What is 'available physical memory' in DBCC MEMORYUSAGE

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What is 'available physical memory' in DBCC MEMORYUSAGE

Jean_G

SSC Veteran

Points: 278
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April 28, 2013 at 9:48 am

#276909

Hi, Am new to SQL Server. Am trying to query the total memory in the system that runs the SQL Server. The field 'available physical memory' returned in the query 'DBCC Memorystatus' (I ran this in a local machine for test) gives 4GB as output, whereas the machine's RAM is 8GB. How do I get the RAM memory space?

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Eddie Wuerch SSChampion Points: 12535 More actions · Answer 1

SELECT physical_memory_in_bytes FROM sys.dm_os_sys_info

Eddie Wuerch
MCM: SQL

durai nagarajan SSCoach Points: 15778 More actions · Answer 2

Eddie,

This is total RAM available in the server , can we get how much it is currently in use and by sql server?

Regards
Durai Nagarajan

himalayadua SSC Enthusiast Points: 199 More actions · Answer 3

you can use the following query

hope it helps-

-- We don't need the row count

SET NOCOUNT ON

-- Get size of SQL Server Page in bytes

DECLARE @pg_size INT, @Instancename varchar(50)

SELECT @pg_size = low from master..spt_values where number = 1 and type = 'E'

-- Extract perfmon counters to a temporary table

IF OBJECT_ID('tempdb..#perfmon_counters') is not null DROP TABLE #perfmon_counters

SELECT * INTO #perfmon_counters FROM sys.dm_os_performance_counters

-- Get SQL Server instance name

SELECT @Instancename = LEFT([object_name], (CHARINDEX(':',[object_name]))) FROM #perfmon_counters WHERE counter_name = 'Buffer cache hit ratio'

-- Print Memory usage details

PRINT '----------------------------------------------------------------------------------------------------'

PRINT 'Memory usage details for SQL Server instance ' + @@SERVERNAME + ' (' + CAST(SERVERPROPERTY('productversion') AS VARCHAR) + ' - ' + SUBSTRING(@@VERSION, CHARINDEX('X',@@VERSION),4) + ' - ' + CAST(SERVERPROPERTY('edition') AS VARCHAR) + ')'

PRINT '----------------------------------------------------------------------------------------------------'

SELECT 'Memory visible to the Operating System'

SELECT CEILING(physical_memory_in_bytes/1048576.0) as [Physical Memory_MB], CEILING(physical_memory_in_bytes/1073741824.0) as [Physical Memory_GB], CEILING(virtual_memory_in_bytes/1073741824.0) as [Virtual Memory GB] FROM sys.dm_os_sys_info

SELECT 'Buffer Pool Usage at the Moment'

SELECT (bpool_committed*8)/1024.0 as BPool_Committed_MB, (bpool_commit_target*8)/1024.0 as BPool_Commit_Tgt_MB,(bpool_visible*8)/1024.0 as BPool_Visible_MB FROM sys.dm_os_sys_info

SELECT 'Total Memory used by SQL Server Buffer Pool as reported by Perfmon counters'

SELECT cntr_value as Mem_KB, cntr_value/1024.0 as Mem_MB, (cntr_value/1048576.0) as Mem_GB FROM #perfmon_counters WHERE counter_name = 'Total Server Memory (KB)'

SELECT 'Memory needed as per current Workload for SQL Server instance'

SELECT cntr_value as Mem_KB, cntr_value/1024.0 as Mem_MB, (cntr_value/1048576.0) as Mem_GB FROM #perfmon_counters WHERE counter_name = 'Target Server Memory (KB)'

SELECT 'Total amount of dynamic memory the server is using for maintaining connections'

SELECT cntr_value as Mem_KB, cntr_value/1024.0 as Mem_MB, (cntr_value/1048576.0) as Mem_GB FROM #perfmon_counters WHERE counter_name = 'Connection Memory (KB)'

SELECT 'Total amount of dynamic memory the server is using for locks'

SELECT cntr_value as Mem_KB, cntr_value/1024.0 as Mem_MB, (cntr_value/1048576.0) as Mem_GB FROM #perfmon_counters WHERE counter_name = 'Lock Memory (KB)'

SELECT 'Total amount of dynamic memory the server is using for the dynamic SQL cache'

SELECT cntr_value as Mem_KB, cntr_value/1024.0 as Mem_MB, (cntr_value/1048576.0) as Mem_GB FROM #perfmon_counters WHERE counter_name = 'SQL Cache Memory (KB)'

SELECT 'Total amount of dynamic memory the server is using for query optimization'

SELECT cntr_value as Mem_KB, cntr_value/1024.0 as Mem_MB, (cntr_value/1048576.0) as Mem_GB FROM #perfmon_counters WHERE counter_name = 'Optimizer Memory (KB) '

SELECT 'Total amount of dynamic memory used for hash, sort and create index operations.'

SELECT cntr_value as Mem_KB, cntr_value/1024.0 as Mem_MB, (cntr_value/1048576.0) as Mem_GB FROM #perfmon_counters WHERE counter_name = 'Granted Workspace Memory (KB) '

SELECT 'Total Amount of memory consumed by cursors'

SELECT cntr_value as Mem_KB, cntr_value/1024.0 as Mem_MB, (cntr_value/1048576.0) as Mem_GB FROM #perfmon_counters WHERE counter_name = 'Cursor memory usage' and instance_name = '_Total'

SELECT 'Number of pages in the buffer pool (includes database, free, and stolen).'

SELECT cntr_value as [8KB_Pages], (cntr_value*@pg_size)/1024.0 as Pages_in_KB, (cntr_value*@pg_size)/1048576.0 as Pages_in_MB FROM #perfmon_counters WHERE object_name= @Instancename+'Buffer Manager' and counter_name = 'Total pages'

SELECT 'Number of Data pages in the buffer pool'

SELECT cntr_value as [8KB_Pages], (cntr_value*@pg_size)/1024.0 as Pages_in_KB, (cntr_value*@pg_size)/1048576.0 as Pages_in_MB FROM #perfmon_counters WHERE object_name=@Instancename+'Buffer Manager' and counter_name = 'Database pages'

SELECT 'Number of Free pages in the buffer pool'

SELECT cntr_value as [8KB_Pages], (cntr_value*@pg_size)/1024.0 as Pages_in_KB, (cntr_value*@pg_size)/1048576.0 as Pages_in_MB FROM #perfmon_counters WHERE object_name=@Instancename+'Buffer Manager' and counter_name = 'Free pages'

SELECT 'Number of Reserved pages in the buffer pool'

SELECT cntr_value as [8KB_Pages], (cntr_value*@pg_size)/1024.0 as Pages_in_KB, (cntr_value*@pg_size)/1048576.0 as Pages_in_MB FROM #perfmon_counters WHERE object_name=@Instancename+'Buffer Manager' and counter_name = 'Reserved pages'

SELECT 'Number of Stolen pages in the buffer pool'

SELECT cntr_value as [8KB_Pages], (cntr_value*@pg_size)/1024.0 as Pages_in_KB, (cntr_value*@pg_size)/1048576.0 as Pages_in_MB FROM #perfmon_counters WHERE object_name=@Instancename+'Buffer Manager' and counter_name = 'Stolen pages'

SELECT 'Number of Plan Cache pages in the buffer pool'

SELECT cntr_value as [8KB_Pages], (cntr_value*@pg_size)/1024.0 as Pages_in_KB, (cntr_value*@pg_size)/1048576.0 as Pages_in_MB FROM #perfmon_counters WHERE object_name=@Instancename+'Plan Cache' and counter_name = 'Cache Pages' and instance_name = '_Total'

SELECT 'Page Life Expectancy - Number of seconds a page will stay in the buffer pool without references'

SELECT cntr_value as [Page Life in seconds],CASE WHEN (cntr_value > 300) THEN 'PLE is Healthy' ELSE 'PLE is not Healthy' END as 'PLE Status' FROM #perfmon_counters WHERE object_name=@Instancename+'Buffer Manager' and counter_name = 'Page life expectancy'

SELECT 'Number of requests per second that had to wait for a free page'

SELECT cntr_value as [Free list stalls/sec] FROM #perfmon_counters WHERE object_name=@Instancename+'Buffer Manager' and counter_name = 'Free list stalls/sec'

SELECT 'Number of pages flushed to disk/sec by a checkpoint or other operation that require all dirty pages to be flushed'

SELECT cntr_value as [Checkpoint pages/sec] FROM #perfmon_counters WHERE object_name=@Instancename+'Buffer Manager' and counter_name = 'Checkpoint pages/sec'

SELECT 'Number of buffers written per second by the buffer manager"s lazy writer'

SELECT cntr_value as [Lazy writes/sec] FROM #perfmon_counters WHERE object_name=@Instancename+'Buffer Manager' and counter_name = 'Lazy writes/sec'

SELECT 'Total number of processes waiting for a workspace memory grant'

SELECT cntr_value as [Memory Grants Pending] FROM #perfmon_counters WHERE object_name=@Instancename+'Memory Manager' and counter_name = 'Memory Grants Pending'

SELECT 'Total number of processes that have successfully acquired a workspace memory grant'

SELECT cntr_value as [Memory Grants Outstanding] FROM #perfmon_counters WHERE object_name=@Instancename+'Memory Manager' and counter_name = 'Memory Grants Outstanding'

SELECT (available_physical_memory_kb/1024.0) AS [Available RAM] FROM sys.dm_os_sys_memory

/*

For SQL 2012 a few columns have been renamed

physical_memory_in_bytes physical_memory_kb

virtual_memory_in_bytes virtual_memory_kb

bpool_commit_target committed_target_kb

bpool_visible visible_target_kb

bpool_commited committed_kb

*/

Regards,
Himalaya Dua
R Systems International Limited
“The IMPOSSIBLE is often UNTRIED”

durai nagarajan SSCoach Points: 15778 More actions · Answer 4

thanks but sys.dm_os_sys_memory is not available in SQL 2005.

Regards
Durai Nagarajan

himalayadua SSC Enthusiast Points: 199 More actions · Answer 5

"sys.dm_os_memory_objects" and "sys.dm_os_sys_info" can be used in 2005.

Not that cool but maybe useful.

Regards,
Himalaya Dua
R Systems International Limited
“The IMPOSSIBLE is often UNTRIED”

Orlando Colamatteo SSC Guru Points: 182279 More actions · Answer 6

This is most of what I use except I dropped the columns that use SQL 2008+ features. Hopefully some of it will help you:

-- memory overview

SELECT CAST((

SELECT CAST(CAST(value_in_use AS INT) / 1024.0 AS DECIMAL(20, 2))

FROM sys.configurations

WHERE name = 'max server memory (MB)'

) / CAST(physical_memory_in_bytes / (1024.0 * 1024.0 * 1024.0) AS DECIMAL(20, 2)) AS DECIMAL(20, 2)) * 100 AS BufferPoolAsPercentOfPhysicalMemory,

CAST(physical_memory_in_bytes / (1024.0 * 1024.0 * 1024.0) AS DECIMAL(20, 2)) AS PhysicalMemoryGB,

CAST(virtual_memory_in_bytes / (1024.0 * 1024 * 1024) AS DECIMAL(20, 2)) AS VasGB,

CAST((bpool_committed * 8) / (1024.0 * 1024.0) AS DECIMAL(20, 2)) AS BufferPoolCommittedMemoryGB,

CAST((bpool_commit_target * 8) / (1024.0 * 1024.0) AS DECIMAL(20, 2)) AS BufferPoolTargetMemoryGB,

(

SELECT CAST(CAST(value_in_use AS INT) AS DECIMAL(20, 2))

FROM sys.configurations

WHERE name = 'min server memory (MB)'

) AS MinServerMemoryMB,

(

SELECT CAST(CAST(value_in_use AS INT) AS DECIMAL(20, 2))

FROM sys.configurations

WHERE name = 'max server memory (MB)'

) AS MaxServerMemoryMB,

(

SELECT value_in_use

FROM sys.configurations

WHERE name = 'awe enabled'

) AS IsAweEnabled,

(

SELECT cntr_value / 1024.0

FROM sys.dm_os_performance_counters

WHERE counter_name = 'Total Server Memory (KB)'

) AS TotalServerMemoryMB

FROM sys.dm_os_sys_info;

There are no special teachers of virtue, because virtue is taught by the whole community.
--Plato

durai nagarajan SSCoach Points: 15778 More actions · Answer 7

BufferPoolCommittedMemoryGB and BufferPoolTargetMemoryGB showing 1.56 does that means it is using only 1.56GB of 8GB (AWE is not eanbled )?.

Regards
Durai Nagarajan

himalayadua SSC Enthusiast Points: 199 More actions · Answer 8

yes, the value shown under this is amount of memory used.

Regards,
Himalaya Dua
R Systems International Limited
“The IMPOSSIBLE is often UNTRIED”

durai nagarajan SSCoach Points: 15778 More actions · Answer 9

durai nagarajan

SSCoach

Points: 15778

April 30, 2013 at 12:53 am

#1611131

Thanks both of you.

Regards
Durai Nagarajan