Spec-Zone .ru
спецификации, руководства, описания, API
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Spec-Zone .ru
спецификации, руководства, описания, API
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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 | Remarks |
|---|---|---|
node_id |
integer | The data node ID |
block_name |
string | Name of the associated NDB kernel block (see ). |
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 isassociated. |
val |
integer | The counter's value |
Each counter is associated with a particular NDB kernel block.
The OPERATIONS counter is associated with the DBLQH
(local query handler) kernel block (see ).
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 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 are associated with the DBSPJ (select push-down join) kernel block (see ).
A number of counters provide information about transporter overload and send buffer sizing when troubleshooting such issues. 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 overload
LQHKEY_OVERLOAD_TC: Count of instances of LQHKEY_OVERLOAD where the TC node transporter was overloaded
LQHKEY_OVERLOAD_READER: Count of instances of LQHKEY_OVERLOAD where the API reader (reads only) node was overloaded.
LQHKEY_OVERLOAD_NODE_PEER: Count of instances of LQHKEY_OVERLOAD where the next backup data node (writes only) was overloaded
LQHKEY_OVERLOAD_SUBSCRIBER: Count of instances of LQHKEY_OVERLOAD where 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.