OPTIMIZER IMPROVED DATA COMPRESSION

Described are techniques for performing compression and decompression of statistical data. This data may be used in connection with performing optimizations. A delta value for each statistic is determined representing a difference between a current value and a previous value. Delta values are stored in a statistics table in a compressed form using a monotonic compression scheme. Small tables are used to determine decompressed values estimating the observed values when information is retrieved for use to within a predetermined relative error. Statistical information is stored and represented in a statistics table and an events table. Statistical information is selectively fetched and loaded into memory from a storage device. Indexing techniques are used to force physical continuity rows of the tables in accordance with a specified retrieval order.