https://www.oraclescripts.com/tags/dba_tab_col_statistics/Recent content in Dba_tab_col_statistics on Oracle ScriptsHugo -- gohugo.ioenOracleScripts.comThu, 12 Dec 2024 00:00:00 +0000https://www.oraclescripts.com/post/understanding-oracle-database-statistics-gathering-using-dbms-stats-a-comprehensive-guide/Thu, 12 Dec 2024 00:00:00 +0000https://www.oraclescripts.com/post/understanding-oracle-database-statistics-gathering-using-dbms-stats-a-comprehensive-guide/ <h2 id="understanding-oracle-database-statistics-gathering-a-comprehensive-guide">Understanding Oracle Database Statistics Gathering: A Comprehensive Guide</h2> <h2 id="purpose">Purpose</h2> <p><code>DBA_TAB_STATISTICS</code> is the view that shows what the optimizer knows about each table: the number of rows, the average row length and the number of data blocks. <code>DBMS_STATS</code> is the package that fills those numbers in. The optimizer reads them to estimate how many rows a step will return. Then it picks the plan with the lowest cost. If the numbers are wrong or old, the estimates are wrong, and the plan can be slow.</p>