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22.5.10.40 The ndbinfo tc_time_track_stats Table
The tc_time_track_stats table provides
time-tracking information obtained from the
DBTC block (TC) instances in the data nodes,
through API nodes access NDB. Each TC
instance tracks latencies for a set of activities it undertakes
on behalf of API nodes or other data nodes; these activities
include transactions, transaction errors, key reads, key writes,
unique index operations, failed key operations of any type,
scans, failed scans, fragment scans, and failed fragment scans.
A set of counters is maintained for each activity, each counter
covering a range of latencies less than or equal to an upper
bound. At the conclusion of each activity, its latency is
determined and the appropriate counter incremented.
tc_time_track_stats presents this information
as rows, with a row for each instance of the following:
Data node, using its ID
TC block instance
Other communicating data node or API node, using its ID
Upper bound value
Each row contains a value for each activity type. This is the number of times that this activity occurred with a latency within the range specified by the row (that is, where the latency does not exceed the upper bound).
The following table provides information about the columns in
tc_time_track_stats. 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.
Table 22.416 Columns of the tc_time_track_stats table
| Column Name | Type | Description |
|---|---|---|
node_id |
integer | Requesting node ID |
block_number |
integer | TC block number |
block_instance |
integer | TC block instance number |
comm_node_id |
integer | Node ID of communicating API or data node |
upper_bound |
integer | Upper bound of interval (in microseconds) |
scans |
integer | Based on duration of successful scans from opening to closing, tracked against the API or data nodes requesting them. |
scan_errors |
integer | Based on duration of failed scans from opening to closing, tracked against the API or data nodes requesting them. |
scan_fragments |
integer | Based on duration of successful fragment scans from opening to closing, tracked against the data nodes executing them |
scan_fragment_errors |
integer | Based on duration of failed fragment scans from opening to closing, tracked against the data nodes executing them |
transactions |
integer | Based on duration of successful transactions from beginning until
sending of commit ACK, tracked against
the API or data nodes requesting them. Stateless
transactions are not included. |
transaction_errors |
integer | Based on duration of failing transactions from start to point of failure, tracked against the API or data nodes requesting them. |
read_key_ops |
integer | Based on duration of successful primary key reads with locks. Tracked against both the API or data node requesting them and the data node executing them. |
write_key_ops |
integer | Based on duration of successful primary key writes, tracked against both the API or data node requesting them and the data node executing them. |
index_key_ops |
integer | Based on duration of successful unique index key operations, tracked against both the API or data node requesting them and the data node executing reads of base tables. |
key_op_errors |
integer | Based on duration of all unsuccessful key read or write operations, tracked against both the API or data node requesting them and the data node executing them. |
The block_instance column provides the
DBTC kernel block instance number. You can
use this together with the block name to obtain information
about specific threads from the
threadblocks table.
Document created the 26/06/2006, last modified the 26/10/2018
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