PGCOPYDB(1)

NAME
pgcopydb - pgcopydb

pgcopydb - copy an entire Postgres database from source to target

SYNOPSIS

pgcopydb provides the following commands

            pgcopydb: pgcopydb tool
            usage: pgcopydb [ --verbose --quiet ]

            Available commands:
              pgcopydb
                clone     Clone an entire database from source to target
                fork      Clone an entire database from source to target
                follow    Replay changes from the source database to the target database
                snapshot  Create and export a snapshot on the source database
              + compare   Compare source and target databases
              + copy      Implement the data section of the database copy
              + dump      Dump database objects from a Postgres instance
              + restore   Restore database objects into a Postgres instance
              + list      List database objects from a Postgres instance
              + stream    Stream changes from the source database
                ping      Attempt to connect to the source and target instances
                help      Print help message
                version   Print pgcopydb version

DESCRIPTION

The pgcopydb command implements a full migration of an entire Postgres database from a source instance to a target instance. Both the Postgres instances must be available for the entire duration of the command.

The pgcopydb command also implements a full Logical Decoding client for Postgres, allowing Change Data Capture to replay data changes (DML) happening on the source database after the base copy snapshot. The pgcopydb logical decoding client code is compatible with both test_decoding and wal2json output plugins, and defaults to using test_decoding.

PGCOPYDB HELP

The pgcopydb help command lists all the supported sub-commands:

            $ pgcopydb help
             pgcopydb
               clone     Clone an entire database from source to target
               fork      Clone an entire database from source to target
               follow    Replay changes from the source database to the target database
               snapshot  Create and export a snapshot on the source database
             + compare   Compare source and target databases
             + copy      Implement the data section of the database copy
             + dump      Dump database objects from a Postgres instance
             + restore   Restore database objects into a Postgres instance
             + list      List database objects from a Postgres instance
             + stream    Stream changes from the source database
               ping      Attempt to connect to the source and target instances
               help      Print help message
               version   Print pgcopydb version

             pgcopydb compare
               schema  Compare source and target schema
               data    Compare source and target data

             pgcopydb copy
               db           Copy an entire database from source to target
               roles        Copy the roles from the source instance to the target instance
               extensions   Copy the extensions from the source instance to the target instance
               schema       Copy the database schema from source to target
               data         Copy the data section from source to target
               table-data   Copy the data from all tables in database from source to target
               blobs        Copy the blob data from the source database to the target
               sequences    Copy the current value from all sequences in database from source to target
               indexes      Create all the indexes found in the source database in the target
               constraints  Create all the constraints found in the source database in the target

             pgcopydb dump
               schema     Dump source database schema as custom files in work directory
               pre-data   Dump source database pre-data schema as custom files in work directory
               post-data  Dump source database post-data schema as custom files in work directory
               roles      Dump source database roles as custome file in work directory

             pgcopydb restore
               schema      Restore a database schema from custom files to target database
               pre-data    Restore a database pre-data schema from custom file to target database
               post-data   Restore a database post-data schema from custom file to target database
               roles       Restore database roles from SQL file to target database
               parse-list  Parse pg_restore --list output from custom file

             pgcopydb list
               databases    List databases
               extensions   List all the source extensions to copy
               collations   List all the source collations to copy
               tables       List all the source tables to copy data from
               table-parts  List a source table copy partitions
               sequences    List all the source sequences to copy data from
               indexes      List all the indexes to create again after copying the data
               depends      List all the dependencies to filter-out
               schema       List the schema to migrate, formatted in JSON
               progress     List the progress

             pgcopydb stream
               setup      Setup source and target systems for logical decoding
               cleanup    Cleanup source and target systems for logical decoding
               prefetch   Stream JSON changes from the source database and transform them to SQL
               catchup    Apply prefetched changes from SQL files to the target database
               replay     Replay changes from the source to the target database, live
             + sentinel   Maintain a sentinel table on the source database
               receive    Stream changes from the source database
               transform  Transform changes from the source database into SQL commands
               apply      Apply changes from the source database into the target database

             pgcopydb stream sentinel
               setup   Setup the sentinel table
               get     Get the sentinel table values on the source database
             + set     Maintain a sentinel table on the source database

             pgcopydb stream sentinel set
               startpos  Set the sentinel start position LSN on the source database
               endpos    Set the sentinel end position LSN on the source database
               apply     Set the sentinel apply mode on the source database
               prefetch  Set the sentinel prefetch mode on the source database

PGCOPYDB VERSION

The pgcopydb version command outputs the version string of the version of pgcopydb used, and can do that in the JSON format when using the --json option.

            $ pgcopydb version
            pgcopydb version 0.13.1.g868ad77
            compiled with PostgreSQL 13.11 (Debian 13.11-0+deb11u1) on x86_64-pc-linux-gnu, compiled by gcc (Debian 10.2.1-6) 10.2.1 20210110, 64-bit
            compatible with Postgres 10, 11, 12, 13, 14, and 15

In JSON:

            $ pgcopydb version --json
            {
                "pgcopydb": "0.13.1.g868ad77",
                "pg_major": "13",
                "pg_version": "13.11 (Debian 13.11-0+deb11u1)",
                "pg_version_str": "PostgreSQL 13.11 (Debian 13.11-0+deb11u1) on x86_64-pc-linux-gnu, compiled by gcc (Debian 10.2.1-6) 10.2.1 20210110, 64-bit",
                "pg_version_num": 130011
            }

The details about the Postgres version applies to the version that's been used to build pgcopydb from sources, so that's the version of the client library libpq really.

PGCOPYDB PING

The pgcopydb ping command attempts to connect to both the source and the target Postgres databases, concurrently.

            pgcopydb ping: Attempt to connect to the source and target instances
            usage: pgcopydb ping  --source ... --target ...

              --source              Postgres URI to the source database
              --target              Postgres URI to the target database

An example output looks like the following:

            $ pgcopydb ping
            18:04:48 84679 INFO   Running pgcopydb version 0.10.31.g7e5fbb8.dirty from "/Users/dim/dev/PostgreSQL/pgcopydb/src/bin/pgcopydb/pgcopydb"
            18:04:48 84683 INFO   Successfully could connect to target database at "postgres://@:/plop?"
            18:04:48 84682 INFO   Successfully could connect to source database at "postgres://@:/pagila?"

This command implements a retry policy (named Decorrelated Jitter) and can be used in automation to make sure that the databases are ready to accept connections.

AUTHOR
Dimitri Fontaine

COPYRIGHT
2022-2024, Dimitri Fontaine