查看Sql Server 数据库的内存使用情况

-- 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、2008
from    sys.dm_os_memory_clerks
group by type
order 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_count
from    sys.dm_exec_cached_plans
group by cacheobjtype, objtype
order 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 ,
        TEXT
FROM    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;