softlang/pgcat repository overview

version: "3"
services:
  postgres:
    image: postgres:14
    environment:
      POSTGRES_PASSWORD: postgres
      POSTGRES_HOST_AUTH_METHOD: md5
  pgcat:
    build: .
    command:
      - "pgcat"
      - "/etc/pgcat/pgcat.toml"
    volumes:
      - "${PWD}/examples/docker/pgcat.toml:/etc/pgcat/pgcat.toml"
    ports:
      - "6432:6432"
      - "9930:9930"

#
# PgCat config example.
#

#
# General pooler settings
[general]
# What IP to run on, 0.0.0.0 means accessible from everywhere.
host = "0.0.0.0"

# Port to run on, same as PgBouncer used in this example.
port = 6432

# Whether to enable prometheus exporter or not.
enable_prometheus_exporter = true

# Port at which prometheus exporter listens on.
prometheus_exporter_port = 9930

# How long to wait before aborting a server connection (ms).
connect_timeout = 5000

# How much time to give `SELECT 1` health check query to return with a result (ms).
healthcheck_timeout = 1000

# How long to keep connection available for immediate re-use, without running a healthcheck query on it
healthcheck_delay = 30000

# How much time to give clients during shutdown before forcibly killing client connections (ms).
shutdown_timeout = 60000

# For how long to ban a server if it fails a health check (seconds).
ban_time = 60 # seconds

# If we should log client connections
log_client_connections = false

# If we should log client disconnections
log_client_disconnections = false

# TLS
# tls_certificate = "server.cert"
# tls_private_key = "server.key"

# Credentials to access the virtual administrative database (pgbouncer or pgcat)
# Connecting to that database allows running commands like `SHOW POOLS`, `SHOW DATABASES`, etc..
admin_username = "postgres"
admin_password = "postgres"

# pool
# configs are structured as pool.<pool_name>
# the pool_name is what clients use as database name when connecting
# For the example below a client can connect using "postgres://sharding_user:sharding_user@pgcat_host:pgcat_port/sharded"
[pools.postgres]
# Pool mode (see PgBouncer docs for more).
# session: one server connection per connected client
# transaction: one server connection per client transaction
pool_mode = "transaction"

# If the client doesn't specify, route 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.
default_role = "any"

# Query parser. If 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.
query_parser_enabled = true

# If the query parser is enabled and this setting is enabled, we'll attempt to
# infer the role from the query itself.
query_parser_read_write_splitting = 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.
primary_reads_enabled = true

# 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
#
sharding_function = "pg_bigint_hash"

# Credentials for users that may connect to this cluster
[pools.postgres.users.0]
username = "postgres"
password = "postgres"
# 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.
pool_size = 9

# Maximum query duration. Dangerous, but protects against DBs that died in a non-obvious way.
statement_timeout = 0

# Shard 0
[pools.postgres.shards.0]
# [ host, port, role ]
servers = [
    [ "postgres", 5432, "primary" ],
    [ "postgres", 5432, "replica" ]
]
# Database name (e.g. "postgres")
database = "postgres"

[pools.postgres.shards.1]
servers = [
    [ "postgres", 5432, "primary" ],
    [ "postgres", 5432, "replica" ],
]
database = "postgres"

[pools.postgres.shards.2]
servers = [
    [ "postgres", 5432, "primary" ],
    [ "postgres", 5432, "replica" ],
]
database = "postgres"