查看索引碎片

命令

SELECT OBJECT_SCHEMA_NAME(ips.object_id) AS schema_name,
       OBJECT_NAME(ips.object_id)        AS table_name,
       i.name                            AS index_name,
       ips.index_type_desc,
       ROUND(ips.avg_fragmentation_in_percent,1) AS frag_pct,
       ips.page_count
FROM   sys.dm_db_index_physical_stats(DB_ID(N'Customer'), NULL, NULL, NULL, 'LIMITED') ips
  JOIN sys.indexes i
    ON i.object_id = ips.object_id AND i.index_id = ips.index_id
WHERE  ips.avg_fragmentation_in_percent > 10
  AND  ips.page_count > 1000
ORDER BY ips.avg_fragmentation_in_percent DESC;

作用

列出索引的碎片百分比和页数；是做出重建/重组决定的依据。

适用场景

维护前，用于决定处理哪些索引。

注意

小索引（< 1000 页）的碎片无关紧要；已被过滤掉。'DETAILED' 模式更准确但开销很大；'LIMITED' 通常就足够。仅查询；无风险。