"One of the common misconceptions about writing XML applications is that creating a parser instance does not incur a large performance cost. "
Thanks Michael, I was under that common misconception. I'll tell my colleague that he does need to pool the parsers after all. cheers andrew On 12 November 2013 19:18, Michael Glavassevich <mrgla...@ca.ibm.com> wrote: > Hi Andrew, > > Creating a new XML parser can be very expensive. The ClassLoader used to > create the parser and its internal components might block or spend a long > time searching its "classpath" for META-INF/services files. This is why > it's generally a good idea to cache and reuse [1] XML parser instances. > > Thanks. > > [1] > http://www.ibm.com/developerworks/xml/library/x-perfap2/index.html#reuse > > Michael Glavassevich > XML Technologies and WAS Development > IBM Toronto Lab > E-mail: mrgla...@ca.ibm.com > E-mail: mrgla...@apache.org > > Andrew Welch <andrew.j.we...@gmail.com> wrote on 11/12/2013 07:48:47 AM: > >> Hi, >> >> A colleague was doing some performance testing and discovered some >> contention at this line of my code: >> >> XMLReaderFactory.createXMLReader("org.apache.xerces.parsers.SAXParser"); >> >> ...which was surprising : ) He informed me it was doing a blocking >> operation every time. >> >> Anyway, he went away and went through the Xerces source and found that >> if the "org.apache.xerces.xni.parser.XMLParserConfiguration" system >> property is not set it does indeed do a blocking operation (in >> parsers.ObjectFactory) >> >> To demonstrate this, run the below code with and without the system >> property set: >> >> public static void main(String... args) throws Exception { >> >> //System.setProperty >> ("org.apache.xerces.xni.parser.XMLParserConfiguration", >> // "org.apache.xerces.parsers.XIncludeParserConfiguration"); >> >> long start = System.nanoTime(); >> >> for (int i = 0; i <= 10000; i++) { >> XMLReaderFactory.createXMLReader >> ("org.apache.xerces.parsers.SAXParser"); >> } >> >> long end = System.nanoTime(); >> double millis = (end - start) * 1e-6; >> >> System.out.println(millis); >> >> } >> >> On my machine it consistently takes around ~2000ms without the system >> property, and ~1300ms with. >> >> This is present in both 2.9 and 2.11 as far as I can see. >> >> >> >> >> -- >> Andrew Welch >> http://andrewjwelch.com >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: j-users-unsubscr...@xerces.apache.org >> For additional commands, e-mail: j-users-h...@xerces.apache.org > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: j-users-unsubscr...@xerces.apache.org > For additional commands, e-mail: j-users-h...@xerces.apache.org > -- Andrew Welch http://andrewjwelch.com --------------------------------------------------------------------- To unsubscribe, e-mail: j-users-unsubscr...@xerces.apache.org For additional commands, e-mail: j-users-h...@xerces.apache.org
