Elapsed Time Grows Drastically Once Compressed Partition (Doc ID 1235141.1)

Last updated on FEBRUARY 02, 2017

Applies to:

Oracle Server - Enterprise Edition - Version: 10.2.0.4 to 11.2.0.2.0 - Release: 10.2 to 11.2
Information in this document applies to any platform.

Symptoms

Once compressed a partitions and subpartitions of a biggest table, then the elapsed time grows drastically
comparing when these partition was not compressed.

For example:

Not Compressed
-------------
SELECT SUM(POSTED_BASE_AMT)
FROM
PS_BCC_LED_CDL_F00 A WHERE A.BUSINESS_UNIT = 'BRC01'AND A.FISCAL_YEAR=
'2009'AND A.ACCOUNTING_PERIOD = '120' AND A.BUSINESS_UNIT_LED= '002' AND
ACCOUNT = :B1 AND GC_LEDGER_BAL_TYPE IN ('PLD', 'PLC') GROUP BY ACCOUNT

call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute 2669 0.59 0.41 0 0 0 0
Fetch 2669 241.25 262.03 2 9888647 0 2669
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 5339 241.84 262.45 2 9888647 0 2669

Compressed
----------
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 1 0.00 0.00 0 0 0 0
Execute 2669 0.36 0.39 0 0 0 0
Fetch 2669 1041.29 1044.81 0 1868302 0 2669
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 5339 1041.65 1045.20 0 1868302 0 2669

When COMPRESSED, elapsed time for the SQL : 1045.2
When NOT COMPRESSED, elapsed time for the SAME SQL : 262.45.

Cause

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