Brother-Eagle™ Oracle Performance
Advice: %Table Scans (Short Tables)

This parameter depicts the percentage of full table scans that are performed on short tables.  An ideal value would be 100%. While table scans are sometimes the desired optimizer execution path, they can present a tuning opportunity, especially when performed on long tables.  Note that long vs. short is determined by the v$sysstat values of ‘table scans(short tables)’ and ‘table scans (long tables)’.

If your query is performing table scans on long tables, you should consider adding indexes in order to optimize the data access.  If queries against short tables are performing full table scans, they are still a candidate for tuning.  However, a full table scan may be desired execution path in these cases.

Some causes of unnecessary full table scans include:

• Missing indexes
• Init.ora parameter settings (optimizer_index_caching)

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