Use ttRepAdmin to Show Replication Status

The output from ttRepAdmin -showstatus includes the status of the main thread and the TRANSMITTER and RECEIVER threads used by the replication agent.

A master database has a TRANSMITTER thread and a subscriber database has a RECEIVER thread. A database that serves a master/subscriber role in a bidirectional replication scheme has both a TRANSMITTER and a RECEIVER thread.

Each replication agent has a single REPLISTENER thread that listens on a port for peer connections. On a master database, the REPLISTENER thread starts a separate TRANSMITTER thread for each subscriber database. On a subscriber database, the REPLISTENER thread starts a separate RECEIVER thread for each connection from a master.

If the TimesTen daemon requests that the replication agent stop or if a fatal error occurs in any of the other threads used by the replication agent, the main thread waits for the other threads to gracefully terminate. The TimesTen daemon may or may not restart the replication agent, depending upon certain fatal errors. The REPLISTENER thread never terminates during the lifetime of the replication agent. A TRANSMITTER or RECEIVER thread may stop but the replication agent may restart it. The RECEIVER thread terminates on errors from which it cannot recover or when the master disconnects.

The following example demonstrates the ttRepAdmin -showstatus output.

Following the examples are sections that describe the meaning of each field in the ttRepAdmin -showstatus output:

The following example is an active standby pair replication scheme in which the rep1 database is the active master and rep2 database is the standby master in an active standby pair replication scheme.

The ReplicationParallelism connection attribute in this example is set to 2, which indicates the number of transmitter threads on the source database and the number of receiver threads on the target database. 

$ ttRepAdmin -showstatus -detail rep1
 
Replication Agent Status as of: 2019-09-03 10:01:31
 
DSN                         : rep1
Process ID                  : 9012 (Started)
Replication Agent Policy    : manual
Host                        : MYHOST
RepListener Port            : 56209 (AUTO)
Main thread's state         : STATE_MM_IDLE_STATE
Last write LSN              : 0.22169832
Last LSN forced to disk     : 0.22169600
Replication hold LSN        : 0.22159592

Note that the Replication hold LSN, the Last write LSN and the Last LSN forced to disk are very close, which indicates that replication is operating satisfactorily. If the Replication hold LSN falls behind the Last write LSN and the Last LSN, then replication is not keeping up with updates to the master. 

Replication Peers:
   Name                     : REP2
   Host                     : MYHOST2
   Port                     : 51509 (AUTO) (Connected)
   Replication State        : STARTED
   Communication Protocol   : 47
 
   Name                     : REP2
   Host                     : MYHOST2
   Port                     : 51509 (AUTO) (Connected)
   Replication State        : STARTED
   Communication Protocol   : 47

Since ReplicationParallelism is set to 2, there are two entries for the replication peer for rep2. 

REPHOLD thread (REPHOLD:140175402608384):
   Start/Restart count   : 1
   Current state         : STATE_REPHOLD_SLEEPING
   Current DB context    : 0x7f7d180008c0
 
REPLISTENER thread (REPLISTENER:140175393158912):
   Start/Restart count   : 1
   Current state         : STATE_LISTENER_WAIT_FOR_PEER_CONN
   Current DB context    : 0x7f7c9c0008c0
   Most recent errors (max 5):
     TT16999 in receiver.c (line 2608) at 09:55:38 on 09-03-2019
     TT16999 in receiver.c (line 2608) at 09:55:55 on 09-03-2019
 
LOGFORCE thread (LOGFORCE:140175407265536):
   Start/Restart count   : 1
   Current state         : STATE_LOGFORCE_SLEEPING
   Current DB context    : 0x7f7d140afae0

With an active standby pair, each master has both transmitters to and receivers from the other master. The number of transmitters and receivers determined by the ReplicationParallelism setting. In this example, since ReplicationParallelism is set to 2, there are two transmitter and receiver threads between the active and standby masters, shown as track 0 and track 1 in the output. 

TRANSMITTER thread(s) (TRANSMITTER(S):140172775343872):
 For                     : REP2 (track 1)(SSL) 
 Start/Restart count   : 1
   Current state         : STATE_XMTR_FLUSH_SENDING_DONE
   Current DB context    : 0x7f7ca44ff640
   Send LSN              : 0.22159592
   Replication Tables CTN: 1567529721.542
   Transactions sent     : 101
   Total packets sent    : 36
   Tick packets sent     : 25
   MIN sent packet size  : 64
   MAX sent packet size  : 16384
   AVG sent packet size  : 876
   Last packet sent at   : 10:01:26
   Total Packets received: 34
   MIN rcvd packet size  : 64
   MAX rcvd packet size  : 128
   AVG rcvd packet size  : 119
   Last packet rcvd'd at : 10:01:26
   TXNs Allocated        : 102
   TXNs In Use           : 0
   ACTs Allocated        : 101
   ACTs In Use           : 0
   ACTs Data Allocated   : 0
   Timeout               : 7200
   Adapted Timeout Max   : 7200
   Adapted Timeout Time  : 1567530021
   current txn           : 0.0
   Longest batch runtime : 0
   Longest batch 1st txn : 0.0
   Longest batch lst txn : 0.0
   Largest txn (ops)     : 1567529721.441
   Largest txn (#ops)    : 1
   Longest txn (time)    : 0.0
   Longest txn (secs)    : 0
   Most recent errors (max 5):
     TT16999 in transmitter.c (line 1465) at 09:55:56 on 09-03-2019
 
RECEIVER thread(s) (RECEIVER:140173241992960):
 For                     : REP2 (track 1)(SSL) 
   Start/Restart count   : 1
   Current state         : STATE_RCVR_READ_NETWORK_LOOP
   Current DB context    : 0x7f7c9c4b0b90
   Transactions received : 0
   Total packets sent    : 28
   Tick packets sent     : 0
   MIN sent packet size  : 64
   MAX sent packet size  : 128
   AVG sent packet size  : 122
   Last packet sent at   : 10:01:19
   Total Packets received: 29
   MIN rcvd packet size  : 64
   MAX rcvd packet size  : 156
   AVG rcvd packet size  : 68
   Last packet rcvd'd at : 10:01:19
   rxWaitCTN             : 0.0
   prevCTN               : 0.0
   current txn           : 0.0
   STA Blk Data Allocated: 0
   STA Data Allocated    : 0
   Longest batch runtime : 0
   Longest batch 1st txn : 0.0
   Longest batch lst txn : 0.0
   Largest txn (ops)     : 0.0
   Largest txn (#ops)    : 0
   Longest txn (time)    : 0.0
   Longest txn (secs)    : 0
 
TRANSMITTER thread(s) (TRANSMITTER(M):140175390009088):
 For                     : REP2 (track 0)(SSL) 
   Start/Restart count   : 1
   Current state         : STATE_META_PEER_INFO
   Current DB context    : 0x7f7c980008c0
   Send LSN              : 0.22159592
   Replication Tables CTN: 1567529721.386
   Transactions sent     : 100
   Total packets sent    : 88
   Tick packets sent     : 74
   MIN sent packet size  : 64
   MAX sent packet size  : 16384
   AVG sent packet size  : 394
   Last packet sent at   : 10:01:26
   Total Packets received: 86
   MIN rcvd packet size  : 64
   MAX rcvd packet size  : 128
   AVG rcvd packet size  : 123
   Last packet rcvd'd at : 10:01:26
   TXNs Allocated        : 101
   TXNs In Use           : 0
   ACTs Allocated        : 100
   ACTs In Use           : 0
   ACTs Data Allocated   : 0
   Timeout               : 7200
   Adapted Timeout Max   : 7200
   Adapted Timeout Time  : 1567529956
   current txn           : 0.0
   Longest batch runtime : 0
   Longest batch 1st txn : 0.0
   Longest batch lst txn : 0.0
   Largest txn (ops)     : 1567529721.286
   Largest txn (#ops)    : 1
   Longest txn (time)    : 0.0
   Longest txn (secs)    : 0
   Most recent errors (max 5):
     TT16999 in transmitter.c (line 1465) at 09:55:38 on 09-03-2019
 
RECEIVER thread(s) (RECEIVER:140173245142784):
 For                     : REP2 (track 0)(SSL) 
   Start/Restart count   : 1
   Current state         : STATE_RCVR_READ_NETWORK_LOOP
   Current DB context    : 0x7f7c944a41f0
   Transactions received : 0
   Total packets sent    : 79
   Tick packets sent     : 0
   MIN sent packet size  : 64
   MAX sent packet size  : 128
   AVG sent packet size  : 125
   Last packet sent at   : 10:01:29
   Total Packets received: 80
   MIN rcvd packet size  : 64
   MAX rcvd packet size  : 156
   AVG rcvd packet size  : 65
   Last packet rcvd'd at : 10:01:29
   rxWaitCTN             : 0.0
   prevCTN               : 0.0
   current txn           : 0.0
   STA Blk Data Allocated: 0
   STA Data Allocated    : 0
   Longest batch runtime : 0
   Longest batch 1st txn : 0.0
   Longest batch lst txn : 0.0
   Largest txn (ops)     : 0.0
   Largest txn (#ops)    : 0
   Longest txn (time)    : 0.0
   Longest txn (secs)    : 0

MAIN Thread Status Fields

The MAIN thread status fields are output for the MAIN thread in the replication agent for the queried database.

MAIN Thread Description

DSN

Name of the database to be queried.

Process ID

Process Id of the replication agent.

Replication Agent Policy

The restart policy, as described in Starting and Stopping the Replication Agents

Host

Name of the machine that hosts this database.

RepListener Port

TCP/IP port used by the replication agent to listen for connections from the TRANSMITTER threads of remote replication agents. A value of 0 indicates that this port has been assigned automatically to the replication agent (the default), rather than being specified as part of a replication scheme.

Main thread's state

Internal use only.

Last write LSN

The location of the most recently generated transaction log record for the database. See Show Replicated Log Records.

Last LSN forced to disk

The location of the most recent transaction log record written to the disk. See Show Replicated Log Records.

Replication hold LSN

The location of the lowest (or oldest) record held in the log for possible transmission to a subscriber. A value of -1/-1 indicates replication is in the stop state with respect to all subscribers. See Show Replicated Log Records.

Replication Peer Status Fields

The replication peer status fields are output for each replication peer that participates in the replication scheme with the queried database. A "peer" could play the role of master, subscriber, propagator or both master and subscriber in a bidirectional replication scheme.

Replication Peers Description

Name

Name of a database that is a replication peer to this database.

Host

Host of the peer database.

Port

TCP/IP port used by the replication agent for the peer database. A value of 0 indicates this port has been assigned automatically to the replication agent (the default), rather than being specified as part of a replication scheme.

Replication State

Current replication state of the replication peer with respect to the queried database See Show Subscriber Database Information.

Communication Protocol

Internal protocol used by replication to communicate between the peers. (For internal use only.)

Note:

The REPHOLD, REPLISTENER and LOGFORCE thread sections are for internal use only.

TRANSMITTER Thread Status Fields

The TRANSMITTER thread status fields are output for each TRANSMITTER thread used by a master replication agent to send transaction updates to a subscriber. A master with multiple subscribers has multiple TRANSMITTER threads.

Note:

The counts in the TRANSMITTER output begin to accumulate when the replication agent is started. These counters are reset to 0 only when the replication agent is started or restarted.

TRANSMITTER Thread Description

For

Name of the subscriber database that is receiving replicated data from this database. Also, whether the replication agent transmitters are using Transport Layer Security (TLS) (indicated with "SSL").

Start/Restart count

Number of times this TRANSMITTER thread was started or restarted by the replication agent due to a temporary error, such as operation timeout, network failure, and so on.

Current state

Internal use only.

Current DB context

Internal use only.

Send LSN

The last LSN transmitted to this peer. See Show Replicated Log Records.

Replication Tables CTN

Internal use only.

Transactions sent

Total number of transactions sent to the subscriber.

Total packets sent

Total number of packets sent to the subscriber (including tick packets).

Tick packets sent

Total number of tick packets sent. Tick packets are used to maintain a "heartbeat" between the master and subscriber. You can use this value to determine how many of the 'Total packets sent' packets are not related to replicated data.

MIN sent packet size

Size of the smallest packet sent to the subscriber.

MAX sent packet size

Size of the largest packet sent to the subscriber.

AVG sent packet size

Average size of the packets sent to the subscriber.

Last packet sent at

Time of day last packet was sent (24-hour clock time).

Total packets received

Total packets received from the subscriber (tick packets and acknowledgement data).

MIN rcvd packet size

Size of the smallest packet received.

MAX rcvd packet size

Size of the largest packet received.

AVG rcvd packet size

Average size of the packets received.

Last packet rcvd at

Time of day last packet was received (24-hour clock time).

TXNs Allocated

TXNs In Use

ACTs Allocated

ACTs In Use

ACTs Data Allocated

Timeout

Adapted Timeout Max

Adapted Timeout Time

current txn

Longest batch runtime

Longest batch 1st txn

Longest batch lst txn

Largest txn (#ops)

Longest txn (time)

Internal use only.

Largest txn (ops)

Number of operations.

Longest txn (secs)

Amount of time in seconds taken to process the longest transaction.

Most recent errors (max 5)

Last five errors generated by this thread.

RECEIVER Thread Status Fields

The RECEIVER thread status fields are output for each RECEIVER thread used by a subscriber replication agent to receive transaction updates from a master. A subscriber that is updated by multiple masters has multiple RECEIVER threads.

Note:

The counts in the RECEIVER output begin to accumulate when the replication agent is started. These counters are reset to 0 only when the replication agent is started or restarted.

RECEIVER Thread Description

For

Name of the master database that is sending replicated data from this database. Also, whether the replication agent receivers are using Transport Layer Security (TLS) (indicated with "SSL").

Start/Restart count

Number of times this RECEIVER thread was started or restarted by the replication agent due to a temporary error, such as operation timeout, network failure, and so on.

Current state

Internal use only.

Current DB context

Internal use only.

Transactions received

Total number of transactions received from the master.

Total packets sent

Total number of packets sent to the master (tick packets and acknowledgement data).

Tick packets sent

Total number of tick packets sent to the master. Tick packets are used to maintain a "heartbeat" between the master and subscriber. You can use this value to determine how many of the 'Total packets sent' packets are not related to acknowledgement data.

MIN sent packet size

Size of the smallest packet sent to the master.

MAX sent packet size

Size of the largest packet sent to the master.

AVG sent packet size

Average size of the packets sent to the master.

Last packet sent at

Time of day last packet was sent to the master (24-hour clock time).

Total packets received

Total packets of acknowledgement data received from the master.

MIN rcvd packet size

Size of the smallest packet received.

MAX rcvd packet size

Size of the largest packet received.

AVG rcvd packet size

Average size of the packets received.

Last packet rcvd at

Time of day last packet was received (24-hour clock time).

rxWaitCTN

prevCTN

current txn

STA Blk Data Allocated

STA Data Allocated

Longest batch runtime

Longest batch 1st txn

Longest batch lst txn

Largest txn (#ops)

Longest txn (time)

Internal use only.

Largest txn (ops)

Number of operations.

Longest txn (secs)

Amount of time in seconds taken to process the longest transaction.