how to use content iterator in sharepoit 2010 - sharepoint

Question

there are 7000 items in my list. i need to filter the list and retrieve result
i am using the following code in my webpart.
string query = "<Where><BeginsWith><FieldRef Name='Project' /><Value Type='Text'>ab</Value></BeginsWith></Where>"
SPQuery spquery = new SPQuery();
spquery.Query = query;
ContentIterator iterator = new ContentIterator();
iterator.ProcessListItems(list, spquery, ProcessListItem, ProcessListItemError)
as i am using ContentIterator still it is giving me the error "The attempted operation is prohibited because it exceeds the list view threshold enforced by the administrator"
Update:
string query2 = #"<Where><Eq><FieldRef Name='Project' /><Value Type='Text'>11759</Value></Eq></Where>";
SPQuery spquery = new SPQuery();
spquery.RowLimit = 10;
spquery.Query = query2;
spquery.QueryThrottleMode = SPQueryThrottleOption.Override;
ContentIterator iterator = new ContentIterator();
iterator.ProcessListItems(list, spquery, ProcessListItem, ProcessListItemError);
In every case weather I used SPCollectionItem or Iterator. when ever I am passing the where condition in spquery. same error comes.

Answer 1

To efficiently use ContentIterator and avoid throttle exception, you should explicitly include OrderBy clauses.
Try to use ContentIterator.ItemEnumerationOrderByNVPField which actually enables the index to be used.
For more details,check this out
http://extreme-sharepoint.com/2012/07/17/data-access-via-caml-queries/

Answer 2

Likely because the the Field you are comparing on is not indexed: http://msdn.microsoft.com/en-us/library/ff798465
If you were to build a query that returns the first 100 items sorted
by the ID field, the query would execute without issue because the ID
column is always indexed. However, if you were to build a query that
returns the first 100 items sorted by a non-indexed Title field, the
query would have to scan all 10,000 rows in the content database in
order to determine the sort order by title before returning the first
100 items. Because of this, the query would be throttled, and rightly
so—this is a resource-intensive operation.

Answer 3

You either have to ...
... set a RowLimit below the configured threshold on your query.
... or define a query that returns less items.
... or change the threshold of the list.

Answer 4

have you seen this:
msdn link
hmmz, just tried this and it still gave an error. If I use this however I can iterate over way more than 7k listitems:
private int GetItems(SPList list){
var query = new SPQuery();
query.Query = "";
query.QueryThrottleMode = SPQueryThrottleOption.Override;
var items = list.GetItems(query);
return items.Count;
}
so my advice is to just use the list.getitems

Answer 5

You just need to change your query.
//Keep your query inside <View></View> tag.
string query = "<View><Where><BeginsWith><FieldRef Name='Project' /><Value Type='Text'>ab</Value></BeginsWith></Where><View>"
SPQuery spquery = new SPQuery();
spquery.Query = query;
ContentIterator iterator = new ContentIterator();
iterator.ProcessListItems(list, spquery, ProcessListItem, ProcessListItemError)
Now run the program and it will work.