mirror of
https://github.com/postgresml/pgcat.git
synced 2026-03-23 01:16:30 +00:00
The TL;DR for the change is that we allow QueryRouter to set the active shard to None. This signals to the Pool::get method that we have no shard selected. The get method follows a no_shard_specified_behavior config to know how to route the query. Original PR description Ruby-pg library makes a startup query to SET client_encoding to ... if Encoding.default_internal value is set (Code). This query is troublesome because we cannot possibly attach a routing comment to it. PgCat, by default, will route that query to the default shard. Everything is fine until shard 0 has issues, Clients will all be attempting to send this query to shard0 which increases the connection latency significantly for all clients, even those not interested in shard0 This PR introduces no_shard_specified_behavior that defines the behavior in case we have routing-by-comment enabled but we get a query without a comment. The allowed behaviors are random: Picks a shard at random random_healthy: Picks a shard at random favoring shards with the least number of recent connection/checkout errors shard_<number>: e.g. shard_0, shard_4, etc. picks a specific shard, everytime In order to achieve this, this PR introduces an error_count on the Address Object that tracks the number of errors since the last checkout and uses that metric to sort shards by error count before making a routing decision. I didn't want to use address stats to avoid introducing a routing dependency on internal stats (We might do that in the future but I prefer to avoid this for the time being. I also made changes to the test environment to replace Ruby's TOML reader library, It appears to be abandoned and does not support mixed arrays (which we use in the config toml), and it also does not play nicely with single-quoted regular expressions. I opted for using yj which is a CLI tool that can convert from toml to JSON and back. So I refactor the tests to use that library.
174 lines
5.5 KiB
Ruby
174 lines
5.5 KiB
Ruby
module Helpers
|
|
module AuthQuery
|
|
def self.single_shard_auth_query(
|
|
pg_user:,
|
|
config_user:,
|
|
pool_name:,
|
|
extra_conf: {},
|
|
log_level: 'debug',
|
|
wait_until_ready: true
|
|
)
|
|
|
|
user = {
|
|
"pool_size" => 10,
|
|
"statement_timeout" => 0,
|
|
}
|
|
|
|
pgcat = PgcatProcess.new(log_level)
|
|
pgcat_cfg = pgcat.current_config.deep_merge(extra_conf)
|
|
|
|
primary = PgInstance.new(5432, pg_user["username"], pg_user["password"], "shard0")
|
|
replica = PgInstance.new(10432, pg_user["username"], pg_user["password"], "shard0")
|
|
|
|
# Main proxy configs
|
|
pgcat_cfg["pools"] = {
|
|
"#{pool_name}" => {
|
|
"default_role" => "any",
|
|
"pool_mode" => "transaction",
|
|
"load_balancing_mode" => "random",
|
|
"primary_reads_enabled" => false,
|
|
"query_parser_enabled" => false,
|
|
"sharding_function" => "pg_bigint_hash",
|
|
"shards" => {
|
|
"0" => {
|
|
"database" => "shard0",
|
|
"servers" => [
|
|
["localhost", primary.port.to_i, "primary"],
|
|
["localhost", replica.port.to_i, "replica"],
|
|
]
|
|
},
|
|
},
|
|
"users" => { "0" => user.merge(config_user) }
|
|
}
|
|
}
|
|
pgcat_cfg["general"]["port"] = pgcat.port.to_i
|
|
pgcat.update_config(pgcat_cfg)
|
|
pgcat.start
|
|
|
|
pgcat.wait_until_ready(
|
|
pgcat.connection_string(
|
|
"sharded_db",
|
|
pg_user['username'],
|
|
pg_user['password']
|
|
)
|
|
) if wait_until_ready
|
|
|
|
OpenStruct.new.tap do |struct|
|
|
struct.pgcat = pgcat
|
|
struct.primary = primary
|
|
struct.replicas = [replica]
|
|
struct.all_databases = [primary]
|
|
end
|
|
end
|
|
|
|
def self.two_pools_auth_query(
|
|
pg_user:,
|
|
config_user:,
|
|
pool_names:,
|
|
extra_conf: {},
|
|
log_level: 'debug'
|
|
)
|
|
|
|
user = {
|
|
"pool_size" => 10,
|
|
"statement_timeout" => 0,
|
|
}
|
|
|
|
pgcat = PgcatProcess.new(log_level)
|
|
pgcat_cfg = pgcat.current_config
|
|
|
|
primary = PgInstance.new(5432, pg_user["username"], pg_user["password"], "shard0")
|
|
replica = PgInstance.new(10432, pg_user["username"], pg_user["password"], "shard0")
|
|
|
|
pool_template = Proc.new do |database|
|
|
{
|
|
"default_role" => "any",
|
|
"pool_mode" => "transaction",
|
|
"load_balancing_mode" => "random",
|
|
"primary_reads_enabled" => false,
|
|
"query_parser_enabled" => false,
|
|
"sharding_function" => "pg_bigint_hash",
|
|
"shards" => {
|
|
"0" => {
|
|
"database" => database,
|
|
"servers" => [
|
|
["localhost", primary.port.to_i, "primary"],
|
|
["localhost", replica.port.to_i, "replica"],
|
|
]
|
|
},
|
|
},
|
|
"users" => { "0" => user.merge(config_user) }
|
|
}
|
|
end
|
|
# Main proxy configs
|
|
pgcat_cfg["pools"] = {
|
|
"#{pool_names[0]}" => pool_template.call("shard0"),
|
|
"#{pool_names[1]}" => pool_template.call("shard1")
|
|
}
|
|
|
|
pgcat_cfg["general"]["port"] = pgcat.port
|
|
pgcat.update_config(pgcat_cfg.deep_merge(extra_conf))
|
|
pgcat.start
|
|
|
|
pgcat.wait_until_ready(pgcat.connection_string("sharded_db0", pg_user['username'], pg_user['password']))
|
|
|
|
OpenStruct.new.tap do |struct|
|
|
struct.pgcat = pgcat
|
|
struct.primary = primary
|
|
struct.replicas = [replica]
|
|
struct.all_databases = [primary]
|
|
end
|
|
end
|
|
|
|
def self.create_query_auth_function(user)
|
|
return <<-SQL
|
|
CREATE OR REPLACE FUNCTION public.user_lookup(in i_username text, out uname text, out phash text)
|
|
RETURNS record AS $$
|
|
BEGIN
|
|
SELECT usename, passwd FROM pg_catalog.pg_shadow
|
|
WHERE usename = i_username INTO uname, phash;
|
|
RETURN;
|
|
END;
|
|
$$ LANGUAGE plpgsql SECURITY DEFINER;
|
|
|
|
GRANT EXECUTE ON FUNCTION public.user_lookup(text) TO #{user};
|
|
SQL
|
|
end
|
|
|
|
def self.exec_in_instances(query:, instance_ports: [ 5432, 10432 ], database: 'postgres', user: 'postgres', password: 'postgres')
|
|
instance_ports.each do |port|
|
|
c = PG.connect("postgres://#{user}:#{password}@localhost:#{port}/#{database}")
|
|
c.exec(query)
|
|
c.close
|
|
end
|
|
end
|
|
|
|
def self.set_up_auth_query_for_user(user:, password:, instance_ports: [ 5432, 10432 ], database: 'shard0' )
|
|
instance_ports.each do |port|
|
|
connection = PG.connect("postgres://postgres:postgres@localhost:#{port}/#{database}")
|
|
connection.exec(self.drop_query_auth_function(user)) rescue PG::UndefinedFunction
|
|
connection.exec("DROP ROLE #{user}") rescue PG::UndefinedObject
|
|
connection.exec("CREATE ROLE #{user} ENCRYPTED PASSWORD '#{password}' LOGIN;")
|
|
connection.exec(self.create_query_auth_function(user))
|
|
connection.close
|
|
end
|
|
end
|
|
|
|
def self.tear_down_auth_query_for_user(user:, password:, instance_ports: [ 5432, 10432 ], database: 'shard0' )
|
|
instance_ports.each do |port|
|
|
connection = PG.connect("postgres://postgres:postgres@localhost:#{port}/#{database}")
|
|
connection.exec(self.drop_query_auth_function(user)) rescue PG::UndefinedFunction
|
|
connection.exec("DROP ROLE #{user}")
|
|
connection.close
|
|
end
|
|
end
|
|
|
|
def self.drop_query_auth_function(user)
|
|
return <<-SQL
|
|
REVOKE ALL ON FUNCTION public.user_lookup(text) FROM public, #{user};
|
|
DROP FUNCTION public.user_lookup(in i_username text, out uname text, out phash text);
|
|
SQL
|
|
end
|
|
end
|
|
end
|