Pavel Luzanov's Blog

Our blog is where our Postgres Pro experts share their knowledge with the community. Blog posts cover a variety of topics, including Postgres internals, extensions and monitoring solutions.

Recent posts

January 12   •   PostgreSQL

The November commitfest is ripe with new interesting features! Without further ado, let’s proceed with the review.

If you missed our July and September commitfest reviews, you can check them out here: 2023-07, 2023-09.

  • ON LOGIN trigger
  • Event triggers for REINDEX
  • ALTER OPERATOR: commutator, negator, hashes, merges
  • pg_dump --filter=dump.txt
  • psql: displaying default privileges
  • pg_stat_statements: track statement entry timestamps and reset min/max statistics
  • pg_stat_checkpointer: checkpointer process statistics
  • pg_stats: statistics for range type columns
  • Planner: exclusion of unnecessary table self-joins
  • Planner: materialized CTE statistics
  • Planner: accessing a table with multiple clauses
  • Index range scan optimization
  • dblink, postgres_fdw: detailed wait events
  • Logical replication: migration of replication slots during publisher upgrade
  • Replication slot use log
  • Unicode: new information functions
  • New function: xmltext
  • AT LOCAL support
  • Infinite intervals
  • ALTER SYSTEM with unrecognized custom parameters
  • Building the server from source


November 5, 2023   •   PostgreSQL

We continue to follow the news of the PostgreSQL 17 development. Let’s find out what the September commitfest brings to the table.

If you missed our July commitfest review, you can check it out here: 2023-07.

  • Removed the parameter old_snapshot_threshold
  • New parameter event_triggers
  • New functions to_bin and to_oct
  • New system view pg_wait_events
  • EXPLAIN: a JIT compilation time counter for tuple deforming
  • Planner: better estimate of the initial cost of the WindowAgg node
  • pg_constraint: NOT NULL constraints
  • Normalization of CALL, DEALLOCATE and two-phase commit control commands
  • unaccent: the target rule expressions now support values in quotation marks
  • Audit of connections without authentication
  • pg_stat_subscription: new column worker_type
  • The behaviour of pg_promote in case of unsuccessful switchover to a replica
  • Choosing the disk synchronization method in server utilities
  • pg_restore: optimization of parallel recovery of a large number of tables
  • pg_basebackup and pg_receivewal with the parameter dbname
  • Parameter names for a number of built-in functions
  • psql: \watch min_rows


September 12, 2023   •   PostgreSQL

We continue to follow the news in the world of PostgreSQL. The PostgreSQL 16 Release Candidate 1 was rolled out on August 31. If all is well, PostgreSQL 16 will officially release on September 14.

What has changed in the upcoming release after the April code freeze? What’s getting into PostgreSQL 17 after the first commitfest? Read our latest review to find out!

PostgreSQL 16

For reference, here are our previous reviews of PostgreSQL 16 commitfests: 2022-07, 2022-09, 2022-11, 2023-01, 2023-03.

Since April, there have been some notable changes.

Let’s start with the losses. The following updates have not made it into the release:

Some patches have been updated:


May 25, 2023   •   PostgreSQL

The end of the March Commitfest concludes the acceptance of patches for PostgreSQL 16. Let’s take a look at some exciting new updates it introduced.

I hope that this review together with the previous articles in the series (2022-07, 2022-09, 2022-11, 2023-01) will give you a coherent idea of the new features of PostgreSQL 16.

As usual, the March Commitfest introduces a ton of new changes. I’ve split them into several sections for convenience.


  • pg_stat_io: input/output statistics
  • Counter for new row versions moved to another page when performing an UPDATE
  • pg_buffercache: new pg_buffercache_usage_counts function
  • Normalization of DDL and service commands, continued
  • EXPLAIN (generic_plan): generic plan of a parameterized query
  • auto_explain: logging the query ID

Client applications

  • psql: variables SHELL_ERROR and SHELL_EXIT_CODE
  • psql: \watch and the number of repetitions
  • psql:\df+ does not show the source code of functions
  • pg_dump: support for LZ4 and zstd compression methods
  • pg_dump and partitioned tables
  • pg_verifybackup --progress
  • libpq: balancing connections

Server administration and maintenance

  • initdb: setting configuration parameters during cluster initialization
  • Autovacuum: balancing I/O impact on the fly
  • Managing the size of shared memory for vacuum and analyze
  • VACUUM for TOAST tables only
  • The vacuum_defer_cleanup_age parameter has been removed
  • pg_walinspect: interpretation of the end_lsn parameter
  • pg_walinspect: pg_get_wal_fpi_info → pg_get_wal_block_info


  • ICU: UNICODE collation
  • ICU: Canonization of locales
  • ICU: custom rules for customizing the sorting algorithm


  • libpq: new parameter require_auth
  • scram_iterations: iteration counter for password encryption using SCRAM-SHA-256

SQL functions and commands

  • SQL/JSON standard support
  • New functions pg_input_error_info and pg_input_is_valid
  • The Daitch-Mokotoff Soundex
  • New functions array_shuffle and array_sample
  • New aggregate function any_value
  • COPY: inserting default values
  • timestamptz: adding and subtracting time intervals
  • XML: formatting values
  • pg_size_bytes: support for "B"
  • New functions: erf, erfc


  • Parallel execution of full and right hash joins
  • Options for the right antijoin
  • Relation extension mechanism rework
  • Don’t block HOT update by BRIN index
  • postgres_fdw: aborting transactions on remote servers in parallel mode
  • force_parallel_mode → debug_parallel_query
  • Direct I/O (for developers only)

Logical replication

  • Logical replication from a physical replica
  • Using non-unique indexes with REPLICA IDENTITY FULL
  • Initial synchronization in binary format
  • Privileges for creating subscriptions and applying changes
  • Committing changes in parallel mode (for developers only)


March 7, 2023   •   PostgreSQL

We continue to follow the news of the PostgreSQL 16 release, and today, the results of the fourth CommitFest are on the table. Let’s have a look.

If you missed the previous CommitFests, check out our reviews for 2022-07, 2022-09 and 2022-11.

Here are the patches I want to talk about this time:

  • New function: random_normal
  • Input formats for integer literals
  • Goodbye, postmaster
  • Parallel execution for string_agg and array_agg
  • New parameter: enable_presorted_aggregate
  • Planner support function for working with window functions
  • Optimized grouping of repeating columns in GROUP BY and DISTINCT
  • pg_dump: lock tables in batches
  • PL/pgSQL: cursor variable initialization
  • Roles with the CREATEROLE attribute
  • Setting parameter values at the database and user level
  • New parameter: reserved_connections
  • postgres_fdw: analyzing foreign tables with TABLESAMPLE
  • postgres_fdw: batch insert records during partition key updates
  • pg_ident.conf: new ways to identify users in PostgreSQL
  • Query jumbling for DDL and utility statements
  • New function: bt_multi_page_stats
  • New function: pg_split_walfile_name
  • pg_walinspect, pg_waldump: collecting page images from WAL


December 31, 2022   •   PostgreSQL

We continue to follow the news of the upcoming PostgreSQL 16. The third CommitFest concluded in early December. Let's look at the results.

If you missed the previous CommitFests, check out our reviews: 2022-07, 2022-09.

Here are the patches I want to talk about:

  • meson: a new source code build system
  • Documentation: a new chapter on transaction processing
  • psql: \d+ indicates foreign partitions in a partitioned table
  • psql: extended query protocol support
  • Predicate locks on materialized views
  • Tracking last scan time of indexes and tables
  • pg_buffercache: a new function pg_buffercache_summary
  • walsender displays the database name in the process status
  • Reducing the WAL overhead of freezing tuples
  • Reduced power consumption when idle
  • postgres_fdw: batch mode for COPY
  • Modernizing the GUC infrastructure
  • Hash index build optimization
  • MAINTAIN ― a new privilege for table maintenance
  • SET ROLE: better role change management
  • Support for file inclusion directives in pg_hba.conf and pg_ident.conf
  • Regular expressions support in pg_hba.conf


November 14, 2022   •   PostgreSQL

It’s official! PostgreSQL 15 is out, and the community is abuzz discussing all the new features of the fresh release.

Meanwhile, the October CommitFest for PostgreSQL 16 had come and gone, with its own notable additions to the code.

If you missed the July CommitFest, our previous article will get you up to speed in no time.

Here are the patches I want to talk about:

  • SYSTEM_USER function
  • Frozen pages/tuples information in autovacuum's server log
  • pg_stat_get_backend_idset returns the actual backend ID
  • Improved performance of ORDER BY / DISTINCT aggregates
  • Faster bulk-loading into partitioned tables
  • Optimized lookups in snapshots
  • Bidirectional logical replication
  • pg_auth_members: pg_auth_members: role membership granting management
  • pg_auth_members: role membership and privilege inheritance
  • pg_receivewal and pg_recvlogical can now handle SIGTERM


August 17, 2022   •   PostgreSQL

August is a special month in PostgreSQL release cycle. PostgreSQL 15 isn't even officially out yet, but the first CommitFest for the 16th release has already been held.

Let's compile the server and check out the cool new stuff! \dconfig server_version List of configuration parameters Parameter | Value ----------------+--------- server_version | 16devel

Notable features

There are 14 patches I want to talk about:

  • psql: \pset xheader_width
  • vacuumdb --schema and --exclude-schema options
  • New createuser features added
  • Checkpoint and redo LSN added to LogCheckpointEnd log message
  • pg_prepared_statements.result_types
  • New parameter log_parameter_max_length for auto_explain
  • Subquery alias in FROM clause became optional
  • REINDEX: syntax improvements and more
  • CREATE STATISTICS: statistic name is now optional
  • CREATE TABLE: the STORAGE attribute
  • The user created during cluster initialization now can't be stripped of superuser privileges
  • TRUNCATE triggers on foreign tables are now supported
  • New argument variation for pg_read_file/pg_read_binary_file
  • Extensible WAL resource managers