-- 查询SqlServer总体的内存使用情况select type , sum(virtual_memory_reserved_kb) VM_Reserved , sum(virtual_memory_committed_kb) VM_Commited , sum(awe_allocated_kb) AWE_Allocated , sum(shared_memory_reserved_kb) Shared_Reserved , sum(shared_memory_committed_kb) Shared_Commited --, sum(single_pages_kb) --SQL2005、2008 --, sum(multi_pages_kb) --SQL2005、2008from sys.dm_os_memory_clerksgroup by typeorder by type-- 查询当前数据库缓存的所有数据页面，哪些数据表，缓存的数据页面数量-- 从这些信息可以看出，系统经常要访问的都是哪些表，有多大？select p.object_id, object_name=object_name(p.object_id), p.index_id, buffer_pages=count(*) from sys.allocation_units a, sys.dm_os_buffer_descriptors b, sys.partitions p where a.allocation_unit_id=b.allocation_unit_id and a.container_id=p.hobt_id and b.database_id=db_id()group by p.object_id,p.index_id order by buffer_pages desc -- 查询缓存的各类执行计划，及分别占了多少内存-- 可以对比动态查询与参数化SQL（预定义语句）的缓存量select cacheobjtype , objtype , sum(cast(size_in_bytes as bigint))/1024 as size_in_kb , count(bucketid) as cache_countfrom sys.dm_exec_cached_plansgroup by cacheobjtype, objtypeorder by cacheobjtype, objtype-- 查询缓存中具体的执行计划，及对应的SQL-- 将此结果按照数据表或SQL进行统计，可以作为基线，调整索引时考虑-- 查询结果会很大，注意将结果集输出到表或文件中SELECT usecounts , refcounts , size_in_bytes , cacheobjtype , objtype , TEXTFROM sys.dm_exec_cached_plans cp CROSS APPLY sys.dm_exec_sql_text(plan_handle)ORDER BY objtype DESC ;GO
原文：https://www.cnblogs.com/zhaoguan_wang/p/4602866.html
其他一些有帮助的语句：
1. 查看SQL语句占用多大内存：
SELECT s2.dbid, s1.sql_handle, (SELECT TOP 1 SUBSTRING(s2.text,statement_start_offset / 2+1 , ( (CASE WHEN statement_end_offset = -1 THEN (LEN(CONVERT(nvarchar(max),s2.text)) * 2) ELSE statement_end_offset END) - statement_start_offset) / 2+1)) AS sql_statement,execution_count, plan_generation_num, last_execution_time, total_worker_time, last_worker_time, min_worker_time, max_worker_time,total_physical_reads, last_physical_reads, min_physical_reads, max_physical_reads, total_logical_writes, last_logical_writes, min_logical_writes, max_logical_writes FROM sys.dm_exec_query_stats AS s1 CROSS APPLY sys.dm_exec_sql_text(sql_handle) AS s2 WHERE s2.objectid is null ORDER BY s1.sql_handle, s1.statement_start_offset, s1.statement_end_offset;