monMemoryUsage

The monMemoryUsage monitoring table provides information about server and kernel memory pools, including metrics about their sizes, usage patterns, and availablility.

Columns

The columns for monMemoryUsage are:

Name Datatype Attribute Description
Flags int   Status flags that describe the memory pool.
ConfigNum int   Configuration number for the primary configuration option controlling the size of the memory pool.
TotalSize bigint   Total size, in bytes, of the memory pool.
UsedSize bigint   Currently used size, in bytes, of the memory pool.

FreeSize

 bigint   Amount of free memory, in bytes, in the pool.
NumAllocs bigint Counter Total number of allocations requested.
NumFrees bigint Counter Total number of frees performed. "Frees” are the opposite of allocations. Adaptive Server allocates memory fragments, and the number of allocations is tracked by NumAllocs. When the task is finished, the memory fragment is freed (that is, returned to the memory pool). NumFrees tracks the total number of these free operations
NumSleeps bigint Counter Total number of sleeps encountered while allocating memory fragments.
PoolOwnerKPID int   Kernel process ID (KPID) of task that owns this fragment of the memory pool.
MemoryPoolName varchar(32) Null, Parameter Name of the memory pool.
PoolType varchar(30) Null, Parameter Type of memory pool. One of:
  • Block
  • Object
  • Fragment
  • Stack
ConfigOption varchar(255) Null Name of the primary configuration option controlling the size of the memory pool.
NumSearches bigint Counter, Null Total number of free fragments examined before satisfying memory allocation requests from this memory pool.
NumRetries bigint Counter, Null Number of retries performed for all free fragments.
ItemSize int Null Size of an individual item (applies to object pool).
MinNumItems int Null Minimum number of items in this pool.
MaxNumItems int Null Maximum number of items in this pool.
NumUsedItems int Null Number of used items in this pool.
NumItemsUsedHWM int Null High-water mark for the number of items used in this pool.
MinUsedItemSize bigint Null Size, in bytes, of smallest used item.
AvgUsedItemSize bigint Null Average size, in bytes, of used items.
MaxUsedItemSize bigint Null Size, in bytes, of largest used item.
NumUsedItemsMinSize int Null Number of minimum-sized used items in this pool.
NumUsedItemsMaxSize int Null Number of maximum-sized used items in this pool.
NumFreeItems   Null Number of free items in this pool.
MinFreeItemSize bigint Null Size, in bytes, of smallest item that is free.
AvgFreeItemSize bigint Null Average size, in bytes, of free items.
MaxFreeItemSize bigint Null Size, in bytes, of largest item that is free.
NumFreeItemsMinSize int Null Number of minimum-sized free items in this pool.
NumFreeItemsMaxSize int Null Number of maximum-sized free items in this pool.
NumBlocks int Null Number of blocks of memory used for this pool.
MemSize1 int Null Memory pool specific request size 1, in bytes.
NumUsedItemsSize1 int Null Number of used items in this pool of size MemSize1 .
NumFreeItemsSize1 int Null Number of free items in this pool of size MemSize1 .
MemSize2 int Null Memory pool specific request size 2, in bytes.
NumUsedItemsSize2 int Null Number of used items in this pool of size MemSize2.
NumFreeItemsSize2 int Null Number of free items in this pool of size MemSize2.

Not all output from all monMemoryUsage columns applies, or is relevant to, all memory pools, and depending on the type of memory pool, you may need to select the relevant columns. Typically, columns return a value of NULL if they do not apply to a specific memory pool.

These columns report the metrics for used versus free fragments for memory pools of type Fragment:
  • NumUsedItems
  • NumItemsUsedHWM
  • MinUsedItemSize
  • AvgUsedItemSize
  • MaxUsedItemSize
  • NumUsedItemsMinSize
  • NumUsedItemsMaxSize
  • NumFreeItems
  • MinFreeItemSize
  • AvgFreeItemSize
  • MaxFreeItemSize
  • NumFreeItemsMinSize
  • NumFreeItemsMaxSize
This example lists memory pools in the server, along with the primary configuration option affecting the size of the memory pool:
select PoolType = convert(varchar(10), PoolType),
MemoryPoolName = convert(varchar(30), MemoryPoolName),
ConfigOption = convert(varchar(30), ConfigOption)
from monMemoryUsage order by 1, 2
PoolType  MemoryPoolName          ConfigOption
--------  ----------------------- ----------------------------
Block     Compression             compression memory size
Block     Global Block Pool       NULL
Block     Kernel Resource Memory  kernel resource memory
Block     Proc Cache Header       procedure cache size
Block     Pss Heap Memory         heap memory per user
Block     RTMS Block Heap         messaging memory
Fragment  CPINFO memory pool      compression info pool size
Fragment  Column Default Pool     column default cache size
Fragment  Data Cache Frag         NULL
Fragment  Data Change Frag        NULL
Fragment  Data Transfer Utility   transfer utility memory size
[...]
This example lists the common metrics that are applicable to most memory pools:
select MemoryPoolName = convert(varchar(30), MemoryPoolName),
TotalSize, UsedSize, FreeSize, NumAllocs, NumFrees
from monMemoryUsage order by 1
This example lists the metrics that apply to fragment memory pools:
select MemoryPoolName = convert(varchar(30), MemoryPoolName),
NumUsedItems, NumItemsUsedHWM, MinUsedItemSize,
AvgUsedItemSize, MaxUsedItemSize
from monMemoryUsage
where PoolType = "Fragment"
MemoryPoolName  NumUsedItems  NumItemsUsedHWM  MinUsedItemSize
  AvgUsedItemSize  MaxUsedItemSize
--------------  ------------  ---------------  ---------------
  ---------------  ---------------
Pss Frag Pool         983048                0            16960
                0                0
Pss Frag Pool        1376267                0            17040
                0                0
Pss Frag Pool        2293778                0            16960
                0                0