F.35. pgxc_ddl

F.35.1. Overview
F.35.2. Options

F.35.1.  Overview

pgxc_ddl is a module for Coordinator catalog table synchronization. It has the following syntax.

pgxc_ddl [ option ]

pgxc_ddl is used to synchronize all Coordinator catalog tables from one chosen by a user. It is also possible to launch a DDL on one Coordinator, and then to synchronize all Coordinator catalog tables from the catalog table of the Coordinator having received the DDL. The copy method is "cold". All Coordinators are stopped, catalog files are copied, then all Coordinators are restarted.

This utility is not really needed in Postgres-XL; DDL is synchronized automatically on all the nodes of the cluster.

F.35.2. Options

Options are specified with preceding '-', each option may be associated with a value.

Options are as follows:

-D

Specify pgxc.conf folder, for characteristics of all the Coordinators.

-l

Specify application folder, in case PATH is not defined.

-f

Specify DDL file location.

-d

Database name.

-n

Coordinator number. Coordinator chosen corresponds to the one defined in pgxc.conf at the nth place.

-t

Specify temporary folder where to copy the configuration files postgresql.conf and pg_hba.conf for each Coordinator.

Because pgxc_ddl requires access to the Coordinator configuration file and data folders, the following parameters have to be set in pgxc.conf:

Table F.27. pgxc.conf entries

NameTypeDescription
coordinator_portsstring Specify the port number of all Coordinators. Maintain the order of the value as the same as those in coordinator_hosts. It is necessary to specify a number of ports equal to the number of hosts. A comma separator is also necessary.
coordinator_foldersstring Specify the data folders of all Coordinators. Maintain the order of the value as the same as those in coordinator_hosts. It is necessary to specify a number of data folders equal to the number of hosts. A comma separator is also necessary.
coordinator_hostsstring Specify the host name or IP address of the Coordinators. Separate each value with comma.

Note

About the temporary folder, this one has the name chosen by the user. As an extension name, the PID of the shell script is added. This folder is by default in /tmp. The user can choose the name freely.

Note

Configuration files of Coordinators that have their catalog files changed are defined with an extension name postgresql.conf.number, "number" being the number of the Coordinator in the order defined in pgxc.conf.