pgpool-II 3.1 released

Pgpool Global Development Group is pleased to announce the
availability of pgpool-II 3.1.

pgpool-II 3.1 can be downloaded here:

http://pgfoundry.org/frs/download.php/3114/pgpool-II-3.1.tar.gz

pgpool-II 3.1 has many new features and enhancements.

Users of prior versions of pgpool-II should be able to upgrade to
pgpool-II 3.1 without much pain. Especially pgpool-II 3.0.x users
should be able to migrate to 3.1 without changing pgpool.conf(it is
recommended to use new pgpool.conf, though).

However be warned that pgpool-II 3.1 has some incompatible changes.
Please look into the documents for more details.

Attached are release note of pgpool-II 3.1.

-----------------------------------------------------------------------
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(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(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(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)

- 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).

- 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)

- 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)

- 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(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(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(Kitagawa)

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

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

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

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

- 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)

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

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

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

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

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

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

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

- Fix some memory leaks(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)

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

- 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)

- 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)

- 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)

- 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(Kitagawa)

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

- Update and sync pgpool-II manuals of English version and Japanese
  version(Tatsuo)
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp