MySQL 5.6 Reference Manual Including MySQL NDB Cluster 7.3-7.4 Reference Guide
This table provides information about data node resource availability and usage.
These resources are sometimes known as super-pools.
The resources
table contains the following
columns:
node_id
The unique node ID of this data node.
resource_name
Name of the resource; see text.
reserved
The amount reserved for this resource.
used
The amount actually used by this resource.
max
The maximum amount of this resource used, since the node was last started.
The resource_name
can be any one of the names
shown in the following table:
RESERVED
: Reserved by the system; cannot
be overridden.
DISK_OPERATIONS
: If a log file group is
allocated, the size of the undo log buffer is used to set
the size of this resource. This resource is used only to
allocate the undo log buffer for an undo log file group;
there can only be one such group. Overallocation occurs as
needed by CREATE LOGFILE
GROUP
.
DISK_RECORDS
: Records allocated for Disk
Data operations.
DATA_MEMORY
: Used for main memory tuples,
indexes, and hash indexes. Sum of DataMemory and
IndexMemory, plus 8 pages of 32 KB each if IndexMemory has
been set. Cannot be overallocated.
JOBBUFFER
: Used for allocating job
buffers by the NDB scheduler; cannot be overallocated. This
is approximately 2 MB per thread plus a 1 MB buffer in both
directions for all threads that can communicate. For large
configurations this consume several GB.
FILE_BUFFERS
: Used by the redo log
handler in the DBLQH
kernel block; cannot be overallocated. Size is
NoOfFragmentLogParts
* RedoBuffer
, plus 1
MB per log file part.
TRANSPORTER_BUFFERS
: Used for send
buffers by ndbmtd; the sum of
TotalSendBufferMemory
and
ExtraSendBufferMemory
.
This resource that can be overallocated by up to 25 percent.
TotalSendBufferMemory
is calculated by
summing the send buffer memory per node, the default value
of which is 2 MB. Thus, in a system having four data nodes
and eight API nodes, the data nodes have 12 * 2 MB send
buffer memory. ExtraSendBufferMemory
is
used by ndbmtd and amounts to 2 MB extra
memory per thread. Thus, with 4 LDM threads, 2 TC threads, 1
main thread, 1 replication thread, and 2 receive threads,
ExtraSendBufferMemory
is 10 * 2 MB.
Overallocation of this resource can be performed by setting
the
SharedGlobalMemory
data node configuration parameter.
DISK_PAGE_BUFFER
: Used for the disk page
buffer; determined by the
DiskPageBufferMemory
configuration parameter. Cannot be overallocated.
QUERY_MEMORY
: Used by the
DBSPJ
kernel block.
SCHEMA_TRANS_MEMORY
: Minimum is 2 MB; can
be overallocated to use any remaining available memory.