EDB Postgres Advanced Server Release Notes v12
With this release of EDB Postgres Advanced Server 12, EnterpriseDB continues to lead as the only worldwide company to deliver innovative and low cost open-source-derived database solutions with commercial quality, ease of use, compatibility, scalability, and performance for small or large-scale enterprises.
EDB Postgres Advanced Server 12 is built on open-source PostgreSQL 12, which introduces myriad enhancements that enable databases to scale up and scale out in more efficient ways.
EDB Postgres Advanced Server 12 adds a number of new outstanding features, including:
- Interval Partition
- Logical decoding on standby
For more information about EnterpriseDB software, visit:
EDB Postgres Advanced Server v12 is packaged and delivered as interactive installers for Windows; visit the EnterpriseDB website:
RPM Packages are available for Linux from:
Debian/Ubuntu Packages are available for download from:
To request the credentials required to access EDB repositories, visit:
Please note: The EnterpriseDB repository structure has changed; for detailed installation instructions, see the EDB Postgres Advanced Server Linux Installation Guide.
Documentation is provided on the EnterpriseDB website, visit:
EDB Postgres Advanced Server v12 installers support 64 bit Linux and Windows server platforms. The Advanced Server 12 RPM packages are supported on the following 64-bit Linux platforms:
- Red Hat Enterprise Linux (x86_64) 7.x and 8.x
- CentOS (x86_64) 7.x and 8.x
- OL (x86_64) 7.x and 8.x
- PPC64LE 8 running CentOS/RHEL 7.x
The EDB Postgres Advanced Server 12 native packages are supported on the following 64-bit Linux platforms:
- Debian 9.x and 10.x
- Ubuntu 18.04 LTS
Graphical installers are supported on the following 64-bit Windows platforms:
- Windows 2019
- Windows Server 2016
- Windows Server 2012 R2 Server
See Platform Compatibility for additional information about supported platforms.
The following components are included in the EDB Postgres Advanced Server v12 release:
- Procedural Language Packs – PL/Perl 5.26, PL/Python 3.7, PL/TCL 8.6
- CloneSchema 1.10
- Parallel Clone 1.5
- pgAgent 4.15
- Slony 2.2.8
- Connectors JDBC 42.2.8, ODBC 12.00.0000 .NET 184.108.40.206, OCI 220.127.116.11
- pgAdmin 4.15
- pgBouncer 1.12.0
- pgPool-II & pgPool-IIExtensions 4.0.6
- MTK 53.0.0
- EDBPlus 38.0.0
- PostGIS-JDBC 2.2.1
The major highlights of this release are :
Advanced Server now supports interval partitioning. Interval partitioning is an extension to range partitioning where the system automatically creates the partition if a new tuple doesn't fit into existing partitions.
For better Redwood compatibility, Advanced Server now treats the
SELECT UNIQUEclause synonymous to
SELECT DISTINCTclause (i.e. they can be used interchangeably in all places).
Advanced Server now supports
COMPOUND TRIGGERS. This provides a way to define a single trigger on a table that enables the user to specify actions for different DML event points. It allows defining
BEFORE EACH ROW,
AFTER EACH ROWtiming events in a single trigger.
Advanced Server allows logical decoding on a standby server. With this feature, the user can now create a logical replication slot on standby server.
Advanced Server now provides
CAST(MULTISET)is an extension to the redwood style casting function
CAST(.. AS ..)where the subquery result is like a table output
CASTto a collection type.
Advanced Server now supports two aggregate functions:
LISTAGGfunction supports string aggregation that concatenates data from multiple rows into a single row in an ordered fashion.
MEDIANfunction calculates a median value from the set of provided values. The aggregate function can be used with numeric, date/time and interval types and much like other aggregate functions, it can be used with window function as well.
In addition to supporting
%rowtypevariables for functions and procedures, Advanced Server now supports the same inside a package as well.
Advanced Server now supports a Redwood compatible
to_timestampimplementation, which facilitates stricter input string parsing for timestamp columns for EDB Loader.
Advanced Server has re-implemented
ROWIDsusing identity data type after PG v12 PostgreSQL community removed support for
Advanced Server has added the
SYS_GUIDfunction to generate and return a globally unique identifier in the form of 16-bytes of RAW data.
Advanced Server now offers new view that provide information which is compatible with the Oracle data dictionary views:
For information about Advanced Server features that are compatible with Oracle databases, see the following guides:
- Database Compatibility for Oracle Developers SQL Guide
- Database Compatibility for Oracle Developers Reference Guide
- Database Compatibility for Oracle Developers Built-in Package Guide
- Database Compatibility for Oracle Developers Tools and Utilities Guide
Advanced Server 12 integrates all of the community PostgreSQL 12 features. To review a complete list of changes to the community PostgreSQL project and the contributors names, see the PostgreSQL 12 Release Notes at:
The following updates are available in PostgreSQL 12:
Improve performance of many operations on partitioned tables.
Allow tables with thousands of child partitions to be processed efficiently by operations that only affect a small number of partitions.
Allow foreign keys to reference partitioned tables.
Improve speed of
COPY into partitioned tables.
Allow partition bounds to be any expression.
Such expressions are evaluated at partitioned-table creation time. Previously, only simple constants were allowed as partition bounds.
CREATE TABLE's tablespace specification for a partitioned table to affect the tablespace of its children.
Avoid sorting when partitions are already being scanned in the necessary order.
ALTER TABLE ATTACH PARTITION is now performed with reduced locking requirements.
Add partition introspection functions.
The new function
pg_partition_root() returns the top-most parent of a partition tree,
pg_partition_ancestors() reports all ancestors of a partition, and
pg_partition_tree() displays information about partitions.
Include partitioned indexes in the system view
Add psql command
\dP to list partitioned tables and indexes.
\z display of partitioned tables.
Fix bugs that could cause
ALTER TABLE DETACH PARTITION to leave behind incorrect dependency state, allowing subsequent operations to misbehave, for example by not dropping a former partition child index when its table is dropped.
Improve performance and space utilization of btree indexes with many duplicates.
Previously, duplicate index entries were stored unordered within their duplicate groups. This caused overhead during index inserts, wasted space due to excessive page splits, and it reduced
VACUUM's ability to recycle entire pages. Duplicate index entries are now sorted in heap-storage order.
pg_upgrade'd from previous releases will not have these benefits.
Allow multi-column btree indexes to be smaller.
Internal pages and min/max leaf page indicators now only store index keys until the change key, rather than all indexed keys. This also improves the locality of index access.
Improve speed of btree index insertions by reducing locking overhead.
INCLUDE columns in
Add support for nearest-neighbor
(KNN) searches of
Reduce the WAL write overhead of
SP-GiST index creation.
Allow index-only scans to be more efficient on indexes with many columns.
Improve the performance of vacuum scans of
Delete empty leaf pages during
Reduce locking requirements for index renaming.
CREATE STATISTICS to create most-common-value statistics for multiple columns.
This improves optimization for queries that test several columns, requiring an estimate of the combined effect of several
WHERE clauses. If the columns are correlated and have non-uniform distributions then multi-column statistics will allow much better estimates.
Allow common table expressions (CTEs) to be inlined into the outer query.
Specifically, CTEs are automatically inlined if they have no side-effects, are not recursive, and are referenced only once in the query. Inlining can be prevented by specifying
MATERIALIZED, or forced for multiply-referenced CTEs by specifying
NOT MATERIALIZED. Previously, CTEs were never inlined and were always evaluated before the rest of the query.
Allow control over when generic plans are used for prepared statements.
This is controlled by the
plan_cache_mode server parameter.
Improve optimization of partition and
UNION ALL queries that have only a single child.
Improve processing of domains that have no check constraints.
Domains that are being used purely as type aliases no longer cause optimization difficulties.
Pre-evaluate calls of
GREATEST when their arguments are constants.
Improve optimizer's ability to verify that partial indexes with IS
NOT NULL conditions are usable in queries.
Usability can now be recognized in more cases where the calling query involves casts or large
x IN (array) clauses.
ANALYZE statistics using the collation defined for each column.
Previously, the database's default collation was used for all statistics. This potentially gives better optimizer behavior for columns with non-default collations.
Improve selectivity estimates for inequality comparisons on
Improve optimization of joins on columns of type
These changes primarily improve the efficiency of self-joins on
Fix the leakproofness designations of some btree comparison operators and support functions.
This allows some optimizations that previously would not have been applied in the presence of security barrier views or row-level security.
Enable Just-in-Time (JIT) compilation by default, if the server has been built with support for it.
Note that this support is not built by default, but has to be selected explicitly while configuring the build.
Speed up keyword lookup.
Improve search performance for multi-byte characters in
position() and related functions.
Allow toasted values to be minimally decompressed.
This is useful for routines that only need to examine the initial portion of a toasted field.
ALTER TABLE ... SET NOT NULL to avoid unnecessary table scans.
This can be optimized when the table's column constraints can be recognized as disallowing nulls.
ALTER TABLE ... SET DATA TYPE changing between timestamp and timestamptz to avoid a table rewrite when the session time zone is UTC.
In the UTC time zone, these two data types are binary compatible.
Improve speed in converting strings to
Allow parallelized queries when in
SERIALIZABLE isolation mode.
Previously, parallelism was disabled when in this mode.
pwrite() for random I/O.
This reduces the number of system calls required for I/O.
Improve the speed of setting the process title on FreeBSD.
Allow logging of statements from only a percentage of transactions.
log_transaction_sample_rate controls this.
Add progress reporting to
CREATE INDEX and
Progress is reported in the
pg_stat_progress_create_index system view.
Add progress reporting to
Progress is reported in the
pg_stat_progress_cluster system view.
Add progress reporting to
This is enabled with the option
Add counter of checksum failures to
Add tracking of global objects in system view
Global objects are shown with a
pg_stat_database.datid value of zero.
Add the ability to list the contents of the archive directory.
The function is
Add the ability to list the contents of temporary directories.
pg_ls_tmpdir(), optionally allows specification of a tablespace.
Add information about the client certificate to the system view
The new columns are
clientdn has been renamed to
client_dn for clarity.
Restrict visibility of rows in
pg_stat_ssl for unprivileged users.
At server start, emit a log message including the server version number.
Prevent logging "incomplete startup packet" if a new connection is immediately closed.
This avoids log spam from certain forms of monitoring.
application_name, if set, in
log_connections log messages.
Make the walreceiver set its application name to the cluster name, if set.
Add the timestamp of the last received standby message to
Add a wait event for
fsync of WAL segments.
Add GSSAPI encryption support.
This feature allows TCP/IP connections to be encrypted when using GSSAPI authentication, without having to set up a separate encryption facility such as SSL. In support of this, add hostgssenc and hostnogssenc record types in
pg_hba.conf for selecting connections that do or do not use GSSAPI encryption, corresponding to the existing hostssl and hostnossl record types. There is also a new
gssencmode libpq option, and a
pg_stat_gssapi system view.
Allow the clientcert
pg_hba.conf option to check that the database user name matches the client certificate's common name.
This new check is enabled with
Allow discovery of an LDAP server using DNS SRV records.
This avoids the requirement of specifying ldapserver. It is only supported if PostgreSQL is compiled with OpenLDAP.
Add ability to enable/disable cluster checksums using
The cluster must be shut down for these operations.
Reduce the default value of
autovacuum_vacuum_cost_delay to 2ms.
This allows autovacuum operations to proceed faster by default.
vacuum_cost_delay to specify sub-millisecond delays, by accepting fractional values.
Allow time-based server parameters to use units of microseconds (us).
Allow fractional input for integer server parameters.
SET work_mem = '30.1GB' is now allowed, even though
work_mem is an integer parameter. The value will be rounded to an integer after any required units conversion.
Allow units to be defined for floating-point server parameters.
wal_init_zero server parameters to control WAL file recycling.
Avoiding file recycling can be beneficial on copy-on-write file systems like ZFS.
Add server parameter
tcp_user_timeout to control the server's TCP timeout.
Allow control of the minimum and maximum SSL protocol versions.
The server parameters are
Add server parameter
ssl_library to report the SSL library version used by the server.
Add server parameter
shared_memory_type to control the type of shared memory to use.
This allows selection of System V shared memory, if desired.
Allow some recovery parameters to be changed with reload.
These parameters are
Allow the streaming replication timeout
(wal_sender_timeout) to be set per connection.
Previously, this could only be set cluster-wide.
pg_promote() to promote standbys to primaries.
Previously, this operation was only possible by using
pg_ctl or creating a trigger file.
Allow replication slots to be copied.
The functions for this are
max_wal_senders not count as part of
Add an explicit value of current for
Make recovery fail if a two-phase transaction status file is corrupt.
Previously, a warning was logged and recovery continued, allowing the transaction to be lost.
REINDEX CONCURRENTLY option to allow reindexing without locking out writes.
This is also controlled by the reindexdb application's --concurrently option.
Add support for generated columns.
The content of generated columns are computed from expressions (including references to other columns in the same table) rather than being specified by
WHERE clause to
COPY FROM to control which rows are accepted.
This provides a simple way to filter incoming data.
Allow enumerated values to be added more flexibly.
ALTER TYPE ... ADD VALUE could not be called in a transaction block, unless it was part of the same transaction that created the enumerated type. Now it can be called in a later transaction, so long as the new enumerated value is not referenced until after it is committed.
Add commands to end a transaction and start a new one.
The commands are
COMMIT AND CHAIN and
ROLLBACK AND CHAIN.
CREATE TABLE options to prevent
VACUUM from truncating trailing empty pages.
These options are
toast.vacuum_truncate. Use of these options reduces
VACUUM's locking requirements, but prevents returning disk space to the operating system.
VACUUM to skip index cleanup.
This change adds a
VACUUM command option
INDEX_CLEANUP as well as a table storage option
vacuum_index_cleanup. Use of this option reduces the ability to reclaim space and can lead to index bloat, but it is helpful when the main goal is to freeze old tuples.
Add the ability to skip
ANALYZE operations on tables that cannot be locked immediately.
This option is called
ANALYZE to take optional Boolean argument specifications.
ANALYZE from requesting a lock on tables for which the user lacks permission.
This prevents unauthorized locking, which could interfere with user queries.
SETTINGS to output non-default optimizer settings.
This output can also be obtained when using
auto_explain by setting
OR REPLACE option to
Allow modifications of system catalogs' options using
Modifications of catalogs' reloptions and autovacuum settings are now supported. (Setting
allow_system_table_mods is still required.)
Use all key columns' names when selecting default constraint names for foreign keys.
Previously, only the first column name was included in the constraint name, resulting in ambiguity for multi-column foreign keys.
Update assorted knowledge about Unicode to match Unicode 12.1.0.
This fixes, for example, cases where psql would misformat output involving combining characters.
Update Snowball stemmer dictionaries with support for new languages.
This adds word stemming support for Arabic, Indonesian, Irish, Lithuanian, Nepali, and Tamil to full text search.
Allow creation of collations that report string equality for strings that are not bitwise equal.
This feature supports "nondeterministic" collations that can define case- and accent-agnostic equality comparisons. Thus, for example, a case-insensitive uniqueness constraint on a text column can be made more easily than before. This is only supported for ICU collations.
Add support for ICU collation attributes on older ICU versions.
This allows customization of the collation rules in a consistent way across all ICU versions.
Allow data type name to more seamlessly be compared to other text types.
Type name now behaves much like a domain over type text that has default collation "C". This allows cross-type comparisons to be processed more efficiently.
Add support for the SQL/JSON path language.
This allows execution of complex queries on JSON values using an SQL-standard language.
Add support for hyperbolic functions.
log10() as an alias for
log(), for standards compliance.
Improve the accuracy of statistical aggregates like variance() by using more precise algorithms.
date_trunc() to have an additional argument to control the time zone.
This is faster and simpler than using the
AT TIME ZONE clause.
to_date() functions to be more forgiving of template mismatches.
This new behavior more closely matches the Oracle functions of the same name.
xmlexists(), fix some cases where nothing was output for a node, or an unexpected error was thrown, or necessary escaping of XML special characters was omitted.
BY VALUE clause in
This SQL-standard clause has no effect in PostgreSQL's implementation, but it was unnecessarily being rejected.
current_schemas() from being run by parallel workers, as they are not parallel-safe.
RECORD to be used as column types in a query's column definition list for a table function that is declared to return
Allow SQL commands and variables with the same names as those commands to be used in the same PL/pgSQL function.
For example, allow a variable called comment to exist in a function that calls the
COMMENT SQL command. Previously this combination caused a parse error.
Add new optional warning and error checks to PL/pgSQL.
The new checks allow for run-time validation of
INTO column counts and single-row results.
Add connection parameter
tcp_user_timeout to control libpq's TCP timeout.
Allow libpq (and thus psql) to report only the SQLSTATE value in error messages.
Add libpq function
PQresultMemorySize() to report the memory used by a query result.
Remove the no-display/debug flag from libpq's options connection parameter.
This allows this parameter to be set by
Allow ecpg to create variables of data type bytea.
This allows ECPG clients to interact with bytea data directly, rather than using an encoded form.
PREPARE AS support to ECPG.
Allow vacuumdb to select tables for vacuum based on their wraparound horizon.
The options are
Allow vacuumdb to disable waiting for locks or skipping all-visible pages.
The options are
Add colorization to the output of command-line utilities.
This is enabled by setting the environment variable
PG_COLOR to always or auto. The specific colors used can be adjusted by setting the environment variable
PG_COLORS, using ANSI escape codes for colors. For example, the default behavior is equivalent to
Add CSV table output mode in psql.
This is controlled by
\pset format csv or the command-line
Show the manual page URL in psql's
\help output for a SQL command.
Display the IP address in psql's
\conninfo (Fabien Coelho).
Improve tab completion of
CREATE EVENT TRIGGER,
ALTER DATABASE, and
ALTER INDEX ALTER COLUMN.
Allow values produced by queries to be assigned to pgbench variables.
The command for this is
Improve precision of pgbench's
Improve pgbench's error reporting with clearer messages and return codes.
Allow control of log file rotation via
Previously, this was only possible via an SQL function or a process signal.
Properly detach the new server process during
This prevents the server from being shut down if the shell script that invoked
pg_ctl is interrupted later.
pg_upgrade to use the file system's cloning feature, if there is one.
--clone option has the advantages of
--link, while preventing the old cluster from being changed after the new cluster has started.
Allow specification of the socket directory to use in
This is controlled by
--socketdir; the default is the current directory.
pg_checksums to disable
This is controlled by the
pg_rewind to disable
pg_test_fsync to report accurate
open_datasync durations on Windows.
pg_dump emits data with
INSERT commands rather than
COPY, allow more than one data row to be included in each
The option controlling this is
pg_dump to emit
INSERT ... ON CONFLICT DO NOTHING.
This avoids conflict failures during restore. The option is
Decouple the order of operations in a parallel
pg_dump from the order used by a subsequent parallel
pg_restore to perform more-fully-parallelized parallel restores, especially in cases where the original dump was not done in parallel. Scheduling of a parallel
pg_dump is also somewhat improved.
extra_float_digits setting to be specified for
This is primarily useful for making dumps that are exactly comparable across different source server versions. It is not recommended for normal use, as it may result in loss of precision when the dump is restored.
--exclude-database option to
CREATE ACCESS METHOD command to create new table types.
This enables the development of new table access methods, which can optimize storage for different use cases. The existing heap access method remains the default.
Add planner support function interfaces to improve optimizer estimates, inlining, and indexing for functions.
This allows extensions to create planner support functions that can provide function-specific selectivity, cost, and row-count estimates that can depend on the function's arguments. Support functions can also supply simplified representations and index conditions, greatly expanding optimization possibilities.
Simplify renumbering manually-assigned
OIDs, and establish a new project policy for management of such
Patches that manually assign
OIDs for new built-in objects (such as new functions) should now randomly choose
OIDs in the range 8000—9999. At the end of a development cycle, the OIDs used by committed patches will be renumbered down to lower numbers, currently somewhere in the 4xxx range, using the new
renumber_oids.pl script. This approach should greatly reduce the odds of
OID collisions between different in-process patches.
While there is no specific policy reserving any
OIDs for external use, it is recommended that forks and other projects needing private manually-assigned
OIDs use numbers in the high 7xxx range. This will avoid conflicts with recently-merged patches, and it should be a long time before the core project reaches that range.
Build Cygwin binaries using dynamic instead of static libraries.
Remove configure switch
A strong random-number source is now required.
printf-family functions, as well as
strerror_r, now behave uniformly across platforms within Postgres code.
%m everywhere; on Windows,
strerror copes with Winsock error codes (it used to do so in backend but not frontend code); and
strerror_r always follows the GNU return convention.
Require a C99-compliant compiler, and MSVC 2013 or later on Windows.
Use pandoc, not lynx, for generating plain-text documentation output files.
This affects only the
INSTALL file generated during make dist and the seldom-used plain-text
postgres.txt output file. Pandoc produces better output than lynx and avoids some locale/encoding issues. Pandoc version 1.13 or later is required.
Support use of images in the PostgreSQL documentation.
ORDER BY sorts and
LIMIT clauses to be pushed to
postgres_fdw foreign servers in more cases.
Improve optimizer cost accounting for
WITH CHECK OPTION on views that reference
CHECK OPTIONs on
postgres_fdw tables are ignored (because the reference is foreign), views on such tables are considered local, so this change enforces
CHECK OPTIONs on them.
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