[MarkLogic Dev General] element search question

[Geert Josten]

Hi John,



>From what I understood from it: XPath uses indexes whenever possible, but
depends a lot on how well the query optimizer is able to translate your
XPath to indexes. Slightly different expressions can give big performance
differences. You can investigate that with amongst others xdmp:plan. More
material on XPath optimizations is available in this thread:
http://marklogic.markmail.org/thread/swmpzuziqvfyqrlt



Apart from the optimizations, the index results often need to be filtered
to eliminate false positives like matches a/c/b. Using cts only, and making
it such that filtering makes no difference, xdmp:estimate returns accurate
results..



Cheers,

Geert



*Van:* general-bounces at developer.marklogic.com [mailto:general-bounces at d
eveloper.marklogic.com] *Namens *John Zhong
*Verzonden:* dinsdag 7 februari 2012 3:53
*Aan:* General MarkLogic Developer Discussion
*Onderwerp:* [MarkLogic Dev General] element search question



Hi all,

I have xmls look like below:

<root>
  <a>
    <b>any text</b>
    <c>
      <b>any text</b>
    </c>
  </a>
</root>

Now, I want to search /root[a/b = 'value'] by cts constructors, for example:

cts:element-query(xs:QName("a"),
  cts:element-value-query(xs:QName("b"), $value)
)

But this searches all the b element under /root/a, like /root/a/c/b, so I
want to ask if there is any way to ignore the /root/a/c/b using cts
constructors? Because I just want to check the /root/a/b. Or I have to use
XPath like /root[a/b = 'value']? If so, how is the performance between cts
constructors and XPath?

Thanks,
John
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://developer.marklogic.com/pipermail/general/attachments/20120207/f1d0d2fd/attachment-0001.html