• scan_errors 

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

• scan_fragments 

Based on duration of successful fragment scans from opening to closing, tracked against the data nodes executing them 

• scan_fragment_errors 

Based on duration of failed fragment scans from opening to closing, tracked against the data nodes executing them 

• transactions 

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 

Based on duration of failing transactions from start to point of failure, tracked against the API or data nodes requesting them. 

• read_key_ops 

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 

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 

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 

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. 

## Notes 

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. 

## 23.5.14.52 The ndbinfo threadblocks Table 

The threadblocks  table associates data nodes, threads, and instances of NDB  kernel blocks. 

The threadblocks  table contains the following columns: 

• node_id 

