nodejs out of memory

Question

I came across a curious issue today. This may be an easy answer for others, but it has me stumped. Why does the code below cause a memory error?

var cur = 167772160; var bcast = 184549375; var addresses = []; while (cur <= bcast){   cur += 1;   addresses.push(cur); } addresses.length  addresses // memory goes from a few megs to over a gig in seconds when trying to print this 

I get one of these two errors...the first when i run this code in node's interpreter and the latter when i run it through nodeunit:

FATAL ERROR: CALL_AND_RETRY_2 Allocation failed - process out of memory

FATAL ERROR: JS Allocation failed - process out of memory

Answer 1

You can increase the default limits by passing --max-old-space-size=<value> which is in MB.

The example will allow node's heap use up to 4GB (4096 megabytes) of memory:

node --max-old-space-size=4096 app 

Answer 2

It happens when I try to access the array. But getting the length does not.

> var cur = 167772160; > var bcast = 184549375; > var addresses = []; > while (cur <= bcast){ ...   cur += 1; ...   addresses.push(cur); ... } 16777216 > addresses.length  16777216 > addresses FATAL ERROR: CALL_AND_RETRY_2 Allocation failed - process out of memory 

Here's another SO question, memory limit in Node.js (and chrome V8) that relates to issue with memory usage.