Problem in ksh script ( String comparison )

hi ,
i am trying to compre two strings

      if [[ $var1 = $var2 ]] or if [[ "$var1" = "$var2" ]]

when the length of var1 is small (around 300-400 char ) it works fine

but when it is large (around 900-1000 chars) it fails

is there any limitations for this type of comparison ???

Duplicated post. See Problem in ksh script ( String comparison )