SOQL Query in Batch Apex start() times out even with multiple filter statements

Question

In my SOQL query in my Apex Batch start() methods I query and order

SELECT TextField__c 
FROM MasterDetailChildWith4MillionRecords__c 
WHERE Active__c = 'Yes' 
AND Revenue__c != 0 
AND Lookup__c = 'a1b50000000F6No' 
ORDER BY UP2GO_2F__txt_DLV_DLIId__c

Master Detail child records. This query times out after 2 minutes. Where does this problem come from? From the schere size of records (4 millions) or the ORDER BY?

Any experiences or hints?

Answer 1

This is probably because the fields you query in the WHERE clause aren't indexed, this way your query will take longer, and will eventually time out with large data sets.

I suggest taking a look at the following webinar, it explains perfectly how to handle big data sets, and what you can do to improve your query times.

Webinar: Extreme Salesforce Data Volumes