Each index access method is described by a row in the pg_am system catalog. The pg_am entry specifies a name and a handler function for the access method. These entries can be created and deleted using the CREATE ACCESS METHOD and DROP ACCESS METHOD SQL commands. An index access method handler function must be declared to accept a single argument of type internal and to return the pseudo-type index_am_handler. The argument is a dummy value that simply serves to prevent handler functions from be

NameSET -- change a run-time parameter Synopsis SET [ SESSION | LOCAL ] configuration_parameter { TO | = } { value | 'value' | DEFAULT } SET [ SESSION | LOCAL ] TIME ZONE { timezone | LOCAL | DEFAULT } Description The SET command changes run-time configuration parameters. Many of the run-time parameters listed in Chapter 19 can be changed on-the-fly with SET. (But some require superuser privileges to change, and others cannot be changed after server or session start.) SET only affects

unaccent is a text search dictionary that removes accents (diacritic signs) from lexemes. It's a filtering dictionary, which means its output is always passed to the next dictionary (if any), unlike the normal behavior of dictionaries. This allows accent-insensitive processing for full text search. The current implementation of unaccent cannot be used as a normalizing dictionary for the thesaurus dictionary. F.44.1. Configuration An unaccent dictionary accepts the following options: RULES is

NameCREATE CAST -- define a new cast Synopsis CREATE CAST (source_type AS target_type) WITH FUNCTION function_name (argument_type [, ...]) [ AS ASSIGNMENT | AS IMPLICIT ] CREATE CAST (source_type AS target_type) WITHOUT FUNCTION [ AS ASSIGNMENT | AS IMPLICIT ] CREATE CAST (source_type AS target_type) WITH INOUT [ AS ASSIGNMENT | AS IMPLICIT ] Description CREATE CAST defines a new cast. A cast specifies how to perform a conversion between two data types. For e

Table 9-39, Table 9-40 and Table 9-41 summarize the functions and operators that are provided for full text searching. See Chapter 12 for a detailed explanation of PostgreSQL's text search facility. Table 9-39. Text Search Operators Operator Return Type Description Example Result @@ boolean tsvector matches tsquery ? to_tsvector('fat cats ate rats') @@ to_tsquery('cat & rat') t @@@ boolean deprecated synonym for @@ to_tsvector('fat cats ate rats') @@@ to_tsquery('cat & rat') t || ts

In addition to the system catalogs, PostgreSQL provides a number of built-in views. Some system views provide convenient access to some commonly used queries on the system catalogs. Other views provide access to internal server state. The information schema (Chapter 35) provides an alternative set of views which overlap the functionality of the system views. Since the information schema is SQL-standard whereas the views described here are PostgreSQL-specific, it's usually better to use the info

If the primary server fails then the standby server should begin failover procedures. If the standby server fails then no failover need take place. If the standby server can be restarted, even some time later, then the recovery process can also be restarted immediately, taking advantage of restartable recovery. If the standby server cannot be restarted, then a full new standby server instance should be created. If the primary server fails and the standby server becomes the new primary, and then

19.8.1. Where To Log log_destination (string) PostgreSQL supports several methods for logging server messages, including stderr, csvlog and syslog. On Windows, eventlog is also supported. Set this parameter to a list of desired log destinations separated by commas. The default is to log to stderr only. This parameter can only be set in the postgresql.conf file or on the server command line. If csvlog is included in log_destination, log entries are output in "comma separated value" (CSV) for

Before you can do anything, you must initialize a database storage area on disk. We call this a database cluster. (The SQL standard uses the term catalog cluster.) A database cluster is a collection of databases that is managed by a single instance of a running database server. After initialization, a database cluster will contain a database named postgres, which is meant as a default database for use by utilities, users and third party applications. The database server itself does not require

See Section 8.17 for an overview of range types. Table 9-49 shows the operators available for range types. Table 9-49. Range Operators Operator Description Example Result = equal int4range(1,5) = '[1,4]'::int4range t <> not equal numrange(1.1,2.2) <> numrange(1.1,2.3) t < less than int4range(1,10) < int4range(2,3) t > greater than int4range(1,10) > int4range(1,5) t <= less than or equal numrange(1.1,2.2) <= numrange(1.1,2.2) t >= greater than or equal numrange