Document: WM-097                                                 P. Webb
Category: Tutorial                                            2026-06-22

                    How to migrate from Gel to Disc

Abstract

   The hardest part is getting your data out of Gel in a useable format,
   the rest is easy.

Body

   Dumping your Gel database to a format other databases can read
   requires arcane knowledge but don't fret, I've uncovered the
   incantations to free your data!

   ```sh
   gel dump --all --format=dir gel-export
   ```

   You should see something like:

   ```
   Connecting to Gel instance 'INSTANCE' at localhost:PORT...
   Starting dump for database `'DATABASE'`...
     Finished dump for `'DATABASE'`. Total size: 181.67 KiB
   ```

   This will create `gel-export` in your current directory. Take note of
   the instance and database names and the port as you'll need these
   later. Next, grab the password to your database:

   ```sh
   gel instance credentials --insecure-dsn -I INSTANCE
   ```

   You should see something like:

   ```
   gel:///DATABASE?port=PORT&password=PASSWORD&tls_ca_file=%3C...%3E&tls_security=no_host_verification
   ```

   Now we can set some variables to make the last bits pseudo-legible.

   ```sh
   DSN="postgresql://edgedb@localhost:PORT/DATABASE?sslmode=require"
   ```

   ```sh
   export PGPASSWORD="PASSWORD"
   ```

   Perform a raw SQL dump to `gel-export/data.sql`:

   ```sh
   pg_dump \
     "$DSN" --data-only --no-owner --no-privileges \
     > gel-export/data.sql
   ```

   We create a `.tsv` file first, without any escaping that could mangle
   the data.

   ```sh
   psql "$DSN" -At -F $'\t' -c "
     SELECT table_schema, table_name
     FROM information_schema.tables
     WHERE table_schema NOT IN ('information_schema', 'pg_catalog')
   " > gel-export/tables.tsv
   ```

   Create our final export directory:

   ```sh
   mkdir gel-export/data
   ```

   Finally, we render our `.csv`s:

   ```sh
   while IFS=$'\t' read -r schema table; do
     out="${schema}_${table}"
     psql "$DSN" --csv -c "SELECT * FROM \"$schema\".\"$table\"" > "gel-export/data/$out.csv"
   done < gel-export/tables.tsv
   ```

   I'll assume you installed Disc[1] already. Great! You'll need to get
   it setup with your schema. Run that migration!

   ```sh
   disc migrate
   ```

   Next, we'll point Disc at your fresh collection of `.csv`s:

   ```sh
   disc db import ./gel-export/data
   ```

   This SHOULD work; it didn't for me because…

   ```
   ✗ Import failed (transaction rolled back): duplicate key value violates unique constraint "log_pkey"
   ```

   …and that's irrelevant to me. Ignoring conflicts like this is okay.

   ```sh
   disc db import ./gel-export/data --on-conflict skip
   ```

   You'll get an import manifest of what was processed and skipped. For
   me, it was abstract types and (empty) computed links.

   Run `disc serve` and navigate to your database's `/ui` and you should
   see populated objects in the Data tab.

   Voila! Now all you gotta do is update your codebase…unfortunately,
   you've gotta handle that yourself. 🕸️

References

   [1] <https://disc.sh>