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What is Pgpool-II?

Pgpool-II is a middleware that works between PostgreSQL servers and a PostgreSQL database client. It is distributed under a license similar to BSD and MIT. It provides the following features.

• Connection Pooling

Pgpool-II saves connections to the PostgreSQL servers, and reuse them whenever a new connection with the same properties (i.e. username, database, protocol version) comes in. It reduces connection overhead, and improves system's overall throughput.

• Replication

Pgpool-II can manage multiple PostgreSQL servers. Using the replication function enables creating a realtime backup on 2 or more physical disks, so that the service can continue without stopping servers in case of a disk failure.

• Load Balancing

If a database is replicated, executing a SELECT query on any server will return the same result. Pgpool-II takes an advantage of the replication feature to reduce the load on each PostgreSQL server by distributing SELECT queries among multiple servers, improving system's overall throughput. At best, performance improves proportionally to the number of PostgreSQL servers. Load balance works best in a situation where there are a lot of users executing many queries at the same time.

• Limiting Exceeding Connections

There is a limit on the maximum number of concurrent connections with PostgreSQL, and connections are rejected after this many connections. Setting the maximum number of connections, however, increases resource consumption and affect system performance. pgpool-II also has a limit on the maximum number of connections, but extra connections will be queued instead of returning an error immediately.

• Watchdog

Watchdog can coordinate multiple Pgpool-II, create a robust cluster system and avoid the single point of failure or split brain. Watchdog can perform lifecheck against other pgpool-II nodes, to detect a fault of Pgpoll-II. If active Pgpool-II goes down, standby Pgpool-II can be promoted to active, and take over Virtual IP.

• In Memory Query Cache

In memory query cache allows to save a pair of SELECT statement and its result. If an identical SELECTs comes in, Pgpool-II returns the value from cache. Since no SQL parsing nor access to PostgreSQL are involved, using in memory cache is extremely fast. On the other hand, it might be slower than the normal path in some cases, because it adds some overhead of storing cache data.

Pgpool-II speaks PostgreSQL's backend and frontend protocol, and relays messages between a backend and a frontend. Therefore, a database application (frontend) thinks that Pgpool-II is the actual PostgreSQL server, and the server (backend) sees Pgpool-II as one of its clients. Because Pgpool-II is transparent to both the server and the client, an existing database application can be used with Pgpool-II almost without a change to its sources.

Pgpool-II License

See License.

Stable versions

• Pgpool-II: 4.5, 4.4, 4.3, 4.2, 4.1

Contacts

• If you have technical questions regarding Pgpool-II, please subscribe Pgpool-II mailing lists and send questions to it (pgpool-general will be a starter). Please do not send technical questions via private email. We will not respond such that messages.

• If you believe that you found a vulnerability/security issues with Pgpool-II, please send a private email to ishii at postgresql.org (he is the project leader).

What's new

News

Pgpool-II 4.5.4, 4.4.9, 4.3.12, 4.2.19 and 4.1.22 officially released (2024/09/09)

Pgpool-II 4.5.4, 4.4.9, 4.3.12, 4.2.19 and 4.1.22 officially released.

This release contains a security fix.

When the query cache feature is enabled, it was possible that a database user can read rows from tables that should not be visible for the user through query cache (CVE-2024-45624).

All versions of Pgpool-II older than 4.5.4, 4.4.9, 4.3.12, 4.2.19, 4.1.22, and all older versions that has the query cache feature (the query cache feature was implemented in 3.2) are affected by the vulnerability. It is strongly recommend to upgrade to Pgpool-II 4.5.4, 4.4.9, 4.3.12, 4.2.19 and 4.1.22 or later. Or you should better turn off the query cache feature.

You can download them here.

• 4.5.4 : English Japanese
• 4.4.9 : English Japanese
• 4.3.12 : English Japanese
• 4.2.19 : English Japanese
• 4.1.22 : English Japanese

Events

PGConf.ASIA 2019 in Bali

Bo Peng is going to give a presentation Setup a High-Availability and Load Balancing PostgreSQL Cluster: New Features of Pgpool-II 4.1 at "PGConf.ASIA 2019" held in Bali from September 8th to 11st.

PGConf.ASIA 2018 in Tokyo

Tatsuo Ishii and Bo Peng are going to give a presentation Celebrating its 15th Anniversary Pgpool-II Past Present and Future Celebrating its 15th Anniversary Pgpool-II Past Present and Future part2 at "PGConf.ASIA 2018" held in Tokyo from December 10th to 12th.

PGConf.ASIA 2017 in Tokyo

Tatsuo Ishii is going to give a presentation "More reliability and support for PostgreSQL 10: Introducing Pgpool-II 3.7" at "PGConf.ASIA 2017", held in Tokyo from December 4th to 6th.

PostgreSQL Conference in Russia 2016

Tatsuo gave a talk "How to manage a herd of elephants" at "PostgreSQL Conference in Russia 2016", held in Moscow from February 4th to 5th. The slides are available in Developer's documentation.

PostgreSQL Conference in China 2015

Tatsuo gave a talk "How to manage a herd of elephants" at "PostgreSQL Conference in China 2015", held in Beijing from November 21th to 22th. The slides are available in Developer's documentation.

pgCon 2015 Cluster Hacker Summit

We participated "6th Postgres Cluster Hacker Summit" which was held as a part of PgCon 2015 Developer Unconference. We reported about Development Status Updates and pgpool-II 3.5 features. The slides are available in Developer's documentation.

Pgpool-II Day 2015 in Tokyo

We had the very first time pgpool-II decicated conference. See the event report.

Stable

Pgpool-II 4.5.4, 4.4.9, 4.3.12, 4.2.19 and 4.1.22 officially released (2024/09/09)

Pgpool-II 4.5.4, 4.4.9, 4.3.12, 4.2.19 and 4.1.22 officially released.

This release contains a security fix.

When the query cache feature is enabled, it was possible that a database user can read rows from tables that should not be visible for the user through query cache (CVE-2024-45624).

All versions of Pgpool-II older than 4.5.4, 4.4.9, 4.3.12, 4.2.19, 4.1.22, and all older versions that has the query cache feature (the query cache feature was implemented in 3.2) are affected by the vulnerability. It is strongly recommend to upgrade to Pgpool-II 4.5.4, 4.4.9, 4.3.12, 4.2.19 and 4.1.22 or later. Or you should better turn off the query cache feature.

You can download them here.

• 4.5.4 : English Japanese
• 4.4.9 : English Japanese
• 4.3.12 : English Japanese
• 4.2.19 : English Japanese
• 4.1.22 : English Japanese

Pgpool-II 4.5.3, 4.4.8, 4.3.11, 4.2.18 and 4.1.21 officially released (2024/08/15)

Pgpool-II 4.5.3, 4.4.8, 4.3.11, 4.2.18 and 4.1.21 officially released.

You can download them here.

• 4.5.3 : English Japanese
• 4.4.8 : English Japanese
• 4.3.11 : English Japanese
• 4.2.18 : English Japanese
• 4.1.21 : English Japanese

Pgpool-II 4.5.2, 4.4.7, 4.3.10, 4.2.17 and 4.1.20 officially released (2024/05/16)

Pgpool-II 4.5.2, 4.4.7, 4.3.10, 4.2.17 and 4.1.20 officially released.

You can download them here.

• 4.5.2 : English Japanese
• 4.4.7 : English Japanese
• 4.3.10 : English Japanese
• 4.2.17 : English Japanese
• 4.1.20 : English Japanese

Pgpool-II 4.5.1, 4.4.6, 4.3.9, 4.2.16 and 4.1.19 officially released (2024/02/29)

Pgpool-II 4.5.1, 4.4.6, 4.3.9, 4.2.16 and 4.1.19 officially released.

You can download them here.

• 4.5.1 : English Japanese
• 4.4.6 : English Japanese
• 4.3.9 : English Japanese
• 4.2.16 : English Japanese
• 4.1.19 : English Japanese

Pgpool-II 4.5.0 released (2023/12/12)

Pgpool-II 4.5.0 is now released. This is the first stable release of Pgpool-II 4.5.x.

V4.5 contains new features and enhancements, including:

• Allow to use more kind of multiple statements in a query string.

• Allow to load balance PREPARE/EXECUTE/DEALLOCATE.

• Allow to set delay_threshold_by_time in milliseconds.

• Avoid session disconnection issue in failover/failback/backend error in some cases.

• Allow to route queries to a specific backend node for a specific user connection.

• Support multiple directories specification for pcp_socket_dir.

• Import PostgreSQL 16's SQL parser.

You can download it from here.

Release notes: English

Pgpool-II 4.4.5, 4.3.8, 4.2.15, 4.1.18 and 4.0.25 officially released (2023/11/30)

Pgpool-II 4.4.5, 4.3.8, 4.2.15, 4.1.18 and 4.0.25 officially released.

Please note that 4.0.25 is the last release of the 4.0.x series.

You can download them here.

• 4.4.5 : English Japanese
• 4.3.8 : English Japanese
• 4.2.15 : English Japanese
• 4.1.18 : English Japanese
• 4.0.25 : English Japanese

Pgpool-II 4.4.4, 4.3.7, 4.2.14, 4.1.17 and 4.0.24 officially released (2023/08/17)

Pgpool-II 4.4.4, 4.3.7, 4.2.14, 4.1.17 and 4.0.24 officially released.

You can download them here.

• 4.4.4 : English Japanese
• 4.3.7 : English Japanese
• 4.2.14 : English Japanese
• 4.1.17 : English Japanese
• 4.0.24 : English Japanese

Pgpool-II 4.4.3, 4.3.6, 4.2.13, 4.1.16 and 4.0.23 officially released (2023/05/18)

Pgpool-II 4.4.3, 4.3.6, 4.2.13, 4.1.16 and 4.0.23 officially released.

You can download them here.

• 4.4.3 : English Japanese
• 4.3.6 : English Japanese
• 4.2.13 : English Japanese
• 4.1.16 : English Japanese
• 4.0.23 : English Japanese

End-of-Life (EOL) Announcement for pgpoolAdmin (2023/02/17)

Pgpool Global Development Group announces end-of-life date for pgpoolAdmin, which is the management tool for Pgpool-II.

Pgpool Global Development Group will provide maintenance for pgpoolAdmin 4.0, 4.1 and 4.2 until December 31, 2023. After this date, bug fixes and security fixes for these versions will no longer be provided.

In addition, pgpoolAdmin for Pgpool-II 4.3 or later will not be released.

We would like to thank you for using pgpoolAdmin over the years.

Pgpool-II 4.4.2, 4.3.5, 4.2.12, 4.1.15 and 4.0.22 officially released (2023/01/23)

Pgpool-II 4.4.2, 4.3.5, 4.2.12, 4.1.15 and 4.0.22 officially released.

This release contains a security fix.

If following conditions are all met, the password of "wd_lifecheck_user" is exposed by "SHOW POOL STATUS" command. The command can be executed by any user who can connect to Pgpool-II. (CVE-2023-22332)

• Version 3.3 or later
• use_watchdog = on
• wd_lifecheck_method = 'query'
• A plain text password is set to wd_lifecheck_password

In this case it is strongly recommended to upgrade to this version (we do not expose wd_lifecheck_password in show pool_status command any more), or use one of following workarounds.

Workarounds for 4.0.x to 4.4.x users:

• Disable watchdog. Set use_watchdog to off.
• Change wd_lifecheck_method to heartbeat.
• Set an empty string to wd_lifecheck_password. This will use password in the pool_passwd file.
• Set an AES encrypted password to wd_lifecheck_password.

In any case we recommend to change "wd_lifecheck_password" in PostgreSQL.

Workarounds for 3.0.x to 3.7.x users:

• Disable watchdog. Set use_watchdog to off.
• Change wd_lifecheck_method to heartbeat.

In any case we recommend to change "wd_lifecheck_password" in PostgreSQL.

Please note that Pgpool-II 3.7.x or before are end of life and no minor updates are provided for those versions.

You can download them here.

• 4.4.2 : English Japanese
• 4.3.5 : English Japanese
• 4.2.12 : English Japanese
• 4.1.15 : English Japanese
• 4.0.22 : English Japanese

Pgpool-II 4.4.1, 4.3.4, 4.2.11, 4.1.14, 4.0.21 and 3.7.26 officially released (2022/12/22)

Pgpool-II 4.4.1, 4.3.4, 4.2.11, 4.1.14, 4.0.21 and 3.7.26 officially released.

You can download them here.

• 4.4.1 : English Japanese
• 4.3.4 : English Japanese
• 4.2.11 : English Japanese
• 4.1.14 : English Japanese
• 4.0.21 : English Japanese
• 3.7.26 : English Japanese

Pgpool-II 4.4.0 released (2022/12/06)

Pgpool-II 4.4.0 is now released. This is the first stable release of Pgpool-II 4.4.x.

V4.4 contains new features and enhancements, including:

• Add new dynamic spare process management feature. This feature allows selecting between static and dynamic process management modes.

• Allow to specify replication delay by time in streaming replication mode. For this purpose new parameter delay_threshold_by_time is introduced.

• As PostgreSQL already does, Pgpool-II now supports unix_socket_directories, unix_socket_group and unix_socket_permissions for more flexible and precise control of UNIX domain sockets.

• Allow to use comma separated multiple listen addresses in listen_addresses and pcp_listen_addresses. They control which interfaces accept connection attempts, which can help prevent repeated malicious connection requests on insecure network interfaces.

• Allow to customize the command used by trusted_servers for checking upstream connection. For this purpose new parameter trusted_server_command is introduced.

• Import PostgreSQL 15's SQL parser.

• Speed up query cache by reducing lock contention. This allows concurrent running clients to fetch cache contents much more quicker.

You can download it from here.

Release notes: English Japanese

Pgpool-II 4.3.3, 4.2.10, 4.1.13, 4.0.20 and 3.7.25 officially released (2022/08/18)

Pgpool-II 4.3.3, 4.2.10, 4.1.13, 4.0.20 and 3.7.25 officially released.

You can download them here.

• 4.3.3 : English Japanese
• 4.2.10 : English Japanese
• 4.1.13 : English Japanese
• 4.0.20 : English Japanese
• 3.7.25 : English Japanese

Pgpool-II 4.3.2, 4.2.9, 4.1.12, 4.0.19 and 3.7.24 officially released (2022/05/19)

Pgpool-II 4.3.2, 4.2.9, 4.1.12, 4.0.19 and 3.7.24 officially released.

You can download them here.

• 4.3.2 : English Japanese
• 4.2.9 : English Japanese
• 4.1.12 : English Japanese
• 4.0.19 : English Japanese
• 3.7.24 : English Japanese

Pgpool-II 4.3.1, 4.2.8, 4.1.11, 4.0.18 and 3.7.23 officially released (2022/02/17)

Pgpool-II 4.3.1, 4.2.8, 4.1.11, 4.0.18 and 3.7.23 officially released.

You can download them here.

• 4.3.1 : English Japanese
• 4.2.8 : English Japanese
• 4.1.11 : English Japanese
• 4.0.18 : English Japanese
• 3.7.23 : English Japanese

Pgpool-II 4.2.7, 4.1.10, 4.0.17 and 3.7.22 officially released (2021/12/23)

Pgpool-II 4.2.7, 4.1.10, 4.0.17 and 3.7.22 officially released.

The purpose of this release is to provide packages for PostgreSQL 14.

You can download them here.

• 4.2.7 : English Japanese
• 4.1.10 : English Japanese
• 4.0.17 : English Japanese
• 3.7.22 : English Japanese

Pgpool-II 4.3.0 released (2021/12/07)

Pgpool-II 4.3.0 is now released. Please take a look at 4.3.0

V4.3.0 contains new features and enhancements, including:

• A new membership mechanism is introduced to Watchdog to allow to keep quorum/VIP when some of watchdog nodes are removed.

• Allow to choose the least replication delay standby node when selecting the load balance node.

• Allow to specify the node id to be promoted in pcp_promote_node.

• Allow to configure to not trigger failover when PostgreSQL is shutdown by admin or killed by pg_terminate_backend.

• Add new fields to pcp_proc_info, SHOW POOL_PROCESSES and SHOW POOL_POOLS command to display more useful information to admin.

• Allow pcp_node_info to list all backend nodes information.

• Add new fields showing actual PostgreSQL status to SHOW POOL NODES command and friends.

• Add a new parameter which represents the recovery source hostname to recovery_1st_stage_command and recovery_2nd_stage_command.

• Add support for log time stamp with milliseconds.

• Import PostgreSQL 14's SQL parser.

• Support include directive in pgppol.conf file. You can have separate sub-config file to be included in pgpool.conf.

• pgpool.conf sample files are unified into single sample file for easier configuration.

• All configuration parameters in pgpool.conf sample file are commented out to clarify which parameter is needed to be changed.

You can download it from here.

Release notes: English

Pgpool-II 4.2.6, 4.1.9, 4.0.16, 3.7.21 and 3.6.28 officially released (2021/11/18)

Pgpool-II 4.2.6, 4.1.9, 4.0.16, 3.7.21 and 3.6.28 officially released.

You can download them here.

• 4.2.6 : English Japanese
• 4.1.9 : English Japanese
• 4.0.16 : English Japanese
• 3.7.21 : English Japanese
• 3.6.28 : English Japanese

Pgpool-II 4.2.5 released (2021/09/14)

Pgpool Global Development Group is pleased to announce the availability of Pgpool-II 4.2.5.

You can download them here.

• 4.2.5 : English Japanese

Pgpool-II 4.2.4, 4.1.8, 4.0.15, 3.7.20 and 3.6.27 officially released (2021/08/05)

Pgpool-II 4.2.4, 4.1.8, 4.0.15, 3.7.20 and 3.6.27 officially released.

You can download them here.

• 4.2.4 : English Japanese
• 4.1.8 : English Japanese
• 4.0.15 : English Japanese
• 3.7.20 : English Japanese
• 3.6.27 : English Japanese

pgpoolAdmin 4.2.0 officially released (2021/06/17)

pgpoolAdmin 4.2.0 officially released.

pgpoolAdmin 4.2.0 adds support for Pgpool-II 4.2. Please take a look at release notes.

You can download them here.

Pgpool-II 4.2.3, 4.1.7, 4.0.14, 3.7.19 and 3.6.26 officially released (2021/05/20)

Pgpool-II 4.2.3, 4.1.7, 4.0.14, 3.7.19 and 3.6.26 officially released.

You can download them here.

• 4.2.3 : English Japanese
• 4.1.7 : English Japanese
• 4.0.14 : English Japanese
• 3.7.19 : English Japanese
• 3.6.26 : English Japanese

Pgpool-II 4.2.2, 4.1.6, 4.0.13, 3.7.18 and 3.6.25 officially released (2021/02/18)

Pgpool-II 4.2.2, 4.1.6, 4.0.13, 3.7.18 and 3.6.25 officially released.

You can download them here.

• 4.2.2 : English Japanese
• 4.1.6 : English Japanese
• 4.0.13 : English Japanese
• 3.7.18 : English Japanese
• 3.6.25 : English Japanese

Pgpool-II 4.2.1 released (2020/12/23)

Pgpool-II 4.2.1 is now released.

You can download them from here.

• 4.2.1 : English Japanese

Pgpool-II 4.2.0 released (2020/11/26)

Pgpool-II 4.2.0 is now released.

V4.2 contains new features and enhancements, including:

• Some items in the configuration file pgpool.conf are vastly enhanced for easier configuration and administration.

• Implement logging_collector for easier log management.

• Implement log_disconnections to collect disconnection logs.

• Implement pg_enc and pg_md5 to allow to register multiple passwords at once.

• Allow to show statistics of health check by using SHOW POOL_HEALTH_CHECK_STATS command, and also allow to show statistics of issued SQL by using SHOW POOL_BACKEND_STATS command.

• New PCP command pcp_reload_config is added.

• Now it is possible to omit write_function_list and read_only_function_list by looking at system catalog information.

• Add new clustering mode snapshot_isolation_mode which guarantees not only data modifications to multiple PostgreSQL but read consistency.

• Support LDAP authentication between clients and Pgpool-II.

• Add ssl_crl_file and ssl_passphrase_command to SSL configuration.

• Import PostgreSQL 13's SQL parser.

You can download it from here.

Release notes: English

Pgpool-II 4.1.5, 4.0.12, 3.7.17, 3.6.24 and 3.5.28 officially released (2020/11/19)

Pgpool-II 4.1.5, 4.0.12, 3.7.17, 3.6.24 and 3.5.28 officially released

You can download them here.

• 4.1.5 : English Japanese
• 4.0.12 : English Japanese
• 3.7.17 : English Japanese
• 3.6.24 : English Japanese
• 3.5.28 : English Japanese

Pgpool-II 4.1.4, 4.0.11, 3.7.16, 3.6.23 and 3.5.27 officially released (2020/09/17)

Pgpool-II 4.1.4, 4.0.11, 3.7.16, 3.6.23 and 3.5.27 officially released

You can download them here.

• 4.1.4 : English Japanese
• 4.0.11 : English Japanese
• 3.7.16 : English Japanese
• 3.6.23 : English Japanese
• 3.5.27 : English Japanese

Pgpool-II 4.1.3, 4.0.10, 3.7.15, 3.6.22 and 3.5.26 officially released (2020/08/20)

Pgpool-II 4.1.3, 4.0.10, 3.7.15, 3.6.22 and 3.5.26 officially released

You can download them here.

• 4.1.3 : English Japanese
• 4.0.10 : English Japanese
• 3.7.15 : English Japanese
• 3.6.22 : English Japanese
• 3.5.26 : English Japanese

Pgpool-II 4.1.2, 4.0.9, 3.7.14, 3.6.21 and 3.5.25 officially released (2020/05/21)

Pgpool-II 4.1.2, 4.0.9, 3.7.14, 3.6.21 and 3.5.25 officially released

You can download them here.

• 4.1.2 : English Japanese
• 4.0.9 : English Japanese
• 3.7.14 : English Japanese
• 3.6.21 : English Japanese
• 3.5.25 : English Japanese

Pgpool-II 4.1.1, 4.0.8, 3.7.13, 3.6.20, 3.5.24 and pgpoolAdmin 4.1.0 officially released (2020/02/20)

Pgpool-II 4.1.1, 4.0.8, 3.7.13, 3.6.20, 3.5.24 and pgpoolAdmin 4.1.0 officially released

You can download them here.

• 4.1.1 : English Japanese
• 4.0.8 : English Japanese
• 3.7.13 : English Japanese
• 3.6.20 : English Japanese
• 3.5.24 : English Japanese

Pgpool-II 4.1.0, 4.0.7, 3.7.12, 3.6.19, 3.5.23 and 3.4.26 RPMs Update 2 officially released (2019/11/19)

Pgpool-II 4.1.0, 4.0.7, 3.7.12, 3.6.19, 3.5.23 and 3.4.26 RPMs Update 2 are officially released. The updated RPM packages fixed the bug which logs are not output, when log_destination = 'syslog' is configured.

You can download them here.

Pgpool-II 4.1.0 released (2019/10/31)

Pgpool-II 4.1.0 is now relased.

Major enhancements in Pgpool-II 4.1 include:

• Statement level load balancing.
• Auto failback.
• Enhance performance in number of areas.
  • Shared relation cache allows to reuse relation cache among sessions to reduce internal queries against PostgreSQL system catalogs.
  • Have separate SQL parser for DML statements to eliminate unnecessary parsing effort.
  • Load balancing control for specific queries.
• Reduce Internal Queries against System Catalogs.
• Import PostgreSQL 12 SQL parser.
• etc.

You can download it from here.

Release notes: English Japanese

Development

Pgpool-II 4.5 RC1 released (2023/11/28)

Pgpool-II 4.5 RC1 is now released.

Note that this is not a stable version but just for developers.

V4.5 contains new features and enhancements, including:

• Allow to use multiple statements in a query string.

• Allow to set delay_threshold_by_time in milliseconds.

• Avoid session disconnection issue in failover/failback/backend error in some cases.

• Allow to route queries to a specific backend node for a specific user connection.

• Support multiple directories specification for pcp_socket_dir.

• Import PostgreSQL 16's SQL parser.

You can download it from here.

Release notes: English

Pgpool-II 4.5 beta1 released (2023/11/14)

Pgpool-II 4.5 beta1 is now released.

Note that this is not a stable version but just for developers.

V4.5 contains new features and enhancements, including:

• Allow to use multiple statements in a query string.

• Allow to set delay_threshold_by_time in milliseconds.

• Avoid session disconnection issue in failover/failback/backend error in some cases.

• Allow to route queries to a specific backend node for a specific user connection.

• Support multiple directories specification for pcp_socket_dir.

• Import PostgreSQL 16's SQL parser.

You can download it from here.

Release notes: English

Pgpool-II 4.4 RC1 released (2022/11/22)

Pgpool-II 4.4 RC1 is now released.

Note that this is not a stable version but just for developers.

V4.4 contains new features and enhancements, including:

• Add new dynamic spare process management feature. This feature allows selecting between static and dynamic process management modes.

• Allow to specify replication delay by time in streaming replication mode. For this purpose new parameter delay_threshold_by_time is introduced.

• As PostgreSQL already does, Pgpool-II now supports unix_socket_directories, unix_socket_group and unix_socket_permissions for more flexible and precise control of UNIX domain sockets.

• Allow to use comma separated multiple listen addresses in listen_addresses and pcp_listen_addresses. They control which interfaces accept connection attempts, which can help prevent repeated malicious connection requests on insecure network interfaces.

• Allow to customize the command used by trusted_servers for checking upstream connection. For this purpose new parameter trusted_server_command is introduced.

• Import PostgreSQL 15's SQL parser.

• Speed up query cache by reducing lock contention. This allows concurrent running clients to fetch cache contents much more quicker.

You can download it from here.

Release notes: English

Pgpool-II 4.4 beta1 released (2022/11/14)

Pgpool-II 4.4 beta1 is now released.

Note that this is not a stable version but just for developers.

V4.4 contains new features and enhancements, including:

• Add new dynamic spare process management feature. This feature allows selecting between static and dynamic process management modes.

• Allow to specify replication delay by time in streaming replication mode. For this purpose new parameter delay_threshold_by_time is introduced.

• As PostgreSQL already does, Pgpool-II now supports unix_socket_directories, unix_socket_group and unix_socket_permissions for more flexible and precise control of UNIX domain sockets.

• Allow to use comma separated multiple listen addresses in listen_addresses and pcp_listen_addresses. They control which interfaces accept connection attempts, which can help prevent repeated malicious connection requests on insecure network interfaces.

• Allow to customize the command used by trusted_servers for checking upstream connection. For this purpose new parameter trusted_server_command is introduced.

• Import PostgreSQL 15's SQL parser.

• Speed up query cache by reducing lock contention. This allows concurrent running clients to fetch cache contents much more quicker.

You can download it from here.

Release notes: English

Pgpool-II 4.3 RC1 released (2021/11/25)

Pgpool-II 4.3 RC1 is now released. Please take a look at 4.3 RC1

Note that this is not a stable version but just for developers.

V4.3 contains new features and enhancements, including:

• A new membership mechanism is introduced to Watchdog to allow to keep quorum/VIP when some of watchdog nodes are removed.

• Allow to choose the least replication delay standby node when selecting the load balance node.

• Allow to specify the node id to be promoted in pcp_promote_node.

• Allow to configure to not trigger failover when PostgreSQL is shutdown by admin or killed by pg_terminate_backend.

• Add new fields to pcp_proc_info, SHOW POOL_PROCESSES and SHOW POOL_POOLS command to display more useful information to admin.

• Allow pcp_node_info to list all backend nodes information.

• Add new fields showing actual PostgreSQL status to SHOW POOL NODES command and friends.

• Add a new parameter which represents the recovery source hostname to recovery_1st_stage_command and recovery_2nd_stage_command.

• Add support for log time stamp with milliseconds.

• Import PostgreSQL 14's SQL parser.

• Support include directive in pgppol.conf file. You can have separate sub-config file to be included in pgpool.conf.

• pgpool.conf sample files are unified into single sample file for easier configuration.

• All configuration parameters in pgpool.conf sample file are commented out to clarify which parameter is needed to be changed.

You can download it from here.

Release notes: English

Pgpool-II 4.3 beta2 released (2021/11/18)

Pgpool-II 4.3 beta2 is now released. Please take a look at 4.3 beta2

Note that this is not a stable version but just for developers.

V4.3 contains new features and enhancements, including:

• A new membership mechanism is introduced to Watchdog to allow to keep quorum/VIP when some of watchdog nodes are removed.

• Allow to choose the least replication delay standby node when selecting the load balance node.

• Allow to specify the node id to be promoted in pcp_promote_node.

• Allow to configure to not trigger failover when PostgreSQL is shutdown by admin or killed by pg_terminate_backend.

• Add new fields to pcp_proc_info, SHOW POOL_PROCESSES and SHOW POOL_POOLS command to display more useful information to admin.

• Allow pcp_node_info to list all backend nodes information.

• Add new fields showing actual PostgreSQL status to SHOW POOL NODES command and friends.

• Add a new parameter which represents the recovery source hostname to recovery_1st_stage_command and recovery_2nd_stage_command.

• Add support for log time stamp with milliseconds.

• Import PostgreSQL 14's SQL parser.

• Support include directive in pgppol.conf file. You can have separate sub-config file to be included in pgpool.conf.

• pgpool.conf sample files are unified into single sample file for easier configuration.

• All configuration parameters in pgpool.conf sample file are commented out to clarify which parameter is needed to be changed.

You can download it from here.

Release notes: English

Pgpool-II 4.3 beta1 released (2021/11/09)

Pgpool-II 4.3 beta1 is now released.

Note that this is not a stable version but just for developers.

V4.3 contains new features and enhancements, including:

• A new membership mechanism is introduced to Watchdog to allow to keep quorum/VIP when some of watchdog nodes are removed.

• Allow to choose the least replication delay standby node when selecting the load balance node.

• Allow to specify the node id to be promoted in pcp_promote_node.

• Allow to configure to not trigger failover when PostgreSQL is shutdown by admin or killed by pg_terminate_backend.

• Add new fields to pcp_proc_info, SHOW POOL_PROCESSES and SHOW POOL_POOLS command to display more useful information to admin.

• Allow pcp_node_info to list all backend nodes information.

• Add new fields showing actual PostgreSQL status to SHOW POOL NODES command and friends.

• Add a new parameter which represents the recovery source hostname to recovery_1st_stage_command and recovery_2nd_stage_command.

• Add support for log time stamp with milliseconds.

• Import PostgreSQL 14's SQL parser.

• Support include directive in pgppol.conf file. You can have separate sub-config file to be included in pgpool.conf.

• pgpool.conf sample files are unified into single sample file for easier configuration.

• All configuration parameters in pgpool.conf sample file are commented out to clarify which parameter is needed to be changed.

You can download it from here.

Release notes: English

Pgpool-II 4.2 beta1 released (2020/10/27)

Pgpool-II 4.2 beta1 is now released.

Note that this is not a stable version but just for developers.

V4.2 contains new features and enhancements, including:

• Some items in the configuration file pgpool.conf are vastly enhanced for easier configuration and administration.

• Implement logging_collector for easier log management.

• Implement log_disconnections to collect disconnection logs.

• Implement pg_enc and pg_md5 to allow to register multiple passwords at once.

• Allow to show statistics of health check by using SHOW POOL_HEALTH_CHECK_STATS command, and also allow to show statistics of issued SQL by using SHOW POOL_BACKEND_STATS command.

• New PCP command pcp_reload_config is added.

• Now it is possible to omit write_function_list and read_only_function_list by looking at system catalog information.

• Add new clustering mode snapshot_isolation_mode which guarantees not only data modifications to multiple PostgreSQL but read consistency.

• Support LDAP authentication between clients and Pgpool-II.

• Add ssl_crl_file and ssl_passphrase_command to SSL configuration.

• Import PostgreSQL 13's SQL parser.

You can download it from here.

Release notes: English

Pgpool-II 4.2 alpha1 released (2020/10/06)

Pgpool-II 4.2 alpha1 is now released.

Note that this is not a stable version but just for developers.

V4.2 contains new features and enhancements, including:

• Some items in the configuration file pgpool.conf are vastly enhanced for easier configuration and administration.

• Implement logging_collector for easier log management.

• Implement log_disconnections to collect disconnection logs.

• Implement pg_enc and pg_md5 to allow to register multiple passwords at once.

• Allow to show statistics of health check by using SHOW POOL_HEALTH_CHECK_STATS command, and also allow to show statistics of issued SQL by using SHOW POOL_BACKEND_STATS command.

• New PCP command pcp_reload_config is added.

• Now it is possible to omit write_function_list and read_only_function_list by looking at system catalog information.

• Add new clustering mode snapshot_isolation_mode which guarantees not only data modifications to multiple PostgreSQL but read consistency.

• Support LDAP authentication between clients and Pgpool-II.

• Add ssl_crl_file and ssl_passphrase_command to SSL configuration.

• Import PostgreSQL 13's SQL parser.

You can download it from here.

Release notes: English

Pgpool-II 4.1 RC1 released (2019/10/16)

Pgpool-II 4.1 RC1 is now released.

This is not intended to be used in production but is close to the release version. So users are encouraged to test it out.

Major enhancements in Pgpool-II 4.1 include:

• Statement level load balancing.
• Auto failback.
• Enhance performance in number of areas.
  • Shared relation cache allows to reuse relation cache among sessions to reduce internal queries against PostgreSQL system catalogs.
  • Have separate SQL parser for DML statements to eliminate unnecessary parsing effort.
  • Load balancing control for specific queries.
• Reduce Internal Queries against System Catalogs.
• Import PostgreSQL 12 SQL parser.
• etc.

You can download it from here.

Release notes: English

Pgpool-II 4.1 beta1 released (2019/09/06)

Pgpool-II 4.1 beta1 is now released.

This is not a stable version but just for developers.

Major enhancements in Pgpool-II 4.1 include:

• Statement level load balancing.
• Auto failback.
• Enhance performance in number of areas.
  • Shared relation cache allows to reuse relation cache among sessions to reduce internal queries against PostgreSQL system catalogs.
  • Have separate SQL parser for DML statements to eliminate unnecessary parsing effort.
  • Load balancing control for specific queries.
• Reduce Internal Queries against System Catalogs.
• Import PostgreSQL 12 SQL parser.
• etc.

You can download it from here.

Release notes: English

Old

See this page.

Where can I get commercial support for Pgpool-II?

Some commercial packages include Pgpool-II support. Consulting and annual support can be purchased from SRA OSS LLC (https://www.sraoss.co.jp/index_en.php).