Pre-Migration Procedure

This guide helps you identify and address Greenplum 6 proprietary features before you migrate to SynxDB 2, or before you install SynxDB 2 as a drop-in replacement to Greenplum 6.

Prerequisites

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

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.
Test all potential changes in a development environment before you apply them to a production system.

While this guide focuses on identifying and addressing proprietary features, note that subsequent migration steps require external access to the Synx Data Labs repository. 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.

About Proprietary Greenplum Features

The key proprietary features to address before migrating to SynxDB 2 are Greenplum Command Center (GPCC) and QuickLZ compression.

Greenplum Command Center (GPCC)

Greenplum Command Center is a Broadcom proprietary offering that is not available in SynxDB. The primary concern during migration is the presence of the GPCC metrics_collector library is configured in shared_preload_libraries. If this library is present, the SynxDB 2 cluster will fail to start after you install SynxDB as a drop-in replacement.

Detection

To check if metrics_collector is configured in shared_preload_libraries execute the command:


gpconfig -s shared_preload_libraries

If metrics_collector appears in the output, follow the remediation steps.

Remediation

Caution: Backup the postgresql.conf files from all segment data directories before you make any changes.

Follow these steps to remove metrics_collector from your installation:

Use gpconfig to remove metrics_collector from shared_preload_libraries.

If metrics_collector was the only entry shown in the gpconfig -s output, remove it using the command:
```
gpconfig -r shared_preload_libraries
```
If metrics_collector appeared with other shared libraries, use the command form:
```
gpconfig -c shared_preload_libraries -v "comma,separated,list"
```
Replace “comma,separated,list” with only those libraries that you want to continue using.
Restart the Greenplum cluster for the changes to take effect.
Verify that metrics_collector no longer appears in the configuration:
```
gpconfig -s shared_preload_libraries
```

2. QuickLZ Compression

The QuickLZ compression algorithm is proprietary to Broadcom, and is not available in SynxDB. Before beginning any migration, you must identify where QuickLZ compression is being used in your environment.

Detection

Run the following script as gpadmin to identify QuickLZ usage across all databases:


#!/bin/bash
echo "Checking if QuickLZ is in use across all databases..."

for db in $(psql -t -A -c "SELECT datname FROM pg_database WHERE datistemplate = false;"); do
  quicklz_count=$(psql -d $db -X -A -t -c "
    SELECT COUNT(*)
    FROM pg_attribute_encoding, LATERAL unnest(attoptions) AS opt
    WHERE opt = 'compresstype=quicklz';
  ")
  
  if [ "$quicklz_count" -gt 0 ]; then
    echo "QuickLZ is in use in database: $db ($quicklz_count columns)"
  else
    echo "QuickLZ is NOT in use in database: $db"
  fi
done

This script checks each non-template database and reports whether QuickLZ compression is in use, along with the number of affected columns.

The presence of QuickLZ compression requires careful consideration in migration planning, as it is not supported in SynxDB. If QuickLZ is detected, you will need to analyze and plan changing to an alternate compression algorithm before you can migrate to SynxDB. Contact Synx Data Labs for help with planning considerations.

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