Try using pg_dump on both databases and diffing the files.

Another free app (that can only compare structure, but not data):

DBeaver - you can select databases, tables, etc to compare with each other

I'm working on a comprehensive comparison tool for Postgres. It will be free while in beta.

PostgresCompare

Initially this is just schema (DDL) comparison but we will probably expand to data also. I believe this is a tool that a lot of shops require in order to move from their current RDBMS without having to also change how their development environments, operations etc work too.

I have evaluated a lot of the tools and found following solution:

Schema comparison:

The most interesting were Liquibase, Persyas and PgCodeKeeper:

(issue) Liquebase converts:

 SET DEFAULT nextval('myschema.name_id_seq'::regclass)

into

BIGSERIAL

So it was rejected to use

(issue) Persyas worked fine untill I added some additional schema and it starts throwing following:

pyrseas_1       | TypeError: 'NoneType' object is not iterable

So I have found PgCodeKeeper it works perfectly and it is alive (you can check releases). I use following command:

./pgcodekeeper-cli.sh -E -I ./ignore.txt \
-s "jdbc:postgresql://localhost/postgres?user=postgres&password=123" \
-t "jdbc:postgresql://localhost/postgres?user=postgres&password=123" \
-o /result/schema-diff-$(date +'%m%d%y_%H%M%S').sql

Data comparison: I have tried to use Liquebase and it just does not work you can see the steps I tried in my unanswered question about data difference of two databases with Liquebase

So I have found another project SQL Workbench/J It works really nice and generate reall diff in sql. I use following command:

  java -jar /sqlworkbench.jar -command="'WbDataDiff -excludeTables=$EXCLUDE_TABLES \
-referenceConnection=$REFERENCE_CONNECTION \ 
-targetConnection=$TARGET_CONNECTION -referenceSchema=$1 \
-targetSchema=$1  -file=$DIFF_RESULT_FILE -singleFile=true \
-includeDelete=true -ignoreMissingTarget=true ;'"

Both tools support objects filtration. It is really convenient.

Migrations

And finally I use Liquebase just for migration/version tracking.

The best tool which I ever seen

1. Get dump from database A dbtoyaml ...

2. Generate migration from A => B yamltodb ... [file generated in step 1]

I created a tool to compare 2 live PostgreSQL databases(not dumps), table data and sequences. Pretty early days but achieved what I wanted it to do, maybe it can help you too.

The tool pgtricks has a command called pg_dump_splitsort

You can execute it on a dump.

Example:

pg_dump > pre-changes.sql
mkdir pre-changes
cd pre-changes
pg_dump_splitsort ../pre-changes.sql

now do some changes to your DB

pg_dump > post-changes.sql
mkdir post-changes
cd post-changes
pg_dump_splitsort ../post-changes.sql

cd ..

meld pre-changes post-changes

I'm also looking for a tool to compare data in databases (in particular I was interested in comparing Redshift DB). So far the best I found is . Unfortunately the free trial expires after one day.

In my opinion Dbforge is the most powerful tool for comapring data in postgresql .It's a product of Devart company.you can download here.

Use for simple databases (without triggers, stored procs and nesting tables).