#PostgreSQL

We continue to follow the news about PostgreSQL 18. The January CommitFest brings in some notable improvements to monitoring, as well as other new features. You can find previous reviews of PostgreSQL 18 CommitFests here: 2024-07 , 2024-09 , 2024-11 . EXPLAIN (analyze): buffers on by default pg_stat_io: input/output statistics in bytes instead of pages pg_stat_io: WAL statistics pg_stat_get_backend_io: I/O statistics for a specific process VACUUM(verbose): visibility map information Total vacuum and analysis time per table autovacuum: change the number of workers without restarting the server psql: connection service information psql: expanded display for \d* commands psql: leakproof flag in \df* output jsonb: null conversion to other types MD5 encryption algorithm: end-of-support preparations New function uuidv7 postgres_fdw: SCRAM authentication without storing the password passwordcheck: minimum password length New function casefold and pg_unicode_fast collation DML commands: RETURNING with OLD and NEW to_number: convert a string of roman numberals to numeric

We continue the series of articles about new patches coming to PostgreSQL 18, this one covering the news of the November CommitFest. If you missed the previous reviews, you can check them out here: 2024-07 , 2024-09 . initdb: checksum calculation enabled by default Planner: array lookup instead of multiple similar conditions under OR Planner: switching around expressions in DISTINCT clauses GROUPING SETS: HAVING -> WHERE Data type cache entry invalidation and temporary tables Planner: incremental sorting during Merge Join New function array_reverse Functions min and max for the type bytea Parallel worker usage statistics New function pg_ls_summariesdir new contrib module: pg_logicalsnapinspect Improved extension installation error messages NOT NULL constraints in the system catalog A TOAST table for pg_index COPY... FROM and file_fdw: rejected row limit LIKE support with nondetermenistic collations TLS v1.3: cipher suites

Statistically , September CommitFests feature the fewest commits. Apparently, the version 18 CommitFest is an outlier. There are many accepted patches and many interesting new features to talk about. If you missed the July CommitFest, get up to speed here: 2024-07 . Conflict detection and logging in logical replication Planner: no more 10000000000 Planner: memory management and usage monitoring for temporary tuple storage Reading buffers during index backwards scan pg_upgrade: asynchronous operations in multiple databases Hash Join speed-up Faster text value processing in JSON Optimized numeric-type multiplication Optimized numeric-type division ANALYZE ONLY and VACUUM ONLY Improved checkpointer statistics pg_stat_statements: normalization of SET commands postgres_fdw_get_connections and remote connection status file_fdw: ignore format conversion errors New function has_largeobject_privilege Functions crc32 and crc32c Client-server protocol: report search_path changes to the client psql: support for named prepared statements pg_verifybackup: integrity verification for tar backups

This article is the first in the series about the upcoming PostgreSQL 18 release. Let us take a look at the features introduced in the July CommitFest. Planner: Hash Right Semi Join support Planner: materializing an internal row set for parallel nested loop join Planner support functions for generate_series EXPLAIN (analyze): statistics for Parallel Bitmap Heap Scan node workers Functions min and max for composite types Parameter names for regexp* functions Debug mode in pgbench pg_get_backend_memory_contexts: column path instead of parent , new column type Function pg_get_acl pg_upgrade: pg_dump optimization Predefined role pg_signal_autovacuum_worker

Since the PostgreSQL 17 RC1 came out, we are on a home run towards the official PostgreSQL release, scheduled for September 26, 2024. Letʼs take a look at the patches that came in during the March CommitFest. Previous articles about PostgreSQL 17 CommitFests: 2023-07 , 2023-09 , 2023-11 , 2024-01 . Together, these give an idea of what the new PostgreSQL will look like. Reverts after code freeze Unfortunately, some previously accepted patches didn't make it in after all. Some of the notable ones: ALTER TABLE... MERGE/SPLIT PARTITION (revert: 3890d90c ) Temporal primary, unique and foreign keys (revert: 8aee330a ) Planner: remove redundant self-joins (revert: d1d286d8 ) pg_constraint: NOT NULL constraints (revert: 16f8bb7c1 ) Now, letʼs get to the new stuff. SQL commands New features of the MERGE command COPY ... FROM: messages about discarded rows The SQL/JSON standard support Performance SLRU cache configuration Planner: Merge Append for the UNION implementation Planner: materialized CTE statistics (continued) Optimization of parallel plans with DISTINCT Optimizing B-tree scans for sets of values VACUUM: new dead tuples storage VACUUM: combine WAL records for vacuuming and freezing Functions with subtransactions in parallel processes Monitoring and management EXPLAIN (analyze, serialize): data conversion costs EXPLAIN: improved display of SubPlan and InitPlan nodes pg_buffercache: eviction from cache Server random: a random number in the specified range transaction_timeout: session termination when the transaction timeout is reached Prohibit the use of ALTER SYSTEM The MAINTAIN privilege and the pg_maintain predefined role Built-in locale provider for C.UTF8 pg_column_toast_chunk_id: ID of the TOAST value pg_basetype function: basic domain type pg_constraint: NOT NULL restrictions for domains New function to_regtypemod Hash indexes for ltree Replication pg_createsubscriber: quickly create a logical replica from a physical one Logical slots: tracking the causes of replication conflicts pg_basebackup -R: dbname in primary_conninfo Synchronization of logical replication slots between the primary server and replicas Logical decoding optimization for subtransactions Client applications libpq: non-locking query cancellation libpq: direct connection via TLS vvacuumdb, clusterdb, reindexdb: processing individual objects in multiple databases reindexdb: --jobs and --index at the same time psql: new implementation of FETCH_COUNT pg_dump --exclude-extension Backup and restore large objects

Spring is in full swing as we bring you the hottest winter news of the January Commitfest. Let’s get to the good stuff right away! Previous articles about PostgreSQL 17: 2023-07 , 2023-09 , 2023-11 . Incremental backup Logical replication: maintaining the subscription status when upgrading the subscriber server Dynamic shared memory registry EXPLAIN (memory): report memory usage for planning pg_stat_checkpointer: restartpoint monitoring on replicas Building BRIN indexes in parallel mode Queries with the IS [NOT] NULL condition for NOT NULL columns Optimization of SET search_path GROUP BY optimization Support planner functions for range types PL/pgSQL: %TYPE and %ROWTYPE arrays Jsonpath: new data conversion methods COPY ... FROM: ignoring format conversion errors to_timestamp: format codes TZ and OF GENERATED AS IDENTITY in partitioned tables ALTER COLUMN ... SET EXPRESSION

The conference gathered about 100 people, including PostgreSQL developers, DBA and customers from all over the world.