I have programmed a php site which loops through posts (600 counting) and creates upon this new custom post entries. This script suddenly stops after 20-30 seconds without error or failure message (every "critical" code is surrounded by try catch error).

At beginning of the script I set these settings:

set_time_limit(0);
ignore_user_abort(true);
ini_set('max_execution_time', 0);'

But it still stops. If I loop through all posts without creating new post entries (just display of metadata), all posts are shown. What could be the problem?