Documentation Home
MySQL 5.7 Reference Manual
Related Documentation Download this Manual
PDF (US Ltr) - 37.2Mb
PDF (A4) - 37.2Mb
PDF (RPM) - 36.6Mb
HTML Download (TGZ) - 10.1Mb
HTML Download (Zip) - 10.2Mb
HTML Download (RPM) - 8.8Mb
Man Pages (TGZ) - 206.0Kb
Man Pages (Zip) - 313.0Kb
Info (Gzip) - 3.4Mb
Info (Zip) - 3.4Mb
Excerpts from this Manual

20.5.10.37 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.

Column NameTypeDescription
node_idintegerRequesting node ID
block_numberintegerTC block number
block_instanceintegerTC block instance number
comm_node_idintegerNode ID of communicating API or data node
upper_boundintegerUpper bound of interval (in microseconds)
scansintegerBased on duration of successful scans from opening to closing, tracked against the API or data nodes requesting them.
scan_errorsintegerBased on duration of failed scans from opening to closing, tracked against the API or data nodes requesting them.
scan_fragmentsintegerBased on duration of successful fragment scans from opening to closing, tracked against the data nodes executing them
scan_fragment_errorsintegerBased on duration of failed fragment scans from opening to closing, tracked against the data nodes executing them
transactionsintegerBased 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_errorsintegerBased on duration of failing transactions from start to point of failure, tracked against the API or data nodes requesting them.
read_key_opsintegerBased 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_opsintegerBased 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_opsintegerBased 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_errorsintegerBased 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.

User Comments
Sign Up Login You must be logged in to post a comment.