FIXED STRING DICTIONARY

摘要

The subject matter described herein relates to implementation of a dictionary in a column-based, in-memory database where values are not stored directly, rather, for each column, a dictionary is created with all distinct values. For each row, a reference to the corresponding value in the dictionary is stored. In one aspect, data is stored in a memory structure organized in a column store format defined by a plurality of columns and a plurality of rows. A dictionary for each column in the memory structure is generated. The dictionary has distinct values for each column. A reference to the dictionary is generated for each column in the memory structure. The dictionary and the reference to the dictionary are stored in the memory structure.

主权项

1. A method comprising:
storing, by one or more processors, data in a memory structure organized in a column store format defined by a plurality of columns and a plurality of rows; generating, by the one or more processors, a dictionary for each column in the memory structure, the dictionary having distinct values for each column; generating, by the one or more processors, a reference to the dictionary for each column in the memory structure; and storing the dictionary and the reference to the dictionary in the memory structure.