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Status Functionality already exists
Workspace Db2
Components BLU Acceleration
Created by Guest
Created on Jun 24, 2023

Estimate the optimal BLU columnar compression rate by sampling data

A technique is needed to determine optimal data compression rates for BLU columnar tables. Such a utility should estimate the optimal compression rate without and with the new string compression enhancements delivered in Db2 11.5 code stream.

In essence, this request is asking for a comparable capability available for row tables: ADMIN_GET_TAB_COMPRESS_INFO. Such a utility should report current compression rates (%saved and x factor), current table sizes (GB), estimated compression rates (%saved, x factor), estimated table sizes (GB), net estimated saved space (GB) by table and for the database.

BLU columnar table compression rates are often less than optimal due to creating the table with INSERT, loading without a sufficient utility heap, and/or evolving data characteristics overtime. Currently, no method exists to determine what the compression rates could be for all the BLU columnar tables if optimal dictionaries were built. With BLU performance a function of BLU columnar data compression, optimal compression dictionaries and compressed data is important providing more benefit than just saving disk space.

Needed By Quarter
  • Admin
    Ned Whelan
    Dec 12, 2023

    Please see the following documentation to support this use case: