1. Enhancing Data Granularity: The objective of
pre-index optimization is to improve text standard-
ization, consistency, and ensure factual accuracy
and contextual richness to guarantee the perfor-
mance of the RAG system. Text standardization in-
volves removing irrelevant information and special
characters to enhance the efficiency of the retriever.
In terms of consistency, the primary task is to elim-
inate ambiguity in entities and terms, along with
eliminating duplicate or redundant information to
simplify the retriever’s focus. Ensuring factual ac-
curacy is crucial, and whenever possible, the accu-
racy of each piece of data should be verified. Con-
text retention, to adapt to the system’s interaction
context in the real world, can be achieved by adding
another layer of context with domain-specific anno-
tations, coupled with continuous updates through
user feedback loops. Time sensitivity is essential
contextual information, and mechanisms should be
Retrieval-AugmentedGenerationforLargeLanguageModels-ASurvey