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How to start/stop db in admin mode?

Admin mode:

The gpstart with option (-R) is stands for Admin mode or restricted mode where only super users can connect to database when database opened using this option.

utility mode:

Utility mode allows you to connect to only individual segments when started using gpstart -m, for example< to connect to only master instance only:

PGOPTIONS='-c gp_session_role=utility' psql

How to run gpcheckperf IO/netperf?

Create a directory where you have free space and common in all hosts.

For network I/O test for each nic card:

gpcheckperf -f seg_host_file_nic-1 -r N -d /data/gpcheckperf > seg_host_file_nic_1.out

gpcheckperf -f seg_host_file_nic-2 -r N -d /data/gpcheckperf > seg_host_file_nic_2.out

For disk I/O:

gpcheckperf -f seg_host_file_nic-1 -r ds -D -d /data/gpdb_p1 -d /data/gpdb_p2 -d /data/gpdb_m1 -d /data/gpdb_m2

How to update postgresql.conf and reload it?

In GP 4.0 version check gpconfig utility to change postgres.conf parameters.

In 3.X version manually change parameters in postgres.conf for more details check Greenplum Administrator's Guide.

How to manage pg_hba.conf?

The pg_hba.conf file of the master instance controls client access and authentication to your Greenplum system. Check Greenplum Administrator's Guidefor instructions to add / change contents of this file.

How to add new user to the database?

Use createuser utility to create users. See createuser --help for more details.

You can also use SQL commands in psql prompt to create users.

For example: CREATE USER or ROLE <ROLE_NAME> ....

How to create a password free trusted env b/w the all the segment hosts?

Use gpssh-exkeys:

gpssh-exkeys -h hostname1 -h hostname2 .. -h hostnameN

How to check db version and version at init db?

To check version:

psql> select version();


postgres --gp-version

To check gp version at install:

psql> select * from gp_version_at_initdb;

How to see the value of GUC?

By connecting GPDB database using psql query catalog or do show parameter.


gpdb# select name,setting from pg_settings where name='GUC';


gpdb# show <GUC_NAME>;

What is the location of pg_hba/logfile/master_data_directory?

cd $MASTER_DATA_DIRECTORY - Master direcoty.

pg_hba.conf and postgres.conf location and other GPDB internal directories.

cd $MASTER_DATA_DIRECTORY/pg_logs -- Master database logfiles location.


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