- 7.10 The ndbinfo MySQL Cluster Information Database
- 7.10.1 The ndbinfo arbitrator_validity_detail Table
- 7.10.2 The ndbinfo arbitrator_validity_summary Table
- 7.10.3 The ndbinfo blocks Table
- 7.10.4 The ndbinfo cluster_operations Table
- 7.10.5 The ndbinfo cluster_transactions Table
- 7.10.6 The ndbinfo config_params Table
- 7.10.7 The ndbinfo counters Table
- 7.10.8 The ndbinfo diskpagebuffer Table
- 7.10.9 The ndbinfo logbuffers Table
- 7.10.10 The ndbinfo logspaces Table
- 7.10.11 The ndbinfo membership Table
- 7.10.12 The ndbinfo memoryusage Table
- 7.10.13 The ndbinfo nodes Table
- 7.10.14 The ndbinfo pools Table
- 7.10.15 The ndbinfo resources Table
- 7.10.16 The ndbinfo server_operations Table
- 7.10.17 The ndbinfo server_transactions Table
- 7.10.18 The ndbinfo threadblocks Table
- 7.10.19 The ndbinfo threadstat Table
- 7.10.20 The ndbinfo transporters Table
The counters table provides running totals of
events such as reads and writes for specific kernel blocks and
data nodes. Counts are kept from the most recent node start or
restart; a node start or restart resets all counters on that
node. Not all kernel blocks have all types of counters.
The following table provides information about the columns in
the counters table. For each column, the
table shows the name, data type, and a brief description.
Additional information can be found in the notes following the
table.
| Column Name | Type | Description |
|---|---|---|
node_id | integer | The data node ID |
block_name | string | Name of the associated NDB kernel block (see
NDB Kernel Blocks). |
block_instance | integer | Block instance |
counter_id | integer | The counter's internal ID number; normally an integer between 1 and 10, inclusive. |
counter_name | string | The name of the counter. See text for names of individual counters and the NDB kernel block with which each counter is associated. |
val | integer | The counter's value |
Each counter is associated with a particular NDB kernel block.
Prior to MySQL Cluster NDB 7.2.0, this was limited to either the
DBLQH kernel block or the
DBTC kernel block.
The OPERATIONS counter is associated with the
DBLQH (local query handler) kernel block (see
The DBLQH Block).
The ATTRINFO,
TRANSACTIONS, COMMITS,
READS, SIMPLE_READS,
WRITES, ABORTS,
TABLE_SCANS, and
RANGE_SCANS counters are associated with the
DBTC (transaction co-ordinator) kernel block (see
The DBTC Block).
MySQL Cluster NDB 7.2.0, as part of its implementation of
distributed pushed-down joins, adds the
LOCAL_TABLE_SCANS_SENT,
READS_RECEIVED,
PRUNED_RANGE_SCANS_RECEIVED,
RANGE_SCANS_RECEIVED,
LOCAL_READS_SENT,
CONST_PRUNED_RANGE_SCANS_RECEIVED,
LOCAL_RANGE_SCANS_SENT,
REMOTE_READS_SENT,
REMOTE_RANGE_SCANS_SENT,
READS_NOT_FOUND,
SCAN_BATCHES_RETURNED,
TABLE_SCANS_RECEIVED, and
SCAN_ROWS_RETURNED counters. These counters
are associated with the DBSPJ (select
push-down join) kernel block (see
The DBSPJ Block).
A number of counters increasing the visibility of transporter overload and send buffer sizing when troubleshooting such issues were added in MySQL Cluster NDB 7.0.37 and MySQL Cluster NDB 7.1.26. (Bug #15935206) For each LQH instance, there is one instance of each counter in the following list:
LQHKEY_OVERLOAD: Number of primary key requests rejected at the LQH block instance due to transporter overloadLQHKEY_OVERLOAD_TC: Count of instances ofLQHKEY_OVERLOADwhere the TC node transporter was overloadedLQHKEY_OVERLOAD_READER: Count of instances ofLQHKEY_OVERLOADwhere the API reader (reads only) node was overloaded.LQHKEY_OVERLOAD_NODE_PEER: Count of instances ofLQHKEY_OVERLOADwhere the next backup data node (writes only) was overloadedLQHKEY_OVERLOAD_SUBSCRIBER: Count of instances ofLQHKEY_OVERLOADwhere a event subscriber (writes only) was overloaded.LQHSCAN_SLOWDOWNS: Count of instances where a fragment scan batch size was reduced due to scanning API transporter overload.
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