Delete Rows older than 1 year in Google Sheets (Large Data Set) - google-sheets

Question

I have a fairly large dataset containing about 40,000 rows (New rows added daily). I want to run a script daily that deletes rows that are older than 1 year.
I have been using this one that has worked ok, but as my dataset gets larger it times out and fails to run.
here is what I have been using:
function deleteFIVEoh() {
var ss = SpreadsheetApp.getActiveSpreadsheet();
var sheet = ss.getSheetByName("theFIVEoh");
var datarange = sheet.getDataRange();
var lastrow = datarange.getLastRow();
var values = datarange.getValues();// get all data in a 2D array
var currentDate = new Date();//today
var yearOld = Date.now() + -365*24*3600*1000;
for (i=lastrow;i>=3;i--) {
var tempDate = values[i-1][4];// arrays are 0 indexed so row1 = values[0] and col12 =.
[11]
if ((tempDate!="") && (tempDate <= (yearOld)))
{
sheet.deleteRow(i);
}
}
}
The data on my sheet is always sorted in ascending order (oldest entries at the top). Is there any way I can get this to work faster? Maybe by looking at the first 500 rows only?
Thanks in advance!
-wes

Answer 1

Since your sheet is sorted in ascending order, it is much better to start at the top, count the number of rows that satisfy your condition, then use a single deleteRows() method.
function deleteFIVEoh() {
const MS_IN_ONE_YEAR = 365*24*3600*1000;
var ss = SpreadsheetApp.getActiveSpreadsheet();
var sheet = ss.getSheetByName("theFIVEoh");
var datarange = sheet.getDataRange();
var values = datarange.getValues();// get all data in a 2D array
var currentDate = new Date();//today
var yearOld = new Date(currentDate.getTime() - MS_IN_ONE_YEAR);
for (i = 0; values[i][4] < yearOld; i++) {}
sheet.deleteRows(1,i);
}
A single call is much faster than a looped API call, and there are less iterations in this code as well as it does not need to go through the entire sheet.
Sample before execution:
Sample after execution: