RE: Thumbs Up on Compression

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_at_slac.stanford.edu] Sent: Tuesday, January 25, 2005 12:10 PM To: oracle-l_at_freelists.org
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

--
http://www.freelists.org/webpage/oracle-l