PHP: do arrays have a maximum size?

Question

Is there a limit for an array in PHP?

Answer 1

Yes, there's a limit on the maximum number of elements. The hash table structure (arrays are basically wrappers around a hash table) is defined like this (PHP 5.3):

typedef struct _hashtable {     uint nTableSize;     uint nTableMask;     uint nNumOfElements;     ulong nNextFreeElement;     Bucket *pInternalPointer;   /* Used for element traversal */     Bucket *pListHead;     Bucket *pListTail;     Bucket **arBuckets;     dtor_func_t pDestructor;     zend_bool persistent;     unsigned char nApplyCount;     zend_bool bApplyProtection; #if ZEND_DEBUG     int inconsistent; #endif } HashTable; 

given that

typedef unsigned int uint; 

the limit is the maximum size of an unsigned int (typically 2^32-1 on a 32-bit OS and on most 64-bit OS).

In practice, however, except on machines with lots of RAM and 32-bit ints, you will always hit the memory limit before this becomes an issue.

Answer 2

The only thing I've come across in reference to php is this from bytes.com/forum:

I don't think there is a limit on how big an array can be, but there is a limit on how much memory your script can use.

The 'memory_limit' directive in the php.ini configuration file holds the max amount of memory your scripts can consume. Try changing this, see if that helps.