> The specific case I had was serializing an array containing a whole
> bunch of arrays representing the data from tables in a database. I
> don't recall how many rows there were, but the serialized data was
> around 5 MB. This was on windows, and feels like realloc doing
> over-time, so a fix could be something as simple as tweaking the
> smart_str chunking code; start with a fair initial size and perhaps
> having it double the size on each realloc.
The default values you find inside php_smart_str.h are tuned
for efficient usage of the engine's allocator. They are not
tuned for huge real-world usage.
The attached patch should change that for var.c.
- Sascha
Index: php_smart_str.h
===================================================================
RCS file: /repository/php-src/ext/standard/php_smart_str.h,v
retrieving revision 1.28
diff -u -r1.28 php_smart_str.h
--- php_smart_str.h 8 Jan 2004 17:32:51 -0000 1.28
+++ php_smart_str.h 24 Oct 2004 11:09:23 -0000
@@ -40,6 +40,10 @@
#define SMART_STR_START_SIZE 78
#endif
+#ifndef SMART_STR_DOUBLE_ALLOC
+#define SMART_STR_DOUBLE_ALLOC 0
+#endif
+
#ifdef SMART_STR_USE_REALLOC
#define SMART_STR_REALLOC(a,b,c) realloc((a),(b))
#else
@@ -49,6 +53,21 @@
#define SMART_STR_DO_REALLOC(d, what) \
(d)->c = SMART_STR_REALLOC((d)->c, (d)->a + 1, (what))
+#if SMART_STR_DOUBLE_ALLOC == 1
+
+#define SMART_STR_NEW_SIZE(d, newlen) do { \
+ do { \
+ (d)->a <<= 1; \
+ } while (newlen >= (d)->a); \
+} while (0)
+#else
+
+#define SMART_STR_NEW_SIZE(d, newlen) do { \
+ (d)->a = newlen + SMART_STR_PREALLOC; \
+} while (0)
+
+#endif
+
#define smart_str_alloc4(d, n, what, newlen) do { \
if (!(d)->c) { \
(d)->len = 0; \
@@ -60,7 +79,7 @@
} else { \
newlen = (d)->len + (n); \
if (newlen >= (d)->a) { \
- (d)->a = newlen + SMART_STR_PREALLOC; \
+ SMART_STR_NEW_SIZE(d, newlen); \
SMART_STR_DO_REALLOC(d, what); \
} \
} \
Index: var.c
===================================================================
RCS file: /repository/php-src/ext/standard/var.c,v
retrieving revision 1.196
diff -u -r1.196 var.c
--- var.c 8 Oct 2004 19:02:00 -0000 1.196
+++ var.c 24 Oct 2004 11:09:23 -0000
@@ -30,6 +30,11 @@
#include "php.h"
#include "php_string.h"
#include "php_var.h"
+
+#define SMART_STR_PREALLOC 1
+#define SMART_STR_START_SIZE 2048
+#define SMART_STR_DOUBLE_ALLOC 1
+
#include "php_smart_str.h"
#include "basic_functions.h"
#include "php_incomplete_class.h"
--
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