postgres

name

postgres

description

Comprehensive PostgreSQL reference for developers and DBAs covering versions 14–18. Use whenever the user asks about PostgreSQL syntax, DDL/DML/DQL, joins, LATERAL, CTEs, window functions, GROUPING SETS, DISTINCT ON, RETURNING, ON CONFLICT, PL/pgSQL, functions, procedures, triggers, views, materialized views, indexes (B-tree/GIN/GiST/BRIN/Hash/Bloom), MVCC, VACUUM, autovacuum, WAL, TOAST, partitioning, replication (streaming/logical), backup, PITR, HA (Patroni/repmgr), pgBouncer, EXPLAIN ANALYZE, RLS, roles, extensions (pgvector, PostGIS, TimescaleDB, Citus, pg_trgm, pg_cron), JSON/JSONB, full-text search, UUID, timestamptz, COPY, system catalogs, collations, large objects, cursors, GUC, or any Postgres administration, performance, security, replication, backup, or recovery topic.

PostgreSQL Skill

This skill is the working reference for PostgreSQL 16, 17, and 18 (current baseline: PG16). Cross-version notes go back to PG14 where behavior changed; PG13 and earlier are end-of-life and out of scope. PG14 reaches end-of-life on 2026-11-12 — flag upgrade urgency when a user is on it.

The skill is provider-neutral: bare-metal/self-hosted, containers, and Kubernetes operators are all covered. Managed-service limitations are called out categorically ("most managed providers disable X") without naming or recommending any specific vendor.

Each topic lives in its own reference file under references/. SKILL.md routes a user question to the right reference; the reference contains the executable detail, version admonitions, and primary-source citations.

Usage Workflow

When this skill is loaded, follow these steps to answer the user's question:

1. Identify the topic. Match the user's question against the Routing Table below using the keyword column. For multi-topic questions (e.g. "the locking behavior of REINDEX CONCURRENTLY") select multiple files.
2. Load the matched reference file(s). Use the Read tool against references/NN-topic.md. Do not paraphrase from memory — the reference holds the authoritative version notes and source URLs.
3. Follow See Also. Each reference ends with a See Also section linking related files. Follow it for cross-cutting questions (e.g. a VACUUM question pulls in MVCC, autovacuum, and wraparound).
4. Answer using the file. Lead with the direct answer or code, then version notes via admonitions, then caveats, then citation URLs.
5. Never answer from memory alone when a reference file exists for the topic. The references are the source of truth for this skill; the model's training data is not version-specific enough.
6. Assume PG16 unless told otherwise. If the user does not state a version, answer for PG16 and add a one-line note for differences on PG17/PG18. Only ask the user which version they are on if the answer materially changes across supported versions (e.g. wraparound mechanics, planner statistics behavior, archive_command vs archive_library).

[!NOTE] When a Postgres question does not obviously match a single file, load these cross-cutting entry points first: references/102-skill-cookbook.md (symptom-driven recipes spanning multiple files), references/22-indexes-overview.md (index decision routing), references/56-explain.md (plan reading), references/64-system-catalogs.md (catalog introspection).

User Response Format

Structure every answer using this skill as follows:

• Lead with the direct answer or pattern. If a SQL snippet or psql command satisfies the question, put that first.
• Add version admonitions inline. Use > [!NOTE] PostgreSQL 17 for new-in-17 features, > [!WARNING] Removed/Deprecated for things gone (with the version they were removed in and the replacement).
• Call out managed-service limitations categorically when relevant. Phrase as "most managed providers disable X" — never name a specific provider.
• End with source links. Cite the official PostgreSQL docs pinned to the correct major version (e.g. https://www.postgresql.org/docs/16/sql-vacuum.html, not /docs/current/).
• For longer answers, use headers matching the reference file's section headings so the user can jump to the source.
• For version-sensitive answers, default to PG16 + add inline > [!NOTE] PG17 / > [!NOTE] PG18 deltas. Only ask the user to confirm version when the answer flips between supported majors.
• For any performance investigation document or slow-query guide, always include an explicit section explaining how to read EXPLAIN plans bottom-up: start at the deepest-indented leaf node (scans execute first), work upward through parents (joins, sorts, aggregates), reach the root last. Identify the first node where actual rows diverges 10× or more from estimated rows — that is the misestimate source; everything above it operates on bad cardinality.

Routing Table

Keywords are matched case-insensitively. A single file can match multiple keyword phrases.

Keywords	File	Scope
CREATE TABLE, ALTER TABLE, DROP TABLE, schema, sequence, generated column, identity column, IF NOT EXISTS	references/01-syntax-ddl.md	DDL syntax reference
SELECT, JOIN, LATERAL, subquery, UNION, INTERSECT, EXCEPT, DISTINCT ON, LIMIT, OFFSET, FETCH FIRST	references/02-syntax-dql.md	Query (DQL) reference
INSERT, UPDATE, DELETE, RETURNING, ON CONFLICT, upsert, MERGE, DEFAULT VALUES	references/03-syntax-dml.md	DML reference
WITH, CTE, recursive CTE, WITH RECURSIVE, MATERIALIZED, modifying CTE	references/04-ctes.md	Common Table Expressions
view, CREATE VIEW, updatable view, INSTEAD OF, security_barrier, security_invoker, materialized view, REFRESH MATERIALIZED VIEW CONCURRENTLY	references/05-views.md	Views and materialized views
CREATE FUNCTION, LANGUAGE, IMMUTABLE, STABLE, VOLATILE, PARALLEL SAFE, SECURITY DEFINER, RETURNS TABLE, polymorphic	references/06-functions.md	Functions
CREATE PROCEDURE, CALL, transaction control in procedure, COMMIT in procedure	references/07-procedures.md	Procedures
PL/pgSQL, plpgsql, DECLARE, BEGIN, EXCEPTION, RAISE, FOR LOOP, cursor in plpgsql, GET STACKED DIAGNOSTICS	references/08-plpgsql.md	PL/pgSQL deep dive
plpython3u, plperl, plperlu, pltcl, plv8, procedural language, untrusted PL	references/09-procedural-languages.md	Non-pgSQL procedural languages
EXECUTE, dynamic SQL, format(), quote_ident, quote_literal, SQL injection in plpgsql	references/10-dynamic-sql.md	Dynamic SQL
OVER, PARTITION BY, window function, ROWS BETWEEN, RANGE BETWEEN, GROUPS, LAG, LEAD, FIRST_VALUE, LAST_VALUE, NTH_VALUE, RANK, DENSE_RANK, ROW_NUMBER, NTILE	references/11-window-functions.md	Window functions
aggregate, FILTER, GROUPING SETS, ROLLUP, CUBE, percentile_cont, percentile_disc, ordered-set aggregate, CREATE AGGREGATE	references/12-aggregates-grouping.md	Aggregates & grouping
DECLARE CURSOR, FETCH, MOVE, WITH HOLD, scrollable cursor, refcursor, PREPARE, EXECUTE, DEALLOCATE, plan_cache_mode	references/13-cursors-and-prepares.md	Cursors & prepared statements
text, varchar, char, numeric, decimal, real, double precision, integer, boolean, bytea, inet, cidr, macaddr, bit, varbit	references/14-data-types-builtin.md	Built-in types
CREATE TYPE, composite type, CREATE DOMAIN, ENUM, ALTER TYPE ADD VALUE, range type, multirange	references/15-data-types-custom.md	Custom types (composite/domain/enum/range)
array, ARRAY[], unnest, array_agg, array_position, ANY, ALL, GIN on array	references/16-arrays.md	Arrays
JSON, JSONB, ->, ->>, #>, #>>, @>, jsonb_set, jsonb_insert, jsonb_path_query, jsonpath, JSON_TABLE, jsonb_ops, jsonb_path_ops	references/17-json-jsonb.md	JSON / JSONB
uuid, gen_random_uuid, uuidv7, uuid-ossp, NUMERIC precision, money, serial, bigserial, IDENTITY column	references/18-uuid-numeric-money.md	UUID, numeric, money, identity
timestamp, timestamptz, AT TIME ZONE, interval, date_trunc, date_part, timezone, DST, infinity timestamp	references/19-timestamp-timezones.md	Timestamps & time zones
tsvector, tsquery, to_tsvector, to_tsquery, plainto_tsquery, phraseto_tsquery, websearch_to_tsquery, ts_rank, ts_headline, FTS, full-text search	references/20-text-search.md	Full-text search
hstore	references/21-hstore.md	hstore extension
index decision, choose index type, multicolumn index, partial index, expression index, INCLUDE	references/22-indexes-overview.md	Index decision matrix
B-tree, btree, deduplication, bottom-up index deletion, fillfactor, INCLUDE columns, covering index	references/23-btree-indexes.md	B-tree indexes
GIN, GiST, KNN-GiST, jsonb_ops, jsonb_path_ops, EXCLUDE USING gist, fastupdate, gin_pending_list_limit	references/24-gin-gist-indexes.md	GIN & GiST indexes
BRIN, minmax_multi, bloom index, hash index, SP-GiST	references/25-brin-hash-spgist-bloom-indexes.md	BRIN, hash, SP-GiST, bloom
CREATE INDEX CONCURRENTLY, REINDEX CONCURRENTLY, INVALID index, pg_repack, pg_squeeze, index bloat	references/26-index-maintenance.md	Index maintenance
MVCC, xmin, xmax, cmin, cmax, infomask, tuple visibility, snapshot, xip, MultiXact	references/27-mvcc-internals.md	MVCC internals
VACUUM, autovacuum, VACUUM FULL, VACUUM FREEZE, autovacuum_vacuum_scale_factor, pg_stat_progress_vacuum, visibility map, parallel vacuum	references/28-vacuum-autovacuum.md	VACUUM & autovacuum
transaction id wraparound, XID wraparound, datfrozenxid, autovacuum_freeze_max_age, MultiXact wraparound, 64-bit XID	references/29-transaction-id-wraparound.md	TXID wraparound
HOT update, heap-only tuple, n_tup_hot_upd, HOT chain	references/30-hot-updates.md	HOT updates
TOAST, oversized attribute, storage strategy, PLAIN, EXTENDED, EXTERNAL, MAIN, pglz, lz4 compression	references/31-toast.md	TOAST
shared_buffers, buffer manager, clock sweep, bgwriter, pg_buffercache, ring buffer	references/32-buffer-manager.md	Buffer manager
WAL, wal_level, full_page_writes, archive_command, archive_library, wal_compression, wal_segment_size, pg_waldump	references/33-wal.md	Write-Ahead Log
checkpoint, checkpointer, checkpoint_timeout, max_wal_size, checkpoint_completion_target, bgwriter_lru_maxpages, pg_stat_checkpointer	references/34-checkpoints-bgwriter.md	Checkpoints & bgwriter
partition, RANGE partition, LIST partition, HASH partition, partition pruning, ATTACH PARTITION, DETACH PARTITION, DEFAULT partition, partition-wise join	references/35-partitioning.md	Declarative partitioning
inheritance, INHERITS, ONLY clause	references/36-inheritance.md	Table inheritance
CHECK constraint, NOT NULL, UNIQUE, UNIQUE NULLS NOT DISTINCT, EXCLUDE constraint, NOT VALID, VALIDATE CONSTRAINT, deferrable	references/37-constraints.md	Constraints
foreign key, FOREIGN KEY, REFERENCES, ON DELETE CASCADE, ON DELETE SET NULL, deferrable FK, partitioned FK, circular FK	references/38-foreign-keys-deep.md	Foreign keys
CREATE TRIGGER, BEFORE trigger, AFTER trigger, INSTEAD OF, FOR EACH ROW, FOR EACH STATEMENT, NEW, OLD, transition table, REFERENCING NEW TABLE	references/39-triggers.md	Triggers
event trigger, CREATE EVENT TRIGGER, ddl_command_start, ddl_command_end, sql_drop, table_rewrite, pg_event_trigger_ddl_commands	references/40-event-triggers.md	Event triggers
BEGIN, COMMIT, ROLLBACK, SAVEPOINT, subtransaction, PREPARE TRANSACTION, 2PC, idle_in_transaction_session_timeout, autocommit	references/41-transactions.md	Transactions
Read Committed, Repeatable Read, Serializable, SSI, snapshot isolation, default_transaction_isolation, serialization failure, retry pattern	references/42-isolation-levels.md	Isolation levels
lock, FOR UPDATE, FOR NO KEY UPDATE, FOR SHARE, FOR KEY SHARE, NOWAIT, SKIP LOCKED, AccessExclusiveLock, RowExclusiveLock, pg_locks, pg_blocking_pids, deadlock	references/43-locking.md	Locking
advisory lock, pg_advisory_lock, pg_advisory_xact_lock, pg_try_advisory_lock	references/44-advisory-locks.md	Advisory locks
LISTEN, NOTIFY, UNLISTEN, pg_notify, notification queue	references/45-listen-notify.md	LISTEN/NOTIFY
CREATE ROLE, GRANT, REVOKE, ALTER DEFAULT PRIVILEGES, pg_read_all_data, pg_monitor, SET ROLE, REASSIGN OWNED, INHERIT, NOINHERIT, BYPASSRLS	references/46-roles-privileges.md	Roles & privileges
row-level security, RLS, CREATE POLICY, USING, WITH CHECK, FORCE ROW LEVEL SECURITY, ENABLE ROW LEVEL SECURITY	references/47-row-level-security.md	Row-Level Security
pg_hba.conf, authentication method, scram-sha-256, md5, peer, trust, ident, ldap, gss, cert auth	references/48-authentication-pg-hba.md	pg_hba.conf & auth
SSL, TLS, sslmode, verify-full, channel binding, server cert, client certificate, ssl_ciphers	references/49-tls-ssl.md	TLS/SSL
pgcrypto, encrypt, decrypt, pgp_sym_encrypt, digest, crypt, gen_salt, TDE	references/50-encryption-pgcrypto.md	pgcrypto
pgaudit, audit log, session auditing, object auditing, compliance logging	references/51-pgaudit.md	pgaudit
CREATE RULE, rule system, ON SELECT DO INSTEAD	references/52-rules-system.md	Rule system
postgresql.conf, postgresql.auto.conf, GUC, pg_settings, ALTER SYSTEM, reload, pg_reload_conf, parameter context	references/53-server-configuration.md	Configuration
shared_buffers, effective_cache_size, work_mem, hash_mem_multiplier, maintenance_work_mem, autovacuum_work_mem, temp_buffers, wal_buffers, huge_pages	references/54-memory-tuning.md	Memory tuning
ANALYZE, pg_statistic, pg_stats, default_statistics_target, extended statistics, CREATE STATISTICS, ndistinct, dependencies, MCV	references/55-statistics-planner.md	Statistics & planner input
EXPLAIN, EXPLAIN ANALYZE, EXPLAIN (BUFFERS), Seq Scan, Index Scan, Index Only Scan, Bitmap Heap Scan, Nested Loop, Hash Join, Merge Join, Memoize, Gather, Append, row estimate, plan node	references/56-explain.md	EXPLAIN deep dive
pg_stat_statements, query stats, top queries, calls, mean_exec_time, shared_blks_hit	references/57-pg-stat-statements.md	pg_stat_statements
pg_stat_activity, wait_event, pg_stat_user_tables, pg_stat_user_indexes, pg_stat_database, pg_stat_io, pg_stat_wal, pg_stat_progress_*, performance diagnostics	references/58-performance-diagnostics.md	pg_stat_* diagnostics
random_page_cost, seq_page_cost, cpu_tuple_cost, effective_io_concurrency, enable_seqscan, enable_hashjoin, join_collapse_limit, geqo, planner tuning	references/59-planner-tuning.md	Planner tuning
parallel query, max_parallel_workers, max_parallel_workers_per_gather, max_parallel_maintenance_workers, parallel append, parallel hash join, force_parallel_mode	references/60-parallel-query.md	Parallel query
JIT, jit_above_cost, jit_inline_above_cost, LLVM, just-in-time compilation	references/61-jit-compilation.md	JIT compilation
tablespace, CREATE TABLESPACE, default_tablespace, temp_tablespaces, SET TABLESPACE	references/62-tablespaces.md	Tablespaces
postmaster, backend process, autovacuum launcher, walwriter, walsender, walreceiver, archiver, bgwriter, checkpointer, logical replication worker, shared memory architecture, fork per connection	references/63-internals-architecture.md	Process & memory architecture
pg_catalog, pg_class, pg_attribute, pg_index, pg_namespace, pg_constraint, pg_proc, pg_type, pg_depend, pg_inherits, pg_partitioned_table, pg_publication, pg_subscription, pg_extension, pg_authid, pg_roles, pg_database, pg_tablespace, pg_settings, relkind, information_schema, ECHO_HIDDEN, catalog exploration	references/64-system-catalogs.md	System catalogs & exploration recipes
collation, ICU, libc, deterministic collation, nondeterministic collation, case-insensitive UNIQUE, collation version, encoding, UTF-8, client_encoding	references/65-collations-encoding.md	Collations & encoding
COPY, \copy, bulk load, CSV import, HEADER, DELIMITER, FREEZE, ON_ERROR, LOG_VERBOSITY, parallel COPY	references/66-bulk-operations-copy.md	COPY / bulk
psql, \d, \dt, \di, \df, \dn, \dx, \timing, \watch, \gexec, pg_isready, createdb, dropdb, vacuumdb, reindexdb, clusterdb	references/67-cli-tools.md	CLI tools
pgbench, benchmark, TPC-B, -c clients, -j threads, scaling factor, custom pgbench script	references/68-pgbench.md	pgbench
CREATE EXTENSION, ALTER EXTENSION UPDATE, pg_extension, trusted extension, contrib	references/69-extensions.md	Extensions overview
FDW, foreign data wrapper, CREATE FOREIGN TABLE, postgres_fdw, file_fdw, IMPORT FOREIGN SCHEMA, dblink, pushdown	references/70-fdw.md	FDW
large object, lo_create, lo_open, lo_read, lo_export, lo_import, pg_largeobject, vacuumlo, bytea vs LO	references/71-large-objects.md	Large objects
extension development, PGXS, PG_MODULE_MAGIC, PG_FUNCTION_INFO_V1, .control, hooks, C extension	references/72-extension-development.md	Extension development
streaming replication, primary_conninfo, primary_slot_name, standby.signal, recovery.signal, synchronous_standby_names, synchronous_commit, cascading replication, hot_standby_feedback	references/73-streaming-replication.md	Streaming replication
logical replication, CREATE PUBLICATION, CREATE SUBSCRIPTION, FOR ALL TABLES, FOR TABLES IN SCHEMA, row filter, column list, replication origin, DDL replication, two-phase decoding	references/74-logical-replication.md	Logical replication
replication slot, pg_create_physical_replication_slot, pg_create_logical_replication_slot, max_slot_wal_keep_size, max_replication_slots, max_wal_senders, pg_replication_slots, slot invalidation	references/75-replication-slots.md	Replication slots
logical decoding, pgoutput, wal2json, decoderbufs, test_decoding, CDC, REPLICA IDENTITY, START_REPLICATION SLOT LOGICAL	references/76-logical-decoding.md	Logical decoding
standby, hot standby, max_standby_streaming_delay, hot_standby_feedback, pg_promote, pg_rewind, timeline ID, failover, switchover	references/77-standby-failover.md	Standby & failover
HA, high availability, Patroni, repmgr, pg_auto_failover, Stolon, cluster manager, fencing, split brain, witness	references/78-ha-architectures.md	HA architectures
Patroni, patroni.yml, DCS, etcd, consul, zookeeper, REST API, /failover, /switchover, watchdog	references/79-patroni.md	Patroni
connection pool, pool sizing, transaction pool, session pool, statement pool, process-per-connection	references/80-connection-pooling.md	Connection pooling concepts
pgBouncer, pool_mode, default_pool_size, reserve_pool_size, server_idle_timeout, prepared statement pgbouncer, SHOW POOLS, SHOW STATS	references/81-pgbouncer.md	pgBouncer
monitoring, postgres_exporter, prometheus, pg_stat_*, alerting thresholds, log-based metrics	references/82-monitoring.md	Monitoring
pg_dump, pg_dumpall, pg_restore, custom format, directory format, parallel dump, --filter, --on-conflict-do-nothing	references/83-backup-pg-dump.md	Logical backup
pg_basebackup, base backup, archive_command, restore_command, recovery_target_time, recovery_target_xid, PITR, point-in-time recovery, continuous archiving	references/84-backup-physical-pitr.md	Physical backup & PITR
pgBackRest, Barman, WAL-G, incremental backup, retention policy, S3 backup	references/85-backup-tools.md	Backup tooling
pg_upgrade, --link, --clone, major upgrade, statistics preservation, preflight check	references/86-pg-upgrade.md	pg_upgrade
major version upgrade, blue-green upgrade, logical replication upgrade, near-zero downtime, catalog version	references/87-major-version-upgrade.md	Major-version upgrade strategy
corruption, data_checksums, pg_amcheck, pg_checksums, pg_resetwal, single-user mode, zero_damaged_pages	references/88-corruption-recovery.md	Corruption recovery
pg_rewind, divergent timeline, wal_log_hints, --source-server, --source-pgdata	references/89-pg-rewind.md	pg_rewind
disaster recovery, RPO, RTO, DR drill, runbook, failover bookkeeping	references/90-disaster-recovery.md	Disaster recovery
docker postgres, docker-entrypoint-initdb.d, POSTGRES_PASSWORD, healthcheck postgres container, volume PGDATA	references/91-docker-postgres.md	Docker postgres image
Kubernetes postgres, CloudNativePG, CNPG, postgres-operator, Zalando, Crunchy PGO, StatefulSet	references/92-kubernetes-operators.md	K8s operators
pg_trgm, trigram, similarity, % operator, GIN trigram, LIKE acceleration, word_similarity	references/93-pg-trgm.md	pg_trgm
pgvector, vector, embedding, HNSW, IVFFLAT, <->, <=>, <#>, halfvec, sparsevec, m, ef_construction, ef_search, lists, probes, ANN	references/94-pgvector.md	pgvector
PostGIS, geometry, geography, SRID, ST_Transform, ST_DWithin, ST_Intersects, ST_Buffer, spatial index	references/95-postgis.md	PostGIS
TimescaleDB, hypertable, continuous aggregate, compression, retention policy, chunk	references/96-timescaledb.md	TimescaleDB
Citus, distributed table, reference table, coordinator, worker, shard, colocated join, columnar storage	references/97-citus.md	Citus
pg_cron, cron.schedule, cron.job, cron.job_run_details, scheduled VACUUM, scheduled REFRESH MATERIALIZED VIEW	references/98-pg-cron.md	pg_cron
pg_partman, partman.create_parent, run_maintenance_proc, partition retention, partman.part_config, sub-partition	references/99-pg-partman.md	pg_partman
PG14, PG15, PG16, PG17, PG18, release notes, version features, support policy	references/100-pg-versions-features.md	Per-major-version feature highlights
managed Postgres, managed PaaS, hosted Postgres, bare-metal, self-hosted, superuser restriction, extension allowlist, shared_preload_libraries restriction, vendor lock-in	references/101-managed-vs-baremetal.md	Managed vs bare-metal trade-offs (provider-agnostic)
recipe, cookbook, bloat triage, slow-query investigation, deadlock investigation, replication lag investigation, PITR walkthrough, upgrade playbook, catalog exploration	references/102-skill-cookbook.md	Multi-file recipes & catalog exploration

Disambiguation Tips

Some terms route to multiple files — load both when in doubt.

Term	Primary file	Secondary file	Why
VACUUM blocking	28-vacuum-autovacuum.md	27-mvcc-internals.md, 29-transaction-id-wraparound.md	Why VACUUM exists is MVCC; what it must do is bounded by wraparound
EXPLAIN plan	56-explain.md	55-statistics-planner.md, 59-planner-tuning.md	Misestimates point to stats; tuning may need GUC changes
Index choice	22-indexes-overview.md	23-btree-indexes.md through 25-brin-hash-spgist-bloom-indexes.md	Overview routes to specifics
Deadlock	43-locking.md	42-isolation-levels.md	Predicate locks (SSI) cause different deadlocks
Replication is lagging	73-streaming-replication.md	75-replication-slots.md, 82-monitoring.md	Lag could be stream pressure or slot retention
Upgrade	86-pg-upgrade.md	87-major-version-upgrade.md	pg_upgrade is one strategy; the other file covers blue/green and logical-repl-based upgrades
JSON column performance	17-json-jsonb.md	24-gin-gist-indexes.md	JSONB indexing happens via GIN
Full-text search ranking	20-text-search.md	24-gin-gist-indexes.md	FTS uses GIN
Bulk load slow	66-bulk-operations-copy.md	33-wal.md, 28-vacuum-autovacuum.md	WAL volume and post-load vacuum dominate
Catalog exploration / inspection	64-system-catalogs.md	102-skill-cookbook.md	The cookbook has runnable recipes
shared_buffers	32-buffer-manager.md	54-memory-tuning.md	Mechanics live in 32; sizing guidance lives in 54
work_mem / hash_mem_multiplier	54-memory-tuning.md	59-planner-tuning.md, 56-explain.md	Sizing in 54; planner cost interaction in 59; spill-to-disk diagnosis in 56
archive_command / archive_library	33-wal.md	84-backup-physical-pitr.md, 85-backup-tools.md	WAL-level mechanics in 33; PITR consumer side in 84; pgBackRest/Barman/WAL-G in 85
wal_level	33-wal.md	74-logical-replication.md, 76-logical-decoding.md	Setting + implications in 33; logical consumers in 74/76
pg_basebackup	84-backup-physical-pitr.md	89-pg-rewind.md, 73-streaming-replication.md	Base backup in 84; rebuild-after-divergence alternative in 89; standby provisioning in 73
Partition rotation / retention	35-partitioning.md	99-pg-partman.md, 98-pg-cron.md	Native partitioning in 35; lifecycle automation in 99; scheduling in 98
Slow query	56-explain.md	57-pg-stat-statements.md, 58-performance-diagnostics.md, 55-statistics-planner.md, 102-skill-cookbook.md	Workload-wide via 57; plan via 56; misestimate root cause in 55; full investigation walk in 102
Connection storm / too many connections	80-connection-pooling.md	81-pgbouncer.md, 63-internals-architecture.md, 46-roles-privileges.md	Pooling concepts in 80; pgBouncer config in 81; fork-per-connection cost in 63; per-role connection limits in 46
Failover / promote	77-standby-failover.md	78-ha-architectures.md, 79-patroni.md, 89-pg-rewind.md	Manual mechanics in 77; cluster-manager landscape in 78; Patroni-specific in 79; rejoin-old-primary in 89

Versioning & Provider Neutrality

• Target compatibility baseline: every SQL example must run on PostgreSQL 16 unless explicitly marked otherwise.
• Version-pin docs URLs. Cite https://www.postgresql.org/docs/16/..., not /docs/current/. The current alias moves with each annual release.
• Provider neutrality is mandatory. Never recommend a managed provider over another. When discussing managed-service limitations, phrase categorically ("most managed providers disable untrusted PLs"), not by name.

Sources

Primary documentation roots (re-fetch before citing in any reference file; version-pin URLs to the matching major):

• PostgreSQL 14 manual (cross-version notes only): https://www.postgresql.org/docs/14/index.html
• PostgreSQL 15 manual (cross-version notes only): https://www.postgresql.org/docs/15/index.html
• PostgreSQL 16 manual (default baseline): https://www.postgresql.org/docs/16/index.html
• PostgreSQL 17 manual: https://www.postgresql.org/docs/17/index.html
• PostgreSQL 18 manual: https://www.postgresql.org/docs/18/index.html
• Per-version release notes: https://www.postgresql.org/docs/release/
• Versioning + support policy: https://www.postgresql.org/support/versioning/
• PostgreSQL Wiki: https://wiki.postgresql.org/
• Source code mirror: https://github.com/postgres/postgres