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If the HISTORY-COMPRESSION=YES is used, how many compressibility is there? (For HSTSTATS and HSTACCTG)

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Article ID: 41693

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Issue/Introduction

Question:

If the HISTORY-COMPRESSION=YES is used, how many compressibility is there?
(For HSTSTATS and HSTACCTG)

Answer:

In terms of the compressibility from using the HISTORY-COMPRESSION = YES parameter , that all depends on the nature of the data being compressed.

The Accounting statistics data tends to get better compression compared to System Statistics data , likely because the Accounting data has more zeroed out and empty fields. Typically System Statistics data can see compression ratios around 50+% , and Accounting data can see compression ratios around 70+%. If the client has compression turned on by default, they can get an idea of the compressibility of their data when they stop the data collector. Part of the audit report written to DBGPRINT when the data collector comes down is information on the compression achieved if it is turned on.

Example)

DBG76024I DB0G 06:00:06 23371K BYTES OF DATA COMPRESSED FOR FILE HSTSTATS
DBG76025I DB0G 06:00:06 10337K BYTES COMPRESSED DATA WRITTEN TO FILE HSTSTATS
DBG76026I DB0G 06:00:06 55 PERCENT COMPRESSION RATIO OBTAINED FOR FILE HSSTATS
DBG76027I DB0G 06:00:06 000:00:00.043951 COMPRESSION TCB CPU USED FOR FILE HSTSTATS

and

DBG76023I DB0G 06:00:06 0 UNCOMPRESSED RECORDS WRITTEN TO FILE HSTACCTG
DBG76024I DB0G 06:00:06 28947K BYTES OF DATA COMPRESSED FOR FILE HSTACCTG
DBG76025I DB0G 06:00:06 6119K BYTES COMPRESSED DATA WRITTEN TO FILE HSTACCTG
DBG76026I DB0G 06:00:06 78 PERCENT COMPRESSION RATIO OBTAINED FOR FILE HSTACCTG
DBG76027I DB0G 06:00:06 000:00:00.000000 COMPRESSION TCB CPU USED FOR FILE HSTACCTG

Insight can handle compressed and uncompressed data in the same history dataset without a problem. Hence message DBG76023I to indicate how many uncompressed records may have been written.

A client experience would be different, based on their environment and data.

 

Environment

Release:
Component: IDB2