Method and apparatus for optimizing access path in database

An apparatus for optimizing an access path in a database, comprising:

• an instance information obtaining unit configured to sample execution of a query statement to obtain information about a plurality of executing instances, wherein the information about each executing instance comprises a literal value of the query statement in the executing instance and a filter factor corresponding to the literal value;
• a grouping unit configured to group the plurality of executing instances into a plurality of groups based on the filter factors corresponding to the literal values, and obtain an average filter factor of each group and an occurrence frequency of the group;
• a candidate path obtaining unit configured to obtain a candidate access path created for the average filter factor of each group;
• and
• an optimal path determining unit configured to, by taking the occurrence frequencies as weights, calculate a weighted execution cost of each candidate access path for each group, and determine the candidate access path with a minimum sum of the weighted execution costs for all groups as an optimal access path.