A system and method for two-level indexing for key-value persistent storage. The method may include: sorting two or more key-value pairs to form a sorted key-value pair set; determining an address of a first key-value pair of the key-value pairs, the first key-value pair including a first key and a first value; determining an address of a second key-value pair of the key-value pairs, the second key-value pair including a second key and a second value; and training a first linear regression model to generate a first line corresponding to the key-value pairs, the training including training the first linear regression model with key-value pairs including the first key-value pair and the second key-value pair.