Methods and systems for creating a compact tree node representation of an XML document. One implementation commences by allocating memory for storing an XML tree index data structure, then allocating another separate portion of memory to store a hash table. Then, traversing an XML document to process the traversed nodes as follows: (a) when the traversed node is an element node, then adding the element node to the XML tree index data structure (b) when the traversed node is a text node, then populating a text node index into the XML tree index data structure and copying the text node values to the hash table, and (c) when the traversed node is an attribute node, then populating an attribute node index into the XML tree index data structure. Such a structure supports fast index-based tree restructuring, and permits very large XML document to be accessed within tight memory size constraints.