Release date: 2018-10-18
Major enhancements in PostgreSQL 11 include:
Improvements to partitioning functionality, including:
Add support for partitioning by a hash key
         Add support for PRIMARY KEY, FOREIGN
         KEY, indexes, and triggers on partitioned tables
        
Allow creation of a “default” partition for storing data that does not match any of the remaining partitions
         UPDATE statements that change a partition key
         column now cause affected rows to be moved to the appropriate
         partitions
        
         Improve SELECT performance through enhanced
         partition elimination strategies during query planning and execution
        
Improvements to parallelism, including:
         CREATE INDEX can now use parallel processing
         while building a B-tree index
        
         Parallelization is now possible in CREATE TABLE
         ... AS,
         CREATE MATERIALIZED VIEW, and certain
         queries using UNION
        
Parallelized hash joins and parallelized sequential scans now perform better
SQL stored procedures that support embedded transactions
Optional Just-in-Time (JIT) compilation for some SQL code, speeding evaluation of expressions
      Window functions now support all framing options shown in the SQL:2011
      standard, including RANGE , distance
      PRECEDING/FOLLOWINGGROUPS mode, and
      frame exclusion options
     
      Covering indexes can now be created, using the
      INCLUDE clause of CREATE INDEX
     
      Many other useful performance improvements, including the ability to
      avoid a table rewrite for ALTER TABLE ... ADD COLUMN
      with a non-null column default
     
The above items are explained in more detail in the sections below.
A dump/restore using pg_dumpall, or use of pg_upgrade, is required for those wishing to migrate data from any previous release.
Version 11 contains a number of changes that may affect compatibility with previous releases. Observe the following incompatibilities:
Make pg_dump dump the properties of a database, not just its contents (Haribabu Kommi)
        Previously, attributes of the database itself, such as database-level
        GRANT/REVOKE permissions and
        ALTER DATABASE SET variable settings, were only
        dumped by pg_dumpall.
        Now pg_dump --create and
        pg_restore --create will restore these database
        properties in addition to the objects within the
        database.  pg_dumpall -g now only dumps role-
        and tablespace-related attributes.
        pg_dumpall's complete output (without
        -g) is unchanged.
       
        pg_dump and
        pg_restore, without
        --create, no longer dump/restore database-level
        comments and security labels; those are now treated as properties of
        the database.
       
        pg_dumpall's output script will now always
        create databases with their original locale and encoding, and hence
        will fail if the locale or encoding name is unknown to the
        destination system.  Previously, CREATE DATABASE
        would be emitted without these specifications if the database locale
        and encoding matched the old cluster's defaults.
       
        pg_dumpall --clean now restores the original
        locale and encoding settings of the postgres
        and template1 databases, as well as those of
        user-created databases.
       
Consider syntactic form when disambiguating function versus column references (Tom Lane)
        When x is a table name or composite
        column, PostgreSQL has traditionally
        considered the syntactic
        forms f(x)x.f
Fully enforce uniqueness of table and domain constraint names (Tom Lane)
PostgreSQL expects the names of a table's constraints to be distinct, and likewise for the names of a domain's constraints. However, there was not rigid enforcement of this, and previously there were corner cases where duplicate names could be created.
        Make power(numeric, numeric)
        and power(float8, float8)
        handle NaN inputs according to the POSIX standard
        (Tom Lane, Dang Minh Huong)
       
        POSIX says that NaN ^ 0 = 1 and 1 ^ NaN
        = 1, but all other cases with NaN
        input(s) should return NaN.
        power(numeric, numeric) just
        returned NaN in all such cases; now it honors the
        two exceptions.  power(float8, float8) followed
        the standard if the C library does; but on some old Unix platforms
        the library doesn't, and there were also problems on some versions
        of Windows.
       
        Prevent to_number()
        from consuming characters when the template separator does not
        match (Oliver Ford)
       
        Specifically, SELECT to_number('1234', '9,999')
        used to return 134.  It will now
        return 1234.  L and
        TH now only consume characters that are not
        digits, positive/negative signs, decimal points, or commas.
       
        Fix to_date(),
        to_number(), and
        to_timestamp() to skip a character for each
        template character (Tom Lane)
       
Previously, they skipped one byte for each byte of template character, resulting in strange behavior if either string contained multibyte characters.
        Adjust the handling of backslashes inside double-quotes in
        template strings for to_char(),
        to_number(), and
        to_timestamp().
       
Such a backslash now escapes the character after it, particularly a double-quote or another backslash.
        Correctly handle relative path expressions
        in xmltable(), xpath(),
        and other XML-handling functions (Markus Winand)
       
Per the SQL standard, relative paths start from the document node of the XML input document, not the root node as these functions previously did.
        In the extended query
        protocol,
        make statement_timeout
        apply to each Execute message separately, not to all commands before
        Sync (Tatsuo Ishii, Andres Freund)
       
        Remove the relhaspkey column from system
        catalog pg_class (Peter Eisentraut)
       
        Applications needing to check for a primary key should consult
        pg_index.
       
        Replace system catalog pg_proc's
        proisagg and
        proiswindow columns with
        prokind (Peter Eisentraut)
       
This new column more clearly distinguishes functions, procedures, aggregates, and window functions.
        Correct information schema column tables.table_type
        to return FOREIGN instead of FOREIGN
        TABLE (Peter Eisentraut)
       
This new output matches the SQL standard.
        Change the ps process display
        labels for background workers to match the pg_stat_activity.backend_type
        labels (Peter Eisentraut)
       
        Cause large object permission checks
        to happen during large object open, lo_open(), not
        when a read or write is attempted (Tom Lane, Michael Paquier)
       
If write access is requested and not available, an error will now be thrown even if the large object is never written to.
Prevent non-superusers from reindexing shared catalogs (Michael Paquier, Robert Haas)
Previously, database owners were also allowed to do this, but now it is considered outside the bounds of their privileges.
        Remove deprecated adminpack functions
        pg_file_read(),
        pg_file_length(), and
        pg_logfile_rotate() (Stephen Frost)
       
        Equivalent functionality is now present in the core backend.
        Existing adminpack installs will continue to have
        access to these functions until they are updated via ALTER
        EXTENSION ... UPDATE.
       
Honor the capitalization of double-quoted command options (Daniel Gustafsson)
        Previously, option names in certain SQL commands were forcibly
        lower-cased even if entered with double quotes; thus for example
        "FillFactor" would be accepted as an index storage
        option, though properly its name is lower-case.  Such cases will now
        generate an error.
       
        Remove server parameter replacement_sort_tuples
        (Peter Geoghegan)
       
Replacement sorts were determined to be no longer useful.
        Remove WITH clause in CREATE
        FUNCTION (Michael Paquier)
       
PostgreSQL has long supported a more standard-compliant syntax for this capability.
        In PL/pgSQL trigger functions, the OLD
        and NEW variables now read as NULL when not
        assigned (Tom Lane)
       
Previously, references to these variables could be parsed but not executed.
Below you will find a detailed account of the changes between PostgreSQL 11 and the previous major release.
Allow the creation of partitions based on hashing a key column (Amul Sul)
Support indexes on partitioned tables (Álvaro Herrera, Amit Langote)
An “index” on a partitioned table is not a physical index across the whole partitioned table, but rather a template for automatically creating similar indexes on each partition of the table.
        If the partition key is part of the index's column set, a
        partitioned index may be declared UNIQUE.
        It will represent a valid uniqueness constraint across the whole
        partitioned table, even though each physical index only enforces
        uniqueness within its own partition.
       
        The new command ALTER
        INDEX ATTACH PARTITION causes an existing index on
        a partition to be associated with a matching index template for its
        partitioned table.  This provides flexibility in setting up a new
        partitioned index for an existing partitioned table.
       
Allow foreign keys on partitioned tables (Álvaro Herrera)
        Allow FOR EACH ROW triggers on partitioned
        tables (Álvaro Herrera)
       
Creation of a trigger on a partitioned table automatically creates triggers on all existing and future partitions. This also allows deferred unique constraints on partitioned tables.
Allow partitioned tables to have a default partition (Jeevan Ladhe, Beena Emerson, Ashutosh Bapat, Rahila Syed, Robert Haas)
The default partition will store rows that don't match any of the other defined partitions, and is searched accordingly.
        UPDATE statements that change a partition key
        column now cause affected rows to be moved to the appropriate
        partitions (Amit Khandekar)
       
        Allow INSERT, UPDATE, and
        COPY on partitioned tables to properly route
        rows to foreign partitions (Etsuro Fujita, Amit Langote)
       
        This is supported by postgres_fdw
        foreign tables.
       
Allow faster partition elimination during query processing (Amit Langote, David Rowley, Dilip Kumar)
This speeds access to partitioned tables with many partitions.
Allow partition elimination during query execution (David Rowley, Beena Emerson)
Previously, partition elimination only happened at planning time, meaning many joins and prepared queries could not use partition elimination.
In an equality join between partitioned tables, allow matching partitions to be joined directly (Ashutosh Bapat)
        This feature is disabled by default
        but can be enabled by changing enable_partitionwise_join.
       
Allow aggregate functions on partitioned tables to be evaluated separately for each partition, subsequently merging the results (Jeevan Chalke, Ashutosh Bapat, Robert Haas)
        This feature is disabled by default
        but can be enabled by changing enable_partitionwise_aggregate.
       
        Allow postgres_fdw
        to push down aggregates to foreign tables that are partitions
        (Jeevan Chalke)
       
Allow parallel building of a btree index (Peter Geoghegan, Rushabh Lathia, Heikki Linnakangas)
Allow hash joins to be performed in parallel using a shared hash table (Thomas Munro)
        Allow UNION to run each
        SELECT in parallel if the individual
        SELECTs cannot be parallelized (Amit Khandekar,
        Robert Haas, Amul Sul)
       
Allow partition scans to more efficiently use parallel workers (Amit Khandekar, Robert Haas, Amul Sul)
        Allow LIMIT to be passed to parallel workers
        (Robert Haas, Tom Lane)
       
This allows workers to reduce returned results and use targeted index scans.
        Allow single-evaluation queries, e.g. WHERE
        clause aggregate queries, and functions in the target list to be
        parallelized (Amit Kapila, Robert Haas)
       
        Add server parameter parallel_leader_participation
        to control whether the leader also executes subplans (Thomas Munro)
       
The default is enabled, meaning the leader will execute subplans.
        Allow parallelization of commands CREATE TABLE
        ... AS, SELECT INTO, and
        CREATE MATERIALIZED VIEW (Haribabu Kommi)
       
Improve performance of sequential scans with many parallel workers (David Rowley)
        Add reporting of parallel workers' sort activity in
        EXPLAIN (Robert Haas, Tom Lane)
       
Allow B-tree indexes to include columns that are not part of the search key or unique constraint, but are available to be read by index-only scans (Anastasia Lubennikova, Alexander Korotkov, Teodor Sigaev)
        This is enabled by the new INCLUDE clause of CREATE INDEX.
        It facilitates building “covering indexes” that optimize
        specific types of queries.  Columns can be included even if their
        data types don't have B-tree support.
       
Improve performance of monotonically increasing index additions (Pavan Deolasee, Peter Geoghegan)
Improve performance of hash index scans (Ashutosh Sharma)
Add predicate locking for hash, GiST and GIN indexes (Shubham Barai)
This reduces the likelihood of serialization conflicts in serializable-mode transactions.
        Add prefix-match
        operator text ^@ text,
        which is supported by SP-GiST (Ildus Kurbangaliev)
       
        This is similar to using var LIKE
        'word%' with a btree index, but it is more efficient.
       
Allow polygons to be indexed with SP-GiST (Nikita Glukhov, Alexander Korotkov)
Allow SP-GiST to use lossy representation of leaf keys (Teodor Sigaev, Heikki Linnakangas, Alexander Korotkov, Nikita Glukhov)
Improve selection of the most common values for statistics (Jeff Janes, Dean Rasheed)
Previously, the most common values (MCVs) were identified based on their frequency compared to all column values. Now, MCVs are chosen based on their frequency compared to the non-MCV values. This improves the robustness of the algorithm for both uniform and non-uniform distributions.
        Improve selectivity estimates for >=
        and <= (Tom Lane)
       
        Previously, such cases used the same selectivity estimates
        as > and <, respectively,
        unless the comparison constants are MCVs.
        This change is particularly helpful for queries
        involving BETWEEN with small ranges.
       
        Reduce var =
        var
        to var IS NOT NULL
        where equivalent (Tom Lane)
       
This leads to better selectivity estimates.
        Improve optimizer's row count estimates for EXISTS
        and NOT EXISTS queries (Tom Lane)
       
        Make the optimizer account for evaluation costs and selectivity
        of HAVING clauses (Tom Lane)
       
Add Just-in-Time (JIT) compilation of some parts of query plans to improve execution speed (Andres Freund)
This feature requires LLVM to be available. It is not currently enabled by default, even in builds that support it.
Allow bitmap scans to perform index-only scans when possible (Alexander Kuzmenkov)
        Update the free space map during VACUUM
        (Claudio Freire)
       
This allows free space to be reused more quickly.
        Allow VACUUM to avoid unnecessary index scans
        (Masahiko Sawada, Alexander Korotkov)
       
Improve performance of committing multiple concurrent transactions (Amit Kapila)
Reduce memory usage for queries using set-returning functions in their target lists (Andres Freund)
Improve the speed of aggregate computations (Andres Freund)
        Allow postgres_fdw
        to push UPDATEs and DELETEs
        using joins to foreign servers (Etsuro Fujita)
       
        Previously, only non-join UPDATEs and
        DELETEs were pushed.
       
Add support for large pages on Windows (Takayuki Tsunakawa, Thomas Munro)
This is controlled by the huge_pages configuration parameter.
        Show memory usage in output from log_statement_stats,
        log_parser_stats,
        log_planner_stats, and
        log_executor_stats (Justin Pryzby, Peter
        Eisentraut)
       
        Add column pg_stat_activity.backend_type
        to show the type of a background worker (Peter Eisentraut)
       
The type is also visible in ps output.
        Make log_autovacuum_min_duration
        log skipped tables that are concurrently being dropped (Nathan
        Bossart)
       
        Add information_schema columns related to table
        constraints and triggers (Peter Eisentraut)
       
        Specifically,
        triggers.action_order,
        triggers.action_reference_old_table,
        and
        triggers.action_reference_new_table
        are now populated, where before they were always null.  Also,
        table_constraints.enforced
        now exists but is not yet usefully populated.
       
Allow the server to specify more complex LDAP specifications in search+bind mode (Thomas Munro)
        Specifically, ldapsearchfilter allows pattern matching using
        combinations of LDAP attributes.
       
Allow LDAP authentication to use encrypted LDAP (Thomas Munro)
        We already supported LDAP over
        TLS by using ldaptls=1.
        This new TLS LDAP method for
        encrypted LDAP is enabled
        with ldapscheme=ldaps
        or ldapurl=ldaps://.
       
Improve logging of LDAP errors (Thomas Munro)
Add default roles that enable file system access (Stephen Frost)
        Specifically, the new roles are:
        pg_read_server_files,
        pg_write_server_files, and
        pg_execute_server_program.  These roles now also
        control who can use server-side COPY and the file_fdw extension.
        Previously, only superusers could use these functions, and that
        is still the default behavior.
       
        Allow access to file system functions to be controlled by
        GRANT/REVOKE permissions,
        rather than superuser checks (Stephen Frost)
       
        Specifically, these functions were modified: pg_ls_dir(),
        pg_read_file(),
        pg_read_binary_file(),
        pg_stat_file().
       
        Use GRANT/REVOKE
        to control access to lo_import()
        and lo_export() (Michael Paquier, Tom Lane)
       
Previously, only superusers were granted access to these functions.
        The compile-time option ALLOW_DANGEROUS_LO_FUNCTIONS
        has been removed.
       
        Use view owner not session owner when
        preventing non-password access to postgres_fdw
        tables (Robert Haas)
       
        PostgreSQL only allows superusers to
        access postgres_fdw tables without
        passwords, e.g. via peer.  Previously, the
        session owner had to be a superuser to allow such access; now
        the view owner is checked instead.
       
        Fix invalid locking permission check in SELECT FOR
        UPDATE on views (Tom Lane)
       
        Add server setting ssl_passphrase_command
        to allow supplying of the passphrase for SSL
        key files (Peter Eisentraut)
       
        Also add ssl_passphrase_command_supports_reload
        to specify whether the SSL configuration
        should be reloaded and ssl_passphrase_command
        called during a server configuration reload.
       
        Add storage parameter toast_tuple_target
        to control the minimum tuple length before TOAST
        storage will be considered (Simon Riggs)
       
The default TOAST threshold has not been changed.
Allow server options related to memory and file sizes to be specified in units of bytes (Beena Emerson)
The new unit suffix is “B”. This is in addition to the existing units “kB”, “MB”, “GB” and “TB”.
Allow the WAL file size to be set during initdb (Beena Emerson)
Previously, the 16MB default could only be changed at compile time.
Retain WAL data for only a single checkpoint (Simon Riggs)
Previously, WAL was retained for two checkpoints.
Fill the unused portion of force-switched WAL segment files with zeros for improved compressibility (Chapman Flack)
        Replicate TRUNCATE activity when using logical
        replication (Simon Riggs, Marco Nenciarini, Peter Eisentraut)
       
Pass prepared transaction information to logical replication subscribers (Nikhil Sontakke, Stas Kelvich)
        Exclude unlogged tables, temporary tables, and
        pg_internal.init files from streaming base
        backups (David Steele)
       
There is no need to copy such files.
Allow checksums of heap pages to be verified during streaming base backup (Michael Banck)
Allow replication slots to be advanced programmatically, rather than be consumed by subscribers (Petr Jelinek)
        This allows efficient advancement of replication slots when the
        contents do not need to be consumed.  This is performed by
        pg_replication_slot_advance().
       
        Add timeline information to the backup_label
        file (Michael Paquier)
       
        Also add a check that the WAL timeline matches
        the backup_label file's timeline.
       
        Add host and port connection information to the
        pg_stat_wal_receiver system view
        (Haribabu Kommi)
       
        Allow ALTER TABLE to add a column with
        a non-null default without doing a table rewrite (Andrew Dunstan,
        Serge Rielau)
       
This is enabled when the default value is a constant.
Allow views to be locked by locking the underlying tables (Yugo Nagata)
        Allow ALTER INDEX to set statistics-gathering
        targets for expression indexes (Alexander Korotkov, Adrien Nayrat)
       
        In psql, \d+ now shows
        the statistics target for indexes.
       
        Allow multiple tables to be specified in one
        VACUUM or ANALYZE command
        (Nathan Bossart)
       
        Also, if any table mentioned in VACUUM uses
        a column list, then the ANALYZE keyword must be
        supplied; previously, ANALYZE was implied in
        such cases.
       
        Add parenthesized options syntax to ANALYZE
        (Nathan Bossart)
       
        This is similar to the syntax supported by
        VACUUM.
       
        Add CREATE AGGREGATE option to specify the
        behavior of the aggregate's finalization function (Tom Lane)
       
This is helpful for allowing user-defined aggregate functions to be optimized and to work as window functions.
Allow the creation of arrays of domains (Tom Lane)
        This also allows array_agg() to be used
        on domains.
       
Support domains over composite types (Tom Lane)
Also allow PL/Perl, PL/Python, and PL/Tcl to handle composite-domain function arguments and results. Also improve PL/Python domain handling.
        Add casts from JSONB scalars to numeric and boolean data
        types (Anastasia Lubennikova)
       
Add all window function framing options specified by SQL:2011 (Oliver Ford, Tom Lane)
        Specifically, allow RANGE mode to use
        PRECEDING and FOLLOWING to
        select rows having grouping values within plus or minus the
        specified offset.  Add GROUPS mode to include plus
        or minus the number of peer groups.  Frame exclusion syntax was also
        added.
       
Add SHA-2 family of hash functions (Peter Eisentraut)
        Specifically, sha224(),
        sha256(), sha384(),
        sha512() were added.
       
Add support for 64-bit non-cryptographic hash functions (Robert Haas, Amul Sul)
        Allow to_char() and
        to_timestamp() to specify the time zone's
        offset from UTC in hours and minutes
        (Nikita Glukhov, Andrew Dunstan)
       
        This is done with format specifications TZH
        and TZM.
       
        Add text search function websearch_to_tsquery()
        that supports a query syntax similar to that used by web search
        engines (Victor Drobny, Dmitry Ivanov)
       
        Add functions json(b)_to_tsvector()
        to create a text search query for matching
        JSON/JSONB values (Dmitry Dolgov)
       
Add SQL-level procedures, which can start and commit their own transactions (Peter Eisentraut)
        They are created with the new CREATE
        PROCEDURE command and invoked via CALL.
       
        The new ALTER/DROP ROUTINE
        commands allow altering/dropping of all routine-like objects,
        including procedures, functions, and aggregates.
       
        Also, writing FUNCTION is now preferred
        over writing PROCEDURE in CREATE
        OPERATOR and CREATE TRIGGER, because the
        referenced object must be a function not a procedure.  However, the
        old syntax is still accepted for compatibility.
       
Add transaction control to PL/pgSQL, PL/Perl, PL/Python, PL/Tcl, and SPI server-side languages (Peter Eisentraut)
        Transaction control is only available within top-transaction-level
        procedures and nested DO and
        CALL blocks that only contain other
        DO and CALL blocks.
       
Add the ability to define PL/pgSQL composite-type variables as not null, constant, or with initial values (Tom Lane)
Allow PL/pgSQL to handle changes to composite types (e.g. record, row) that happen between the first and later function executions in the same session (Tom Lane)
Previously, such circumstances generated errors.
        Add extension jsonb_plpython to
        transform JSONB to/from PL/Python types (Anthony
        Bykov)
       
        Add extension jsonb_plperl to transform
        JSONB to/from PL/Perl types (Anthony Bykov)
       
Change libpq to disable compression by default (Peter Eisentraut)
Compression is already disabled in modern OpenSSL versions, so that the libpq setting had no effect with such libraries.
        Add DO CONTINUE option
        to ecpg's WHENEVER
        statement (Vinayak Pokale)
       
        This generates a C continue statement, causing a
        return to the top of the contained loop when the specified condition
        occurs.
       
Add an ecpg mode to enable Oracle Pro*C-style handling of char arrays.
        This mode is enabled with -C.
       
        Add psql command \gdesc
        to display the names and types of the columns in a query result
        (Pavel Stehule)
       
Add psql variables to report query activity and errors (Fabien Coelho)
        Specifically, the new variables are ERROR,
        SQLSTATE, ROW_COUNT,
        LAST_ERROR_MESSAGE, and
        LAST_ERROR_SQLSTATE.
       
Allow psql to test for the existence of a variable (Fabien Coelho)
        Specifically, the syntax :{?variable_name} allows
        a variable's existence to be tested in an \if
        statement.
       
        Allow environment variable PSQL_PAGER to control
        psql's pager (Pavel Stehule)
       
        This allows psql's default pager to
        be specified as a separate environment variable from the pager
        for other applications.  PAGER is still honored
        if PSQL_PAGER is not set.
       
        Make psql's \d+ command always show the table's
        partitioning information (Amit Langote, Ashutosh Bapat)
       
Previously, partition information would not be displayed for a partitioned table if it had no partitions. Also indicate which partitions are themselves partitioned.
Ensure that psql reports the proper user name when prompting for a password (Tom Lane)
        Previously, combinations of -U and a user name
        embedded in a URI caused incorrect reporting.
        Also suppress the user name before the password prompt when
        --password is specified.
       
        Allow quit and exit to
        exit psql when given with no prior input
        (Bruce Momjian)
       
        Also print hints about how to exit when quit and
        exit are used alone on a line while the input
        buffer is not empty.  Add a similar hint for help.
       
        Make psql hint at using control-D
        when \q is entered alone on a line but ignored
        (Bruce Momjian)
       
        For example, \q does not exit when supplied
        in character strings.
       
        Improve tab completion for ALTER INDEX
        RESET/SET (Masahiko Sawada)
       
Add infrastructure to allow psql to adapt its tab completion queries based on the server version (Tom Lane)
Previously, tab completion queries could fail against older servers.
Add pgbench expression support for NULLs, booleans, and some functions and operators (Fabien Coelho)
        Add \if conditional support to
        pgbench (Fabien Coelho)
       
Allow the use of non-ASCII characters in pgbench variable names (Fabien Coelho)
        Add pgbench option
        --init-steps to control the initialization steps
        performed (Masahiko Sawada)
       
Add an approximately Zipfian-distributed random generator to pgbench (Alik Khilazhev)
Allow the random seed to be set in pgbench (Fabien Coelho)
        Allow pgbench to do exponentiation
        with pow() and power()
        (Raúl Marín Rodríguez)
       
Add hashing functions to pgbench (Ildar Musin)
        Make pgbench statistics more
        accurate when using --latency-limit and
        --rate (Fabien Coelho)
       
Add an option to pg_basebackup that creates a named replication slot (Michael Banck)
        The option --create-slot creates
        the named replication slot (--slot)
        when the WAL streaming method
        (--wal-method=stream) is used.
       
Allow initdb to set group read access to the data directory (David Steele)
        This is accomplished with the new initdb option
        --allow-group-access.  Administrators
        can also set group permissions on the empty data
        directory before running initdb.  Server variable data_directory_mode
        allows reading of data directory group permissions.
       
Add pg_verify_checksums tool to verify database checksums while offline (Magnus Hagander)
        Allow pg_resetwal
        to change the WAL segment size via
        --wal-segsize (Nathan Bossart)
       
Add long options to pg_resetwal and pg_controldata (Nathan Bossart, Peter Eisentraut)
        Add pg_receivewal
        option --no-sync to prevent synchronous
        WAL writes, for testing (Michael Paquier)
       
        Add pg_receivewal option
        --endpos to specify when WAL
        receiving should stop (Michael Paquier)
       
        Allow pg_ctl
        to send the SIGKILL signal to processes
        (Andres Freund)
       
This was previously unsupported due to concerns over possible misuse.
Reduce the number of files copied by pg_rewind (Michael Paquier)
        Prevent pg_rewind from running as
        root (Michael Paquier)
       
        Add pg_dumpall option
        --encoding to control output encoding
        (Michael Paquier)
       
pg_dump already had this option.
        Add pg_dump option
        --load-via-partition-root to force loading of
        data into the partition's root table, rather than the original
        partition (Rushabh Lathia)
       
This is useful if the system to be loaded to has different collation definitions or endianness, possibly requiring rows to be stored in different partitions than previously.
Add an option to suppress dumping and restoring database object comments (Robins Tharakan)
        The new pg_dump,
        pg_dumpall, and
        pg_restore option is
        --no-comments.
       
Add PGXS support for installing include files (Andrew Gierth)
        This supports creating extension modules that depend on other
        modules.  Formerly there was no easy way for the dependent module to
        find the referenced one's include files.  Several
        existing contrib modules that define data types
        have been adjusted to install relevant files.  Also, PL/Perl and
        PL/Python now install their include files, to support creation of
        transform modules for those languages.
       
        Install errcodes.txt to allow extensions to access
        the list of error codes known to PostgreSQL
        (Thomas Munro)
       
Convert documentation to DocBook XML (Peter Eisentraut, Alexander Lakhin, Jürgen Purtz)
        The file names still use an sgml extension
        for compatibility with back branches.
       
        Use stdbool.h to define type bool
        on platforms where it's suitable, which is most (Peter Eisentraut)
       
        This eliminates a coding hazard for extension modules that need
        to include stdbool.h.
       
Overhaul the way that initial system catalog contents are defined (John Naylor)
The initial data is now represented in Perl data structures, making it much easier to manipulate mechanically.
Prevent extensions from creating custom server parameters that take a quoted list of values (Tom Lane)
This cannot be supported at present because knowledge of the parameter's property would be required even before the extension is loaded.
Add ability to use channel binding when using SCRAM authentication (Michael Paquier)
Channel binding is intended to prevent man-in-the-middle attacks, but SCRAM cannot prevent them unless it can be forced to be active. Unfortunately, there is no way to do that in libpq. Support for it is expected in future versions of libpq and in interfaces not built using libpq, e.g. JDBC.
Allow background workers to attach to databases that normally disallow connections (Magnus Hagander)
Add support for hardware CRC calculations on ARMv8 (Yuqi Gu, Heikki Linnakangas, Thomas Munro)
Speed up lookups of built-in functions by OID (Andres Freund)
The previous binary search has been replaced by a lookup array.
Speed up construction of query results (Andres Freund)
Improve speed of access to system caches (Andres Freund)
Add a generational memory allocator which is optimized for serial allocation/deallocation (Tomas Vondra)
This reduces memory usage for logical decoding.
        Make the computation of
        pg_class.reltuples
        by VACUUM consistent with its computation
        by ANALYZE (Tomas Vondra)
       
        Update to use perltidy version
        20170521 (Tom Lane, Peter Eisentraut)
       
        Allow extension pg_prewarm
        to restore the previous shared buffer contents on startup (Mithun
        Cy, Robert Haas)
       
        This is accomplished by having pg_prewarm store
        the shared buffers' relation and block number data to disk
        occasionally during server operation, and at shutdown.
       
        Add pg_trgm
        function strict_word_similarity() to compute
        the similarity of whole words (Alexander Korotkov)
       
        The function word_similarity() already
        existed for this purpose, but it was designed to find similar
        parts of words, while strict_word_similarity()
        computes the similarity to whole words.
       
        Allow creation of indexes that can be used by LIKE
        comparisons
        on citext columns
        (Alexey Chernyshov)
       
        To do this, the index must be created using the
        citext_pattern_ops operator class.
       
        Allow btree_gin
        to index bool, bpchar, name
        and uuid data types (Matheus Oliveira)
       
        Allow cube
        and seg
        extensions to perform index-only scans using GiST indexes
        (Andrey Borodin)
       
        Allow retrieval of negative cube coordinates using
        the ~> operator (Alexander Korotkov)
       
This is useful for KNN-GiST searches when looking for coordinates in descending order.
        Add Vietnamese letter handling to the unaccent
        extension (Dang Minh Huong, Michael Paquier)
       
        Enhance amcheck
        to check that each heap tuple has an index entry (Peter Geoghegan)
       
        Have adminpack
        use the new default file system access roles (Stephen Frost)
       
        Previously, only superusers could call adminpack
        functions; now role permissions are checked.
       
        Widen pg_stat_statement's query ID
        to 64 bits (Robert Haas)
       
This greatly reduces the chance of query ID hash collisions. The query ID can now potentially display as a negative value.
        Remove the contrib/start-scripts/osx scripts
        since they are no longer recommended
        (use contrib/start-scripts/macos instead)
        (Tom Lane)
       
        Remove the chkpass extension (Peter Eisentraut)
       
This extension is no longer considered to be a usable security tool or example of how to write an extension.
The following individuals (in alphabetical order) have contributed to this release as patch authors, committers, reviewers, testers, or reporters of issues.
| Abhijit Menon-Sen | 
| Adam Bielanski | 
| Adam Brightwell | 
| Adam Brusselback | 
| Aditya Toshniwal | 
| Adrián Escoms | 
| Adrien Nayrat | 
| Akos Vandra | 
| Aleksander Alekseev | 
| Aleksandr Parfenov | 
| Alexander Korotkov | 
| Alexander Kukushkin | 
| Alexander Kuzmenkov | 
| Alexander Lakhin | 
| Alexandre Garcia | 
| Alexey Bashtanov | 
| Alexey Chernyshov | 
| Alexey Kryuchkov | 
| Alik Khilazhev | 
| Álvaro Herrera | 
| Amit Kapila | 
| Amit Khandekar | 
| Amit Langote | 
| Amul Sul | 
| Anastasia Lubennikova | 
| Andreas Joseph Krogh | 
| Andreas Karlsson | 
| Andreas Seltenreich | 
| André Hänsel | 
| Andrei Gorita | 
| Andres Freund | 
| Andrew Dunstan | 
| Andrew Fletcher | 
| Andrew Gierth | 
| Andrew Grossman | 
| Andrew Krasichkov | 
| Andrey Borodin | 
| Andrey Lizenko | 
| Andy Abelisto | 
| Anthony Bykov | 
| Antoine Scemama | 
| Anton Dignös | 
| Antonin Houska | 
| Arseniy Sharoglazov | 
| Arseny Sher | 
| Arthur Zakirov | 
| Ashutosh Bapat | 
| Ashutosh Sharma | 
| Ashwin Agrawal | 
| Asim Praveen | 
| Atsushi Torikoshi | 
| Badrul Chowdhury | 
| Balazs Szilfai | 
| Basil Bourque | 
| Beena Emerson | 
| Ben Chobot | 
| Benjamin Coutu | 
| Bernd Helmle | 
| Blaz Merela | 
| Brad DeJong | 
| Brent Dearth | 
| Brian Cloutier | 
| Bruce Momjian | 
| Catalin Iacob | 
| Chad Trabant | 
| Chapman Flack | 
| Christian Duta | 
| Christian Ullrich | 
| Christoph Berg | 
| Christoph Dreis | 
| Christophe Courtois | 
| Christopher Jones | 
| Claudio Freire | 
| Clayton Salem | 
| Craig Ringer | 
| Dagfinn Ilmari Mannsåker | 
| Dan Vianello | 
| Dan Watson | 
| Dang Minh Huong | 
| Daniel Gustafsson | 
| Daniel Vérité | 
| Daniel Westermann | 
| Daniel Wood | 
| Darafei Praliaskouski | 
| Dave Cramer | 
| Dave Page | 
| David Binderman | 
| David Carlier | 
| David Fetter | 
| David G. Johnston | 
| David Gould | 
| David Hinkle | 
| David Pereiro Lagares | 
| David Rader | 
| David Rowley | 
| David Steele | 
| Davy Machado | 
| Dean Rasheed | 
| Dian Fay | 
| Dilip Kumar | 
| Dmitriy Sarafannikov | 
| Dmitry Dolgov | 
| Dmitry Ivanov | 
| Dmitry Shalashov | 
| Don Seiler | 
| Doug Doole | 
| Doug Rady | 
| Edmund Horner | 
| Eiji Seki | 
| Elvis Pranskevichus | 
| Emre Hasegeli | 
| Erik Rijkers | 
| Erwin Brandstetter | 
| Etsuro Fujita | 
| Euler Taveira | 
| Everaldo Canuto | 
| Fabien Coelho | 
| Fabrízio de Royes Mello | 
| Feike Steenbergen | 
| Frits Jalvingh | 
| Fujii Masao | 
| Gao Zengqi | 
| Gianni Ciolli | 
| Greg Stark | 
| Gunnlaugur Thor Briem | 
| Guo Xiang Tan | 
| Hadi Moshayedi | 
| Hailong Li | 
| Haribabu Kommi | 
| Heath Lord | 
| Heikki Linnakangas | 
| Hugo Mercier | 
| Igor Korot | 
| Igor Neyman | 
| Ildar Musin | 
| Ildus Kurbangaliev | 
| Ioseph Kim | 
| Jacob Champion | 
| Jaime Casanova | 
| Jakob Egger | 
| Jean-Pierre Pelletier | 
| Jeevan Chalke | 
| Jeevan Ladhe | 
| Jeff Davis | 
| Jeff Janes | 
| Jeremy Evans | 
| Jeremy Finzel | 
| Jeremy Schneider | 
| Jesper Pedersen | 
| Jim Nasby | 
| Jimmy Yih | 
| Jing Wang | 
| Jobin Augustine | 
| Joe Conway | 
| John Gorman | 
| John Naylor | 
| Jon Nelson | 
| Jon Wolski | 
| Jonathan Allen | 
| Jonathan S. Katz | 
| Julien Rouhaud | 
| Jürgen Purtz | 
| Justin Pryzby | 
| KaiGai Kohei | 
| Kaiting Chen | 
| Karl Lehenbauer | 
| Keith Fiske | 
| Kevin Bloch | 
| Kha Nguyen | 
| Kim Rose Carlsen | 
| Konstantin Knizhnik | 
| Kuntal Ghosh | 
| Kyle Samson | 
| Kyotaro Horiguchi | 
| Lætitia Avrot | 
| Lars Kanis | 
| Laurenz Albe | 
| Leonardo Cecchi | 
| Liudmila Mantrova | 
| Lixian Zou | 
| Lloyd Albin | 
| Luca Ferrari | 
| Lucas Fairchild | 
| Lukas Eder | 
| Lukas Fittl | 
| Magnus Hagander | 
| Mai Peng | 
| Maksim Milyutin | 
| Maksym Boguk | 
| Mansur Galiev | 
| Marc Dilger | 
| Marco Nenciarini | 
| Marina Polyakova | 
| Mario de Frutos Dieguez | 
| Mark Cave-Ayland | 
| Mark Dilger | 
| Mark Wood | 
| Marko Tiikkaja | 
| Markus Winand | 
| Martín Marqués | 
| Masahiko Sawada | 
| Matheus Oliveira | 
| Matthew Stickney | 
| Metin Doslu | 
| Michael Banck | 
| Michael Meskes | 
| Michael Paquier | 
| Michail Nikolaev | 
| Mike Blackwell | 
| Minh-Quan Tran | 
| Mithun Cy | 
| Morgan Owens | 
| Nathan Bossart | 
| Nathan Wagner | 
| Neil Conway | 
| Nick Barnes | 
| Nicolas Thauvin | 
| Nikhil Sontakke | 
| Nikita Glukhov | 
| Nikolay Shaplov | 
| Noah Misch | 
| Noriyoshi Shinoda | 
| Oleg Bartunov | 
| Oleg Samoilov | 
| Oliver Ford | 
| Pan Bian | 
| Pascal Legrand | 
| Patrick Hemmer | 
| Patrick Krecker | 
| Paul Bonaud | 
| Paul Guo | 
| Paul Ramsey | 
| Pavan Deolasee | 
| Pavan Maddamsetti | 
| Pavel Golub | 
| Pavel Stehule | 
| Peter Eisentraut | 
| Peter Geoghegan | 
| Petr Jelínek | 
| Petru-Florin Mihancea | 
| Phil Florent | 
| Philippe Beaudoin | 
| Pierre Ducroquet | 
| Piotr Stefaniak | 
| Prabhat Sahu | 
| Pu Qun | 
| QL Zhuo | 
| Rafia Sabih | 
| Rahila Syed | 
| Rainer Orth | 
| Rajkumar Raghuwanshi | 
| Raúl Marín Rodríguez | 
| Regina Obe | 
| Richard Yen | 
| Robert Haas | 
| Robins Tharakan | 
| Rod Taylor | 
| Rushabh Lathia | 
| Ryan Murphy | 
| Sahap Asci | 
| Samuel Horwitz | 
| Scott Ure | 
| Sean Johnston | 
| Shao Bret | 
| Shay Rojansky | 
| Shubham Barai | 
| Simon Riggs | 
| Simone Gotti | 
| Sivasubramanian Ramasubramanian | 
| Stas Kelvich | 
| Stefan Kaltenbrunner | 
| Stephen Froehlich | 
| Stephen Frost | 
| Steve Singer | 
| Steven Winfield | 
| Sven Kunze | 
| Taiki Kondo | 
| Takayuki Tsunakawa | 
| Takeshi Ideriha | 
| Tatsuo Ishii | 
| Tatsuro Yamada | 
| Teodor Sigaev | 
| Thom Brown | 
| Thomas Kellerer | 
| Thomas Munro | 
| Thomas Reiss | 
| Tobias Bussmann | 
| Todd A. Cook | 
| Tom Kazimiers | 
| Tom Lane | 
| Tomas Vondra | 
| Tomonari Katsumata | 
| Torsten Grust | 
| Tushar Ahuja | 
| Vaishnavi Prabakaran | 
| Vasundhar Boddapati | 
| Victor Drobny | 
| Victor Wagner | 
| Victor Yegorov | 
| Vik Fearing | 
| Vinayak Pokale | 
| Vincent Lachenal | 
| Vitaliy Garnashevich | 
| Vitaly Burovoy | 
| Vladimir Baranoff | 
| Xin Zhang | 
| Yi Wen Wong | 
| Yorick Peterse | 
| Yugo Nagata | 
| Yuqi Gu | 
| Yura Sokolov | 
| Yves Goergen | 
| Zhou Digoal |