Event Reports Generated in NDB Cluster • Local writes.   This contains the number of primary-key read operations that were performed using a transaction coordinator on a node that also holds the primary fragment replica of the record. This count can also be obtained from the  LOCAL_WRITES  counter in the  ndbinfo.counters  table. Local query handler statistics (Operations).   There is 1 cluster event per local query handler block (that is, 1 per data node process). Operations are recorded in the LQH where the data they are operating on resides. A single transaction may operate on data stored in multiple LQH blocks. The  Operations  statistic provides the number of local operations performed by this LQH block in the last reporting interval, and includes all types of read and write operations (insert, update, write, and delete operations). This also includes operations used to replicate writes. For example, in a cluster with two fragment replicas, the write to the primary fragment replica is recorded in the primary LQH, and the write to the backup is recorded in the backup LQH. Unique key operations may result in multiple local operations; however, this does  not  include local operations generated as a result of a table scan or ordered index scan, which are not counted. Process scheduler statistics.  In addition to the statistics reported by the transaction coordinator and local query handler, each  ndbd  process has a scheduler which also provides useful metrics relating to the performance of an NDB Cluster. This scheduler runs in an infinite loop; during each loop the scheduler performs the following tasks: Process scheduler statistics include the following: Setting the threshold for  STATISTICS  to 15 causes the cluster log to become very verbose, and to grow quite rapidly in size, in direct proportion to the number of cluster nodes and the amount of activity in the NDB Cluster. For more information about NDB Cluster management client commands relating to logging and reporting, see Section 23.5.3.1, “NDB Cluster Logging Management Commands” . To cause all cluster log statistics to be logged, you can use the following command in the  NDB management client: Note 1. Read any incoming messages from sockets into a job buffer. 2. Check whether there are any timed messages to be executed; if so, put these into the job buffer as well. 3. Execute (in a loop) any messages in the job buffer. 4. Send any distributed messages that were generated by executing the messages in the job buffer. 5. Wait for any new incoming messages. • Mean Loop Counter.   This is the number of loops executed in the third step from the preceding list. This statistic increases in size as the utilization of the TCP/IP buffer improves. You can use this to monitor changes in performance as you add new data node processes. • Mean send size and Mean receive size.   These statistics enable you to gauge the efficiency of, respectively writes and reads between nodes. The values are given in bytes. Higher values mean a lower cost per byte sent or received; the maximum value is 64K. ndb_mgm>  ALL CLUSTERLOG STATISTICS=15 Note 4474