Blog dedicated to Oracle Applications (E-Business Suite) Technology; covers Apps Architecture, Administration and third party bolt-ons to Apps

Thursday, April 23, 2009

New features in Oracle RDBMS

I found this from a presentation on new features in Oracle RDBMS for SAP

RAC Features
Non-blocking Thread Architecture for CRS Background Processes
• Improved Cluster Stacks:
• AIX 5.3 / 6.1 – GPFS 3.2
• Faster Detection of Node Failures
• Improved Recovery Times after Node Failures
• Linux – OCFS 1.4
• Included in SLES10 SP2 and RHEL5.2
• New Features include Online Resizing, Sparse Files, Shared writable mmap, Preparation for Cluster LVM (Stretched Cluster)

Cost Based Optimizer
• Multi Column Statistics (MCS)
• Dynamic Sampling

Benefit of MCS
• Allows detection of column correlation for concatenated indexes
• Important especially for bind variable usage
Example: create index aaa_1 on aaa (www, xxx, yyy);
create index aaa_2 on aaa (www, xxx, zzz);
select * from aaa where www = :a0 and xxx = :a1 and yyy = :a2;
• Without MCS wrong index aaa_2 may be chosen !
• MCS enabled in through following parameters
• _fix_control=5765456:7
• _fix_control=6221403:ON

Benefit of Dynamic Sampling
• Allows better calculation of optimizer statistics due to non-existing or outdated statistics for tables
• Statistics are collected during query execution by sampling data
• Dynamic Sampling enabled in through following parameter
• Optimizer_dynamic_sampling = 6

Opatch and OCM
• Patchset includes OPatch
• version or (depending on platform)
• includes OCM (Oracle Configuration Manager)

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