Common Reference

General Questions

1How do you change the replicator heap size after installation

You can change the configuration by adding/adjusting the following property in the /etc/tungsten/tungsten.ini and then issuing tpm update

java-mem-size=2048

2What effect do triggers have on replication, either row or statement-based?

The use of triggers can cause many issues with replication, and the effects can differ between different binlog-format settings (Such as ROW vs STATEMENT) For a full explanation see "Triggers"

3On a Tungsten Replicator Replica, how do I set both the local Replica THL listener port and the upstream Primaries THL listener port?

You need to specify two options: thl-port to set the Replica THL listener port and master-thl-port to define the upstream Primary THL listener port. Otherwise thl-port alone sets BOTH.

4Does the replicate filter (i.e. replicate.do and replicate.ignore) address both DML and DDL?

Both filters replicate.do and replicate.ignore will either do or ignore both DML and DDL DDL is currently ONLY replicated for MySQL to MySQL topologies, or within Tungsten Clusters, although it would be advisable not to use ignore/do filters in a clustered environment where data/structural integrity is key. With replicate.do, all DML and DDL will be replicated ONLY for any database or table listed as part of the do filter. With replicate.ignore, all DML and DDL will be replicated exceptfor any database or table listed as part of the ignore filter.

5One of my hosts is regularly a number of seconds behind my other Replicas?

The most likely culprit for this issue is that the time is different on the machine in question. If you have ntp or a similar network time tool installed on your machine, use it to update the current time across **all** the hosts within your deployment:

shell> ntpdate pool.ntp.org

Once the command has been executed across all the hosts, trying sending a heartbeat on the Primary to Replicas and checking the latency:

shell> trepctl heartbeat

6During reprovisioning, the replicator does not appear to be advancing and is stuck. What do I do?

The reprovisioning process creates large events, that doesn't mean the replicator is stuck. Watch the output of trepctl status -name tasks and look for changes in the numbers associated with 'thl-to-q'. Do not restart the replicator, it will just cause you to reprocess transactions.

7What's the last digit mean in the event id (the "-1" or "0")?

That is a session id from the binary log and is not used by the replicator.

Tungsten Clustering Specific

1How do I update the IP address of one or more hosts in the cluster?

To update the IP address used by one or more hosts in your cluster, you must perform the following steps:

If possible, switch the node into SHUNNED mode.
Reconfigure the IP address on the machine.
Update the hostname lookup, for example, by editing the IP configuration in /etc/hosts.
Restart the networking to reconfigure the service.
On the node that has changed IP address, run the following from the software staging directory:
```
shell> tools/tpm update --replace-release
```
On all other nodes within the cluster:
1. Update the hostname lookup for the new node, for example, by updating the IP configuration in /etc/hosts.
2. Place the cluster into MAINTENANCE mode.
3. Execute the following from the software staging directory:
```
shell> tools/tpm update --replace-release
```

2How do I update the password for the replication user in the cluster?

If you need to change the password used by Tungsten Cluster to connect to a dataserver and apply changes, the password can be updated first by changing the information within the your dataserver, and then by updating the configuration using tpm update. The new password is not checked until the Tungsten Replicator process is starting. Changing the password and then updating the configuration will keep replication from failing.

Within cctrl set the MAINTENANCE policy mode:
```
cctrl> set policy maintenance
```
Within MySQL, update the password for the user, allowing the change to be replicated to the other datasources:
```
mysql> SET PASSWORD FOR tungsten@'%' = PASSWORD('new_pass');
```
Update the values for replication-password=new_pass in your /etc/tungsten/tungsten.ini and issue tpm update
Set the policy mode in cctrl back to AUTOMATIC
```
cctrl> set policy automatic
```

3How do I force a failover when the Primary is partially responsive?

To force a failover when the Primary is partially responsive, you can issue from cctrl:

set force true
datasource nas-db-mt01-b.safemls.net fail

4We are in the process of preparing a Tungsten test environment. The Tungsten installation is complete, and the remaining part is restoring the database backup into test servers. Please explain the procedure that must be followed before starting database restoration:
Is there any need to shun affected host?
Is stopping tungsten services is a requirement?

If you are restoring onto this entire test cluster from your production system you should do the following on each host:

stopall
rm -rf /opt/continuent/thl/*
restore the MySQL backup
startall