How to speed up searching DriveApp files using GAS - google-apps-script

Question

I noticed that just looping through the files stored on Google Drive takes a LOT of time.
var startTime = Date.now();
var count = 0;
var files = DriveApp.getFiles();
while (files.hasNext()) { count++; var file=files.next();};
var endTime = Date.now();
Logger.log('Loop through ' + count + ' files takes ' + ((endTime-startTime)/1000) + ' seconds');
It takes about 1 seconds to loop through 100 files.
Storing fileinfo in cache and looping through it after retrieval makes it possible to handle about 20000 files a second (on my system)
var startTime = Date.now();
var fileIds = getFileIds(); // retrieve info cache (stored before)
var count = 0;
var numFiles = fileIds.length;
for (var i=0; i<numFiles; i++) { count++; var file = fileIds[i];};
var endTime = Date.now();
Logger.log('Loop through ' + count + ' files takes ' + ((endTime-startTime)/1000) + ' seconds');
The results above are nothing special, but it makes you think if it will be possible to speedup certain action once you have stored fileinfo in cache.
In my case I notice that specifying several searchcriteria and performing a search
var files = DriveApp.searchFiles(criteria);
might take a lot of time (over 20 seconds) processing results.
So I wonder if there is a way to speedup searching for files.
Does anybody have ideas how to speedup and/or to avoid looping through all files the way described in the first test?

Answer 1

Not possible to speed it up. The comparison you make is not very relevant because the 2nd time you are not making any drive api calls.
That 2nd call is just measusing the time it takes to run a right loop with no api calls.
The first time, all time is consumed calling next which does a roundgrip to the drive api.
If your data doesnt change often you can use the cache to avoid making the same searches again. Make sure to deal with stale results and such.