Patent ID: 8635195

Claim:
A method for compressing index pages in a database system comprising a table, wherein the table comprises table columns, the method comprising: providing an index associated with the table, wherein the index is stored on at least one index page of the database system, wherein the index comprises index columns related to a part of the table columns, wherein the at least one index page is stored on a long term storage medium; providing a first sequence of the index columns, wherein the first sequence of the index columns comprises a logical sequence; providing a second sequence of the index columns, wherein the second sequence of the index columns comprises a physical sequence that is determined such that an index column having a lowest cardinality is a first column of the index columns in the second sequence; arranging the index columns stored on the at least one index page stored on the long term storage medium according to the second sequence; performing a prefix compression on entries of the at least one index page; transferring the at least one index page from the long term storage medium to a cache; arranging the index columns according to the first sequence of the index columns such that the index columns are stored in the cache according to the first sequence of the index columns; and accessing the index using the first sequence of the index columns after arranging the index columns according to the first sequence of the index columns in the cache.