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The techniques described here can be used when initial diagnosis of a database performance problem suggests that further investigation needs to concentrate on finding and tuning the most resource intensive SQL statements according to specific criteria, e.g.[@more@]Applies to: Oracle Server - Enterprise Edition - Version: 9.2.0.1 to 11.1.0.7 - Release: 9.2 to 11.1Information in this document applies to any platform.PurposeThis article provides guidance on how to identify the most resource intensi

Information to help diagnose log file sync can be obtained using the script. found in Note 1064487.1.（metalink artic)[@more@]Information to help diagnose log file sync can be obtained using the script. found in Note 1064487.1.A: Log file sync waits occur when sessions wait for redo data to be written to disk. Typically this is caused by slow writes or committing too frequently in the application. Checking the "user commits" section in the AWR report can reveal if the issue is related

cost =blevel +ceiling(leaf_blocks * effective index selectivity) +ceiling(clustering_factor * effective table selectivity)[@more@]cost =blevel +ceiling(leaf_blocks * effective index selectivity) +ceiling(clustering_factor * effective table selectivity)Historically it has been common practice to say that a good index has a low clustering_factor, and a badindex has a high clustering_factor.There is obviously a degree of truth in this comment, especially in the light of what the clustering_factorre