Hi Everyone,

I am new to Salesforce Apex Coding and would greatly appreaciate if someone can help me out.

We have custom object called "Custom Payment" with a lookup field to Contact.
The following is my Apex Class that I am using as an Extension for a Visualforce Page to autopopulate the information from Contact Object when the Users Select a Contact on the Visualforce Page.

Everything is working fine and the record is also getting saved but than I recieve the Apex Governor Limit Warning emails from Salesforce.

Approaching limit for non-selective query against large object type (more than 100000 rows). Current size is approximately 90261 rows. When the limit is reached, the query will fail. 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) null

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public class manualpaymentcntrl{
    public Custom_Payment__c ptxn { get; set; }
    public Contact con { get; set; }
        
public manualpaymentcntrl(ApexPages.StandardController std) {
    ptxn=new Custom_Payment__c ();//Create a new instance 
    con=new Contact();
}

public pagereference obtaindetails() {
   
       for ( Contact con : [select FirstName,LastName,Email,AccountID,Phone,MobilePhone,Title, MailingStreet,MailingCity,MailingState,MailingCountry,MailingPostalCode from Contact where Id = :ptxn.Contact__c]){
   
        ptxn.FirstName__c = con.FirstName;
        ptxn.LastName__c = con.LastName;
        ptxn.Email__c = con.Email;
        ptxn.Account__c = con.AccountID;
        ptxn.Phone__c = con.Phone;
        ptxn.MobilePhone__c = con.MobilePhone;
        ptxn.Salutation__c = con.Title;
        ptxn.MailingStreet__c = con.MailingStreet;
        ptxn.MailingCity__c = con.MailingCity;
        ptxn.MailingState__c = con.MailingState;
        ptxn.MailingCountry__c = con.MailingCountry;
        ptxn.MailingPostalCode__c = con.MailingPostalCode;
        
        ptxn.Payment_Setting__c = 'a0x900000012re5';
        ptxn.Frequency_Type__c = 'a0p9000000opqn1';
            
   
   }
    return null;
  }

    public PageReference save(){
       
        upsert ptxn;
      
        PageReference reRend = new PageReference('/apex/custommanualpayment');
        reRend.setRedirect(true);
        return reRend;
    }
    
    public PageReference cancel(){
       
            
        PageReference reRend = new PageReference('/apex/home/home.jsp');
        reRend.setRedirect(true);
        return reRend;
    }
}


Thanks In Advance......