+ <xsl:param name="power"/>
+
+ <xsl:variable name="int_power" select="round( $power )"/>
+ <xsl:variable name="rest">
+ <xsl:choose>
+ <xsl:when test="$int_power > 0">
+ <xsl:call-template name="pow_function">
+ <xsl:with-param name="number"
+ select="$number"/>
+ <xsl:with-param name="power"
+ select="$int_power - 1"/>
+ </xsl:call-template>
+ </xsl:when>
+ <xsl:when test="$int_power < 0">
+ <xsl:call-template name="pow_function">
+ <xsl:with-param name="number"
+ select="$number"/>
+ <xsl:with-param name="power"
+ select="$int_power + 1"/>
+ </xsl:call-template>
+ </xsl:when>
+ <xsl:otherwise>1</xsl:otherwise>
+ </xsl:choose>
+ </xsl:variable>
+ <xsl:variable name="result">
+ <xsl:choose>
+ <xsl:when test="$int_power > 0">
+ <xsl:value-of select="$rest * $number"/>
+ </xsl:when>
+ <xsl:when test="$int_power < 0">
+ <xsl:value-of select="$rest div
+ $number"/>
+ </xsl:when>
+ <xsl:otherwise>
+ 1
+ </xsl:otherwise>
+ </xsl:choose>
+ </xsl:variable>
+ <xsl:value-of select="$result"/>
+ </xsl:template>
+ <xsl:template name="log10"><!-- Log (base 10). -->
+ <xsl:param name="x"/>
+ <xsl:variable name="numerator">
+ <xsl:call-template name="ln">
+ <xsl:with-param name="x" select="$x"/>
+ </xsl:call-template>
+ </xsl:variable>
+ <!-- ln(10) -->
+ <xsl:variable name="denominator"
+ select="2.302585092994045684"/>
+ <xsl:value-of select="$numerator div $denominator"/>
+ </xsl:template>
+
+
+ </xsl:stylesheet>
+
+ XML
+ ---
+
+
+ <bugTotals>
+
+ <byState>
+ <open>
+ <total date="may 1" value="3"/>
+ <total date="may 2" value="13"/>
+ <total date="may 3" value="12"/>
+ <total date="may 4" value="22"/>
+ <total date="may 5" value="5"/>
+ <total date="may 6" value="8"/>
+ <total date="may 7" value="2"/>
+ <total date="may 8" value="4"/>
+ <total date="may 9" value="1"/>
+ </open>
+
+ <testing>
+ <total date="may 1" value="0"/>
+ <total date="may 2" value="3"/>
+ <total date="may 3" value="10"/>
+ <total date="may 4" value="2"/>
+ <total date="may 5" value="15"/>
+ <total date="may 6" value="4"/>
+ <total date="may 7" value="8"/>
+ <total date="may 8" value="2"/>
+ <total date="may 9" value="0"/>
+ </testing>
+
+ <closed>
+ <total date="may 1" value="0"/>
+ <total date="may 2" value="3"/>
+ <total date="may 3" value="4"/>
+ <total date="may 4" value="7"/>
+ <total date="may 5" value="15"/>
+ <total date="may 6" value="22"/>
+ <total date="may 7" value="22"/>
+ <total date="may 8" value="24"/>
+ <total date="may 9" value="28"/>
+ </closed>
+
+ </byState>
+
+ </bugTotals>