## 23.5.14.51 The ndbinfo tc_time_track_stats Table 

• last_replica_gci 

Last GCI of last crashed fragment replica instance 

• is_replica_alive 

1 if this fragment replica is alive, 0 otherwise 

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 tc_time_track_stats  table contains the following columns: 

• node_id 

Requesting node ID 

• block_number 

TC block number 

• block_instance 

TC block instance number 

• comm_node_id 

Node ID of communicating API or data node 

• upper_bound 

Upper bound of interval (in microseconds) 

• scans 

Based on duration of successful scans from opening to closing, tracked against the API or data nodes requesting them. 

