Memory allocation issue

[ramyaragupathy]

Here's a tile-reduce process that's run for the planet. I'm expecting the script to release memory after processing a tile. Instead process keeps taking up more memory space without freeing up memory for the processed tiles and fails at a point due to memory allocation issue.

Time Spent	Memory
Before beginning the process
10s
30s
After 1 minute

Map script

'use strict';
module.exports = function(tileLayers, tile, writeData, done) {
done();
};

Reduce script

'use strict';

var tileReduce = require('@mapbox/tile-reduce');
tileReduce({
 zoom: 12,
  map: path.join(__dirname, 'index.js'),
  sources: [{
    name: 'osm',
    mbtiles: 'latest.planet.mbtiles',
  }

  ]
})

I'd need help to resolve this issue.

[ramyaragupathy]

Before the failure message process freezes at a particular tile for more than 10 mins and the free memory at this point comes down to 400MB.

cc @tcql @mourner @morganherlocker @bkowshik