Re: Max size of an array used in perl.

rajendra wrote:
Hello All,
I would like to know the max size that an array can store in terms of bytes.

As much as your memory system allows.

WinXP% uname -a
CYGWIN_NT-5.1 wiggin 1.5.23(0.156/4/2) 2006-12-19 10:52 i686 Cygwin
WinXP% perl -le '$,=$a=",";for(;;){print time()-$^T,$b++, length $a; $a.=$a}'
0,0,1
0,1,2
0,2,4
0,3,8
0,4,16
0,5,32
0,6,64
0,7,128
0,8,256
0,9,512
0,10,1024
0,11,2048
0,12,4096
0,13,8192
0,14,16384
0,15,32768
0,16,65536
0,17,131072
0,18,262144
0,19,524288
0,20,1048576
0,21,2097152
0,22,4194304
0,23,8388608
0,24,16777216
0,25,33554432
1,26,67108864
1,27,134217728
1,28,268435456
2,29,536870912
Out of memory!

There it took 2 seconds to go from 256M to 512M

On an 800 MHz P-III with 256M RAM:
0,25,33554432
0,26,67108864
1,27,134217728
2,28,268435456
21,29,536870912
155,30,1073741824
panic: realloc at -e line 1.

That is 21 seconds to double after exceeding physical memory and
155 seconds to double after that. After 1GB, it used up all the
available swap space on that poor little machine.

I haven't tried that test on a 16GB machine where perl is compiled with use64bitall.
-Joe
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