Files
pgcat/tests/ruby/helpers/pgcat_helper.rb
Mostafa Abdelraouf 7894bba59b Introduce least-outstanding-connections load balancing (#282)
Least outstanding connections load balancing can improve the load distribution between instances but for Pgcat it may also improve handling slow replicas that don't go completely down. With LoC, traffic will quickly move away from the slow replica without waiting for the replica to be banned.

If all replicas slow down equally (due to a bad query that is hitting all replicas), the algorithm will degenerate to Random Load Balancing (which is what we had in Pgcat until today).

This may also allow Pgcat to accommodate pools with differently-sized replicas.
2023-01-17 06:52:18 -06:00

148 lines
4.8 KiB
Ruby

require 'json'
require 'ostruct'
require_relative 'pgcat_process'
require_relative 'pg_instance'
module Helpers
module Pgcat
def self.three_shard_setup(pool_name, pool_size, pool_mode="transaction", lb_mode="random")
user = {
"password" => "sharding_user",
"pool_size" => pool_size,
"statement_timeout" => 0,
"username" => "sharding_user"
}
pgcat = PgcatProcess.new("info")
primary0 = PgInstance.new(5432, user["username"], user["password"], "shard0")
primary1 = PgInstance.new(7432, user["username"], user["password"], "shard1")
primary2 = PgInstance.new(8432, user["username"], user["password"], "shard2")
pgcat_cfg = pgcat.current_config
pgcat_cfg["pools"] = {
"#{pool_name}" => {
"default_role" => "any",
"pool_mode" => pool_mode,
"load_balancing_mode" => lb_mode,
"primary_reads_enabled" => false,
"query_parser_enabled" => false,
"sharding_function" => "pg_bigint_hash",
"shards" => {
"0" => { "database" => "shard0", "servers" => [["localhost", primary0.port.to_s, "primary"]] },
"1" => { "database" => "shard1", "servers" => [["localhost", primary1.port.to_s, "primary"]] },
"2" => { "database" => "shard2", "servers" => [["localhost", primary2.port.to_s, "primary"]] },
},
"users" => { "0" => user }
}
}
pgcat.update_config(pgcat_cfg)
pgcat.start
pgcat.wait_until_ready
OpenStruct.new.tap do |struct|
struct.pgcat = pgcat
struct.shards = [primary0, primary1, primary2]
struct.all_databases = [primary0, primary1, primary2]
end
end
def self.single_instance_setup(pool_name, pool_size, pool_mode="transaction", lb_mode="random")
user = {
"password" => "sharding_user",
"pool_size" => pool_size,
"statement_timeout" => 0,
"username" => "sharding_user"
}
pgcat = PgcatProcess.new("trace")
pgcat_cfg = pgcat.current_config
primary = PgInstance.new(5432, user["username"], user["password"], "shard0")
# Main proxy configs
pgcat_cfg["pools"] = {
"#{pool_name}" => {
"default_role" => "primary",
"pool_mode" => pool_mode,
"load_balancing_mode" => lb_mode,
"primary_reads_enabled" => false,
"query_parser_enabled" => false,
"sharding_function" => "pg_bigint_hash",
"shards" => {
"0" => {
"database" => "shard0",
"servers" => [
["localhost", primary.port.to_s, "primary"]
]
},
},
"users" => { "0" => user }
}
}
pgcat_cfg["general"]["port"] = pgcat.port
pgcat.update_config(pgcat_cfg)
pgcat.start
pgcat.wait_until_ready
OpenStruct.new.tap do |struct|
struct.pgcat = pgcat
struct.primary = primary
struct.all_databases = [primary]
end
end
def self.single_shard_setup(pool_name, pool_size, pool_mode="transaction", lb_mode="random")
user = {
"password" => "sharding_user",
"pool_size" => pool_size,
"statement_timeout" => 0,
"username" => "sharding_user"
}
pgcat = PgcatProcess.new("info")
pgcat_cfg = pgcat.current_config
primary = PgInstance.new(5432, user["username"], user["password"], "shard0")
replica0 = PgInstance.new(7432, user["username"], user["password"], "shard0")
replica1 = PgInstance.new(8432, user["username"], user["password"], "shard0")
replica2 = PgInstance.new(9432, user["username"], user["password"], "shard0")
# Main proxy configs
pgcat_cfg["pools"] = {
"#{pool_name}" => {
"default_role" => "any",
"pool_mode" => pool_mode,
"load_balancing_mode" => lb_mode,
"primary_reads_enabled" => false,
"query_parser_enabled" => false,
"sharding_function" => "pg_bigint_hash",
"shards" => {
"0" => {
"database" => "shard0",
"servers" => [
["localhost", primary.port.to_s, "primary"],
["localhost", replica0.port.to_s, "replica"],
["localhost", replica1.port.to_s, "replica"],
["localhost", replica2.port.to_s, "replica"]
]
},
},
"users" => { "0" => user }
}
}
pgcat_cfg["general"]["port"] = pgcat.port
pgcat.update_config(pgcat_cfg)
pgcat.start
pgcat.wait_until_ready
OpenStruct.new.tap do |struct|
struct.pgcat = pgcat
struct.primary = primary
struct.replicas = [replica0, replica1, replica2]
struct.all_databases = [primary, replica0, replica1, replica2]
end
end
end
end