Odyssey

Advanced multi-threaded PostgreSQL connection pooler and request router.

Project status

Odyssey is production-ready, it is being used in large production setups. We appreciate any kind of feedback and contribution to the project.

Design goals and main features

Multi-threaded processing

Odyssey can significantly scale processing performance by specifying a number of additional worker threads. Each worker thread is responsible for authentication and proxying client-to-server and server-to-client requests. All worker threads are sharing global server connection pools. Multi-threaded design plays important role in SSL/TLS performance.

Advanced transactional pooling

Odyssey tracks current transaction state and in case of unexpected client disconnection can emit automatic Cancel connection and do Rollback of abandoned transaction, before putting server connection back to the server pool for reuse. Additionally, last server connection owner client is remembered to reduce a need for setting up client options on each client-to-server assignment.

Better pooling control

Odyssey allows to define connection pools as a pair of Database and User. Each defined pool can have separate authentication, pooling mode and limits settings.

Authentication

Odyssey has full-featured SSL/TLS support and common authentication methods like: md5 and clear text both for client and server authentication. Odyssey supports PAM & LDAP authentication, this methods operates similarly to clear text auth except that it uses PAM/LDAP to validate user name/password pairs. PAM optionally checks the connected remote host name or IP address. Additionally it allows to block each pool user separately.

Logging

Odyssey generates universally unique identifiers uuid for client and server connections. Any log events and client error responses include the id, which then can be used to uniquely identify client and track actions. Odyssey can save log events into log file and using system logger.

CLI

Odyssey supports multiple command line options. Use /path/to/odyssey --help to see more

Architecture and internals

Odyssey has sophisticated asynchronous multi-threaded architecture which is driven by custom made coroutine engine: machinarium. Main idea behind coroutine design is to make event-driven asynchronous applications to look and feel like being written in synchronous-procedural manner instead of using traditional callback approach.

One of the main goal was to make code base understandable for new developers and to make an architecture easily extensible for future development.

More information: Architecture and internals.

Build instructions

Currently Odyssey runs only on Linux. Supported platforms are x86/x86_64.

To build you will need:

• cmake >= 3.12.4
• gcc >= 4.6
• openssl
• postgresql-server-dev-13
• pg_config utility is in the PATH

git clone git://github.com/yandex/odyssey.git
cd odyssey
make local_build

Adapt odyssey-dev.conf then:

make local_run

Alternatively:

make console_run

Use docker environment for development (helpful for Mac users)

make start-dev-env

Set up your CLion to build project in container, manual.

Configuration reference

Service

• include
• daemonize
• sequential_routing
• priority
• pid_file
• unix_socket_dir
• unix_socket_mode

Logging

• log_file
• log_format
• log_to_stdout
• log_syslog
• log_syslog_ident
• log_syslog_facility
• log_debug
• log_config
• log_session
• log_query
• log_stats
• stats_interval

Performance

• workers
• resolvers
• readahead
• cache_coroutine
• nodelay
• keepalive

System

• coroutine_stack_size

Global limits

• client_max

Listen

• host
• port
• backlog
• tls
• tls_ca_file
• tls_key_file
• tls_cert_file
• tls_protocols
• example

Routing

• overview

Storage

• overview
• type
• host
• port
• tls
• tls_ca_file
• tls_key_file
• tls_cert_file
• tls_protocols
• example

Database and user

• overview
• authentication
• password
• auth_common_name
• auth_query
• auth_query_db
• auth_query_user
• auth_pam_service
• client_max
• storage
• storage_db
• storage_user
• storage_password
• password_passthrough
• ldap_storage_credentials
• ldap_storage_credentials_attr
• ldap_endpoint
• ldap_endpoint_name
• ldap_pool_ttl
• pool
• pool_size
• pool_timeout
• pool_ttl
• pool_discard
• pool_cancel
• pool_rollback
• client_fwd_error
• log_debug
• example
• example console

Architecture and Internals

• overview
• error codes