How Oracle Handles Skew

When Oracle detects skew, it can collect a histogram to model the actual frequency of column values. This helps the optimizer make better decisions, especially in bind-sensitive or filter-heavy queries.

You can check for skewed columns using:

SELECT column_name, histogram, num_distinct
FROM dba_tab_col_statistics
WHERE table_name = '<target-table>' AND owner = '<my-owner>';

Look for FREQUENCY or TOP-FREQUENCY histograms—that means Oracle found skew and is tracking it.