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meskill merged 2 commits into from
Sep 16, 2026
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fix(resharding): describe the schema_admin user and the permissions #116

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fix(resharding): describe the schema_admin user and the permissions
meskill Sep 16, 2026
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Update docs/configuration/users.toml/users.md
meskill Sep 16, 2026
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19 changes: 19 additions & 0 deletions docs/configuration/users.toml/users.md
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Expand Up @@ -17,6 +17,12 @@ This configuration controls which users are allowed to connect to PgDog. This is
name = "bob"
database = "prod"
password = "opensesame"

[[users]]
name = "migrator"
database = "prod"
password = "hunter_prod"

@levkk levkk Sep 16, 2026

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hunter_prod

😆 😆 😆 😆 😆

schema_admin = true
```
=== "Helm chart"
```yaml
Expand All @@ -27,6 +33,10 @@ This configuration controls which users are allowed to connect to PgDog. This is
- name: bob
database: prod
password: opensesame
- name: migrator
database: prod
password: hunter_prod
schemaAdmin: true
```

### `name`
Expand Down Expand Up @@ -157,3 +167,12 @@ Default: **none** (not set)
Overrides [`two_phase_commit_auto`](../pgdog.toml/general.md#two_phase_commit_auto) for this user.

Default: **none** (not set)

### `schema_admin`

Marks this user as a schema administrator. Such user should have sufficient privileges to be able to run DDL commands and use replication protocol commands (e.g., `CREATE_REPLICATION_SLOT`).

A `schema_admin` database user is required for following features:

- [Sharding schema management](../../features/sharding/schema_management/manager.md)
- [Resharding](../../features/sharding/resharding/index.md#schema-admin)
12 changes: 12 additions & 0 deletions docs/features/sharding/resharding/index.md
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Expand Up @@ -58,6 +58,18 @@ Unlike `RESHARD`, the manual path does not cut over automatically: the data move
!!! note "Traffic cutover"
Traffic cutover requires careful synchronization to avoid data loss and a split-brain situation. The `RESHARD` command supports this for **single node** PgDog deployments only. The [Enterprise Edition](../../../enterprise_edition/index.md) provides a control plane, which supports traffic cutover with multiple PgDog containers.

## Requirements

### Schema admin

During the resharding the following permissions are required for the user used for connecting to the source and destination databases:

- `CREATE` permissions on database and target schemas for creating tables and indexes
- `REPLICATION` role attribute for creating replication slots and reading the replication stream
- `SET ON PARAMETER session_replication_role` permission to bypass triggers during replication

Users with these permissions should be defined in `users.toml` and marked as [`schema_admin`](../../../configuration/users.toml/users.md#schema_admin). PgDog will use this user to connect to the source and destination databases, so make sure to specify one for source and destination databases in the configuration (could be the same user or different for each database).

## Terminology

| Term | Description |
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22 changes: 0 additions & 22 deletions docs/features/sharding/resharding/schema.md
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Expand Up @@ -153,28 +153,6 @@ Since creating indexes on large tables can take some time, PgDog provides an adm
sql | CREATE INDEX CONCURRENTLY IF NOT EXISTS "users_email_idx" ON "public"."users" USING btree ("email")
```

### Schema admin

Schema sync creates tables, indexes, and other entities on the destination database. To make sure that this is done with a user with sufficient privileges (e.g., `CREATE` and `REPLICATION` permissions on the database), make sure to add such a user to [`users.toml`](../../../configuration/users.toml/users.md) and mark it as the schema administrator:

=== "users.toml"
```toml
[[users]]
name = "migrator"
database = "prod"
password = "hunter2"
schema_admin = true
```
=== "Helm chart"
```yaml
users:
- name: migrator
database: prod
password: hunter2
```

PgDog will use this user to connect to the source and destination databases, so make sure to specify one for both databases in the configuration.

## Cutover

During the cutover, PgDog will execute last minute schema synchronization commands to make sure the destination sharded cluster works as expected. This involves putting back constraints that were removed for logical replication to work and moving sequence values.
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