Firebase cloud function run out of memory

Question

I use firebase's cloud function and got a problem. I know cloud functions can set memory like this runWith({ timeoutSeconds: 540, memory: '8GB' }).https.onCall

I've set the memory to 8g, but it's still not enough I need to get all players' docs and write something to another collection. My player number is about 30k+. and when I get all players' docs it always says run out of memory. See picture below

Do you know how to handle this? Many thanks.