Manual In my system (Arch Linux), the file is /var/lib/postgres/data/postgresql.conf.
FILE LOCATIONS data_directory = /var/lib/postgres/data hba_file = /var/lib/postgres/data/pg_hba.conf ident_file = /var/lib/postgres/data/pg_ident.conf external_pid_file = '' CONNECTIONS AND AUTHENTICATION RESOURCE USAGE (except WAL) shared_buffers = 128MB Resource Usage The default shared_buffers = 128MB should be raised to between 15% and 25% of available RAM according to How to tune PostgreSQL for memory
Logging Reporting deadlocks and resource exhaustion. — PostgreSQL Logging
The defaults are:
Postgresql uses WITH RECURSIVE to traverse graphs stored as databases.
UNION ALL vs UNION The result of UNION does not contain any duplicate rows unless the ALL option is specified. ALL prevents elimination of duplicates. (Therefore, UNION ALL is usually significantly quicker than UNION; use ALL when you can.) DISTINCT can be written to explicitly specify the default behavior of eliminating duplicate rows. — UNION Clause
Sometimes, using UNION instead of UNION ALL can accomplish this by discarding rows that duplicate previous output rows.
The CAST syntax conforms to SQL; the syntax with :: is historical PostgreSQL usage. — Type Casts
manual
Numeric Monetary Character Binary Date/Time Boolean AND, OR, NOT Comparison Enumerated Geometric Network Address Bit String Text Search UUID XML JSON Functions Arrays Composite Range Domain Object Identifier pg_lsn Pseudo
CREATE OR REPLACE FUNCTION My Style RETURN vs OUT parameters Postgresql functions can either be written
CREATE OR REPLACE FUNCTION add(a integer, b integer) RETURNS integer LANGUAGE plpgsql AS $code$ BEGIN RETURN a + b; END; $code$; Alternatively, it can be written in a more Prologish style with parameters labeled IN or OUT (or INOUT).
CREATE OR REPLACE FUNCTION add(IN a integer, IN b integer, OUT c integer) LANGUAGE plpgsql AS $code$ BEGIN c = a + b; END; $code$; Since most of the functions for my project involve message broker patterns message_broker(IN json_in JSONB, OUT json_out JSONB), I find the Prologish style better.