Starting and Stopping Greenplum Database
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Starting and Stopping Greenplum Database
In a Greenplum Database DBMS, the database server instances (the master and all
segments) are started or stopped across all of the hosts in the system in such a way that they
can work together as a unified DBMS.
Because a Greenplum Database system is distributed across many machines, the process for
starting and stopping a Greenplum Database system is different than the process for starting
and stopping a regular PostgreSQL DBMS.
Use the gpstart and gpstop utilities to start and stop
Greenplum Database, respectively. These utilities are located in the
$GPHOME/bin directory on your Greenplum Database master host.
Important: Do not issue a
kill command to end any Postgres process.
Instead, use the database command
pg_cancel_backend().
Issuing a
kill -9 or kill -11 can introduce database corruption
and prevent root cause analysis from being performed.
For information about gpstart and gpstop, see the
Greenplum Database Utility Guide.
Starting Greenplum Database
Start an initialized Greenplum Database system by running the
gpstart utility on the master instance.
Use the gpstart utility to start a Greenplum Database system that
has already been initialized by the gpinitsystem utility, but has been
stopped by the gpstop utility. The gpstart utility starts
Greenplum Database by starting all the Postgres database instances on the Greenplum Database
cluster. gpstart orchestrates this process and performs the process in
parallel.
Run gpstart on the master host to start Greenplum Database:
Restarting Greenplum Database
Stop the Greenplum Database system and then restart it.
The gpstop utility with the -r option can stop and
then restart Greenplum Database after the shutdown completes.
To restart Greenplum Database, enter the following command on the master host:
Reloading Configuration File Changes Only
Reload changes to Greenplum Database configuration files without interrupting the
system.
The gpstop utility can reload changes to the
pg_hba.conf configuration file and to runtime parameters in
the master postgresql.conf file and pg_hba.conf
file without service interruption. Active sessions pick up changes when they reconnect to
the database. Many server configuration parameters require a full system restart
(gpstop -r) to activate. For information about server configuration
parameters, see the Greenplum Database Reference Guide.
Reload configuration file changes without shutting down the system using the
gpstop utility:
Starting the Master in Maintenance Mode
Start only the master to perform maintenance or administrative tasks without
affecting data on the segments.
Maintenance mode should only be used with direction from
Pivotal Technical Support. For example, you could connect to a database only on the
master instance in maintenance mode and edit system catalog settings. For more information
about system catalog tables, see the Greenplum Database Reference
Guide.
-
Run gpstart using the -m option:
-
Connect to the master in maintenance mode to do catalog maintenance. For
example:
$ PGOPTIONS='-c gp_session_role=utility' psql postgres
-
After completing your administrative tasks, stop the master in utility mode. Then,
restart it in production mode.
Warning:
Incorrect use of maintenance mode connections can result in an inconsistent system
state. Only Technical Support should perform this operation.
Stopping Greenplum Database
The gpstop utility stops or restarts your Greenplum Database system
and always runs on the master host. When activated, gpstop stops all
postgres processes in the system, including the master and all segment
instances. The gpstop utility uses a default of up to 64 parallel worker
threads to bring down the Postgres instances that make up the Greenplum Database cluster.
The system waits for any active transactions to finish before shutting down. To stop
Greenplum Database immediately, use fast mode.
