pgcat/CONFIG.md

# PgCat Configurations 
## `general` Section

### host
```
path: general.host
default: "0.0.0.0"
```

What IP to run on, 0.0.0.0 means accessible from everywhere.

### port
```
path: general.port
default: 6432
```

Port to run on, same as PgBouncer used in this example.

### enable_prometheus_exporter
```
path: general.enable_prometheus_exporter
default: true
```

Whether to enable prometheus exporter or not.

### prometheus_exporter_port
```
path: general.prometheus_exporter_port
default: 9930
```

Port at which prometheus exporter listens on.

### connect_timeout
```
path: general.connect_timeout
default: 5000 # milliseconds
```

How long to wait before aborting a server connection (ms).

### idle_timeout
```
path: general.idle_timeout
default: 30000 # milliseconds
```

How long an idle connection with a server is left open (ms).

### idle_client_in_transaction_timeout
```
path: general.idle_client_in_transaction_timeout
default: 0 # milliseconds
```

How long a client is allowed to be idle while in a transaction (ms).

### healthcheck_timeout
```
path: general.healthcheck_timeout
default: 1000 # milliseconds
```

How much time to give the health check query to return with a result (ms).

### healthcheck_delay
```
path: general.healthcheck_delay
default: 30000 # milliseconds
```

How long to keep connection available for immediate re-use, without running a healthcheck query on it

### shutdown_timeout
```
path: general.shutdown_timeout
default: 60000 # milliseconds
```

How much time to give clients during shutdown before forcibly killing client connections (ms).

### ban_time
```
path: general.ban_time
default: 60 # seconds
```

How long to ban a server if it fails a health check (seconds).

### log_client_connections
```
path: general.log_client_connections
default: false
```

If we should log client connections

### log_client_disconnections
```
path: general.log_client_disconnections
default: false
```

If we should log client disconnections

### autoreload
```
path: general.autoreload
default: false
```

When set to true, PgCat reloads configs if it detects a change in the config file.

### worker_threads
```
path: general.worker_threads
default: 5
```

Number of worker threads the Runtime will use (4 by default).

### tcp_keepalives_idle
```
path: general.tcp_keepalives_idle
default: 5
```

Number of seconds of connection idleness to wait before sending a keepalive packet to the server.

### tcp_keepalives_count
```
path: general.tcp_keepalives_count
default: 5
```

Number of unacknowledged keepalive packets allowed before giving up and closing the connection.

### tcp_keepalives_interval
```
path: general.tcp_keepalives_interval
default: 5
```

Number of seconds between keepalive packets.

### tls_certificate
```
path: general.tls_certificate
default: <UNSET>
example: "server.cert"
```

Path to TLS Certificate file to use for TLS connections

### tls_private_key
```
path: general.tls_private_key
default: <UNSET>
example: "server.key"
```

Path to TLS private key file to use for TLS connections

### admin_username
```
path: general.admin_username
default: "admin_user"
```

User name to access the virtual administrative database (pgbouncer or pgcat)
Connecting to that database allows running commands like `SHOW POOLS`, `SHOW DATABASES`, etc..

### admin_password
```
path: general.admin_password
default: <UNSET>
```

Password to access the virtual administrative database

### auth_query (experimental)
```
path: general.auth_query
default: <UNSET>
```

Query to be sent to servers to obtain the hash used for md5 authentication. The connection will be
established using the database configured in the pool. This parameter is inherited by every pool
and can be redefined in pool configuration.

### auth_query_user (experimental)
```
path: general.auth_query_user
default: <UNSET>
```

User to be used for connecting to servers to obtain the hash used for md5 authentication by sending the query
specified in `auth_query_user`. The connection will be established using the database configured in the pool.
This parameter is inherited by every pool and can be redefined in pool configuration.

### auth_query_password (experimental)
```
path: general.auth_query_password
default: <UNSET>
```

Password to be used for connecting to servers to obtain the hash used for md5 authentication by sending the query
specified in `auth_query_user`. The connection will be established using the database configured in the pool.
This parameter is inherited by every pool and can be redefined in pool configuration.

## `pools.<pool_name>` Section

### pool_mode
```
path: pools.<pool_name>.pool_mode
default: "transaction"
```

Pool mode (see PgBouncer docs for more).
`session` one server connection per connected client
`transaction` one server connection per client transaction

### load_balancing_mode
```
path: pools.<pool_name>.load_balancing_mode
default: "random"
```

Load balancing mode
`random` selects the server at random
`loc` selects the server with the least outstanding busy conncetions

### default_role
```
path: pools.<pool_name>.default_role
default: "any"
```

If the client doesn't specify, PgCat routes traffic to this role by default.
`any` round-robin between primary and replicas,
`replica` round-robin between replicas only without touching the primary,
`primary` all queries go to the primary unless otherwise specified.

### query_parser_enabled (experimental)
```
path: pools.<pool_name>.query_parser_enabled
default: true
```

If Query Parser is enabled, we'll attempt to parse
every incoming query to determine if it's a read or a write.
If it's a read query, we'll direct it to a replica. Otherwise, if it's a write,
we'll direct it to the primary.

### primary_reads_enabled
```
path: pools.<pool_name>.primary_reads_enabled
default: true
```

If the query parser is enabled and this setting is enabled, the primary will be part of the pool of databases used for
load balancing of read queries. Otherwise, the primary will only be used for write
queries. The primary can always be explicitly selected with our custom protocol.

### sharding_key_regex (experimental)
```
path: pools.<pool_name>.sharding_key_regex
default: <UNSET>
example: '/\* sharding_key: (\d+) \*/'
```

Allow sharding commands to be passed as statement comments instead of
separate commands. If these are unset this functionality is disabled.

### sharding_function
```
path: pools.<pool_name>.sharding_function
default: "pg_bigint_hash"
```

So what if you wanted to implement a different hashing function,
or you've already built one and you want this pooler to use it?
Current options:
`pg_bigint_hash`: PARTITION BY HASH (Postgres hashing function)
`sha1`: A hashing function based on SHA1

### automatic_sharding_key (experimental)
```
path: pools.<pool_name>.automatic_sharding_key
default: <UNSET>
example: "data.id"
```

Automatically parse this from queries and route queries to the right shard!

### idle_timeout
```
path: pools.<pool_name>.idle_timeout
default: 40000
```

Idle timeout can be overwritten in the pool

### connect_timeout
```
path: pools.<pool_name>.connect_timeout
default: 3000
```

Connect timeout can be overwritten in the pool

### auth_query (experimental)
```
path: general.auth_query
default: <UNSET>
```

Auth query can be overwritten in the pool

### auth_query_user (experimental)
```
path: general.auth_query_user
default: <UNSET>
```

Auth query user can be overwritten in the pool

### auth_query_password (experimental)
```
path: general.auth_query_password
default: <UNSET>
```

Auth query password can be overwritten in the pool

## `pools.<pool_name>.users.<user_index>` Section

### username
```
path: pools.<pool_name>.users.<user_index>.username
default: "sharding_user"
```

Postgresql username

### password
```
path: pools.<pool_name>.users.<user_index>.password
default: "sharding_user"
```

Postgresql password

### pool_size
```
path: pools.<pool_name>.users.<user_index>.pool_size
default: 9
```

Maximum number of server connections that can be established for this user
The maximum number of connection from a single Pgcat process to any database in the cluster
is the sum of pool_size across all users.

### statement_timeout
```
path: pools.<pool_name>.users.<user_index>.statement_timeout
default: 0
```

Maximum query duration. Dangerous, but protects against DBs that died in a non-obvious way.
0 means it is disabled.

## `pools.<pool_name>.shards.<shard_index>` Section

### servers
```
path: pools.<pool_name>.shards.<shard_index>.servers
default: [["127.0.0.1", 5432, "primary"], ["localhost", 5432, "replica"]]
```

Array of servers in the shard, each server entry is an array of `[host, port, role]`

### mirrors (experimental)
```
path: pools.<pool_name>.shards.<shard_index>.mirrors
default: <UNSET>
example: [["1.2.3.4", 5432, 0], ["1.2.3.4", 5432, 1]]
```

Array of mirrors for the shard, each mirror entry is an array of `[host, port, index of server in servers array]`
Traffic hitting the server identified by the index will be sent to the mirror.

### database
```
path: pools.<pool_name>.shards.<shard_index>.database
default: "shard0"
```

Database name (e.g. "postgres")