gpactivatestandby
Activates a standby master host and makes it the active master for the Greengage DB system.
Synopsis
gpactivatestandby [-d <standby_master_datadir>] [-f] [-a] [-q]
[-l <logfile_directory>]
gpactivatestandby -v
gpactivatestandby -? | -h | --helpDescription
The gpactivatestandby utility activates a standby master host and brings it into operation as the active master instance for a Greengage DB system.
The activated standby master effectively becomes the Greengage DB master, accepting client connections on the master port.
Before running gpactivatestandby, be sure to run gpstate -f to confirm that the standby master is synchronized with the current master node.
If synchronized, the final line of the gpstate -f output will look similar to this:
20251219:06:59:29:000222 gpstate:mdw:gpadmin-[INFO]:--Sync state: sync
When you initialize a standby master, the default is to use the same port as the active master. For information about the master port for the standby master, see gpinitstandby.
You must run this utility from the master host you are activating, not the failed master host you are deactivating. Running this utility assumes you have a standby master host configured for the system.
The utility will perform the following steps:
-
Stops the synchronization process (
walreceiver) on the standby master. -
Updates the system catalog tables of the standby master using the logs.
-
Activates the standby master to be the new active master for the system.
-
Restarts the Greengage DB system with the new master host.
A standby Greengage DB master host serves as a warm standby in the event of the primary Greengage DB master host becoming non-operational.
The standby master is kept up to date by transaction log replication processes (walsender and walreceiver), which run on the primary master and standby master hosts and keep the data between the primary and standby master hosts synchronized.
If the primary master fails, the log replication process is shut down, and the standby master can be activated in its place by using the gpactivatestandby utility.
Upon activation of the standby master, the replicated logs are used to reconstruct the state of the Greengage DB master host at the time of the last successfully committed transaction.
In order to use gpactivatestandby to activate a new primary master host, the master host that was previously serving as the primary master cannot be running.
The utility checks for a postmaster.pid file in the data directory of the deactivated master host, and if it finds it there, it will assume the old master host is still active.
In some cases, you may need to remove the postmaster.pid file from the deactivated master host data directory before running gpactivatestandby (for example, if the deactivated master host process was terminated unexpectedly).
After activating a standby master, run ANALYZE to update the database query statistics. For example:
$ psql <dbname> -c 'ANALYZE;'After you activate the standby master as the primary master, the Greengage DB system no longer has a standby master configured.
You might want to specify another host to be the new standby with the gpinitstandby utility.
Options
- -a
-
Do not prompt the user for confirmation.
- -d <standby_master_datadir>
-
The absolute path of the data directory for the master host you are activating.
If this option is not specified,
gpactivatestandbyuses the value of the MASTER_DATA_DIRECTORY environment variable setting on the master host you are activating. If this option is specified, it overrides any setting ofMASTER_DATA_DIRECTORY.If a directory cannot be determined, the utility returns an error.
- -f
-
Use this option to force activation of the standby master host. Use this option only if you are sure that the standby and primary master hosts are consistent.
- -l <logfile_directory>
-
The directory to write the log file. Defaults to ~/gpAdminLogs.
- -q
-
Run in quiet mode. Command output is not displayed on the screen, but is still written to the log file.
- -v
-
Display the version, status, last updated date, and checksum of this utility.
- -? | -h | --help
-
Display help.
Examples
Activate the standby master and make it the active master instance for a Greengage DB system (run from the standby master host you are activating):
$ gpactivatestandby -d /data1/master/gpseg-1