                                Release Notes

===============================================================================
3.2 Series (2012/07/xx - )
===============================================================================

                    3.2.0 (namameboshi) 2012/07/xx
                    CURRENT AS OF 2012/07/06

* Version 3.2.0

      This is the first version of pgpool-II 3.2 series.
      That is, a "major version up" from 3.1 series.

      __________________________________________________________________

* Incompatible changes


    - The new query cache "On memory query cache" took the place of the old
      one.
      - Now the parameter "enable_query_cache" is deleted.

      __________________________________________________________________

* New features

  ** Memory based query cache

    Original author is Masanori Yamazaki, improved by Development Group.
   (Tatsuo Ishii, Nozomi Anzai, Yugo Nagata)

    Overview:

        On memory query cache is faster because cache storage is on memory.
        Moreover you don't need to restart pgpool-II when the cache is outdated
        because the underlying table gets updated.

        On memory cache saves pair of SELECT statements (with its Bind parameters
        if the SELECT is an extended query). If the same SELECTs comes in, it
        returns the value from cache. Since no SQL parsing nor access to
        PostgreSQL are involed, it's extremely fast.

        On the other hand, it might be slower than the normal path because it
        adds some overhead to store cache. Moreover when a table is updated,
        pgpool automatically deletes all the caches related to the table. So the
        prformace will be degraded by a system with a lot of updates. If the
        cache_hit_ratio is lower than 70%, you might want to disable onl memory
        cache.

    Choosing cache strage:

        You can choose a cache strage: shared memory or memcached (you can't use
        the both).
        Query cache with shared memory is fast and easy because you don't have
        to install and config memcached, but restricted the max size of cache by
        the one of shared memory. Query cache with memcached needs a overhead to
        access network, but you can set the size as you like.

    Restrictions:

      - On memory query cache deletes the all cache of an updated table
        automatically with monitoring if the executed query is UPDATE, INSERT,
        ALTER TABLE and so on. But pgpool-II isn't able to recognize implicit
        updates due to trigers, foreign keys and DROP TABLE CASCADE.
        You can avoid this problem with memqcache_expire by which pgpool deletes
        old cache in a fixed time automatically, or with black_memqcache_table_list
        by which pgpool's memory cache flow ignores the tables.

      - If you want to use multiple instances of pgpool-II with online memory
        cache which uses shared memory, it could happen that one pgpool deletes
        cache, and the other one doesn't do it thus finds old cached result
        when a table gets updated. Memcached is the better cache strage in this
        case.

    New parameters:

      - Add parameters for on memoey query cache as follows:
        memory_cache_enabled, memqcache_method, memqcache_expire,
        memqcache_maxcache, memqcache_oiddir. (Tatsuo Ishii)

      - Add parameters about shared memory for on memory query cache as
        follows:
        memqcache_total_size, memqcache_max_num_cache,
        memqcache_cache_block_size. (Tatsuo Ishii)

      - Add parameters about memcached for on memory query cache as follows:
        memqcache_memcached_host, memqcache_memcached_port. (Tatsuo Ishii)

      - Add parameters about relation cache for on memory query cache as
        follows:
        relcache_expire, relcache_size. (Tatsuo Ishii)

      - Add a parameter "check_temp_table" to check if the SELECTed table is
        temp table. (Tatsuo Ishii)

      - Add the parameters of white_memqcache_table_list,
        black_memqcache_table_list that check if the SELECTed tables, temp
        tables and views are to be cached or not. (Nozomi Anzai)

      - Add a parameter "memqcache_auto_cache_invalidation" of the flag if
        query cache is triggered by corresponding DDL/DML/DCL (and
        memqcache_expire). (Yugo Nagata)

    New commands:

      - Add "SHOW pool cache" which shows hit ratio of query cache and the
        status of cache strage.

      - Add "--with-memcached" option to configure. (Nozomi Anzai)

      - Add "-C, --clear-oidmaps" option to "pgpool" command. (Nozomi Anzai)
        If pgpool with memcached starts / restarts with -C option, discard oid
        maps, if not, it can reuse old oid maps and query caches.

  ** Watchdog

    The author is Atsushi Mitani, tested by Yugo Nagata.

    Overview:

        "Watchdog" is a sub process of pgpool-II aiming for adding high
        availability feature to it. Features added by watchdog include:

        - Life checking of pgpool service

          Watchdog monitors responses of pgpool service rather than process. It
          sends queries to PostgreSQL via pgpool which is being monitored by
          watchdog and watchdog checks the response. Also watchdog monitors
          connections to up stream servers (application servers etc.) from the
          pgpool. The connection between the up stream servers and the pgpool is
          monitored as service of pgpool.

        - Mutual monitoring of watchdog processes

          Watchdog processes exchange information on the monitored servers to
          keep the information up to date, and to allow watchdog processes to
          mutually monitor each other.

        - Changing active/standby state in case of certain faults detected

          When a fault is detected in the pgpool service, watchdog notifies the
          other watchdogs of it. Watchdogs decide the new active pgpool if
          previous active pgpool is broken by voting and change active/standby
          state.

        - Automatic virtual IP address assigning synchronous to server switching

          When a standby pgpool server promotes to active, the new active server
          brings up virtual IP interface. Meanwhile, the previous active server
          brings down the virtual IP interface. This enables the active pgpool to
          work using the same IP address even when servers is switched over.

        - Automatic registration of a server as standby in recovery

          When broken server recovers or new server is attached, the watchdog
          process notifies the other watchdog process along with information of
          the new server, and the watchdog process receives information on the
          active server and other servers. Then, the attached server is
          registered as standby.

    New parameters:

        - Add a parameter to enable watchdog: use_watchdog. (Atsushi Mitani)

        - Add the parameters about life checking of pgpool service as follows:
          wd_interval,other_pgpool_port wd_life_point, wd_lifecheck_query,
          other_pgpool_hostname, other_pgpool_port. (Atsushi Mitani)

        - Add the parameters about up to stream connection (e.g. to application
          servers) as follows:
          trusted_servers, ping_path. (Atsushi Mitani)

        - Add the parameters about mutual monitoring of watchdog processes
          as follows:
          wd_port, other_wd_port. (Atsushi Mitani)

        - Add the parameters about virtual IP as follows:
          ifconfig_path, if_up_cmd, if_down_cmd, arping_path, arping_cmd.
          (Atsushi Mitani)

      __________________________________________________________________

* Enhancements

    - Retry if health check faied rather than immediately do failover. For
      this purpose new directives "health_check_max_retries" and
      "health_check_retry_delay" were added. (Tatsuo Ishii)
      Patch contributed by Matt Solnit.

        Subject: [Pgpool-hackers] Health check retries (patch)
        From: Matt Solnit
        Date: Fri, 18 Nov 2011 16:28:44 -0500

    - Log client IP and port number when pgpool failed to parse given query.
      (Tasuo)

      This is usefull to identify which client gives wrong query without
      enabling log_connections, which produces too many log entries on busy web
      systems.

    - Refactor pool_process_query(). (Tatsuo Ishii)

      Deal with the case when:
        1) query not in progress
        2) other than master node has pending data.
      It is reported that pgpool goes into infinite loop in this case.

        [pgpool-general: 43]
        Re: [Pgpool-general] seemingly hung pgpool process consuming 100% CPU
        http://www.pgpool.net/pipermail/pgpool-general/2011-December/000042.html

    - Add "role" which represents "primary" or "standby" iin streaming
      replication mode for example to "SHOW pool_nodes" command.(Tatsuo Ishii)

    - Add params to the result of "SHOW pool_status": backend_data_directory,
      ssl_ca_cert, ssl_ca_cert_dir, and sort by orders in pgpool.conf. (Anzai)

    - Commentout params about system db from pgpool.conf.sample-*. (Nozomi Anzai)

    - Add new parameter to failover/failback/followmaster command. (Tatsuo Ishii)

        %r: new master port number
        %R: new master database cluster path

    - Allow to reload to recognize md5 password change. (Tatsuo Ishii)
      Before, the only way to recognize md5 password change was restarting
      pgpool-II. Patch contributed by Gurjeet Singh.

    - Improve the design of manuals. (Nozomi Anzai)

      __________________________________________________________________

* Bug Fix

    - Fix memory leak in Raw mode.(Tatsuo Ishii)

    - Fix failover/failback in Raw mode. (Tatsuo Ishii)
      - Simply does not failover if target node is not master.
      - Fail to select master node if the node is in CON_UP.

    - Allow health check retry while connect(). (Tatsuo Ishii)

      It is reported that connect() blocks sigalarm under some conditions, for
      example: When system is configured for security reasons not to return
      destination host unreachable messages ([pgpool-general: 131])
      Part of changes are contributed by Stevo Slavic.

      [pgpool-general: 131] Healthcheck timeout not always respected
      http://www.sraoss.jp/pipermail/pgpool-general/2012-January/000131.html

    - Fix pool_send_and_wait() to send or not to send COMMIT / ABORT depending
      on the transaction state on each node. (Tatsuo Ishii)

      It is possible that only primary is in an explicit transaction but
      standby is not in it if multi statement query has been sent.
      Per bug report [pgpool-general-jp: 1049].

    - Fix load balance in Solaris. (Tatsuo Ishii)

      Problem is, random() in using random() in Solaris results in strange
      load balancing calculation.
      Use srand()/rand() instead although they produce lesser quality random
      Problem reported at [pgpool-general: 396].

      [pgpool-general: 396] strange load balancing issue in Solaris
      http://www.sraoss.jp/pipermail/pgpool-general/2012-April/000397.html

    - Fix segfault of pcp_systemdb_info not in parallel mode. (Nozomi Anzai)

    - Fix "unnamed prepared statment does not exist" error. (Tatsuo Ishii)

      This is caused by pgpool's internal query, which breaks client's unnamed
      statements. To fix this, if extended query is used, named
      statement/portal for internal are used for internal query.

    - Fix hangup when query conflict occurs in Hot-Standby mode. (Yugo Nagata)
      Query example to reproduce:

          (S1) BEGIN;
          (S1) SELECT * FROM t;
          (S2) DELETE FROM t;
          (S2) VACUUM t;

===============================================================================
3.1 Series (2011/09/08 - )
===============================================================================

                    3.1.3 (hatsuiboshi) 2012/04/23

* Version 3.1.3

      This is a bugfix release against pgpool-II 3.1.2.

      __________________________________________________________________

* Bug fixes

      - Add m4 files. This should prevent compiling problem on older
        OS's. (Tatsuo Ishii)

      - Fix to handle failover properly in detect_postmaster_down_error().
        (Tatsuo Ishii)

        It is possible that it fails to read backend socket after detecting
        backend errors and before actually detaching the backend.

      - Fix bug that the process exits before unlocking semaphore by a
        signal interrupt. (Tatsuo Ishii)

      - Fix a memory leak in case of reset_query. (Tatsuo Ishii)

      - Fix pool_ssl_read() to deal with large data reading. (Tatsuo Ishii)

        Original complain is here:
        http://www.pgpool.net/pipermail/pgpool-general/2012-March/000299.html

      - Fix deadlock by enabling log_destination = syslog. (Tatsuo Ishii)

        Reported in bug tracker http://www.pgpool.net/mantisbt/view.php?id=9.
        Patch provided by Gilles Darold.

      - Allow to use multi statement in master/slave mode. (Tatsuo Ishii)

        From 3.1 transactional statements such as "BEGIN" are sent to not only
        primary but also standbys. This brings an unfortunate side effect: if
        the multi statement is "BEGIN;DELETE FROM table;END", this will be
        sent to standy as well and cause an error because standby does notallow
        write SQL. So fix is, if a query is a multi statement one, then send it
        to primary only.

      - Allow to have private cache of master node id. (Tatsuo Ishii)

        When master goes down running pgpool children look into NULL pointer
        because the process does not connect to the new master yet. The private
        cache returns the old master node id and will avoid the situation.

        Per bug reported in http://www.pgpool.net/mantisbt/view.php?id=51

      - Fix pool_start_query() so that it uses my_master_node_id instead of
        REAL_MASTER_NODE_ID for initial virtual_master_node_id. (Tatsuo Ishii)

        Real master node could be changed while pgpool is running in streaming
        replication mode. Previously it is assigned REAL_MASTER_NODE_ID, which
        could have no connections after fail over and cause segafult.

      - Fix pool_setall_node_to_be_sent() to use private_backend_status instead
        of BACKEND_INFO macro. (Tatsuo Ishii)

        It is possible that while processing, the node returned by BACKEND_INFO
        is not usable any more.

      - Fix failover(). (Tatsuo Ishii)

        Before it only restarts worker child only when pgpool child do not need
        restart. This is wrong. We need to restart worker child in any case.
        Otherwise it continues to send replication time lag check request to down
        the node.

      - Fix debug log message so that it does not contain null characters.
        (Toshihiro Kitagawa)

      - Fix SimpleQuery() so that it restores parser memory context when:
          1) Builtin show commands are used
          2) Parallel query mode
          3) Query cache is used
        (Tatsuo Ishii)

      - Fix hangup when PREPARE statement causes error. (Toshihiro Kitagawa)

        This issue was reported by Tomonari Katsumata:
        Subject: [pgpool-general: 121] question of pgpool's behavior

      - Add doc/pgpool-fr.html to Makefile.am. (Tatsuo Ishii)

        This had been forgotten when the doc was added.

      - Fix  hangup during md5 authentication that occurs in daemon mode
        and log_destination is 'syslog'. (Yugo Nagata)

        Reported in bug tracker http://www.pgpool.net/mantisbt/view.php?id=2.

===============================================================================

                        3.1.2 (hatsuiboshi) 2012/01/31

* Version 3.1.2

      This is a bugfix release against pgpool-II 3.1.1.

      __________________________________________________________________

* Bug fixes

      - Fix to recognize READ UNCOMMITTED and REPEATABLE READ of transaction
        isolation levels. (Tatsuo Ishii)

      - Fix infinite loop reported in this thread (Tatsuo Ishii):
        http://www.pgpool.net/pipermail/pgpool-general/2011-December/000099.html

        It was not considered the case that, when received buffer in primary was
        empty but the one in a standby was not, the standby spontaneously sent
        packet to pgpool.
        This could happen when, for example, reloading postgresql.conf.
        The fix is that such buffer in standby is discarded.


===============================================================================

                        3.1.1 (hatsuiboshi) 2011/12/06

* Version 3.1.1

      This is a bugfix release against pgpool-II 3.1.

      __________________________________________________________________

* Bug fixes

      - Fix add_regex_pattern(). It does not allocate enough memory
        for each black/white_function_list items.
        The function adds "^" and "$" to each function items which do not
        contain those characters. Unfortunately the function forgot to add
        extra 2 bytes for those characters. This may lead to memory
        corruption errors when pgpool starting up.

      - Fix error message of check_replication_time_lag(Tatsuo Ishii).
        It emitted wrong error message when it failed to connect to PostgreSQL
        while checking streaming replication delay.
        Because it does not use health_check_user anymore.

      - Fix memory leak(Toshihiro Kitagawa). This is essentially same
        as the fix made for 3.0.5
        (commit 19a4ea9215da0b61728741fc0da2271958b09238).

      - Major cleanup for strncpy(Tatsuo Ishii).
        There are several places where strncpy() is used. Problem is some of
        them do not consider the case when copy lengh == buffer size.
        In this case copied buffer is not null terminated and may cause
        tons of problems later.  To fix this, most of them are replaced by
        strlcpy().

      - Update cached backend status whenever possible(Tatsuo Ishii).
        This solves the problem of follow_master_command not being
        able to lookup backend status correctly which was reported by
        Jeff Frost: Subject: [Pgpool-general] diagnosing BackendError
        from pcp_recovery_node To: pgpool-general@pgfoundry.org Date:
        Wed, 05 Oct 2011 15:15:07 -0700

      - Fix buffer overrun problem when pcp password is longer than 32
        (Tatsuo Ishii).

      - Remove PGDLLIMPORTI which is only neccessary for Windows and
        cause a problem for non gcc. Patch contributed by Ibrar Ahmed.

===============================================================================

                        3.1 (hatsuiboshi) 2011/09/08

* Version 3.1

      This is the first version of pgpool-II 3.1 series.
      That is, a "major version up" from 3.0 series.

      __________________________________________________________________

* Incompatible changes

      - Change the lock method of insert_lock. The previous insert_lock uses
        row locking against the sequence relation, but the current one uses
        row locking against pgpool_catalog.insert_lock table.
        The reason is that PostgreSQL core developers decided to disallow row
        locking against the sequence relation to avoid an internal error
        which it leads. So creating insert_lock table in all databases which are
        accessed via pgpool-II beforehand is required.
        If does not exist insert_lock table, pgpool-II locks the insert target
        table. This behavior is same as pgpool-II 2.2 and 2.3 series.
        If you want to use insert_lock which is compatible with older releases,
        you can specify lock method by configure options: --enable-sequence-lock,
        --enable-table-lock(Toshihiro Kitagawa)

      - Deprecate backend_socket_dir. Instead, if backend_hostname starts
        with '/' it is regarded the as path to Unix domain. If backend_hostname
        is left empty, then default Unix domain path(/tmp) is used. This
        follows the convention of libpq interface. Patch contributed by
        Jehan-Guillaume (ioguix) de Rorthais.

      - Now "pgpool_walrecrunning()" was not used. pgpool-II used to consider
        the node that is promoted a primary node using the function. Now,
        pgpool-II waits for completing of the promotion to primary node
        because it did not work as we intended. But we still have a problem
        that pgpool-II waits while recovery_timeout, when there is no primary
        node(Toshihiro Kitagawa)

      - Add node_id to each PostgreSQL DB node info in the output of
        show pool_nodes(Jean-Paul Argudo)

      - Change the handling of sequence functions(nextval, setval) so that
        they completely obey setting of black/white_function_list. They were
        always handled as write functions before(Toshihiro Kitagawa)

      __________________________________________________________________

* New features

      - Add syslog support. Patch contributed by Gilles Darold. Review and
        editing by Guillaume Lelarge.

      - Adapt application_name introduced in PostgreSQL 9.0. When reusing
        connection, send application_name in the startup packet to backend
        and send parameter status to frontend(Tatsuo Ishii)

      - Add relcache_expire directive to control the expiration of the
        internal system catalog cache. ALTER TABLE might make these
        cache values obsoleted and the new directive will make the risk
        lower(Tatsuo Ishii).

      - Add follow_master_command directive. This directive specifies a
        command to run in master/slave streaming replication only after
        a master failover. Patch contributed by Gilles Darold.

      - Add pcp_promote_node command. This command promotes a new master
        node to pgpool-II. This can use in master/slave streaming replication
        only. Patch contributed by Gilles Darold.

      - Add pcp_pool_status command which produces similar output of show
        pool_status. Also C API for this command is added. Patch
        contributed by Jehan-Guillaume (ioguix) de Rorthais.

      - Add new per backend directive "backend_flag". This controls per
        backend behavior. Currently "ALLOW_TO_FAILOVER" or
        "DISALLOW_TO_FAILOVER" are allowed(Tatsuo Ishii)

      - Add health_check_password directive(Nicolas Thauvin)

      - Add sr_check_period, sr_check_user and sr_check_password directives.
        These are used for streaming replication delay checking and
        determining primary node(Tatsuo Ishii)

      - Add --username(or -u) option to pg_md5 command. This allows to manage
        users which do not have UNIX accounts. Japanese document change by
        Tatsuo Ishii(Nicolas Thauvin)

      - Add pgpool_adm functions to pgpool_adm/. These are user-defined
        functions written in C language which work like pcp commands
        (Jehan-Guillaume (ioguix) de Rorthais)

      - Add Simplified Chinese version of documents(Huang Jian, Sun Peng)

      - Add SQL files to uninstall functions to sql/(Nicolas Thauvin)

      - In master/slave mode, SELECTs to unlogged table execute only on
        master/primary(Toshihiro Kitagawa)

      __________________________________________________________________

* Bug fixes

      - Fix bug which cannot use the cursors of JDBC driver on standby
        node. The transaction commands come to be sent to all nodes by
        this fix in master/slave mode(Toshihiro Kitagawa)

      - Fix bug with the handling of empty queries. The empty queries
        come to be handled the same as SELECT queries. This fix allows
        load-balance after the empty query(Toshihiro Kitagawa)

      - Fix insert_lock so that it works correctly even if the column
        definition such as "DEFAULT nextval(('"x_seq"'::text)::regclass)"
        (Toshihiro Kitagawa)

      - Fix pcp_attach_node command so that it emits error message while
        doing failover(Toshihiro Kitagawa)

      - Fix log message which is emitted when pgpool-II cannot parse the
        query in the extended query protocol so that it shows the query
        (Toshihiro Kitagawa)

      - Fix description about backend_weight inpgpool-II manual. It can
        be changed by reloading pgpool.conf(Tatsuo Ishii)

      - Fix and enhance wording in English tutorial document.
        Fix suggested by Huang Jian(Tatsuo Ishii)

      - Fix bug which does not update the node status when reattaching the
        node in raw mode(Guillaume Lelarge)

      - Fix incorrect calculation of the replication delay in streaming
        replication mode(Tatsuo Ishii)

      - Replace wrong function name "notice_backend_error" with correct one
        "degenerate_backend_set" in the failover log message(Tatsuo Ishii)

      - Remove unnecessary logging at the end of pgpool.conf parsing
        (Tatsuo Ishii)

      - Fix possible crash of pgpool/worker child after attaching new backend.
        Fix suggested by Gurjeet Singh(Tatsuo Ishii)

      - Fix bug that SELECTs which have subquery with FOR SHARE/UPDATE clause
        are sent to slave/standby(Tatsuo Ishii)

      - Fix bug which rewriting timestamp of default value fails in PREPARE
        statements. This used to work but was broken in 3.0(Toshihiro Kitagawa)

      - Fix fail to compile pcp commands on the environment without
        getopt_long()(Tatsuo Ishii)

      - Fix crash of pgpool child when frontend connects if in raw mode,
        enable_hba is off and more than 2 backends(Toshihiro Kitagawa)

      - Fix some memory leaks(Toshihiro Kitagawa)

      __________________________________________________________________

* Enhancements

      - Enhance online recovery in streaming replication mode.
        Now restarting pgpool-II children is avoided when recovery finished.
        So existing sessions can be continued while doing online recovery
        (Tatsuo Ishii)

      - pcp_attach_node does not diconnect existing sessions in
        streaming replication mode. In other mode, pcp_attache_node
        still disconnects existing sessions(Tatsuo Ishii).

      - Import PostgreSQL 9.0 parser. This allows to use CREATE INDEX with
        implicit index name, which is new in 9.0. Patch contributed by
        Akio Ishida.

      - Allow to use regular expressions in black and white function list.
        Patch contributed by Gilles Darold. Patch reviewed by Guillaume Lelarge.

      - Reorganize pgpool.conf sample files so that they are easier to read
        (Guillaume Lelarge)

      - Add <a name="..."> tags into all parameters in the pgpool-II user
        manual(Haruka Takatsuka)

      - Enhance online recovery documents in streaming replication(Tatsuo Ishii)

      - Change the function to check the replication delay in streaming
        replication mode. Currently, pgpool uses
        pg_last_xlog_replay_location() instead of
        pg_last_xlog_receive_location(). Fix suggested by Anton Yuzhaninov
        (Tatsuo Ishii)

      - Allow time stamp rewriting to work with arbitrary expression in
        default value of a column. Before we detected anything including
        now() then simply replaced it to now(). This will lead to wrong
        rewriting of default value. for example, timezone('utc'::text, now()).
        Note that, however, this only adopts to simple queries. Extended
        protocols(for example Java, PHP PDO) or SQL "PREPARE" still remain
        same(Tatsuo Ishii)

      - Enhance the error message which is emitted when failed to check
        replication delay(Nicolas Thauvin)

      - Change error message "do_md5: read_password_packet failed" into debug
        level(Toshihiro Kitagawa)

      - Allow to compile pgpool-regclass() against PostgreSQL 9.1(Tatsuo Ishii)

      - Update and sync pgpool-II manuals of English version and Japanese
        version(Tatsuo Ishii)


===============================================================================
3.0 Series (2010/09/10 - )
===============================================================================

                        3.0.7 (umiyameboshi) 2012/04/23

* Version 3.0.7

      This is a bugfix release against pgpool-II 3.0.6.

      __________________________________________________________________

* Bug fixes

      - Add m4 files. This should prevent compiling problem on older
        OS's. (Tatsuo Ishii)

      - Fix bug that the process exits before unlocking semaphore by a
        signal interrupt. (Tatsuo Ishii)

      - Fix a memory leak in case of reset_query. (Tatsuo Ishii)

      - Fix SimpleQuery() so that it restores parser memory context when:
         1) Builtin show commands are used
         2) Parallel query mode
         3) Query cache is used
       (Tatsuo Ishii)

      - Fix pool_ssl_read() to deal with large data reading. (Tatsuo Ishii)

        Original complain is here:
        http://www.pgpool.net/pipermail/pgpool-general/2012-March/000299.html

      - Fix hangup when PREPARE statement causes error. (Toshihiro Kitagawa)

        This issue was reported by Tomonari Katsumata:
        Subject: [pgpool-general: 121] question of pgpool's behavior

===============================================================================

                        3.0.6 (umiyameboshi) 2012/01/31

* Version 3.0.6

      This version fixes various bugs since 3.0.5.

      - Fix infinite loop reported in this thread (Tatsuo Ishii):
        http://www.pgpool.net/pipermail/pgpool-general/2011-December/000099.html

        It was not considered the case that, when received buffer in primary was
        empty but the one in a standby was not, the standby spontaneously sent
        packet to pgpool.
        This could happen when, for example, reloading postgresql.conf.
        The fix is that such buffer in standby is discarded.

===============================================================================

                        3.0.5 (umiyameboshi) 2011/10/31

* Version 3.0.5

      This version fixes various bugs since 3.0.4.

      __________________________________________________________________

* Bug fixes

      - Fix bug with the handling of empty queries. The empty queries
        come to be handled the same as SELECT queries. This fix allows
        load-balance after the empty query(Toshihiro Kitagawa)

      - Fix insert_lock so that it works correctly even if the column
        definition such as "DEFAULT nextval(('"x_seq"'::text)::regclass)"
        (Toshihiro Kitagawa)

      - Fix log message which is emitted when pgpool-II cannot parse the
        query in the extended query protocol so that it shows the query
        (Toshihiro Kitagawa)

      - Fix description about backend_weight inpgpool-II manual. It can
        be changed by reloading pgpool.conf(Tatsuo Ishii)

      - Fix bug which does not update the node status when reattaching the
        node in raw mode(Guillaume Lelarge)

      - Fix bug that SELECTs which have subquery with FOR SHARE/UPDATE clause
        are sent to slave/standby(Tatsuo Ishii)

      - Fix bug which rewriting timestamp of default value fails in PREPARE
        statements. This used to work but was broken in 3.0(Toshihiro Kitagawa)

      - Fix crash of pgpool child when frontend connects if in raw mode,
        enable_hba is off and more than 2 backends(Toshihiro Kitagawa)

      - Fix some memory leaks(Toshihiro Kitagawa)

      __________________________________________________________________

* Enhancements

      - Allow time stamp rewriting to work with arbitrary expression in
        default value of a column. Before we detected anything including
        now() then simply replaced it to now(). This will lead to wrong
        rewriting of default value. for example, timezone('utc'::text, now()).
        Note that, however, this only adopts to simple queries. Extended
        protocols(for example Java, PHP PDO) or SQL "PREPARE" still remain
        same(Tatsuo Ishii)

      - Change error message "do_md5: read_password_packet failed" into debug
        level(Toshihiro Kitagawa)

===============================================================================

                        3.0.4 (umiyameboshi) 2011/06/01

* Version 3.0.4

      This version fixes various bugs since 3.0.3.

      __________________________________________________________________

* Incompatible changes

      - In streaming replication, if delay_threshold is 0 or health
        checking is disabled, the delay checking is not performed. 
        This is the behaviour according to a description of the
        pgpool-II manual. But, so far the delay checking was performed
        even if health checking was disabled(Guillaume Lelarge)

      __________________________________________________________________

* Bug fixes

      - Fix pgpool-regclass() to be compiled in PostgreSQL 8.0 or later.
        7.4 still produces errors(Tatsuo Ishii)

      - Fix possible hangup when using /*NO LOAD BALANCE*/ comment in
        streaming replication(Toshihiro Kitagawa)

      - Fix hangup when received Flush(H) message or CloseComplete(C)
        message(Toshihiro Kitagawa)

      - Fix possible hangup that happen for the receiving timing of
        ReadyForQuery(Z) message after pgpool-II connects to backends
        (Toshihiro Kitagawa)

      - Add description about parameters for recovery_1st_stage_command
        and recovery_2nd_stage_command(Tatsuo Ishii)

      - Increase size of the internal system catalog cache from 32 to 128.
        This has the effect of reducing "unnamed prepared statement does
        not exist" error(Tatsuo, Kitagawa)

      - Fix bug with pcp_connect() which causes double free. Patch
        contributed by Jehan-Guillaume (ioguix) de Rorthais(Tatsuo Ishii)

      - Fix bug with start_recoery() which is apparently wrong usage of
        PQfinish()(Tatsuo Ishii)

      - Fix incorrect error message which is sent to the frontend when
        client idle time reached client_idle_limit(Tatsuo Ishii)

      - Fix "backend status" variable name correctly in pool_status.
        Replace the space with a '_'(Guillaume Lelarge)

      - Fix hangup when using md5 authentication method and running as
        daemon. Patch contributed by Nicolas Thauvin(Tatsuo Ishii)

      - Fix log_per_node_statement so that it prints statements in the
        extended query protocol. This used to work but was broken in 3.0
        (Toshihiro Kitagawa)

      __________________________________________________________________

* Enhancements

      - Add currval() and lastval() to black_function_list of sample
        configuration files. If they are load balanced, currval() or
        lastval() may be called before the result of nextval() or setval()
        is propagated to slaves(Tatsuo Ishii)

===============================================================================

                        3.0.3 (umiyameboshi) 2011/02/23

* Version 3.0.3

      This version fixes various bugs since 3.0.1. Please note that
      3.0.2 was canceled due to a packaging problem.

      __________________________________________________________________

* Incompatible changes

      - Now installing C function "pgpool_walrecrunning()" is recommended
        if you plan to use streaming replication mode.
        This is necessary for better use of online recovery in the mode.
        Also new variable "%P" can be used in the online recovery script.
        If you do not install the function, these functionalities Cannot
        be used(Tatsuo Ishii).

      - In raw mode if there's only one DB node and if a problem arises
        with the DB node, it will be brought to down status. However if
        the DB node goes into good condition again, you can use the DB
        node without restarting pgpool. This change has been included in
        3.0, but did not work(Tatsuo, Kitagawa)

      __________________________________________________________________

* Bug fixes

      - Fix non portable code in password authentication.
        Bug report from a FreeBSD user(Tatsuo Ishii)

      - Fix bug that insert_lock locks all rows in user table
        (Tatsuo, Kitagawa)

      - Fix bug with password authentication. If user name is 32 bytes
        long, pgpool child segfaults.(Tatsuo Ishii)

      - Fix bug with md5 authentication. If raw mode or number of
        backend is 1, pgpool child segfaults. Patch contributed by
        Rob Shepherd(Tatsuo Ishii)

      - Fix long standing bug with timestamp rewriting against array
        and complex types. Patch contributed by Akio Ishida(Tatsuo Ishii)

      - Fix bug that debug_level directive doesn't work. Patch
        contributed by Gilles Darold(Tatsuo Ishii)

      - Fix possible crash of pgpool child while doing failover
        (Toshihiro Kitagawa)

      - Fix white/black_function_list so that it works correctly when user
        calls function with schema name(Tatsuo Ishii)

      - Fix bug that DROP DATABASE fails by connection cache
        (Toshihiro Kitagawa)

      - Fix bug that failover fails in raw mode(Toshihiro Kitagawa)

      - Fix possible termination of pgpool child when both simple query
        protocol and extended query protocol are used in one session
        (Toshihiro Kitagawa)

      - Fix possible hang up when an error occurs while using extended
        query protocol(Toshihiro Kitagawa)

      - Fix pgpool-regclass() so that it doesn't use PG_TRY/CATCH.
        It appeared that using PG_TRY/CATCH is not safe, sometimes backend
        dies with PANIC:  ERRORDATA_STACK_SIZE exceeded.(Tatsuo Ishii)

      - Fix bug that select query isn't sent to master node when it meets
        the following conditions(Toshihiro Kitagawa)
        - in MASTER/SLAVE mode
        - use extended query protocol
        - started transaction explicitly
        - after write queries

      - Fix bug with load_balance that JDBC driver sends BEGIN to master node
        many times(Toshihiro Kitagawa)

      - Fix pool_status so that failback_command and fail_over_on_backend_error
        show correct values(Toshihiro Kitagawa)

      - Remove parameters from pool_status: recovery_password,
        system_db_password(Toshihiro Kitagawa)

      - Fix online recovery problem in the streaming replication
        mode(Tatsuo Ishii).
        Consider following scenario. Suppose node 0 is the initial primary server
        and 1 is the initial standby server.

        1) Node 0 going down and node 1 promotes to new primary.
        2) Recover node 0 as new standby.
        3) pgpool-II assumes that node 0 is the new primary.

        This problem happens because pgpool-II regarded unconditionally
        the youngest node to be the primary. pgpool-II 3.0.3 now checks
        each node by using pgpool_walrecrunning() to see if it is a
        actually primary or not and is able to avoid the problem and
        regards node as standby correctly. Also you can use new
        variable "%P" to be used in the recovery script.  If you do
        not install the function, the above problem is not resolved.

      - Fix backend complaining "unexpected EOF on client connection"
        while doing failover in streaming replication mode(Tatsuo Ishii)

      - Fix pgpool crashes when all backends go down(Tatsuo Ishii)

      - Fix replication delay checking so that it does not keep persistent
        connection to backends. Because the persistent connection may
        become bogus if a node down and then wake up between replication
        delay checking period(Tatsuo Ishii)

      - Rewrite and review english document(Marc Cousin, Gleu)

      __________________________________________________________________

* Enhancements

      - Emit log if particular backend is down status while reading
        the status file(Tatsuo Ishii)

      - Emit error message if an error occurred by the query that
        pgpool executed(Tatsuo Ishii)

      - Add sql directories main Makefile(Tatsuo Ishii)

===============================================================================

                        3.0.1 (umiyameboshi) 2010/10/19

* Version 3.0.1

      This version fixes various bug in 3.0.

      __________________________________________________________________

* Bug fixes

      - Fix bug with md5 auth. If there's more than 1 servers to be
        authenticated, it segfaults(Tatsuo Ishii)

      - Fix bug that a child process crashes when clients execute a query
        contains syntax error in extended query protocol(Toshihiro Kitagawa)

      - Fix bug with handling of portal information, it terminates
        a child process(Toshihiro Kitagawa)

      - Fix hungup when a query sent to one node caused an error
        in extended query protocol(Toshihiro Kitagawa)

      - Fix typo in English doc. Patch contributed by Asaf Ohaion(Tatsuo Ishii)

===============================================================================

                        3.0 (umiyameboshi) 2010/09/10

* Version 3.0

      This is the first version of pgpool-II 3.0 series.
      That is, a "major version up" from 2.2 or 2.3 series.

      The biggest news is, this version adapts to PostgreSQL 9.0's new
      feature: Streaming Replication/Hot Standby. Streaming
      replication can be used as a sub mode of master slave
      mode. Master slave mode itself heavily enhanced:

      - SELECTs in explicit transactions can be load balanced

      - In extended protocol, PARSE/BIND/DESCRIBE messages are sent to
        the node which execute EXECUTE message, not all node. This
        will reduce lock contentions.

      - Auto start of transaction happens only when it needed.

      - Temporary tables can be used safely.

      - SELECT which calls functions possibly write to database
        executes on master(primary)

      Also many new features are added and major refactoring has been
      made to the internal structure of pgpoo-II. For example, in
      replication mode, SELECTs calling functions possibly write to
      database will not allow to load balance.

      __________________________________________________________________

* New features

      - Online recovery can be used with master/slave/streaming
        replication mode(Tatsuo Ishii)

      - New directive "delay_threshold" is added to monitor
        replication delay in master/slave/streaming replication
        mode. If replication delay is too much, SELECTs are not load
        balanced(Tatsuo Ishii)

      - show pool_status shows replication delay in
        master/slave/streaming replication mode(Tatsuo Ishii)

      - New directive "log_standby_delay" is added to control logging of
        replication delay in master/slave/streaming replication
        mode(Tatsuo Ishii)

      - When insert_lock is enabled and the table includes SERIAL data
        type, issue row lock on the sequence table. Before we issues
        table lock. Problem is, the table lock conflicts with auto
        vacuum and sometimes caused excessive lock waiting(Tatsuo Ishii)

      - Add support for more "SHOW" commands: pool_nodes,
        pool_processes, pool_pools, and pool_version(Guillaume Lelarge)

      - Backend process id and whether frontend connects to this
        connection pool or not are added to pcp_proc_info's
        output(Tatsuo Ishii)

      - "Gracefuly detach" option is added to pcp_detatch_node. With
        this option, pcp_detatch_node waits until all frontends
        disconnected(Tatsuo Ishii)

      - New directive "white_function_list" and "black_function_list"
        are added to register functions those do not or do write to
        database(Tatsuo Ishii)

      - In master/slave mode, SELECTs to system catalogs executes only
        on master/primary(Tatsuo Ishii)

      - In master/slave mode, SELECTs to temporary table executes only
        on master/primary(Tatsuo Ishii)

      - In master/slave mode, write queries outside of explicit
        transactions no longer trigger to start internal
        transaction(Tatsuo Ishii)

      - In master/slave mode, SELECTs inside explicit transactions are
        load balanced(Tatsuo Ishii, Toshihiro Kitagawa)

      - In master/slave mode, commands are no longer sent to all DB
        nodes. This will prevent unnecessary locking
        (Tatsuo Ishii, Toshihiro Kitagawa)

      - New command option adds to ignore the status file when
        starting up(Tatsuo Ishii)

      - Supports PostgreSQL 9.0's new VACUUM syntax(Tatsuo Ishii)

      - New directive "failover_if_affected_tuples_mismatch" controls
        the behavior when number of result rows of
        INSERT/UPDATE/DELETE are differ(Tatsuo Ishii)

      - When number of result rows of INSERT/UPDATE/DELETE are
        differ, each number are logged(Tatsuo Ishii)

      - md5 authentication is supported in replication mode and
        master/slave mode(Tatsuo Ishii)

      - Allow to force to move to online recovery second stage even
        there are connecting frontends(Tatsuo Ishii)

      - If there's only one DB node and it triggers failover,
        pgpool-II will automatically connects if the DB node coming
        up(Tatsuo Ishii)

      - Pcp commands supports long options(Guillaume Lelarge)

      - New directive "debug_level" added to control the debug message
        logging(Tatsuo Ishii)

      - Allow to use various boolean representations as PostgreSQL in
        pgpool.conf(Toshihiro Kitagawa)

      - New C language function pgpool_switch_xlog for online recovery
        added(Toshihiro Kitagawa)

      - New C language function pgpool_regclass added to avoid a trouble
        about handling of duplicate table names in different schema
        (Tatsuo Ishii)

      __________________________________________________________________

* Bug fixes

      - Do not rewrite statement which accesses columns having now()
        etc. as the default value but the data type are not timestamp
        etc.  Otherwise we have an error in DMLs(Tatsuo Ishii)

      - Fix timestamp rewriting not to omit schema qualification(Tatsuo Ishii)

      - Fix bug with timeout handling in pcp commands(Tatsuo Ishii)

      - Fix SSL hang when large amount of data transfered(Tatsuo Ishii)

      - Fix failover when there's only one DB node(Tatsuo Ishii)

      - Fix bug with postmaster start check in online recovery.
        Before it continued infinitely to try to connect to postmaster
        if the first attempt failed(Tatsuo Ishii)


===============================================================================
2.3 Series (2009/12/07 - 2010/02/22)
===============================================================================

                        2.3.3 (tomiteboshi) 2010/04/23

* Version 2.3.3

      This version fixes various bugs since 2.3.2.2.

      __________________________________________________________________

* Incompatible changes

      - Please note that this version of pgpool consumes more shared
        memory than before. If you encounter problems when starting up
        pgpool, please look into pgpool log. If you find messages
        something like "could not create shared memory segment: Cannot
        allocate memory", please increase the shared memory on your
        system.

      - Now parallel mode requires replication mode turned
        on. parallel mode without replication mode turned on has been
        broken since pgpool-II was born anyway(Toshihiro Kitagawa)

      - Change default value for insert_lock to false since there's no
        point in turning this on in master/slave mode. Fix suggested by
        Fujii Masao(Tatsuo Ishii)

      __________________________________________________________________

* Newly added documents

      - README.online-recovery, which is an internal document of
        online recovery, added(Tatsuo Ishii)

      __________________________________________________________________

* Bug fixes

      - Fix long standing bug since pgpool-II 1.0 which causes
        segfault of pgpool child process.  This was caused by
        miscalculation of shmem size in pgpool parent. Bug analysis by
        Kitagawa patch created by Tatsuo

      - Add restriction for parallel mode(Toshihiro Kitagawa)
        - The Natural Join is not supported
        - The USING CLAUSE is converted to ON CLAUSE by query rewrite
          process

      - Fix possible crash during rewriting JOIN syntax that have
        USING in parallel query mode(Toshihiro Kitagawa)

        This fix is supporting such as following JOIN syntax.

         example:
         - SELECT * FROM a JOIN b USING (aid) JOIN c USING (cid);
         - SELECT * FROM a JOIN b USING (aid) JOIN c USING (cid)
           JOIN d USING (did)

      - Fix parallel query so that it can parse INSERT statements that
        have current_time before a partitioning key column
        (Toshihiro Kitagawa)

      - Fix SimpleForwardToBackend() so that pgpool doesn't keep
        waiting for reply from a backend, when clients using the
        extended query protocol cause a command error such as bind
        error. This bug occur in master/slave, raw, and connection
        pool mode.  This fix is, sending SYNC message to recover error
        after command error(Toshihiro Kitagawa)

      - Fix SIGINT/SIGQUIT is ignored if pgpool child is in
        select(). In this case pgpool retries select() thus the signal
        is ignored(Tatsuo Ishii)

      - Fix connect_inet_domain_socket_by_port/
        connect_unix_domain_socket_by_port so that they check if
        SIGTERM/SIGINT/SIGQUIT signal has been delivered.  Per bug
        report from Daniel Codina(Tatsuo Ishii)

      - Fix possible crash during creating "kind mismatch" error
        message. This used to work but was broken in 2.3.2(Tatsuo Ishii)

      - Fix bug with healh checking. If a network problem such as
        unplugged wire happens while calling connect(), health
        checking does not work since
        connect_unix_domain_socket()/connect_inet_domain_socket() do
        retry if connect() is interrupted by ALARM signal. Added new
        retry argument which controls the retrying behavior to those
        functions.  Per bug report and problem analysis by Daniel
        Codina(Tatsuo Ishii)

      - Fix enbug in 2.3.2.2 with time stamp rewriting in
        SimpleForwardToBackend. Per bug report from Bugtrack #1010771.
        Report from Peter Pramberge(Tatsuo Ishii)

      - Fix rewriting "*" in paralell query.  Patch conributed by
        sho-san(Toshihiro Kitagawa)

      - Fix connect_inet_domain_socket_by_port() so that it print out
        error message by using hstrerror(), rather than
        strerror()(Tatsuo Ishii)

===============================================================================

                    2.3.2.2 (tomiteboshi) 2010/02/22

* Version 2.3.2.2

      This version fixes various bug in 2.3.x.

      - When rewriting timestamp in extended query, it allocated less
        than what it actually needed. This causes random problematic
        behavior, typically "message: invalid string in message" error
        in backend(Tatsuo Ishii).

      - In extended query, if one of parameters contains NULL, ppool
        crashes(Tatsuo Ishii).

      - If in previous status file all nodes were marked down status,
        it is regarded that this file is bogus. This will prevent "all
        node down" syndrome(Tatsuo Ishii).

===============================================================================

                    2.3.2.1 (tomiteboshi) 2010/02/11

* Version 2.3.2.1

      This version fixes bug in 2.3.x. It is identfied that
      pgpool-II 2.3.x has a problem with erroneous query
      processing(Akio Ishida).

===============================================================================

                    2.3.2 (tomiteboshi) 2010/02/07

* Version 2.3.2

      This version includes various fixes for bugs in 2.3.1 or before.
      All 2.3.x users are encouraged to upgrade to 2.3.2 as soon as
      possible.

      Also this version enables long awaited SSL support and large
      object replication support.

      __________________________________________________________________

* Enhancements

      - SSL support(Sean Finney)

      - Large object replication support. You need PostgreSQL 8.1 or
        later, however(Tatsuo Ishii)

      - Emit statement log when error or notice message comes from
        query parsing process. This is usefull because PostgreSQL does
        not log particular statement if the error was detected
        *before* raw parser get executed.  This typlically happens
        when encoding error was found(Tatsuo Ishii)

      - Display original query to log if kind mismatch error was
        caused by DEALLOCATE(Tatsuo Ishii)

      - While health checking and recovery use postgres database if
        possible.  If postgres database does not exist, use template1
        as it stands now.  While connecting template1, certain
        commands, for example DROP DATABASE cannot used. Using postgres
        database allows to use these commands while recovery(Tatsuo Ishii)

      __________________________________________________________________

* Bug fixes

      - Fix errors in timestamp rewriting which occasionaly cause
        broken packet sentto slave nodes(Tatsuo Ishii)

      - Fix errors when timestamp rewriting is used with V2
        protocol(Toshihiro Kitagawa)

      - Propagate Bind, Describe and Close messages to only master
        node if running in master/slave and in transaction (Tatsuo Ishii)

      - Fix do_child() so that check_stop_request() exits immediately
        when smart shutdown signal has been sent.  This has been used
        to work in 2.2(Toshihiro Kitagawa)

      - Fix ProcessFrontendResponse not to accept invalid frotend
        packet(Xavier Noguer)

      - Use %dz for sizeof in fprintf for more portability(Tatsuo Ishii)

      - Fix compiler warnings(Tatsuo Ishii)

      - Do not force replication of DEALLOCATE if operated in
        master/slave mode. Now that pgpool do not execute PARSE in all
        nodes, this was pointless and caused problem (kind mismatch
        when executing DEALLOCATE)(Tatsuo Ishii)

===============================================================================

                        2.3.1 (tomiteboshi) 2009/12/18

* Version 2.3.1

      This version includes various fixes for bugs in 2.3 or before.
      All 2.3 users are encouraged to upgrade to 2.3.1 as soon as
      possible.
      __________________________________________________________________

* Bug fixes

      - If all of following conditions met, incorrect data is written
        to DB(Tatsuo Ishii)

        - pgpool is running in replication mode
        - pgpool is running on 64bit OS
        - INSERT or UPDATE are used which explicitly include now(),
        - CURRENT_TIMESTAMP, CURRENT_DATE, CURRENT_TIME. Or the target
        - Table's default value use above functions
        - The SQL statement inclludes out of 32bit
          integer value(-2147483648 to 2147483647 in decimal)

        Example SQL: INSERT INTO t1(id, regdate) VALUES(98887776655,
        NOW());

      - Fix crush in case of more than 18 DB nodes are used(Tatsuo Ishii)

      - Enhance kind mismatch error message. If kind is ERROR or
        NOTICE, the error or notice message from PostgreSQL will be printed
        (Tatsuo Ishii)

===============================================================================

                            2.3 (tomiteboshi) 2009/12/07

* Version 2.3

      This version enhances replication, especially CURRENT_TIMESTAMP,
      CURRENT_DATE, now() etc. now can be properly replicated. Also
      perforance of replication when num_init_children == 1 is
      enhanced. Pgpool-II now records the status of down nodes, and
      remember when it restarts to ensure that keep the node status as
      before. Also some logs are enhanced and more fine fail over
      controls are added. Please note that pgpool-II 2.3 includes all
      of enhancements and fixes of pgpool-II 2.2.1 to 2.2.6.

      __________________________________________________________________

* Incompatibilities from 2.2.x

      - pgpool_status file is created under logdir. So you need to
        give write permission to the directory so that pgpool-II can
        read/write pgpool_status file.

      __________________________________________________________________

* Enhancements

      - Enable proper replication of results of temporal functions
        (CURRENT_TIMESTAMP, CURRENT_DATE, now() etc.). Now
        applications can execute INSERT/UPDATE tables which include
        defaut values using those temporal functions. There are small
        limitations. See restriction sections of docs for more
        details (Akio Ishida)

      - Use PostgreSQL 8.4's SQL parser(Akio Ishida)

      - Enhance the performance 20% to 100% of replication when
        num_init_children == 1(Tatsuo Ishii)

      - Add new directive log_per_node_statement which is similar to
        log_statement except that prints info for each DB node to make
        it easier which query is sent to which DB node(Tatsuo Ishii)

      - Add new directive fail_over_on_backend_error to control the
         behaviro of fail over(Tatsuo Ishii)

      - Record DB node status and remember when pgpool-II restarts(Tatsuo Ishii)

      - EXPLAIN and EXPLAIN ANALYZE for SELECT query are now load
        balanced. This will prevent unwanted kind mismatch errors when
        EXPLAIN produces slightly different plan(Tatsuo Ishii)

      - Enhance CSS of pgpool-ja.html(Tatsuo Ishii)

      - Add sample configuration file for replication mode and
        master/slave mode(Tatsuo Ishii)

     - Add test for temporal data(Akio Ishida)


===============================================================================
2.2 Series (2009/02/08 - 2010/04/15)
===============================================================================

                    2.2.7 (urukiboshi) 2010/04/15

* Version 2.2.7

      This version enhances displaying error messages when kind
      mismatch error occurs. Also it includes various fixes for bugs
      in 2.2.6 or before as usual.

      __________________________________________________________________

* Bug fixes

      - Fix occasional hangup in extend protocol + master/slave mode,
        row mode or connection pool mode. Back patch from 2.3 
        tree(Toshihiro Kitagawa)

      - Fix long standing bug since pgpool-II 1.0 which causes
        segfault of pgpool child process. This was caused by
        miscalculation of shmem size in pgpool parent. Bug analysis by
        Kitagawa patch created by Tatsuo

      - Send Parse, Bind, Describe and Close message to only master
        node if operated in explicit transaction and master/slave
        mode(Tatsuo Ishii).

      - Emit a log when postmaster goes down(Tatsuo Ishii)

      - Fix memory leak in make_persistent_db_connection(Xavier
        Noguer)

      - Do not force replication of DEALLOCATE if operated in
        master/slave mode. Now that pgpool do not execute PARSE in all 
        nodes, this was pointless and caused problem (kind mismatch
        when executing DEALLOCATE) (Tatsuo Ishii)

      - Fix crash with show pool_status when there many (more than 18) 
        DB nodes(Tatsuo Ishii)

      - Enhance "kind mismatch" message. If kind is ERROR or NOTICE,
        print the ERROR/NOTICE message to help users to find what's
        going on(Tatsuo Ishii)

===============================================================================

                        2.2.6 (urukiboshi) 2009/12/01

* Version 2.2.6

      This version enhances handling of backend weight. Also it allows
      to use temp tables in master/slave mode. It includes various
      fixes for bugs in 2.2.5 or before as usual.

      __________________________________________________________________

* Bug fixes

      - Do not allow to load balance DECLARE, CLOSE, FETCH and
        MOVE. If data gets updated and CLOSE issued after transaction
        commit(i.e. holdbale cursor), this will cause data
        inconsistency since CLOSE is executed one of the severs,
        rather than all(Tatsuo Ishii)

      - In master/slave mode, execute Parse message on only master
        node. In previous versions Parse executed on all nodes, which
        grabbed unneccessary lock(Tatsuo Ishii)

      - Remove init script from all runlevels before uninstall(Devrim)

      - Fix pgpoo.spec(Devrim)

      - Do not execute REINDEX DATABASE or SYSTEM, CREATE/DROP TABLE
        SPACE inside a transaction block(Tatsuo Ishii)

      __________________________________________________________________

* Enhancements

      - Allow to change weight by reloading pgool.conf. This will take
        effect for next client sessions(Tatsuo Ishii)

      - Reply with usefull error messages, rather than "server closed
        the connection unexpectedly" when authentication fails(Glyn
        Astill)

      - Add info to logs when writing to sockets falis to know if it
        was for backend or frontend(Tatsuo Ishii)

      - Do not complain when writing to socket of frontend
        fails(Tatsuo Ishii)

      - Allow to use temp tables in master/slave
        mode. INSERT/UPDATE/DELETE will automatically be sent to
        master only. Still SELECT you need to add /*NO LOAD BALANCE*/
        comment(Tatsuo Ishii)

      - Add temp table test to test/jdbc(Tatsuo Ishii)

===============================================================================

                        2.2.5 (urukiboshi) 2009/10/4

* Version 2.2.5

      This version fixes various bugs in 2.2.4 or before.

      __________________________________________________________________

* Bug fixes

      - Fix connection_count_down(). It decrements the connection
        counter too much in some corner cases and causes online
        recover never completes(Tatsuo Ishii)

      - Detect frontend exiting while waiting for commands complete in
        other cases such as internal locks are issued and Parse
        (Tatsuo Ishii)

      - Fix inifinit loop in reset_backend(Xavier Noguer, Tatsuo)

      - Fix Parse() to print actual query when it detects kind
        mismatch error(Tatsuo Ishii)

      - Document enhancements(Tatsuo Ishii)

===============================================================================

                        2.2.4 (urukiboshi) 2009/8/24

* Version 2.2.4

      This version fixes various bugs in 2.2.3 or before.

      __________________________________________________________________

* Bug fixes

      - Fix possible bug introduced in pgpool-II 2.2.2.  Load balance
        control variables may remain not be restored and subsequent
        DML/DDL call might sent to only master node(Tatsuo Ishii)

      - Send NOTICE message to frontend periodically if V2 protocol is
        used. This is ifdef out since it affectes visible change to
        applications.  2.2.3 unconditionaly sends param packet to
        client even it uses version 2 protocol, which is apparentlt
        wrong. Also tweak checking period from 1 second to 30 seconds
        since 1 second seems too aggressive(Tatsuo Ishii)

      - Block signals before forking children rather after.  Otherwise
        parent will be killed by failover signal if it receives a
        signal before establishing signal handler(Tatsuo Ishii)

      - Remove unnecessary spaces and tabs at the end of line(Jun Kuriyama)

===============================================================================

                            2.2.3 (urukiboshi) 2009/8/11

* Version 2.2.3

      This version fixes various bugs in 2.2.2 or before.

      __________________________________________________________________

* Bug fixes

      - Fix child process death if one of backends is not available(Tatsuo Ishii).

      - Fix various parallel query bugs(Yoshiharu Mori)

      - Fix message corruption for kid mismatch error(Akio Ishida)

      - Now stetmemt_time works(Tatsuo Ishii)

      - Enhance health checking to detect postmaster stopping by
        SIGSTOP(Tatsuo Ishii)

      - Detect frontend abnormal exiting while waiting for reply from
        backend. This only works with V3 protocol(Tatsuo Ishii)

      - Do not start internal transaction if command is CLUSTER
        without arguments(Tatsuo Ishii)

      - Fix bug with COPY FROM in that backend process remains after
        COPY failed(Tatsuo Ishii)

      __________________________________________________________________

* Enhancements

      - Show last query for extended protocol(Akio Ishida)

      - Allow to compile sql/pgpool-recovery/pgpool-recovery.c with
        PostgreSQL 8.4(Tatsuo Ishii)

===============================================================================

                        2.2.2 (urukiboshi) 2009/5/5

* Version 2.2.2

      This version fixes various bugs in 2.2.1 or before. Please note
      that an importan fix is made to avoid data incositency risk,
      which could happen when client does not exit gracely(without
      sending "X" packet) while pgpool is trying to send data to
      it. This could happen with all version of pgpool-II.

      __________________________________________________________________

* Bug fixes

      - Ignore write error on frontend connection. This is needed to
        continue processing with backend, otherwise we risk data
        incositency(Tatsuo Ishii)

      - Fix bug introduced in 2.2.1 (In master slave mode, sometimes
          DEALLOCATE fails). If prepared statement reused, pgpool
          hangs(Toshihiro Kitagawa)

      - Fix pgpool crash when SQL command PREPARE and protocol level
        EXECUTE are mixed. The bug was introduced in 2.2(Tatsuo Ishii)

      - Avoid "unexpected EOF on client connection" error in PostgreSQL
        when reset query fails(Tatsuo Ishii)

===============================================================================

                        2.2.1 (urukiboshi) 2009/4/25

* Version 2.2.1

      This version fixes various bugs in 2.2.

      __________________________________________________________________

* Bug fixes

      - In master slave mode, sometimes DEALLOCATE fails. This is
        caused by that the first PREPARE was not executed on the
        slave(Toshihiro Kitagawa)

      - Update pgpool.spec along with related files(Devrim)

      - Fix inser_lock so that it is ignored when protocol version is
        2(Tatsuo Ishii)

      - Remove excessive log messages regarding parameter change notice(Tatsuo Ishii)

      - Add missing files to doc(Tatsuo Ishii)

===============================================================================

                            2.2 (urukiboshi) 2009/2/28

* Version 2.2

      This version enhances SERIAL data type handling and on line
      recovery. Also an important bug, serializable transactions could
      cause data inconsistency among DB nodes, is fixed. Query
      cancelation, which never worked since pgpool-II was born, is
      finally fixed.

      __________________________________________________________________

* New features/enhancements

        - With insert_lock, now a table is locked only if it has
          SERIAL data type and now the default value for insert_lock
          is true(Tatsuo Ishii)

        - Start internal transaction other than INSERT, UPDATE, DELETE
          and SELECT to keep node consistency(Tatsuo Ishii)

        - Add client_idle_limit_in_recovery directive. This will
          prevent 2nd stage of on line recovery from not going forward
          by idle clients sitting forever(Tatsuo Ishii)

        - Add pid_file_name directive which specifies a path to the
          file containing pgpool process id. "logdir" is no more used(Tatsuo Ishii)

        - Allow to load balance DECLARE, FETCH and CLOSE(Tatsuo Ishii)

        - Add -d option to pcp commands(Jun Kuriyama)

        - Enahnce kind mismatch error message to include originarl
          query string(Tatsuo Ishii)

      __________________________________________________________________

* Bug fixes

        - Close all file descriptors when running in daemon mode.
          Otherwise we inherit sockets from apache when it's
          started by pgpoolAdmin. This results in that port 80 is
          occupied for example.  Patch provided by Akio
          Ishida. Also add chdir("/"). This is always good for
          daemon programs(Tatsuo Ishii)

        - Allow MD5 authentication in raw mode as stated in docs(Tatsuo Ishii)

        - Check transaction serialization failure error in
          serializable mode and abort all nodes if so. Otherwise
          we allow data inconsistency among DB nodes(Tatsuo Ishii).

          See following scenario: (M:master, S:slave)

            M:S1:BEGIN;
            M:S2:BEGIN;
            S:S1:BEGIN;
            S:S2:BEGIN;
            M:S1:SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
            M:S2:SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
            S:S1:SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
            S:S2:SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
            M:S1:UPDATE t1 SET i = i + 1;
            S:S1:UPDATE t1 SET i = i + 1;
            M:S2:UPDATE t1 SET i = i + 1; <-- blocked
            S:S1:COMMIT;
            M:S1:COMMIT;
            M:S2:ERROR:  could not serialize access due to concurrent update
            S:S2:UPDATE t1 SET i = i + 1; <-- success in UPDATE and data
                                              becomes inconsistent!

        - avoid kind mismatch error caused by "SET TRANSACTION
          ISOLATION LEVEL must be called before any query"(Tatsuo Ishii).

           This could happen in following scenario:

            M:S1:BEGIN;
            S:S1:BEGIN;
            M:S1:SELECT 1; <-- only sent to MASTER
            M:S1:SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
            S:S1:SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
            M: <-- error
            S: <-- ok since no previous SELECT is sent. kind mismatch error occurs!

        - Process status display has extra space on FreeeBSD(Jun Kuriyama)

        - Fix incorrect kind mismatch detection case. e.g: BEGIN;
          BEGIN; (Tatsuo Ishii)

        - If PostgreSQL sends lots of DEBUG message, sometimes pgpool
          complains:
          2008-11-08 22:41:53 ERROR: pid 23744: do_command: backend does not
          return ReadyForQuery. This due to a wrong assumption for the
          client/server protocol(Tatsuo Ishii)

        - Fix the case when sending an erronous query to abort
          transaction. It assumed that after sending an error query,
          always ReadyForQuery came right after that. If some
          debugging or logging verboseness is set, PostgreSQL might
          sends NOTICE before ReadyForQuery(Tatsuo Ishii)

        - Query cancelation now works. It never worked since pgpool-II
          was born(Tatsuo Ishii)

        - Fix online recovery to wait for failback done before
          allowing to accept connections from clients. It was supposed
          to work like this but actually was not since the day 0 when
          online recovery was born. Without the fix there could be
          potential data inconsistency among DB nodes(Tatsuo Ishii)

        - Fix pgpool-II crash after on line recovery. This happens
          after the failback process adds a recovered node which has
          no connection to the node(Tatsuo Ishii)

        - Fix pgpool-II errors when postgresql.conf is reloaded. This
          was caused by parameter status packet sent asynchronously
          from backend, which indicates the internal setting of
          backend has been changed(Tatsuo Ishii)

      __________________________________________________________________

* Incompatible changes

        - Always fail over and restart all children. Before we do
          restart only if master has not been changed. This is
          wrong. If we have trouble with network cable or something,
          TCP/IP stack keeps on retrying for long time and the only
          way to prevent it is restarting process(Tatsuo Ishii)

        - "logdir" is no more used. Instead use
          "pid_file_name"(Tatsuo Ishii)

        - Default value for insert_lock is now true(Tatsuo Ishii)


===============================================================================
2.1 Series (2008/07/25 - 2008/07/25)
===============================================================================

                            2.1 (inamiboshi) 2008/7/25

* Version 2.1

      __________________________________________________________________

* New feature

        - Add '%m' format to failover_command and failback_command to
          obtain new master node ID. (Yoshiyuki Asaba)
        - Add '%m' format to failover_command and failback_command to
          obtain old master node ID. (Yoshiyuki Asaba)
        - Add new directive "recovery_timeout" to specify recovery
          timeout in second. (Taiki Yamaguchi)
        - Add optino '-v' to print pgpool version. (Yoshiyuki Asaba)

      __________________________________________________________________

* Incompatibility

        - Restrict pgpool_recovery() and pgpool_remote_start()
          functions to superusers. (Yoshiyuki Asaba)
        - Do not create a connection pool to standby node in raw
          mode. (Yoshiyuki Asaba)
        - Remove "replication_timeout" parameter. (Yoshiyuki Asaba)
          - This enabled if replication_strict was false. However,
            replication_strict was already removed.
        - Ignore timeout argument of pcp commands. (Taiki Yamaguchi)
        - Do not replicate "COPY TO STDOUT" when replicate_select is
          false. (Yoshiyuki Asaba)

      __________________________________________________________________

* Bug fix

    ** General

        - Fix crash when CloseComplete message was
          received. (Yoshiyuki Asaba)
        - Improve network I/O routine. (Yoshiyuki Asaba)
        - Fix compile errors on Solaris 10. (Yoshiyuki Asaba)
        - Improve log messages of health check and recovery. (Tatsuo Ishii)
        - Change error level of the "failed to read kind from
          frontend" message from ERROR to LOG. (Yoshiyuki Asaba)
        - Fix failover failure in raw mode. (Taiki Yamaguchi)
        - Fix zombie process bug. (Yoshiyuki Asaba)
        - Fix health_check_timeout to work correctly. (Kenichi Sawada)
        - Support ps status on FreeBSD. (ISHIDA Akio)
        - Improve bind(2) failure report. (Jun Kuriyama)
        - Improve error message when client authentication
          failed. (Tatsuo Ishii)

    ** Replication

        - Fix replicate_select to work correctly. (Tatsuo Ishii)
        - Fix a wrong rollback bug with extended query. (Yoshiyuki Asaba)
        - Fix a bug with asynchronous query. (Yoshiyuki Asaba)
        - Fix hint clause handling like /*REPLICATION*/ with extended
          query. (Yoshiyuki Asaba)
        - Fix crash of "DEALLOCATE ALL". (Yoshiyuki Asaba)
        - Fix hang up when a backend node does immediate
          shutdown. (Yoshiyuki Asaba)
        - Fix hang up online recovery in high load. (Yoshiyuki Asaba)
        - Fix hang up with extended query protocol when SELECT is
          failed inside a transaction block. (Yoshiyuki Asaba)

    ** Master Slave

        - Fix load balancing to work correctly. (Yoshiyuki Asaba)
        - Fix crash if SET, PREPARE or DEALLOCATE is executed inside a
          transaction block. (Yoshiyuki Asaba)

    ** Parallel query

        - Fix INSERT failure. (Yoshiharu Mori)
        - Fix syntax error when a query contains "AS" in FROM
          clause. (sho)
        - Fix Hung up when two or more statment was executed
          in parallel mode (Yoshiharu Mori)
        - Fix Query rewriting of Join Expression and DISTINCT ON
          (Yoshiharu Mori)

===============================================================================
2.0 Series (2007/11/16 - 2007/11/21)
===============================================================================

                    2.0.1 (hikitsuboshi) 2007/11/21

      * Version 2.0.1
      * Fix process down with UPDATE or DELETE query.(Yoshiyuki Asaba)
      * Send a syntax query only to a master node if master_slave is
        true.(Yoshiyuki Asaba)

===============================================================================

                    2.0 (hikitsuboshi) 2007/11/16

* Version 2.0

      __________________________________________________________________

* Incompatibility since pgpool-II 1.x

        - the default value for ignore_leading_white_space is now
          true(Yoshiyuki Asaba)
        - replicate_strict is removed. The value is always
          true(Yoshiyuki Asaba)

      __________________________________________________________________

* General
        - Allow to reload pgpool.conf(Yoshiyuki Asaba)
        - The paraser is now compatible with PostgreSQL 8.3(Yoshiyuki Asaba)
        - Add new directive "failover_command" to specify command when
          a node is detached(Yoshiyuki Asaba)
        - Add new directive "client_idle_limit" to specify the time out since
          the last command is arrived from a client(Tatsuo Ishii)

      __________________________________________________________________

* Replication

        - Always start a new transaction even if the query is not in
          an explicit transaction to enhance the reliabilty of
          replication(Yoshiyuki Asaba)
        - Enhance the performance of replication for write
          queries. Now the worst case is 1/2 compared with single DB
          node regardless the number of DB nodes. Previous release
          tends to degrade according to the numer of DB
          nodes(Yoshiyuki Asaba)
        - Add "online recovery" which allows to add a DB node and sync
          with other DB nodes without stopping the pgpool
          server(Yoshiyuki Asaba)
        - Abort a transaction if INSERT, UPDATE and DELETE reports
          different number of result rows(Yoshiyuki Asaba)

          x=# update t set a = a + 1;
          ERROR:  pgpool detected difference of the number of update tuples
          HINT:  check data consistency between master and other db node

        - If the results from DB nodes do not match, select the
          possible correct result by "decide by majority". Previous
          release always trust the result of the master DB
          node(Yoshiyuki Asaba)
        - Allow load balance in V2 frontend/backend protocol(Yoshiyuki Asaba)

      __________________________________________________________________

* Parallel query

        - Allow "partial replication" to enhance the performance of
          the parallel query(Yoshiharu Mori)


===============================================================================
1.3 Series (2007/10/23 - 2007/10/23)
===============================================================================

                        1.3 (sohiboshi) 2007/10/23

      * Version 1.3
      * Add new "authentication_timeout" directive, being the default
        value is 60. (Yoshiyuki Asaba)
        - Maximum time in seconds to complete client authentication.
      * Reject a connection when startup packet length is greater than
        10,000 byte. (Yoshiyuki Asaba)
      * Fix invalid memory access when pgpool processed DEALLOCATE
        statement. (Yoshiyuki Asaba)
      * Fix hang up in load balance mode. (Yoshiyuki Asaba)
        - This was introduced in V1.2.
      * Fix segmentation fault in 64-bit environment when query cache
        is enable. (Yoshiyuki Asaba)


===============================================================================
1.2 Series (2007/08/01 - 2007/09/28)
===============================================================================

                        1.2.1 (tomoboshi) 2007/09/28

      * Version 1.2.1
      * Fix deadlock while processing Parse message. (Yoshiyuki Asaba)
      * Fix memory leak in reset_prepared_list(). (Yoshiyuki Asaba)
      * Fix compile error on FreeBSD 4.11. (Yoshiyuki Asaba)
      * SET, PREPARE and DEALLOCATE statements are replicated in
        master/slave mode. (Yoshiyuki Asaba)

===============================================================================

                        1.2 (tomoboshi) 2007/08/01

      * Version 1.2
      * Add new "replicate_select" directive, being the default value
        is false. (Yoshiyuki Asaba)
        - If it is true, SELECT query is replicated. This behavior is
          same as V3.2 or earlier.
      * Improve signal handling. (Yoshiyuki Asaba)
        - Occasionaly, zombie processes were remained. Or processes
          were unstable.
      * Fix hang up when SELECT was error inside a transaction
        block. The bug was introduced in V3.3. (Yoshiyuki Asaba)
      * Fix PREPARE/EXECUTE handling in master slave mode. (Yoshiyuki Asaba)
      * Fix "kind mismatch error" when deadlock error
      * Fix hang up and SEGV in extended query protocol when a warning
        SQL like "SELECT '\'';" executed. (Yoshiyuki Asaba)
      * Fix hang up when postmaster did fast or immediate
        shutdown. (Yoshiyuki Asaba)
      * Fix memory leak when connection cache was full. (Yoshiyuki Asaba)
      * Load balancing node is selected when a session
        starts. (Yoshiyuki Asaba)
      * Fix buffer overrun if connection_life_time was
        set. (Yoshiyuki Asaba)


===============================================================================
1.1 Series (2007/5/25 - 2007/6/15)
===============================================================================

                            1.1.1 (amiboshi) 2007/6/15

      * Version 1.1.1
      * Fix "kind mismatch" bug when load_balance_mode is true
        introduced in 1.1 (Yoshiyuki Asaba)
      * Fix deadlock with extended query protocol(Yoshiyuki Asaba)
      * Fix numerous bugs with protocol V2(Yoshiyuki Asaba)

===============================================================================

                            1.1 (amiboshi) 2007/5/25

      * Version 1.1
      * Support HBA authentication(Taiki Yamaguchi)
      * Support log_connections(Taiki Yamaguchi)
      * Support log_hostname(Taiki Yamaguchi)
      * Show pgpool status in ps command(Taiki Yamaguchi)
      * Fix compile error on MacOS X(Yoshiyuki Asaba)
      * Allow load balancing with extended protocol(Yoshiyuki Asaba)
      * Improve replication. SELECT nextval() and SELECT setval() are
        now replicated. (Yoshiyuki Asaba)
      * Change SELECT query is only sent to the master node. (Yoshiyuki Asaba)
        - Use /*REPLICATION*/ comment to repliate a SELECT query.
      * Fix unexpected failover error due to receiving an interrupt
        signal while connecting to the backend. (Yoshiyuki Asaba)
      * Add "pgpool.pam" file, for PAM configuration file, to be
        installed under "$PREFIX/share/pgpool-II/". (Taiki Yamaguchi)
      * Fix core dump when executing large SQL. (Yoshiyuki Asaba)


===============================================================================
1.0 Series (2006/09/08 - 2007/02/12)
===============================================================================

                            1.0.2 (suboshi) 2007/02/12

      * Version 1.0.2
      * Fix bug when executing large SQL to prevent pgpool goes into
        infinite loop(Yoshiyuki Asaba)
      * Fix bug with extended protocol handling(Yoshiyuki Asaba)
      * Enhance log for failover and failback(Tatsuo Ishii)
      * Add backend status info to show pool_status(Tatsuo Ishii)
      * Fix UPDATE/DELETE returns wrong number of rows(Tatsuo Ishii)
      * Fix configure fails to link libpq when used with older
        version of gcc(Yoshiyuki Asaba)
      * Fix DEALLOCATE treatment when used with PHP:PDO DBD-Pg(Yoshiyuki Asaba)
      * Do not load balance SELECT FOR UPDATE, SELECT INTO and SELECT
        with comments. This behavior is compatible with
        pgpool-I(Yoshiyuki Asaba)
      * Obtain path to libpq using pg_config. --with-pgsql will be
        removed in next version(Yoshiyuki Asaba)
      * When reusing connection pool, reconnect to backend if the
        socket is broken(Yoshiyuki Asaba)
      * Fix error with configure when used with PostgreSQL
        7.4(Yoshiyuki Asaba)

===============================================================================

                            1.0.1 (suboshi) 2006/09/22

      * Version 1.0.1
      * This version fixes bugs including master/slave not being
        working, deadlock problem in COPY FROM STDIN. Also documents
        are improved.

===============================================================================

                            1.0.0 (suboshi) 2006/09/08

      * Initial release

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