ndbinfo: The NDB Cluster Information Database Since  NDB  does not use single-key access for ordered indexes, the counts for  tot_key_reads , tot_key_inserts ,  tot_key_updates ,  tot_key_writes , and  tot_key_deletes  are not incremented by ordered index operations. When using  tot_key_writes , you should keep in mind that a write operation in this context updates the row if the key exists, and inserts a new row otherwise. (One use of this is in the  NDB  implementation of the  REPLACE  SQL statement.) The  tot_key_refs  column shows the number of key operations refused by the LDM. Generally, such a refusal is due to duplicate keys (inserts),  Key not found  errors (updates, deletes, and reads), or the operation was rejected by an interpreted program used as a predicate on the row matching the key. The  attrinfo  and  keyinfo  attributes counted by the  tot_key_attrinfo_bytes  and tot_key_keyinfo_bytes  columns are attributes of an  LQHKEYREQ  signal (see The NDB Communication Protocol) used to initiate a key operation by the LDM. An  attrinfo  typically contains tuple field values (inserts and updates) or projection specifications (for reads);  keyinfo  contains the primary or unique key needed to locate a given tuple in this schema object. The value shown by  tot_frag_scans  includes both full scans (that examine every row) and scans of subsets. Unique indexes and  BLOB  tables are never scanned, so this value, like other scan-related counts, is 0 for fragment replicas of these. tot_scan_rows_examined  may display less than the total number of rows in a given fragment replica, since ordered index scans can limited by bounds. In addition, a client may choose to end a scan before all potentially matching rows have been examined; this occurs when using an SQL statement containing a  LIMIT  or  EXISTS  clause, for example.  tot_scan_rows_returned  is always less than or equal to tot_scan_rows_examined . tot_scan_bytes_returned  includes, in the case of pushed joins, projections returned to the  DBSPJ block in the NDB kernel. tot_qd_frag_scans  can be effected by the setting for the  MaxParallelScansPerFragment  data node configuration parameter, which limits the number of scans that may execute concurrently on a single fragment replica. This table provides information regarding the latency of disk operations for NDB Cluster Disk Data tablespaces. The  pgman_time_track_stats  table contains the following columns: Unique node ID of this node in the cluster Block number (from  blocks  table) Block instance number • node_id • block_number • block_instance • upper_bound 23.5.14.40 The ndbinfo pgman_time_track_stats Table 4571 Note