在线重建索引，按大小降序排列

SELECT *
FROM (
SELECT 'ALTER INDEX ' || owner || '.' || index_name || ' REBUILD ONLINE;' AS rebuild_command
FROM (
    SELECT 
        i.owner,
        i.index_name,
        s.bytes / 1024 / 1024 AS index_size_mb  -- 转换为MB
    FROM 
        dba_indexes i
    JOIN 
        dba_segments s ON i.owner = s.owner AND i.index_name = s.segment_name
    WHERE 
        i.index_type NOT LIKE '%LOB%'  -- 排除LOB索引
        AND i.owner NOT IN ('SYS', 'SYSTEM', 'SYSMAN', 'DBSNMP')  -- 排除系统用户
    ORDER BY 
        s.bytes DESC  -- 按大小降序排列
)
ORDER BY 
    index_size_mb DESC
)
WHERE ROWNUM <= 20;