/*[itemMeta/url/@href eq $public_url] is fully searchable on MarkLogic 5, but not 4.1
dunno why From: evan.l...@marklogic.com To: general@developer.marklogic.com Date: Wed, 11 Jan 2012 14:36:40 -0800 Subject: Re: [MarkLogic Dev General] Are xml attributes indexed by default Or slightly more simply: /*[itemMeta/url/@href eq $public_url] However, I gave this to xdmp:plan() and, for some reason, it's not fully leveraging the indexes here, despite my assumption that it would. At index resolution, the above query selects all the XML documents in the database (same as /*). It turns out xdmp:plan() is pretty essential here to figure out a formulation that works to fully leverage the indexes (even though they theoretically all should work). The following reformulation is no better: xdmp:plan( collection()[/*/itemMeta/url/@href eq $public_url]/*) However, strangely, the following (equivalent) reformulation hits the mark (selects 0 fragments in my database, which has no <itemMeta> elements): xdmp:plan( collection()[*/itemMeta/url/@href eq $public_url]/*) And it's the only one that gives me this reassuring message: Step 1 predicate 1 contributed 3 constraints: */itemMeta/url/@href eq "some_string" Moral of the story is that xdmp:plan() is your friend. And the last query above is the most efficient. Evan LenzSoftware Developer, CommunityMarkLogic Corporationhttp://developer.marklogic.com From: Geert Josten <geert.jos...@dayon.nl> Reply-To: General MarkLogic Developer Discussion <general@developer.marklogic.com> Date: Wed, 11 Jan 2012 13:47:33 -0800 To: General MarkLogic Developer Discussion <general@developer.marklogic.com> Subject: Re: [MarkLogic Dev General] Are xml attributes indexed by default Re: [MarkLogic Dev General] Are xml attributes indexed by defaultHi Jon, Your original expression was like this: /*[ /*/itemMeta/url[@href=$public_url] ] That would return every root element in the database if there is any doc which meets the predicate expression. I think writing it as follows might improve things: /*[ ./itemMeta/url[@href=$public_url] ] (note the period before /itemMeta) You could also use cts functions to explicitly rely on indexes: cts:search(collection(), cts:element-query(xs:QName(“itemMeta”), cts:element-attribute-value-query(xs:QName(“url”), xs:QName(“href”), $public_url)))/* Using CQ or Query Console Profile features, or functions like xdmp:plan can also help to pinpoint and analyze performance problems.. Kind regards,Geert Van: general-boun...@developer.marklogic.com [mailto:general-boun...@developer.marklogic.com] Namens Jonathan Cook - FM&T Verzonden: woensdag 11 januari 2012 15:02 Aan: General MarkLogic Developer Discussion Onderwerp: Re: [MarkLogic Dev General] Are xml attributes indexed by default Thanks for the reply, In words I want to select the document that matches a given href eg return the whole document which matches itemMeta/url[@href=$public_url] Xml could look like this: <?xml version="1.0" encoding="UTF-8"?> <story> <itemMeta> <url href="news/business-1234"/> <assetTypeCode>STY</assetTypeCode> <headline>Full Headline</headline> <shortHeadline>Headline</shortHeadline> <summary>Summary</summary> <section id="1" name="Technology"/> <firstCreated>2011-10-17T14:47:52+00:00</firstCreated> <lastUpdated>2011-12-05T13:40:19+00:00</lastUpdated> <publicationStatus>PUBLISHED</publicationStatus> <language>en-GB</language> <siteId>News v6</siteId> <provider>cps</provider> </itemMeta> <pageOptions/> <body/> <media> <images/> </media> <relatedGroups/> </story> So you would want to return the whole story document. However other documents could have a different root node. ItemMeta will always exist under the root node with this structure so as you say I suspect there is a more efficient way of doing it. I had a quick play with let $results := xinc:node-expand(//bbc:itemMeta/bbc:url[@href=$public_url]) but that just returns the actual url element not the whole document. Thanks Jon On 11/01/2012 13:39, "Geert Josten" <geert.jos...@dayon.nl> wrote:Hi Jon, You always have the Word index (Word lexicon), which can be explicitly used with cts:element-attribute-word-query (and the element counterpart cts:element-word-query. You will have to enable wildcard switches on the database to use wildcards within the searched values. If you want to lookup exact values, you might be better off with a range index, which can be explicitly used with cts:element-value-query and cts:element-attribute-value-query. Whether or not XPath expressions are backed by these indexes and lexicons, depends how well the query optimizer is able to match them. You might be interested in this blog item from Evan, which explains how you can analyze this: http://developer.marklogic.com/blog/learning-with-query-trace However, I think you are asking something different here, looking at your code. To be honest, the argument of xinc:node-expand looks rather suspicious. /* accesses the entire database, but you do it a second time in the predicate. That is indeed very expensive. Can you put in words what you are trying to do? We might be able to suggest better ways of handling this.. Kind regards, Geert Van: general-boun...@developer.marklogic.com [mailto:general-boun...@developer.marklogic.com] Namens Jonathan Cook - FM&T Verzonden: woensdag 11 januari 2012 12:56 Aan: general@developer.marklogic.com Onderwerp: [MarkLogic Dev General] Are xml attributes indexed by default Hi, Are attributes indexed by default in Mark Logic Server? The documentation says the whole document structure is indexed but that doesn’t answer the question really. For example I want to ensure the href attribute is indexed for the following xquery: xquery version "1.0-ml"; import module namespace xinc = "http://marklogic.com/xinclude"; at "/MarkLogic/xinclude/xinclude.xqy"; let $public_url := "%s" let $results := xinc:node-expand(/*[ /*/itemMeta/url[@href=$public_url] ]) let $asset := $results[1] return $asset Perhaps the above xquery isn’t very efficient as I also read widcards couldn’t be used with indexes? This option is set to false but I suspect this is something different: “Index attribute value positions for faster near searches involving element-attribute-value-query (slower document loads and larger database files).” Thanks Jon http://www.bbc.co.ukThis e-mail (and any attachments) is confidential and may contain personal views which are not the views of the BBC unless specifically stated.If you have received it in error, please delete it from your system.Do not use, copy or disclose the information in any way nor act in reliance on it and notify the sender immediately.Please note that the BBC monitors e-mails sent or received.Further communication will signify your consent to this._______________________________________________ General mailing list General@developer.marklogic.com http://developer.marklogic.com/mailman/listinfo/general http://www.bbc.co.uk/ This e-mail (and any attachments) is confidential and may contain personal views which are not the views of the BBC unless specifically stated. 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