Replacement and Fallback Procedures

This topic describes the process of replacing a running Greenplum 6 installation with SynxDB 2 while maintaining fallback capability.

Important Notes

The Greenplum 6 installation is intentionally preserved to enable fallback if needed.
The drop-in replacement process uses symbolic links to switch between Greenplum and SynxDB.
Always start a new gpadmin shell after switching between versions to ensure proper environment setup.

Prerequisites

Before you make any configuration changes to your Greenplum 6 system:

Perform the SynxDB 2: Pre-Migration Procedure to ensure that GPCC and QuickLZ are not being used in your Greenplum 6 installation.
Perform a full backup of your data.
Backup the postgresql.conf files from each segment data directory.
Document any existing configuration changes that you have made to Greenplum 6 or to Greenplum 6 host machines.
Create an all_hosts.txt file that lists each hostname in the Greenplum 6 cluster.
Ensure that the gpadmin user has sudo access to all cluster hosts.
Preserve the existing Greenplum 6 installation for fallback capability.

This guide assumes that each host can access the Synx Data Labs repositories. If your environment restricts internet access, or if you prefer to host repositories within your infrastructure to ensure consistent package availability, contact Synx Data Labs to obtain a complete repository mirror for local hosting.

Installation and Start-up Procedure

Follow these steps to install the SynxDB software to Greenplum 6 hosts, and then start the SynxDB cluster.

1. Import the SynxDB GPG Key Across Cluster

This step establishes trust for signed SynxDB packages across your cluster:

# Download and verify GPG key
gpssh -f ~/all_hosts.txt -e 'wget -nv https://synxdb-repo.s3.us-west-2.amazonaws.com/gpg/RPM-GPG-KEY-SYNXDB'

# Import the verified key into the RPM database
gpssh -f ~/all_hosts.txt -e 'sudo rpm --import RPM-GPG-KEY-SYNXDB'

# Verify the key was imported correctly
gpssh -f ~/all_hosts.txt -e 'rpm -q gpg-pubkey --qf "%{NAME}-%{VERSION}-%{RELEASE} %{SUMMARY}\n" | grep SynxDB'

2. Install the SynxDB Repository

Each package is verified for authenticity and integrity:

# Download release package
gpssh -f ~/all_hosts.txt -e 'wget -nv https://synxdb-repo.s3.us-west-2.amazonaws.com/repo-release/synxdb2-release-1-1.rpm'

# Verify package signature against imported GPG key
gpssh -f ~/all_hosts.txt -e 'rpm --checksig synxdb2-release-1-1.rpm'

# Install repository package
gpssh -f ~/all_hosts.txt -e 'sudo dnf install -y synxdb2-release-1-1.rpm'

# Verify repository installation
gpssh -f ~/all_hosts.txt -e 'sudo dnf repolist'
gpssh -f ~/all_hosts.txt -e 'rpm -qi synxdb-release'

3. Install SynxDB

# Install SynxDB package
gpssh -f ~/all_hosts.txt -e 'sudo dnf install -y synxdb'

# Verify installation
gpssh -f ~/all_hosts.txt -e 'ls -ld /usr/local/synxdb*'
gpssh -f ~/all_hosts.txt -e 'rpm -q synxdb'
gpssh -f ~/all_hosts.txt -e 'rpm -qi synxdb'

4. Verify the Current Greenplum 6 Installation

psql -c 'select version()'
which postgres
postgres --version
postgres --gp-version
which psql
psql --version

5. Stop the Greenplum Cluster

gpstop -a

6. Configure SynxDB as a Drop-in Replacement

# Create symbolic links for drop-in replacement
gpssh -f ~/all_hosts.txt -e 'sudo rm -v /usr/local/greenplum-db'
gpssh -f ~/all_hosts.txt -e 'sudo ln -s /usr/local/synxdb /usr/local/greenplum-db'
gpssh -f ~/all_hosts.txt -e 'sudo ln -s /usr/local/synxdb/synxdb_path.sh /usr/local/synxdb/greenplum_path.sh'

7. Start the Cluster using SynxDB

⚠️ IMPORTANT: Start a new gpadmin shell session before proceeding. This ensures that:

Old environment variables are cleared
The new environment is configured via /usr/local/greenplum-db/greenplum_path.sh
The correct binaries are referenced in PATH

# In your new gpadmin shell:
gpstart -a

# Verify SynxDB is running
psql -c 'select version()'
which postgres
postgres --version
postgres --gp-version
which psql
psql --version

Fallback Procedure

If necessary, you can revert to using the Greenplum 6 software by following these steps.

1. Stop the Cluster

gpstop -a

2. Restore the Greenplum Symbolic Links

# Adjust the version number to match your Greenplum installation
gpssh -f ~/all_hosts.txt -e 'sudo rm -v /usr/local/greenplum-db'
gpssh -f ~/all_hosts.txt -e 'sudo ln -s /usr/local/greenplum-db-6.26.4 /usr/local/greenplum-db'

3. Start the Cluster with Greenplum 6

⚠️ IMPORTANT: Start a new gpadmin shell session before proceeding. This ensures that:

Old environment variables are cleared
The new environment is configured via /usr/local/greenplum-db/greenplum_path.sh
The correct binaries are referenced in PATH

# In your new gpadmin shell:
gpstart -a

# Verify Greenplum is running
psql -c 'select version()'
which postgres
postgres --version
postgres --gp-version
which psql
psql --version

Disclaimer & Attribution

SynxDB is derived from the last open-source version of Greenplum, originally developed by Pivotal Software, Inc., and maintained under Broadcom Inc.’s stewardship. Greenplum® is a registered trademark of Broadcom Inc. Synx Data Labs, Inc. and SynxDB are not affiliated with, endorsed by, or sponsored by Broadcom Inc. References to Greenplum are provided for comparative, interoperability, and attribution purposes in compliance with open-source licensing requirements.

SynxDB 2 Documentation