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FOR ALL INDEXED COLUMNS size skewonly',This is for generating histograms on the indexed columns where column data is skewed. Collects the optimizer statistics for the table, columns, indexes and histograms for columns where the data shape is skewed. Only collects histograms for skewed column. In general it is slower to execute therefore it would not be suitable when the optimizer statistic collection window is short.
ownname => '<table owner>',
tabname => '<table name>',
method_opt => 'FOR ALL COLUMNS SIZE SKEWONLY',
granularity => 'ALL',
cascade => TRUE,
degree => DBMS_STATS.DEFAULT_DEGREE)
This is for generating histograms on the indexed columnsThis is wrong. Sorry. When the option FOR ALL INDEXED COLUMNS is specified, columns statistics are gathered only for the indexed columns.
where column data is skewed. Collects the optimizer
statistics for the table, columns, indexes and histograms
for columns where the data shape is skewed.
I also believe when you specify "FOR ALL INDEXED COLUMNS " inIf the size clause is not specified, whether the histograms are gathered depends on the version and, as of 10g, on the configuration.
the method_opt , it generates histogram for the said columns.
My point was that the parameter method_opt not only impacts histograms, but also column statistics.