COMMAND NAME: gpactivatestandby 

Activates a standby master host and makes it the active master for the 
Greenplum Database system. 


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SYNOPSIS
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gpactivatestandby -d <standby_master_datadir> [-f] [-a] [-q] 
  [-l <logfile_directory>] 

gpactivatestandby -? | -h | --help 

gpactivatestandby -v 


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DESCRIPTION
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The gpactivatestandby utility activates a backup, standby master host 
and brings it into operation as the active master instance for a 
Greenplum Database system. The activated standby master effectively 
becomes the Greenplum Database master, accepting client connections on 
the master port. 

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 disabling. Running this utility assumes 
you have a standby master host configured for the system (see 
gpinitstandby). 

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 Greenplum Database system with the new master host 

A backup, standby Greenplum master host serves as a 'warm standby' in 
the event of the primary Greenplum master host becoming non-operational. 
The standby master is kept up to date by transaction log replication 
processes (the 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 shutdown, 
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 Greenplum 
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 disabled 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 disabled master host data 
directory before running gpactivatestandby (for example, if the disabled 
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 
Greenplum Database system no longer has a standby master configured. You 
might want to specify another host to be the new standby with the 
gpinitstandby utility. 


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OPTIONS
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-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, gpactivatestandby uses the value 
 specified by the environment variable MASTER_DATA_DIRECTORY of the 
 master host you are activating. 

 If a directory cannot be determined, the utility returns an error. 


-f

 Use this option to force activation of the backup 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

 Displays the version, status, last updated date, and check sum of this 
 utility. 


-? | -h | --help (help) 

 Displays the online help. 


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EXAMPLES
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Activate the standby master host and make it the active master instance 
for a Greenplum Database system (run from backup master host you are 
activating): 

gpactivatestandby -d /gpdata 


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SEE ALSO
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gpinitsystem, gpinitstandby 

