PostgreSQL to PostgreSQL migration guide

IntoSQL reads a plain PostgreSQL dump and writes one PostgreSQL script with the same tables, columns, keys, indexes, foreign keys, defaults, identities, enum types, comments and rows. It reads the dump itself, without a database server, and lists in the report every value PostgreSQL can't hold as it is and every object it doesn't carry. The script loads on PostgreSQL 13 to 18.

Convert in the browser: PostgreSQL to PostgreSQL opens the converter set up for this pair.

Dump for the best result#

Any plain dump from pg_dump or pg_dumpall from PostgreSQL 10 on works, as .sql or .sql.gz, with COPY rows (the default) or --inserts:

pg_dump --no-owner --no-privileges shop | gzip > shop.sql.gz

• --no-owner --no-privileges leave out roles and grants, which the converter skips anyway.
• A custom or directory archive (-Fc, -Fd) is binary: pg_restore -f shop.sql shop.backup turns it into plain SQL without a server. The converter says so when it gets an archive (dump_archive).
• pg_dumpall writes every database in one file; each database's tables are named after it, so nothing collides.

A dump made with --data-only still converts: the types are read from the values, and the report says the schema was missing (no_schema). Partitioned tables arrive as one table with every partition's rows (partitions_dropped).

Convert#

In the browser, open PostgreSQL to PostgreSQL or the converter on the home page, drop the dump and choose PostgreSQL. It reads the file from your disk in pieces, twice, and writes the script as it goes, so the dump is never uploaded and its size isn't limited by memory. The desktop app does the same with the file on disk.

With the command line:

intosql inspect shop.sql.gz
intosql convert shop.sql.gz --to postgresql --output shop.postgresql.sql --report shop.report.json

inspect lists the tables, their rows and what won't be converted, without writing anything. convert writes the script and, with --report, the report as JSON.

Through the API, a dump converts like any other file: open a conversion with its name ending in .sql or .sql.gz and "output": {"dialect": "postgresql"}.

Load into PostgreSQL#

createdb shop
psql -v ON_ERROR_STOP=1 -d shop -f shop.postgresql.sql

The script creates the schemas, enum types and tables without keys, copies the rows with COPY, then adds keys, indexes, foreign keys and identities, so it loads fast and stops at the first error. Names, values and types stay as the dump wrote them, so a dump from PostgreSQL 18 loads on 13. Foreign keys are added as NOT VALID and then validated, and CHECK ... NOT VALID constraints are added after the rows, still not valid. Each identity continues from the value its sequence had reached.

Or load it straight in#

intosql load and the desktop app load the dump into PostgreSQL without a script, with the same tables, keys and indexes the script creates:

intosql load shop.sql.gz --into postgres://ana@localhost/shop

It stops before writing anything when one of the dump's tables already exists. It loads in one transaction, so a failed load leaves nothing. Loading into a database server is part of IntoSQL Pro, with a 14-day trial. See Loading.

What isn't converted#

Views, materialized views, functions, procedures, triggers, rules, row security policies, extensions and types are written in PostgreSQL's own language. They are listed in the report by kind and name, never dropped silently, so you can recreate them in PostgreSQL.

Data types#

PostgreSQL data types between versions lists each type that changes in the script: what it becomes, why, and the report line.

Every other rule#

Generated from the engine, where each rule is decided.