RE: Thumbs Up on Compression

  • From: "Post, David (Corporate)" <Dave.Post@xxxxxxxxxxx>
  • To: oracle-l@xxxxxxxxxxxxx
  • Date: Wed, 26 Jan 2005 12:42:47 -0500

These are much larger changes in results then I experienced with table
compression with no indexes.  The compression ratio measured in blocks was
also 50%.  But the run time difference was minimal.  At the time I my
thought was that logical IO was slower on compressed tables because of the
symbol table lookups for compressed columns and rebuilding each row.    

-----Original Message-----
From: MacGregor, Ian A. [mailto:ian@xxxxxxxxxxxxxxxxx] 
Sent: Tuesday, January 25, 2005 12:10 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: Thumbs Up on Compression

I built a non-partitioned, uncompressed table with 709,652,582 rows and =
indexed it with a non-compressed index on (timestamp, pv_id) with the =
most restrictive column first.  A sample query

SELECT value, timestamp, nanosecs, stat, sevr, ostat from
chanarch_pepii.new_archive_data_f
WHERE pv_id =3D :CUR_PV_ID AND
timestamp BETWEEN :START_TIME_ORACLE_DATE AND
:END_TIME_ORACLE_DATE AND
ostat <> 1
ORDER BY timestamp, nanosecs


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