Is it possible to loop through a query so that if (for example) 500,000 rows are found, it'll return results for the first 10,000 and then rerun the query again?

So, what I want to do is run a query and build an array, like this:

$result = pg_query("SELECT * FROM myTable");

$i = 0;
while($row = pg_fetch_array($result) ) {
  $myArray[$i]['id'] = $row['id'];
  $myArray[$i]['name'] = $row['name'];
  $i++;
}

But, I know that there will be several hundred thousand rows, so I wanted to do it in batches of like 10,000... 1- 9,999 and then 10,000 - 10,999 etc... The reason why is because I keep getting this error:

Fatal error: Allowed memory size of 536870912 bytes exhausted (tried to allocate 3 bytes)

Which, incidentally, I don't understand how 3 bytes could exhaust 512M... So, if that's something that I can just change, that'd be great, although, still might be better to do this in batches?