The present invention is a system for enhancing the decoding performance of text indexes of an indexed collection of text documents. The posting list includes a plurality of list entries being of variable size depending on the value stored in each posting list entry. The inventive system is based on a statistical analysis of the posting list entries of the plurality of list entries. Prior to decoding, the system can select a decoding routine being appropriate to decode the most frequent type of posting list entries or of a plurality of various posting list entries. After selecting a particular decoding routine and executing the decoding routine for decoding of the entire posting list, a failure check is performed. In the exceptional case that a failure has occurred, a second alternative decoding routine is selected and executed.