Oracle index data tuning can start from the following aspects:
Determine the columns that need to be indexed and create appropriate indexes. Create indexes only on those columns we need instead of improving performance by creating redundant indexes.
Optimize index selectivity. The selectivity of the index depends on the number of unique index values. If most data rows have the same non-unique value, the selectivity of the index will be very low, resulting in poor index scan performance. The workaround is that you can add additional columns to a composite index or multi-column index to increase index selectivity.
Compressed indexes: Oracle provides two types of index compression: prefix compression and column value compression. Prefix compression stores duplicate data only once, improving storage efficiency, while column value compression only stores different column values. Using index compression can save a lot of disk space and improve storage performance when targeting indexes on tables larger than 300MB.