Hi,

We have an after update trigger which pulls some tasks based on one field on Task record and update a field on opportunity.

The following loop:

for(Task t :[SELECT id,subject,WhatId,createdDate,Distributor_To_See__c FROM Task WHERE WhatId IN :opportunityIds AND Distributor_To_See__c = 'DSC' LIMIT 49999])
    {
        If(oppIdToTasks.ContainsKey(t.WhatId))
        {
                oppIdToTasks.get(t.WhatId).add(t);
        }
        else
         {
                List<Task> tempList = new List<Task>();
                tempList.add(t);
                oppIdToTasks.put(t.WhatId,tempList);          
        }
   
    }

that Query line in bold above - is causing this error.

Update error code CANNOT_INSERT_UPDATE_ACTIVATE_ENTITY: AutoShareTasks: execution of AfterUpdate

caused by: System.QueryException: Non-selective query against large object type (more than 100000 rows). Consider an indexed filter or contact salesforce.com about custom indexing.
Even if a field is indexed a filter might still not be selective when:
1. The filter value includes null (for instance binding with a list that contains null)
2. Data skew exists whereby the number of matching rows is very large (for instance, filtering for a particular foreign key value that occurs many times)

Trigger.AutoShareTasks: line 23, column 1



Any one suggest what needs to be done for this ?

Thank you.