|PostgreSQL Reference Manual - Volume 3 - Server Administration Guide|
by The PostgreSQL Global Development Group
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4.10.1 Statement Behavior
This variable specifies the order in which schemas are searched
when an object (table, data type, function, etc.) is referenced by a
simple name with no schema component. When there are objects of
identical names in different schemas, the one found first
in the search path is used. An object that is not in any of the
schemas in the search path can only be referenced by specifying
its containing schema with a qualified (dotted) name.
The value for
search_pathhas to be a comma-separated list of schema names. If one of the list items is the special value
$user, then the schema having the name returned by
SESSION_USERis substituted, if there is such a schema. (If not,
$useris ignored.) The system catalog schema,
pg_catalog, is always searched, whether it is mentioned in the path or not. If it is mentioned in the path then it will be searched in the specified order. If
pg_catalogis not in the path then it will be searched before searching any of the path items. It should also be noted that the temporary-table schema,
pg_temp_nnn, is implicitly searched before any of these. When objects are created without specifying a particular target schema, they will be placed in the first schema listed in the search path. An error is reported if the search path is empty. The default value for this parameter is
'"$user", public'(where the second part will be ignored if there is no schema named
public). This supports shared use of a database (where no users have private schemas, and all share use of
public), private per-user schemas, and combinations of these. Other effects can be obtained by altering the default search path setting, either globally or per-user. The current effective value of the search path can be examined via the SQL function
current_schemas(). This is not quite the same as examining the value of
current_schemas()shows how the requests appearing in
search_pathwere resolved. For more information on schema handling, see Volume 1: Schemas.
This variable specifies the default tablespace in which to create
objects (tables and indexes) when a
CREATEcommand does not explicitly specify a tablespace. The value is either the name of a tablespace, or an empty string to specify using the default tablespace of the current database. If the value does not match the name of any existing tablespace, PostgreSQL will automatically use the default tablespace of the current database. For more information on tablespaces, see section 6.6 Tablespaces.
This parameter is normally on. When set to
off, it disables validation of the function body string during
CREATE FUNCTION. Disabling validation is occasionally useful to avoid problems such as forward references when restoring function definitions from a dump.
Each SQL transaction has an isolation level, which can be
either “read uncommitted”, “read
committed”, “repeatable read”, or
“serializable”. This parameter controls the
default isolation level of each new transaction. The default
is “read committed”.
Consult Volume 1: Concurrency Control and
SET TRANSACTIONfor more information.
A read-only SQL transaction cannot alter non-temporary tables.
This parameter controls the default read-only status of each new
transaction. The default is
SET TRANSACTIONfor more information.
Abort any statement that takes over the specified number of
milliseconds, starting from the time the command arrives at the server
from the client. If
log_min_error_statementis set to
ERRORor lower, the statement that timed out will also be logged. A value of zero (the default) turns off the limitation.
Specifies the cutoff age (in transactions) that
VACUUMshould use to decide whether to replace transaction IDs with
FrozenXIDwhile scanning a table. The default is 100 million transactions. Although users can set this value anywhere from zero to one billion,
VACUUMwill silently limit the effective value to half the value of
autovacuum_freeze_max_age, so that there is not an unreasonably short time between forced autovacuums. For more information see section 9.1.3 Preventing transaction ID wraparound failures.
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