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This topic covers the preparatory steps for upgrading your cluster with Greenplum Upgrade. Review these steps early in the process to help you understand the time needed to prepare the source cluster for a successful upgrade.

We strongly recommend that you run through the upgrade process in a test environment first. This will familiarize you with the workflow and enable you to fully test your data on the upgraded Greenplum version before proceeding with the production upgrade.

Pre-upgrade Checklist

Review the following pre-upgrade checklist, preferably a few weeks before the upgrade project.

Install the gpupgrade Utility

You may install the gpupgrade utility to the default location or to a location you specify.

  1. Download the gpupgrade utility from Broadcom Support Portal to a location of your choice.
Note

For more information about download prerequisites, troubleshooting, and instructions, see Download Broadcom products and software.

  1. Install the gpupgrade utility to the default or a user-defined location.

    • To install to the default /usr/local/bin/ location on all hosts, use the yum command with sudo (or as root):

      sudo yum install gpugrade-<version>.el7.x86_64.rpm

    • Alternatively, install the gpupgrade utility to a user-specified location:

      sudo rpm  --prefix=<USER_DIRECTORY> -ivh gpupgrade-<version>.el7.x86_64.rpm

      Ensure the gpupgrade binaries are available in the user’s executable path:

      export PATH=<USER_DIRECTORY>:$PATH

      Change the owner and group of the installed files to gpadmin:

      sudo chown gpadmin:gpadmin <USER_DIRECTORY>/gpupgrade*                                                                                             
sudo chown -R gpadmin:gpadmin <USER_DIRECTORY>/greenplum/gpupgrade/*

  2. If desired, install bash completion for ease of use, with the following command:

    yum install bash-completion

Install the Greenplum Database Target Version

Install the target Greenplum Database 6.x package on each Greenplum system host, using the system’s package manager software. For example, for RHEL/CentOS systems, execute the yum command with sudo (or as root):

sudo yum install ./greenplum-db-<target-version>-<platform>.rpm

Change the owner and group of the installed files to gpadmin:

sudo chown -R gpadmin:gpadmin /usr/local/greenplum*

Prepare the Source Cluster

Certain components of Greenplum 5 cannot be automatically upgraded by the gpupgrade utility. There are also certain configuration items that are not supported when movin when moving from 5 to 6. Follow the recommendations below to prepare the source Greenplum cluster.

Upgrade the source 5.x Greenplum Cluster

The minimum supported Greenplum 5 version is 5.29.10. Upgrade the source 5.x Greenplum cluster to the latest version you downloaded. For upgrade details see Upgrading to Greenplum Database 5.29.x.

Prepare Installed Extensions

Greenplum Database supports a variety of extensions. To determine what extensions are installed on your source cluster, query the pg_extension catalog table:

SELECT * FROM pg_extension;

During the upgrade process, extensions are handled differently depending on the type of extension:

Upgrading with PostgreSQL Extensions

Greenplum Database ships with some PostgreSQL native extensions, such as amcheck, dblink, hstore, fuzzystrmatch, citext, and pgcrypto. gpupgrade handles these PostgreSQL extensions automatically through the upgrade process. There is no action required in preparation for the upgrade regarding these extensions.

For other PostgreSQL native extensions that are not shipped with Greenplum, you must install them on the target cluster by placing the .so library files inside $libdir directory. Do not run CREATE EXTENSION <extension_name> as gpupgrade handles this part.

You must copy any custom user defined files such as dictionary, synonym, or thesaurus to the target cluster.

Upgrade Supported Greenplum Extensions

Greenplum supported extensions can be upgraded by gpupgrade as part of the upgrade process and are listed below. Upgrade the supported Greenplum extensions to their latest version on the source cluster before upgrading the Greenplum Database.

Extension Action Documentation
GPText Upgrade to 3.9.0+ Upgrading Greenplum Text
MADlib Upgrade to 1.20.0+ Upgrading MADlib
PostGIS Upgrade to 2.1.5+pivotal.3 Upgrading PostGIS
PXF Upgrade to 5.16.4+ or 6.3.0+ Upgrading PXF

Additionally, check if any of your extensions is installed outside of the default $GPHOME directory. You will need this information when editing the gpupgrade_config file when you Run gpupgrade initialize.

Uninstall Unsupported Greenplum Extensions

Greenplum unsupported extensions cannot be upgraded by gpupgrade and are listed below. Uninstall them from the source cluster, you will re-install them once the cluster is upgraded.

Extension Uninstalling
Oracle Compatibility Functions Uninstalling Oracle Compatibility Functions
Greenplum PL/Java Language Extension Uninstalling PL/Java
Python Data Science Module Package Uninstalling the Python Data Science Module Package
R Data Science Library Package Uninstalling the R Data Science Library Package
VMware Greenplum Command Center See the GPCC Pre-Upgrade Steps below

Keep track of the extensions you uninstall, and the related modifications you had to make to the source Greenplum Database system, so that you can re-apply them after you finalize the upgrade.

Drop or alter any tables, views, or user-defined functions (UDFs) you have created that reference UDFs or custom data types supplied by the unsupported extensions. Remove any files the extension creates in the Greenplum Database master data directory.

Caution

Dropping any extension that defines user defined types, aggregates, functions, operators, or views, will drop the data associated with those objects. For example, if an extension declares a user defined type, any tables and columns that use that type will be dropped when the extension is dropped. One specific example is the PostGIS extension that defines a geometry data type. A column that uses the geometry type will be dropped when PostGIS is dropped.

GPCC Pre-Upgrade Steps

Perform these steps on the source cluster to uninstall Greenplum Command Center:

  1. Upgrade to the latest version of Greenplum Command Center. Refer to Upgrading Greenplum Command Center.
  2. Access the Workload Mgmt page from Command Center to ensure all previous settings have been migrated.
  3. Stop Command Center by issuing the gpcc stop command.
  4. Issue the the following commands against Greenplum Database: 
    DROP EXTERNAL WEB TABLE gpmetrics.gpcc_size_ext_table FROM gpperfmon;
DROP VIEW gpmetrics.gp_data_dirs FROM gpperfmon;
DROP EXTENSION gp_wlm FROM postgres;
  5. Back up the contents of the $MASTER_DATA_DIRECTORY/gpmetrics directory to a safe location.

Review pg_upgrade consistency checks

During the upgrade process, gpupgrade runs scripts that perform consistency checks. You may decide to review the scripts and checks beforehand and if applicable, manually address the issues before continuing with the upgrade process. See pg_upgrade Checks for the list of checks.

Analyze pg_catalog

During the upgrade process, the utility runs multiple queries against the catalog tables, which take longer to complete if the statistics are outdated. Run ANALYZE against each database catalog table to significantly reduce the duration of gpupgrade initialize and gpupgrade execute commands.

analyzedb -a -s pg_catalog -d <database_name>

Perform catalog health check

Run gpcheckcat to ensure that the source catalog is in a healthy state. See the gpcheckcat reference page for further details.

Check for CAST in pg_catalog

The upgrade process fails if the source cluster contains any CAST backing funtion defined in the pg_catalog system catalog. Use these steps to check your source cluster and prepare for the upgrade:

  1. While logged into the master node, find all casts with functions defined in pg_catalog:

    SELECT c.oid AS castoid, c.castsource::regtype, c.casttarget::regtype, c.castfunc::regprocedure \
FROM pg_cast c JOIN pg_proc p ON c.castfunc = p.oid \
WHERE p.pronamespace = 11 AND c.oid >= 16384;

    For example, if the original cast and function were created similar to:

    CREATE FUNCTION pg_catalog.text(date) \
RETURNS text STRICT IMMUTABLE LANGUAGE SQL \
AS 'SELECT textin(date_out($1));';

    CREATE CAST (date AS text) WITH FUNCTION pg_catalog.text(date) AS IMPLICIT;

  2. Drop the function with CASCADE. For example:

    DROP FUNCTION pg_catalog.text(date) CASCADE;

  3. Recreate the function in a different schema. For example, if the new schema is public:

    CREATE FUNCTION public.text(date) \
RETURNS text STRICT IMMUTABLE LANGUAGE SQL \
AS 'SELECT textin(date_out($1));';
  4. Recreate cast with the new function: 
    CREATE CAST (date AS text) WITH FUNCTION public.text(date) AS IMPLICIT;

Update .bashrc or .bash_profile

Since gpupgrade does major version in-place upgrades, it can be easy to mix source and target environments, causing Greenplum utilities to fail. To prevent such failures, perform the following steps:

  • On all segments, remove from .bashrc or .bash_profile files any lines that source greenplum_path.sh or set Greenplum variables.

  • Start a new shell and ensure PATH, LD_LIBRARY_PATH, PYTHONHOME, and PYTHONPATH are clear of any Greenplum values.

  • Log in to a segment host, and verfiy the above values are clear of any Greenplum values.

Prepare test queries

Prepare test queries to use after gpupgrade execute and during the post-upgrade phase, to test and verify that the new installation runs as expected. Your test queries should not create new tables or data.

Review Link vs Copy Mode and Disk Space Requirements

gpupgrade supports two upgrade modes, copy and link, with copy being the default. Decide on which mode to use based on the following information:

Attribute Copy Mode Link Mode
Description Copies source cluster’s files to the target cluster Uses hard links to modify the source cluster’s data in place
Upgrade Time Slow, since it copies data before upgrading Fast, since it modifies the data in place
Disk Space
Requirements		 ~60% free space on each host ~20% free space on each host
Revert Speed
(after gpupgrade execute)		 Fast, since the source cluster is untouched Slow, since it uses rsync to revert the source primary segments and mirrors
Risk No risk since the source cluster is untouched The source cluster is modified
Note

If your Greenplum cluster has no standby or mirror hosts, you will not be able to revert the upgrade after gpupgrade execute. Consider using copy mode, or adding standby and mirrors to your cluster.

About Disk Space Requirements

You must ensure that enough free disk space is available for the upgrade process. Before initializing the upgrade, you configure the gpupgrade_config file when you Prepare for gpupgrade initialize. The parameter disk_free_ratio in this file sets the free space requirement for the upgrade, and it offers default values depending on the upgrade mode you choose. However, you may tune the parameter disk_free_ratio based on your specific environment characteristics. Estimate how much free space you need using the guidelines below. Note that copy mode requires additional space, since it copies the files to the target cluster.

  • On the Greenplum master host the available space should be at least the sum of:

    • 2 times the size of the MASTER_DATA_DIRECTORY.
    • The size of all user defined master tablespaces.

  • On all segment hosts the available space should be at least the sum of:

    • The size of MASTER_DATA_DIRECTORY.
    • The size of all user defined master tablespaces.
    • For copy mode: the size of all primary data directories.

During the upgrade process, the utility creates a backup copy of the master data directory and user defined tablespaces. You may optionally configure the parent_backup_dirs parameter in the gpupgrade_config file to set the internal location to store this backup. See gpupgrade Configuration File for more information.

Next Steps

Continue with the Initialize the Upgrade (gpupgrade initialize).

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