[jira] Commented: (XMLBEANS-389) List accessors generated with -javasource=1.5 produce lists that scale poorly with the size of the list
[ https://issues.apache.org/jira/browse/XMLBEANS-389?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12664417#action_12664417 ] Philip Aston commented on XMLBEANS-389: --- Unless I'm missing something, the List accessors aren't documented anywhere. Its probably easier to phrase it as an FAQ. > List accessors generated with -javasource=1.5 produce lists that scale poorly > with the size of the list > --- > > Key: XMLBEANS-389 > URL: https://issues.apache.org/jira/browse/XMLBEANS-389 > Project: XMLBeans > Issue Type: Bug > Components: Compiler >Affects Versions: Version 2, Version 2.1, Version 2.2, Version 2.2.1, > Version 2.3, Version 2.3.1, Version 2.4 , Version 2.4.1 >Reporter: Philip Aston > Attachments: testcase.tgz > > > When a schema is compiled with -javasource=1.5, convenient list based > accessors are generated as well as the array accessors. E.g. > java.util.List getParamList() > The implementation of the List is built upon java.lang.AbstractList. The > AbstractList iterator's hasNext() method calls size(). For an XMLBean > generated list, size() walks the store and so iteration scales quadratically. > Here are some numbers showing the problem: > XMLBeans backed list of 1 strings: 0.013766 ms > XMLBeans backed list of 16 strings: 0.255458 ms > XMLBeans backed list of 256 strings: 1.612057 ms > XMLBeans backed list of 1024 strings: 25.458934 ms > XMLBeans backed list of 2048 strings: 123.393447 ms > XMLBeans backed list of 4096 strings: 505.594661 ms > plain list of 1 strings: 0.002304 ms > plain list of 16 strings: 0.007788 ms > plain list of 256 strings: 0.013384 ms > plain list of 1024 strings: 0.052215 ms > plain list of 2048 strings: 0.103550 ms > plain list of 4096 strings: 0.206648 ms > I think the generated list should override iterator(), and return an Iterator > that calculates the list size once per iteration. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online. - To unsubscribe, e-mail: dev-unsubscr...@xmlbeans.apache.org For additional commands, e-mail: dev-h...@xmlbeans.apache.org
[jira] Commented: (XMLBEANS-389) List accessors generated with -javasource=1.5 produce lists that scale poorly with the size of the list
[ https://issues.apache.org/jira/browse/XMLBEANS-389?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12664059#action_12664059 ] Philip Aston commented on XMLBEANS-389: --- Of course. I guess I was really expecting the list accessors to take a snapshot like the array accessor. Here's a jump start for the doc: When a schema is compiled with -javasource=1.5, java.util.List based accessors are generated as well as the array accessors. Unlike the array accessors, the returned lists are live. Changes to a List are reflected in the underlying XMLBean, and changes to the XMLBean are reflected in the List. This live behavior makes iteration over large lists inefficient. Each time an Iterator.hasNext() or Iterator.next() is called, the iterator walks over the underlying XMLBean structure. This scales poorly with as the size of the list grows, so the list accessors should only be used for small sequences. To create a non-live list efficiently, avoid the list accessors. Instead construct a new java.util.ArrayList around an array returned from an array accessor. > List accessors generated with -javasource=1.5 produce lists that scale poorly > with the size of the list > --- > > Key: XMLBEANS-389 > URL: https://issues.apache.org/jira/browse/XMLBEANS-389 > Project: XMLBeans > Issue Type: Bug > Components: Compiler >Affects Versions: Version 2, Version 2.1, Version 2.2, Version 2.2.1, > Version 2.3, Version 2.3.1, Version 2.4 , Version 2.4.1 >Reporter: Philip Aston > Attachments: testcase.tgz > > > When a schema is compiled with -javasource=1.5, convenient list based > accessors are generated as well as the array accessors. E.g. > java.util.List getParamList() > The implementation of the List is built upon java.lang.AbstractList. The > AbstractList iterator's hasNext() method calls size(). For an XMLBean > generated list, size() walks the store and so iteration scales quadratically. > Here are some numbers showing the problem: > XMLBeans backed list of 1 strings: 0.013766 ms > XMLBeans backed list of 16 strings: 0.255458 ms > XMLBeans backed list of 256 strings: 1.612057 ms > XMLBeans backed list of 1024 strings: 25.458934 ms > XMLBeans backed list of 2048 strings: 123.393447 ms > XMLBeans backed list of 4096 strings: 505.594661 ms > plain list of 1 strings: 0.002304 ms > plain list of 16 strings: 0.007788 ms > plain list of 256 strings: 0.013384 ms > plain list of 1024 strings: 0.052215 ms > plain list of 2048 strings: 0.103550 ms > plain list of 4096 strings: 0.206648 ms > I think the generated list should override iterator(), and return an Iterator > that calculates the list size once per iteration. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online. - To unsubscribe, e-mail: dev-unsubscr...@xmlbeans.apache.org For additional commands, e-mail: dev-h...@xmlbeans.apache.org
[jira] Commented: (XMLBEANS-389) List accessors generated with -javasource=1.5 produce lists that scale poorly with the size of the list
[ https://issues.apache.org/jira/browse/XMLBEANS-389?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12663707#action_12663707 ] Philip Aston commented on XMLBEANS-389: --- Thanks Radu. I may be missing something for the first issue. Why can't you use the AbstactList.modCount to implement a fail fast iterator? The second issue is the killer of course. Could the iterator use an XmlCursor? If nothing can be done, I suggest the FAQ is updated to warn that the List accessors should not be used for large arrays. > List accessors generated with -javasource=1.5 produce lists that scale poorly > with the size of the list > --- > > Key: XMLBEANS-389 > URL: https://issues.apache.org/jira/browse/XMLBEANS-389 > Project: XMLBeans > Issue Type: Bug > Components: Compiler >Affects Versions: Version 2, Version 2.1, Version 2.2, Version 2.2.1, > Version 2.3, Version 2.3.1, Version 2.4 , Version 2.4.1 >Reporter: Philip Aston > Attachments: testcase.tgz > > > When a schema is compiled with -javasource=1.5, convenient list based > accessors are generated as well as the array accessors. E.g. > java.util.List getParamList() > The implementation of the List is built upon java.lang.AbstractList. The > AbstractList iterator's hasNext() method calls size(). For an XMLBean > generated list, size() walks the store and so iteration scales quadratically. > Here are some numbers showing the problem: > XMLBeans backed list of 1 strings: 0.013766 ms > XMLBeans backed list of 16 strings: 0.255458 ms > XMLBeans backed list of 256 strings: 1.612057 ms > XMLBeans backed list of 1024 strings: 25.458934 ms > XMLBeans backed list of 2048 strings: 123.393447 ms > XMLBeans backed list of 4096 strings: 505.594661 ms > plain list of 1 strings: 0.002304 ms > plain list of 16 strings: 0.007788 ms > plain list of 256 strings: 0.013384 ms > plain list of 1024 strings: 0.052215 ms > plain list of 2048 strings: 0.103550 ms > plain list of 4096 strings: 0.206648 ms > I think the generated list should override iterator(), and return an Iterator > that calculates the list size once per iteration. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online. - To unsubscribe, e-mail: dev-unsubscr...@xmlbeans.apache.org For additional commands, e-mail: dev-h...@xmlbeans.apache.org
[jira] Updated: (XMLBEANS-389) List accessors generated with -javasource=1.5 produce lists that scale poorly with the size of the list
[ https://issues.apache.org/jira/browse/XMLBEANS-389?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Philip Aston updated XMLBEANS-389: -- Attachment: testcase.tgz Test case. > List accessors generated with -javasource=1.5 produce lists that scale poorly > with the size of the list > --- > > Key: XMLBEANS-389 > URL: https://issues.apache.org/jira/browse/XMLBEANS-389 > Project: XMLBeans > Issue Type: Bug > Components: Compiler >Affects Versions: Version 2, Version 2.1, Version 2.2, Version 2.2.1, > Version 2.3, Version 2.3.1, Version 2.4 , Version 2.4.1 >Reporter: Philip Aston > Attachments: testcase.tgz > > > When a schema is compiled with -javasource=1.5, convenient list based > accessors are generated as well as the array accessors. E.g. > java.util.List getParamList() > The implementation of the List is built upon java.lang.AbstractList. The > AbstractList iterator's hasNext() method calls size(). For an XMLBean > generated list, size() walks the store and so iteration scales quadratically. > Here are some numbers showing the problem: > XMLBeans backed list of 1 strings: 0.013766 ms > XMLBeans backed list of 16 strings: 0.255458 ms > XMLBeans backed list of 256 strings: 1.612057 ms > XMLBeans backed list of 1024 strings: 25.458934 ms > XMLBeans backed list of 2048 strings: 123.393447 ms > XMLBeans backed list of 4096 strings: 505.594661 ms > plain list of 1 strings: 0.002304 ms > plain list of 16 strings: 0.007788 ms > plain list of 256 strings: 0.013384 ms > plain list of 1024 strings: 0.052215 ms > plain list of 2048 strings: 0.103550 ms > plain list of 4096 strings: 0.206648 ms > I think the generated list should override iterator(), and return an Iterator > that calculates the list size once per iteration. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online. - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
[jira] Created: (XMLBEANS-389) List accessors generated with -javasource=1.5 produce lists that scale poorly with the size of the list
List accessors generated with -javasource=1.5 produce lists that scale poorly with the size of the list --- Key: XMLBEANS-389 URL: https://issues.apache.org/jira/browse/XMLBEANS-389 Project: XMLBeans Issue Type: Bug Components: Compiler Affects Versions: Version 2, Version 2.1, Version 2.2, Version 2.2.1, Version 2.3, Version 2.3.1, Version 2.4 , Version 2.4.1 Reporter: Philip Aston When a schema is compiled with -javasource=1.5, convenient list based accessors are generated as well as the array accessors. E.g. java.util.List getParamList() The implementation of the List is built upon java.lang.AbstractList. The AbstractList iterator's hasNext() method calls size(). For an XMLBean generated list, size() walks the store and so iteration scales quadratically. Here are some numbers showing the problem: XMLBeans backed list of 1 strings: 0.013766 ms XMLBeans backed list of 16 strings: 0.255458 ms XMLBeans backed list of 256 strings: 1.612057 ms XMLBeans backed list of 1024 strings: 25.458934 ms XMLBeans backed list of 2048 strings: 123.393447 ms XMLBeans backed list of 4096 strings: 505.594661 ms plain list of 1 strings: 0.002304 ms plain list of 16 strings: 0.007788 ms plain list of 256 strings: 0.013384 ms plain list of 1024 strings: 0.052215 ms plain list of 2048 strings: 0.103550 ms plain list of 4096 strings: 0.206648 ms I think the generated list should override iterator(), and return an Iterator that calculates the list size once per iteration. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online. - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
