In-place Postgres major version upgrades v5

You can upgrade a PGD node to a newer major version of Postgres using the command-line utility bdr_pg_upgrade.

bdr_pg_upgrade is a wrapper around the standard pg_upgrade that adds PGD-specific logic to the process to ensure a smooth upgrade.

Terminology

This terminology is used when describing the upgrade process and components involved:

Postgres cluster The database files, both executables and data, that make up a Postgres database instance on a system when run.

Old Postgres cluster The existing Postgres cluster to upgrade, the one from which to migrate data.

New Postgres cluster The new Postgres cluster that data is migrated to. This Postgres cluster must be one major version ahead of the old cluster.

Precautions

Standard Postgres major version upgrade precautions apply, including the fact both Postgres clusters must meet all the requirements for pg_upgrade.

Additionally, don't use bdr_pg_upgrade if other tools are using replication slots and replication origins. Only PGD slots and origins are restored after the upgrade.

You must meet several prerequisites for bdr_pg_upgrade:

  • Disconnect applications using the old Postgres cluster. You can, for example, redirect them to another node in the PGD cluster.
  • Configure peer authentication for both Postgres clusters. bdr_pg_upgrade requires peer authentication.
  • The same PGD version must be installed on both clusters.
  • The PGD version must be 4.1.0 or later. Version 3.7.22 and later is also supported.
  • The new cluster must be in a shutdown state.
  • You must install PGD packages in the new cluster.
  • The new cluster must already be initialized and configured as needed to match the old cluster configuration.
  • Databases, tables, and other objects must not exist in the new cluster.

We also recommend having the old Postgres cluster up prior to running bdr_pg_upgrade. The CLI starts the old Postgres cluster if it's shut down.

Usage

To upgrade to a newer major version of Postgres, you must first install the new version.

bdr_pg_upgrade command-line

bdr_pg_upgrade passes all parameters to pg_upgrade. Therefore, you can specify any parameters supported by pg_upgrade.

Synopsis

bdr_pg_upgrade [OPTION] ...

Options

In addition to the options for pg_upgrade, you can pass the following parameters to bdr_pg_upgrade.

Required parameters

Specify these parameters either in the command line or, for all but the --database parameter, in their equivalent environment variable. They're used by bdr_pg_upgrade.

  • -b, --old-bindir Old Postgres cluster bin directory.
  • -B, --new-bindir New Postgres cluster bin directory.
  • -d, --old-datadir Old Postgres cluster data directory.
  • -D, --new-datadir New Postgres cluster data directory.
  • --database PGD database name.

Optional parameters

These parameters are optional and are used by bdr_pg_upgrade:

  • -p, --old-port Old cluster port number.
  • -s, --socketdir Directory to use for postmaster sockets during upgrade.
  • --check Specify to only perform checks and not modify clusters.

Other parameters

Any other parameter that's not one of the above is passed to pg_upgrade. pg_upgrade accepts the following parameters:

  • -j, --jobs Number of simultaneous processes or threads to use.
  • -k, --link Use hard links instead of copying files to the new cluster.
  • -o, --old-options Option to pass to old postgres command. Multiple invocations are appended.
  • -O, --new-options Option to pass to new postgres command. Multiple invocations are appended.
  • -N, --no-sync Don't wait for all files in the upgraded cluster to be written to disk.
  • -P, --new-port New cluster port number.
  • -r, --retain Retain SQL and log files even after successful completion.
  • -U, --username Cluster's install user name.
  • --clone Use efficient file cloning.

Environment variables

You can use these environment variables in place of command-line parameters:

  • PGBINOLD Old Postgres cluster bin directory.
  • PGBINNEW New Postgres cluster bin directory.
  • PGDATAOLD Old Postgres cluster data directory.
  • PGDATANEW New Postgres cluster data directory.
  • PGPORTOLD Old Postgres cluster port number.
  • PGSOCKETDIR Directory to use for postmaster sockets during upgrade.

Example

Given a scenario where:

  • Old Postgres cluster bin directory is /usr/lib/postgresql/13/bin.
  • New Postgres cluster bin directory is /usr/lib/postgresql/14/bin.
  • Old Postgres cluster data directory is /var/lib/postgresql/13/main.
  • New Postgres cluster data directory is /var/lib/postgresql/14/main.
  • Database name is bdrdb.

You can use the following command to upgrade the cluster:

bdr_pg_upgrade \
--old-bindir /usr/lib/postgresql/13/bin \
--new-bindir /usr/lib/postgresql/14/bin \
--old-datadir /var/lib/postgresql/13/main \
--new-datadir /var/lib/postgresql/14/main \
--database bdrdb

Steps performed

These steps are performed when running bdr_pg_upgrade.

Note

When --check is supplied as an argument to bdr_pg_upgrade, the CLI skips steps that modify the database.

PGD Postgres checks

Steps--check supplied
Collecting pre-upgrade new cluster control datarun
Checking new cluster state is shutdownrun
Checking PGD versionsrun
Starting old cluster (if shutdown)skip
Connecting to old clusterskip
Checking if bdr schema existsskip
Turning DDL replication offskip
Terminating connections to databaseskip
Waiting for all slots to be flushedskip
Disconnecting from old clusterskip
Stopping old clusterskip
Starting old cluster with PGD disabledskip
Connecting to old clusterskip
Collecting replication originsskip
Collecting replication slotsskip
Disconnecting from old clusterskip
Stopping old clusterskip

pg_upgrade steps

Standard pg_upgrade steps are performed.

Note

If supplied, --check is passed to pg_upgrade.

PGD post-upgrade steps

Steps--check supplied
Collecting old cluster control dataskip
Collecting new cluster control dataskip
Advancing LSN of new clusterskip
Starting new cluster with PGD disabledskip
Connecting to new clusterskip
Creating replication origin, repeated for each originskip
Advancing replication origin, repeated for each originskip
Creating replication slot, repeated for each slotskip
Stopping new clusterskip