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MySQL NDB Cluster 7.5
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6.14.31 The ndbinfo resources Table

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.