Non-Selective Query on Object with 200,000+ Records

What does this error mean?

This is the same underlying error as a non-selective query, but thrown specifically in the context of Apex triggers or classes running against large objects — particularly important in trigger contexts where the error can halt record saves entirely. Salesforce requires that queries on objects with 200,000+ records use at least one selective filter on an indexed field.

Selectivity is calculated per-filter: a filter is selective if it reduces the result set below 10% of the first million records, or below 5% of records beyond one million, with a maximum of 333,333 records. If no individual filter meets the threshold, the query is considered non-selective.

Common Causes

1. Trigger queries not scoped to trigger records

A trigger that queries related records using a non-indexed field instead of the trigger's record IDs — for example, querying all cases for an account using a custom field rather than the AccountId lookup.

2. Negation operators on any field

Filters using !=, NOT IN, or NOT LIKE are inherently non-selective regardless of the field — they potentially match most records.

3. OR conditions between non-indexed fields

OR conditions prevent index use even when one of the fields is indexed, because both branches must be evaluated.

How to Fix It

Solution 1: Anchor trigger queries to trigger.newMap.keySet()

// ❌ BAD — non-indexed filter on large Case object
List<Case> cases = [
    SELECT Id FROM Case
    WHERE Custom_Category__c = 'Support'
];

// ✅ GOOD — indexed Id field, always selective
List<Case> cases = [
    SELECT Id FROM Case
    WHERE Id IN :Trigger.newMap.keySet()
];

// ✅ GOOD — indexed date range + additional filter
List<Case> cases = [
    SELECT Id, Custom_Category__c FROM Case
    WHERE CreatedDate = LAST_N_DAYS:7
      AND Custom_Category__c = 'Support'
];

Solution 2: Use the Developer Console Query Plan tool

Open the Developer Console → Query Editor → paste your SOQL → click Plan (not Execute). The Query Plan shows cardinality estimates and whether any index will be used. A "TableScan" in the plan means the query will be non-selective on large objects.