SQLServer内存故障排除
SQLServer内存故障排除
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翻译自:https://blogs.msdn.microsoft.com/karthick_pk/2012/06/15/troubleshooting-sql-server-memory/
SQL Server内存故障排除的第一步,是识别是否低内存条件出现在了MemToLeave或BPool或者因为外部内存压力。
注意:如果你不知道什么是BPOOL或者MemToLeave。在排除SQLServer内存故障之前,请阅读SQLServer内存架构基础。
如果你通过这篇博文不能找到原因,或者如果你想说明在SQL Server错误日志里dbcc memorystatus打印输出的错误,在这篇博文的评论部分或者在facebook用户组贴出来。我们将尝试协助你。
MemToLeave errors:
SQL Server 2000 WARNING: Failed to reserve contiguousmemory of Size= 65536. WARNING: Clearing procedure cache to freecontiguous memory. Error: 17802 “Could not create server eventthread.” SQL Server could not spawn process_loginreadthread.
SQL Server 2005/2008 Failed Virtual Allocate Bytes:FAIL_VIRTUAL_RESERVE 122880 Failed to initialize the CommonLanguage Runtime (CLR) v2.0.50727 due to memory pressure. This is probably dueto memory pressure in the MemToLeave region of memory
Buffer Pool errors:
BPool::Map: no remappableaddress found. BufferPool out of memorycondition LazyWriter: warning, no freebuffers found.
Either BPool (or) MemToLeave errors:
Error: 17803 “Insufficient memory available..” Buffer Distribution: Stolen=7901 Free=0 Procedures=1 Inram=201842Dirty=0 Kept=572… Error: 701, Severity: 17,State: 123. There is insufficient system memory to runthis query. There is insufficient system memory inresource pool ‘default’ to run this query
Working set trim and page out errors(external memory pressure)
A significant part of SQL Server processmemory has been paged out. This may result in performance degradation. A significant part of sql server processmemory has been paged out. This may result in a performance degradation.Duration: 0 seconds. Working set (KB): 2007640, committed (KB): 4594040, memoryutilization: 43%.
如果你看到以上错误,请跳转到SQLServer进程内存的重要部分被页交换出。
第1部分(MTL错误):
如果问题是使用MTL,我们需要要确定SQL Server或者一些Non-SQL组件使用了大多数MemToLeave内存(记得MTL是什么吗?请参阅SQLServer内存架构)。
SQL Server 2000:在DBCCmemorystatus输出中,OS Reserved和OS Committed计数器将会告诉你SQL Server自己在MTL中使用了多少页。
注意:每页是8192字节,因此,MultipyOS Committed * 8192字节/1024 得到MB。
SQL Server 2005/2008:在SQL Server错误日志中OOM错误之后,立即打印的DBCCmemorystatus输出中,捕获所有节点(内存节点Id = 0,1..n)的MultiPage Allocator总和。这将告诉你SQL Server自己在MTL使用了多少KB。
你也可以从sys.dm_os_memory_clerks求multi_pages_kb的总和:
select sum(multi_pages_kb) fromsys.dm_os_memory_clerks
如果SQL Server自身使用了MemToLeave内存的大部分,查看DBCC MEMORYSTATUS输出的MultiPage Allocator值,确定哪个memory clerk消耗内存的大多数。
Sys.dm_os_memory_clerks输出也将表明哪个memoryclerk正消耗MTL内存的大多数。使用以下查询。使用sys.dm_os_memory_objects将会深入了解。
select * from sys.dm_os_memory_clerksorder by multi_pages_kb desc select b.type,a.type,* fromsys.dm_os_memory_objects a,sys.dm_os_memory_clerks b wherea.page_allocator_address=b.page_allocator_address order by b.multi_pages_kb desc ,a.max_pages_allocated_count desc
如果SQL Server拥有的内存非常少,确定是否有COM对象、SQL Mail或第三方扩展存储过程正被使用,如果可能将它们从进程中移出。
COM对象:
COM对象可以在每个sp_OACreate调用中利用可选的第三个参数([context])从进程中移出。如果传递给sp_OACreate的第三个参数的int值为4,SQL将尝试在它自己的dllhost.exe进程的外部实例化该对象。更多关于[context]参数可以在联机帮助“sp_OACreate”专题里找到。
警告:大多数COM对象在进程外运行良好,而某些会失败。我们应该使用context=4运行一些功能性测试,确保它们的对象可以成功在进程外运行。
链接服务器OLEDB提供者:
链接服务器OLEDB提供者可以通过设置“AllowInProcess”OLEDB提供者选项将该提供者设置为0来移出进程。对于每个SQL实例提供者选项存储在注册表的以下位置:
Default Instance:HKLM\SOFTWARE\Microsoft\MSSQLServer\Providers Named Instance: HKLM\SOFTWARE\Microsoft\Microsoft SQL Server\\Providers
如果对于相关第三方提供者的AllowInProcess注册表值不存在,以REG_DWORD值创建它并赋值为0.有些OLEDB提供者不能被成功移出进程,但是大多数可以。
扩展存储过程:
扩展存储过程总是在进程内运行;没有直接的方法移出进程。然而,在某些情况下可以将扩展存储过程放在一个独立的SQL实例,并使用服务器对服务器的RPC调用来在远程实例执行它们。该技术在KB 243428中有详细描述。
第2部分(BPOOL错误):
如果问题是使用BPOOL,在SQL Server错误日志的OOM错误后立即打印的DBCC memorystatus输出,捕获所有节点(内存节点Id=0,1..n)的singlePageAllocator总和。这将会告诉你在MTL中每个memory clerk使用了多少KB。
Sys.dm_os_memory_clerks输出也表明哪个memoryclerk正消耗大多数BPOOL(single_pages_kb)内存。使用以下查询,你可以通过sys.dm_os_memory_objects深入了解:
select * from sys.dm_os_memory_clerksorder by Single_pages_kb desc select b.type,a.type,* fromsys.dm_os_memory_objects a,sys.dm_os_memory_clerks b wherea.page_allocator_address=b.page_allocator_address order by b.single_pages_kb desc
sys.dm_os_memory_clerks可以提供SQLServer内存状态的完整图片,并可以sys.dm_os_memory_objects细化。
注意:single_pages_kb是Bpool,multi_pages_kb是MTL
可以帮助SQL Server内存故障排除的其他视图:
select * from sys.dm_os_memory_objects select * from sys.dm_os_memory_pools select * from sys.dm_os_memory_nodes select * fromsys.dm_os_memory_cache_entries select * fromsys.dm_os_memory_cache_hash_tables
一些用于SQL Server内存故障排除的查询:
--Bpool statistics select (cast(bpool_committed as bigint) * 8192)/(1024*1024) as bpool_committed_mb, (cast(bpool_commit_target as bigint) *8192) / (1024*1024) as bpool_target_mb, (cast(bpool_visible as bigint)* 8192) /(1024*1024) as bpool_visible_mb from sys.dm_os_sys_info go -- Get me physical RAM installed and sizeof user VAS select physical_memory_in_bytes/(1024*1024)as phys_mem_mb, virtual_memory_in_bytes/(1024*1024) asuser_virtual_address_space_size from sys.dm_os_sys_info go --System memory information select total_physical_memory_kb/(1024) asphys_mem_mb, available_physical_memory_kb/(1024) asavail_phys_mem_mb, system_cache_kb/(1024) as sys_cache_mb, (kernel_paged_pool_kb+kernel_nonpaged_pool_kb)/(1024)as kernel_pool_mb, total_page_file_kb/(1024) as total_virtual_memory_mb, available_page_file_kb/(1024) asavailable_virtual_memory_mb, system_memory_state_desc from sys.dm_os_sys_memory go -- Memory utilized by SQLSERVR processGetMemoryProcessInfo() API used for this select physical_memory_in_use_kb/(1024) assql_physmem_inuse_mb, locked_page_allocations_kb/(1024) asawe_memory_mb, total_virtual_address_space_kb/(1024) asmax_vas_mb, virtual_address_space_committed_kb/(1024)as sql_committed_mb, memory_utilization_percentage asworking_set_percentage, virtual_address_space_available_kb/(1024)as vas_available_mb, process_physical_memory_low asis_there_external_pressure, process_virtual_memory_low asis_there_vas_pressure from sys.dm_os_process_memory go --Reosurce monitor ringbuffer select * from sys.dm_os_ring_buffers where ring_buffer_type like'RING_BUFFER_RESOURCE%' go --Memory in each node select memory_node_id as node,virtual_address_space_reserved_kb/(1024) as VAS_reserved_mb, virtual_address_space_committed_kb/(1024)as virtual_committed_mb, locked_page_allocations_kb/(1024) aslocked_pages_mb, single_pages_kb/(1024) as single_pages_mb, multi_pages_kb/(1024) as multi_pages_mb, shared_memory_committed_kb/(1024) asshared_memory_mb from sys.dm_os_memory_nodes where memory_node_id != 64 go --Vas summary with vasummary(Size,reserved,free) as (select size = vadump.size, reserved = SUM(case(convert(int,vadump.base) ^ 0) when 0 then 0 else 1end), free = SUM(case(convert(int, vadump.base) ^0x0) when 0 then 1 else 0 end) from (select CONVERT(varbinary,sum(region_size_in_bytes)) as size, region_allocation_base_address as base from sys.dm_os_virtual_address_dump where region_allocation_base_address<> 0x0 group by region_allocation_base_address UNION( select CONVERT(varbinary,region_size_in_bytes), region_allocation_base_address from sys.dm_os_virtual_address_dump where region_allocation_base_address = 0x0) ) as vadump group by size) select * from vasummary go -- Clerks that are consuming memory select * from sys.dm_os_memory_clerks where (single_pages_kb > 0) or(multi_pages_kb > 0) or (virtual_memory_committed_kb > 0) go -- Get me stolen pages -- select (SUM(single_pages_kb)*1024)/8192 astotal_stolen_pages from sys.dm_os_memory_clerks go -- Breakdown clerks with stolen pages select type, name,sum((single_pages_kb*1024)/8192) as stolen_pages from sys.dm_os_memory_clerks where single_pages_kb > 0 group by type, name order by stolen_pages desc go -- Non-Bpool allocation from SQL Serverclerks select SUM(multi_pages_kb)/1024 astotal_multi_pages_mb from sys.dm_os_memory_clerks go -- Who are Non-Bpool consumers -- select type, name, sum(multi_pages_kb)/1024as multi_pages_mb from sys.dm_os_memory_clerks where multi_pages_kb > 0 group by type, name order by multi_pages_mb desc go -- Let's now get the total consumption ofvirtual allocator -- selectSUM(virtual_memory_committed_kb)/1024 as total_virtual_mem_mb from sys.dm_os_memory_clerks go -- Breakdown the clerks who use virtualallocator select type, name,sum(virtual_memory_committed_kb)/1024 as virtual_mem_mb from sys.dm_os_memory_clerks where virtual_memory_committed_kb > 0 group by type, name order by virtual_mem_mb desc go -- memory allocated by AWE allocator API'S select SUM(awe_allocated_kb)/1024 astotal_awe_allocated_mb from sys.dm_os_memory_clerks go -- Who clerks consumes memory using AWE select type, name,sum(awe_allocated_kb)/1024 as awe_allocated_mb from sys.dm_os_memory_clerks where awe_allocated_kb > 0 group by type, name order by awe_allocated_mb desc go -- What is the total memory used by theclerks? select (sum(multi_pages_kb)+ SUM(virtual_memory_committed_kb)+ SUM(awe_allocated_kb))/1024 from sys.dm_os_memory_clerks go -- -- Does this sync up with what the nodethinks? -- selectSUM(virtual_address_space_committed_kb)/1024 as total_node_virtual_memory_mb, SUM(locked_page_allocations_kb)/1024 astotal_awe_memory_mb, SUM(single_pages_kb)/1024 astotal_single_pages_mb, SUM(multi_pages_kb)/1024 astotal_multi_pages_mb from sys.dm_os_memory_nodes where memory_node_id != 64 go -- -- Total memory used by SQL Server throughSQLOS memory nodes -- including DAC node -- What takes up the rest of the space? select(SUM(virtual_address_space_committed_kb)+ SUM(locked_page_allocations_kb)+ SUM(multi_pages_kb))/1024 astotal_sql_memusage_mb from sys.dm_os_memory_nodes go -- -- Who are the biggest cache stores? select name, type,(SUM(single_pages_kb)+SUM(multi_pages_kb))/1024 as cache_size_mb from sys.dm_os_memory_cache_counters where type like 'CACHESTORE%' group by name, type order by cache_size_mb desc go -- -- Who are the biggest user stores? select name, type,(SUM(single_pages_kb)+SUM(multi_pages_kb))/1024 as cache_size_mb from sys.dm_os_memory_cache_counters where type like 'USERSTORE%' group by name, type order by cache_size_mb desc go -- -- Who are the biggest object stores? select name, type,(SUM(single_pages_kb)+SUM(multi_pages_kb))/1024 as cache_size_mb from sys.dm_os_memory_clerks where type like 'OBJECTSTORE%' group by name, type order by cache_size_mb desc go --Which object is really consuming fromclerk select * from sys.dm_os_memory_clerks a ,sys.dm_os_memory_objects b where a.page_allocator_address =b.page_allocator_address --group by a.type, b.type order by a.type, b.type go --To get the list of 3rd party DLL loadedinside SQL server memory select * from sys.dm_os_loaded_moduleswhere company <> 'Microsoft Corporation' go --Which database page is in my memory select db_name(database_id),(cast(count(*)as bigint)*8192)/1024/1024 as "size in mb" fromsys.dm_os_buffer_descriptors group by db_name(database_id)
其他SQL Server内存博文:
https://mssqlwiki.com/sqlwiki/sql-performance/basics-of-sql-server-memory-architecture/
https://mssqlwiki.com/2012/05/18/sql-server-performance-degraded-in-32-bit-sql-server-after-i-adding-additional-ram/
https://mssqlwiki.com/2012/06/27/a-significant-part-of-sql-server-process-memory-has-been-paged-out/
其他性能博文:
https://mssqlwiki.com/sqlwiki/sql-performance/io-bottlenecks/
https://mssqlwiki.com/sqlwiki/sql-server-agent/sql-agent-maxworkerthreads-and-agent-subsystem/
https://mssqlwiki.com/sqlwiki/sql-performance/async_network_io-or-network_io/
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