> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pg-sharding.tech/llms.txt
> Use this file to discover all available pages before exploring further.

# Router with Init SQL

> Simple SPQR deployment using init_sql for static sharding configuration

## Overview

The bare router deployment is the **simplest** way to run SPQR. It's ideal for testing, development, and scenarios where your sharding rules don't need to be updated dynamically.

In this deployment mode:

* You run `spqr-router` with an `init_sql` file
* The router reads the sharding configuration from this local file on startup
* No external coordinator or etcd cluster is required
* You can run multiple router instances simultaneously
* Each router instance operates independently

## Setup

### 1. Create Router Configuration File

Create a YAML configuration file (e.g., `router.yaml`):

```yaml router.yaml theme={null}
host: 'localhost'
router_port: '6432'
admin_console_port: '7432'
grpc_api_port: '7001'

# Enable init SQL mode
use_init_sql: true
init_sql: "/path/to/init.sql"
exit_on_init_sql: true  # Exit if init SQL parsing fails

router_mode: PROXY
log_level: info

frontend_rules:
  - db: mydb
    usr: myuser
    pool_mode: TRANSACTION
    auth_rule:
      auth_method: ok

backend_rules:
  - db: mydb
    usr: myuser
    connection_limit: 100
    pool_discard: false
    pool_rollback: true

shards:
  shard1:
    db: mydb
    usr: myuser
    pwd: password
    type: DATA
    hosts:
      - 'shard1-host:5432'
  shard2:
    db: mydb
    usr: myuser
    pwd: password
    type: DATA
    hosts:
      - 'shard2-host:5432'
```

### 2. Create Init SQL File

Create an SQL file with your sharding configuration (e.g., `init.sql`):

```sql init.sql theme={null}
-- Create a distribution for your sharding key
CREATE DISTRIBUTION ds1 COLUMN TYPES integer;

-- Attach tables to the distribution
ALTER DISTRIBUTION ds1 ATTACH RELATION orders DISTRIBUTION KEY id;
ALTER DISTRIBUTION ds1 ATTACH RELATION order_items DISTRIBUTION KEY order_id;

-- Define key ranges
CREATE KEY RANGE krid1 FROM 0 ROUTE TO shard1 FOR DISTRIBUTION ds1;
CREATE KEY RANGE krid2 FROM 10000 ROUTE TO shard2 FOR DISTRIBUTION ds1;
```

### 3. Start the Router

```bash theme={null}
spqr-router run --config router.yaml
```

Connect to the admin console to verify the configuration:

```bash theme={null}
psql "host=localhost port=6432 dbname=spqr-console user=spqr-console sslmode=disable"
```

Check the configured shards and key ranges:

```sql theme={null}
-- List all shards
SHOW shards;

-- List distributions
SHOW distributions;

-- List key ranges
SHOW key_ranges;
```

### 4. Connect

Clients can now connect to the router:

```bash theme={null}
psql "host=localhost port=6432 dbname=mydb user=myuser sslmode=disable"
```

The router will automatically route queries to the appropriate shard based on the sharding key.

## Considerations

* Configuration changes require updating the `init.sql` file and restarting the router
* No dynamic updates are possible while the router is running
* For persistence you may set `memqdb_backup_path`. This feature is deprecated and may be removed in a future release — use at your own risk.

For configuration reference, see the [Router Configuration](/configuration/router) reference.