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Date: Mon, 16 Apr 2007 12:19:07 +0200
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Subject: Trapping "memory exhausted" error
From: david.sklar@gmail.com ("David Sklar")

I am interested in being able to trap the (currently) fatal error that
results when memory usage exceeds the defined memory limit.

I was thinking it could work as follows:

- in addition to a memory_limit configuration directive, there could
be a "memory_limit_grace" configuration directive. This gets stored in
the struct _zend_mm_heap, along with the limit.

- Also added to struct _zend_mm_heap is a "initial limit reached" flag

- When zend_mm_safe_error() in Zend/zend_alloc.c is invoked under the
current conditions (memory_limit exceeded), it sets the "initial limit
reached" flag, adjusts the heap limit to the "memory_limit_grace"
value and throws some non-fatal error (or an exception if it is
feasible from here.)

- When zend_mm_safe_error() is invoked and the "initial limit reached"
flag is already set, it throws the fatal error exactly as it does now.

This "grace period" would provide a way to gracefully exit when a
memory limit is reached, but also has the hard limit still enforced so
that code which is supposed to be gracefully exiting doesn't chew up
too much additional memory.

Is it feasible to adjust the heap limit and throw a non-fatal error
from within zend_mm_safe_error()?

David