I use cts:uris to get a list of the uris that I want to delete and then I
spawn an xquery to delete each document.  You have to be careful that you
don't spawn more deletion tasks than can be accommodated on the task server
queue.

 

Tim Meagher

 

From: [email protected]
[mailto:[email protected]] On Behalf Of
[email protected]
Sent: Monday, June 06, 2011 10:07 PM
To: Marklogic Developer Mailing List
Subject: [MarkLogic Dev General] Deleting large number of documents from
large database

 

I need to delete all of the documents in a collection in Marklogic.    The
database in which we have the documents stored has over 4.4 million
documents.    The collection itself has approximately 1.7 million documents.
We are currently running 4.0-4 of MarkLogic.   We will be upgrading in the
near future to 4.2, but that does not help us with this problem.

 

I have attempted to use the code below to perform the delete, but I am only
able to delete 5 documents per second using this method.

 

(: Delete documents in a collection :)
xquery version "1.0-ml";

let $assert :=
   if (xdmp:request-timestamp()) then ()
   else
   error((), 'NOTIMESTAMP', text { 'outer query is not read-only' })
let $path := '/documents/7615990080550346622/'
let $map := map:map()
let $list-uris :=
  for $i in xdmp:directory($path, 'infinity')[1 to 10000]
    return map:put($map, xdmp:node-uri($i), true())
let $do := xdmp:eval('
  declare variable $URIS as map:map external;
  xdmp:document-delete(map:keys($URIS))
',
  (xs:QName('URIS'), $map),
  <options xmlns="xdmp:eval">
  <isolation>different-transaction</isolation>
  <prevent-deadlocks>true</prevent-deadlocks>
  </options>
)
return count(map:keys($map))

I read another post on this mailing list that indicated that if you set
directory creation to "manual" and did not have any triggers enabled in the
database, that doing a directory delete would be extremely fast.  However,
we DO have CPF enabled (and cannot disable it) and cannot set directory
creation to manual since we depend on the automatic directory creation in
our application.

 

Any suggestions as to how we can get better throughput for deleting all of
the documents in a collection OR deleting a large number of documents from a
large database?   Clearing a collection as quickly as possible while
retaining the collection itself is the goal at this time.

 

Thanks,

 

Allen Shatzer

 

 

_______________________________________________
General mailing list
[email protected]
http://developer.marklogic.com/mailman/listinfo/general

Reply via email to