SQL Tuning First Checks

Global Statistics:

1.   Statistics_level= ALL , problem with Linux if we set to this. May be a bug.
2.   Db_file_multiblock_read_count
3.   NLS_sort is need to Binary.
4.   Optimizer_dynamic_sampling between 1 and 3.
5.  Stats gathering should not
6.    High version count
7.    Using First Rows
8.   Fixed objects stats missing
9.   CBO stats with non-defaults values
10.   System stats are need to gather if not default stats are used which are calculated at the first DB startup
11.  Sreadtim < 2 or mreadtim <3
12.  Sreadtim > 18 and mreadtim > 522
13.  Table with Bitmap indexes
14.  Need to check any change in the indexes