Example: ctdb statistics¶

CTDB version 1
Current time of statistics  :                Fri Sep 12 13:32:32 2014
Statistics collected since  : (000 01:49:20) Fri Sep 12 11:43:12 2014


 num_clients                        6


 frozen                             0


 recovering                         0


 num_recoveries                     2


 client_packets_sent           281293


 client_packets_recv           296317


 node_packets_sent             452387


 node_packets_recv             182394


 keepalive_packets_sent          3927


 keepalive_packets_recv          3928


 node


     req_call                   48605


     reply_call                     1


     req_dmaster                23404


     reply_dmaster              24917


     reply_error                    0


     req_message                  958


     req_control               197513


     reply_control             153705


 client


     req_call                  130866


     req_message                  770


     req_control               168921


 timeouts


     call                           0


     control                        0


     traverse                       0


 locks


     num_calls                    220


     num_current                    0


     num_pending                    0


     num_failed                     0


 total_calls                   130866


 pending_calls                      0


 childwrite_calls                   1


 pending_childwrite_calls             0


 memory_used                   334490


 max_hop_count                     18


 total_ro_delegations               2


 total_ro_revokes                   2


 hop_count_buckets: 42816 5464 26 1 0 0 0 0 0 0 0 0 0 0 0 0


 lock_buckets: 9 165 14 15 7 2 2 0 0 0 0 0 0 0 0 0


 locks_latency      MIN/AVG/MAX     0.000685/0.160302/6.369342 sec out of 214


 reclock_ctdbd      MIN/AVG/MAX     0.004940/0.004969/0.004998 sec out of 2


 reclock_recd       MIN/AVG/MAX     0.000000/0.000000/0.000000 sec out of 0


 call_latency       MIN/AVG/MAX     0.000006/0.000719/4.562991 sec out of 126626


 childwrite_latency MIN/AVG/MAX     0.014527/0.014527/0.014527 sec out of 1
	

CTDB version¶

Version of the ctdb protocol used by the node.

Current time of statistics¶

Time when the statistics are generated.

This is useful when collecting statistics output periodically for post-processing.

Statistics collected since¶

Time when ctdb was started or the last time statistics was reset. The output shows the duration and the timestamp.

num_clients¶

Number of processes currently connected to CTDB's unix socket. This includes recovery daemon, ctdb tool and samba processes (smbd, winbindd).

frozen¶

1 if the databases are currently frozen, 0 otherwise.

recovering¶

1 if recovery is active, 0 otherwise.

num_recoveries¶

Number of recoveries since the start of ctdb or since the last statistics reset.

client_packets_sent¶

Number of packets sent to client processes via unix domain socket.

client_packets_recv¶

Number of packets received from client processes via unix domain socket.

node_packets_sent¶

Number of packets sent to the other nodes in the cluster via TCP.

node_packets_recv¶

Number of packets received from the other nodes in the cluster via TCP.

keepalive_packets_sent¶

Number of keepalive messages sent to other nodes.

CTDB periodically sends keepalive messages to other nodes. See KeepaliveInterval tunable in ctdb-tunables(7) for more details.

keepalive_packets_recv¶

Number of keepalive messages received from other nodes.

node¶

This section lists various types of messages processed which originated from other nodes via TCP.

req_call

reply_call

req_dmaster

reply_dmaster

reply_error

req_message

req_control

reply_control

req_tunnel

client¶

This section lists various types of messages processed which originated from clients via unix domain socket.

req_call

req_message

req_control

req_tunnel

timeouts¶

This section lists timeouts occurred when sending various messages.

call

control

traverse

locks¶

This section lists locking statistics.

num_calls

num_current

num_pending

num_failed

total_calls¶

Number of req_call messages processed from clients. This number should be same as client --> req_call.

pending_calls¶

Number of req_call messages which are currently being processed. This number indicates the number of record migrations in flight.

childwrite_calls¶

Number of record update calls. Record update calls are used to update a record under a transaction.

pending_childwrite_calls¶

Number of record update calls currently active.

memory_used¶

The amount of memory in bytes currently used by CTDB using talloc. This includes all the memory used for CTDB's internal data structures. This does not include the memory mapped TDB databases.

max_hop_count¶

The maximum number of hops required for a record migration request to obtain the record. High numbers indicate record contention.

total_ro_delegations¶

Number of readonly delegations created.

total_ro_revokes¶

Number of readonly delegations that were revoked. The difference between total_ro_revokes and total_ro_delegations gives the number of currently active readonly delegations.

hop_count_buckets¶

Distribution of migration requests based on hop counts values. Buckets are 0, < 2, < 4, < 8, < 16, < 32, < 64, < 128, < 256, < 512, < 1024, < 2048, < 4096, < 8192, < 16384, ≥ 16384.

lock_buckets¶

Distribution of record lock requests based on time required to obtain locks. Buckets are < 1ms, < 10ms, < 100ms, < 1s, < 2s, < 4s, < 8s, < 16s, < 32s, < 64s, ≥ 64s.

locks_latency¶

The minimum, the average and the maximum time (in seconds) required to obtain record locks.

reclock_ctdbd¶

The minimum, the average and the maximum time (in seconds) required to check if recovery lock is still held by recovery daemon when recovery mode is changed. This check is done in ctdb daemon.

reclock_recd¶

The minimum, the average and the maximum time (in seconds) required to check if recovery lock is still held by recovery daemon during recovery. This check is done in recovery daemon.

call_latency¶

The minimum, the average and the maximum time (in seconds) required to process a REQ_CALL message from client. This includes the time required to migrate a record from remote node, if the record is not available on the local node.

childwrite_latency¶

Default: 0

The minimum, the average and the maximum time (in seconds) required to update records under a transaction.

Example: ctdb dbstatistics notify_index.tdb¶

DB Statistics: notify_index.tdb


 ro_delegations                     0


 ro_revokes                         0


 locks


     total                        131


     failed                         0


     current                        0


     pending                        0


 hop_count_buckets: 9890 5454 26 1 0 0 0 0 0 0 0 0 0 0 0 0


 lock_buckets: 4 117 10 0 0 0 0 0 0 0 0 0 0 0 0 0


 locks_latency      MIN/AVG/MAX     0.000683/0.004198/0.014730 sec out of 131


 Num Hot Keys:     3


     Count:7 Key:2f636c75737465726673


     Count:18 Key:2f636c757374657266732f64617461


     Count:7 Key:2f636c757374657266732f646174612f636c69656e7473
	

DB Statistics¶

Name of the database.

ro_delegations¶

Number of readonly delegations created in the database.

ro_revokes¶

Number of readonly delegations revoked. The difference in ro_delegations and ro_revokes indicates the currently active readonly delegations.

locks¶

This section lists locking statistics.

total

failed

current

pending

hop_count_buckets¶

Distribution of migration requests based on hop counts values. Buckets are 0, < 2, < 4, < 8, < 16, < 32, < 64, < 128, < 256, < 512, < 1024, < 2048, < 4096, < 8192, < 16384, ≥ 16384.

lock_buckets¶

Distribution of record lock requests based on time required to obtain locks. Buckets are < 1ms, < 10ms, < 100ms, < 1s, < 2s, < 4s, < 8s, < 16s, < 32s, < 64s, ≥ 64s.

locks_latency¶

The minimum, the average and the maximum time (in seconds) required to obtain record locks.

Num Hot Keys¶

Number of contended records determined by hop count. CTDB keeps track of top 10 hot records and the output shows hex encoded keys for the hot records.