It is possible to discover discrepancies which can help define new theories. The survey minimises the danger of repeating research through ignorance of work that has already been done.
Literature surveys take time and require some discipline.
They tend to gather momentum as papers tend to refer to other relevant sources of information. The discipline might be that you spend a couple of hours each day studying and writing. Deadlines are important, and you should plan your work so that your supervisor has sufficient time to study the survey, suggest amendments or more references before the final version has to be submitted. Students starting in October should submit their final versions to their supervisors by the end of March . It is good practice to get someone else to read the draft before submission to your supervisor.