CODEWITHSUNDEEP
nosqlxquerymarklogicmarklogic-8
Sunil Chouhan
Sunil Chouhan

Reputation: 83

MarkLogic: Committing multiple statements within a single transaction

I want to version a document, for which we are followed below approach to check-out and check-in the document in a single transaction.

(:--------------------------- XQuery Starts ---------------------------:)
xquery version "1.0-ml";
declare namespace html = "http://www.w3.org/1999/xhtml";
import module namespace dls = "http://marklogic.com/xdmp/dls" at "/MarkLogic/dls.xqy";

declare function local:ManageDocument($docUri)
{
    let $query := fn:concat('
      xquery version "1.0-ml";
      declare namespace html = "http://www.w3.org/1999/xhtml";
      import module namespace dls = "http://marklogic.com/xdmp/dls" at "/MarkLogic/dls.xqy";
      declare variable $docUri as xs:string external;
      dls:document-manage($docUri,fn:false(),fn:concat("First Version of ", $docUri))'
    )

    return xdmp:eval(
      $query,
      (xs:QName("docUri"), $docUri),
      <options xmlns="xdmp:eval">
        <prevent-deadlocks>true</prevent-deadlocks>
      </options>
    )
};

let $docUri := "/searchable/as-2018-1981_standard.pdf.xml"
let $isManaged  := dls:document-is-managed($docUri)
let $manageDoc := if($isManaged) then() else local:ManageDocument($docUri)

let $chechoutStatus := dls:document-checkout-status($docUri)
let $checkOut   := if($chechoutStatus and $isManaged) then (fn:error(xs:QName('Error'), "Already Editing")) else dls:document-checkout-update-checkin($docUri, element {"ROOT"} {"HELLO WORLD!"}, "document-checkout-update-checkin", fn:true())

return $manageDoc
(:--------------------------- XQuery Ends ---------------------------:)

However, it is throwing below exception:

[1.0-ml] XDMP-PREVENTDEADLOCKS: xdmp:eval("&#10; xquery version &quot;1.0-
ml&quot;;&#10; declare ...", (fn:QName("","docUri"), "/searchable
/as-2018-1981_standard.pdf.xml"), <options xmlns="xdmp:eval"><prevent-
deadlocks>true</prevent-deadlocks></options>) -- Processing an update from an
update with different-transaction isolation could deadlock

To overcome this I modified the XQuery to solve our purpose:

(:--------------------------- New XQuery Starts ---------------------------:)
xquery version "1.0-ml";
declare namespace html = "http://www.w3.org/1999/xhtml";
import module namespace dls = "http://marklogic.com/xdmp/dls" at "/MarkLogic/dls.xqy";

declare function local:ManageDocument($docUri)
{
    let $query := fn:concat('
      xquery version "1.0-ml";
      declare namespace html = "http://www.w3.org/1999/xhtml";
      import module namespace dls = "http://marklogic.com/xdmp/dls" at "/MarkLogic/dls.xqy";
      declare variable $docUri as xs:string external;
      dls:document-manage($docUri,fn:false(),fn:concat("First Version of ", $docUri))'
    )

    return xdmp:eval(
      $query,
      (xs:QName("docUri"), $docUri),
      <options xmlns="xdmp:eval">
        <prevent-deadlocks>true</prevent-deadlocks>
      </options>
    )
};

declare function local:CheckouotDocument($docUri)
{
  let $query := fn:concat('
    xquery version "1.0-ml";
    declare namespace html = "http://www.w3.org/1999/xhtml";
    import module namespace dls = "http://marklogic.com/xdmp/dls" at "/MarkLogic/dls.xqy";
    declare variable $docUri as xs:string external;
    (: dls:document-checkout($docUri, fn:true(), "updating doc", 3600) :)
    dls:document-checkout-update-checkin($docUri, element {"ROOT"} {"HELLO WORLD!"}, "document-checkout-update-checkin", fn:true())
   ')

   return xdmp:eval(
      $query,
      (xs:QName("docUri"), $docUri),
      <options xmlns="xdmp:eval">
        <prevent-deadlocks>true</prevent-deadlocks>
      </options>
    )
};

let $docUri := "/searchable/as-2018-1981_standard.pdf.xml"
let $isManaged  := dls:document-is-managed($docUri)
let $manageDoc := if($isManaged) then() else local:ManageDocument($docUri)

let $chechoutStatus := dls:document-checkout-status($docUri)
let $checkOut   := if($chechoutStatus and $isManaged) then (fn:error(xs:QName('Error'), "Already Editing")) else local:CheckouotDocument($docUri)

return $manageDoc
(:--------------------------- New XQuery Ends ---------------------------:)

Above XQuery is working as expected, however, it would be great if anyone can help me in solving my purpose in more efficient and simplified manner.

Upvotes: 3

Views: 248

Answers (1)

Mads Hansen
Mads Hansen

Reputation: 66783

You could simplify your code a bit by using xdmp:invoke-function() instead of constructing strings for xdmp:eval(), and avoid repeating the options by declaring a variable:

xquery version "1.0-ml";
declare namespace html = "http://www.w3.org/1999/xhtml";
import module namespace dls = "http://marklogic.com/xdmp/dls" at "/MarkLogic/dls.xqy";

declare variable $OPTIONS := 
  <options xmlns="xdmp:eval">
    <prevent-deadlocks>true</prevent-deadlocks>
  </options>;

declare function local:ManageDocument($docUri)
{
  xdmp:invoke-function(function() {
    dls:document-manage($docUri, fn:false(), "First Version of "||$docUri)
  }, $OPTIONS)
};

declare function local:CheckouotDocument($docUri)
{
  xdmp:invoke-function(function() {
    (: dls:document-checkout($docUri, fn:true(), "updating doc", 3600) :)
    dls:document-checkout-update-checkin($docUri, element {"ROOT"} {"HELLO WORLD!"}, "document-checkout-update-checkin", fn:true())
  }, $OPTIONS)
};

let $docUri := "/searchable/as-2018-1981_standard.pdf.xml"
let $isManaged  := dls:document-is-managed($docUri)
let $manageDoc := if ($isManaged) then() else local:ManageDocument($docUri)

let $chechoutStatus := dls:document-checkout-status($docUri)
let $checkOut   := if ($chechoutStatus and $isManaged) then (fn:error(xs:QName('Error'), "Already Editing")) else local:CheckouotDocument($docUri)

return $manageDoc

Upvotes: 3

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