google apps script very very slow - google-apps-script

Question

I am using a google spreadsheet as a simple database of members and I want to create a user interface for searching through them (The primary users for this are not very technically adept and there is quite allot of data associated with each member so viewing it as a spreadsheet can be a bit tedius)
I have written the folowing script which worked last night but appears to run so slowly it times out today and I have no idea why.
function findMember() {
// set spreadsheet variable
var SS = SpreadsheetApp.getActiveSpreadsheet();
// set sheet variables
var memberSearchSheet = SS.getActiveSheet();
var memberDataSheet = SS.getSheetByName("Member Data");
// get the search variables
var searchFirstName = memberSearchSheet.getRange('C2').getValue();
var searchLastName = memberSearchSheet.getRange('C3').getValue();
// get last row of data
var lastRow = memberDataSheet.getLastRow();
for (var i = 2;lastRow;i=i+1){
if (searchFirstName == memberDataSheet.getRange('R'+i+'C2').getValue() && searchLastName == memberDataSheet.getRange('R'+i+'C3').getValue()){
memberSearchSheet.getRange('C5').setValue(memberDataSheet.getRange('R'+i+'C5').getValue());
//throw new Error("ouch")
}
}
// small pop up notification in bottom right corner .toast(message, title, display time)
//var message = "Your search for " + searchFirstName + " " + searchLastName + " is complete.";
//SS.toast(message,"Search Complete",15);
};

Answer 1

You can probably trying getting all the data inside an array in one step and then quickly compare your value with those in the array. Something like this:
var sheet = SpreadsheetApp.getActive().getSheetByName("Member Data");
var data = sheet.getDataRange().getValues();
for (var i = 1; i < data.length; i++) {
if (data[i][0] == firstName && data[i][1] == secondName) {
throw("Found");
}
}