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CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="RUNTIME-CONFIG-CLIENT"
>18.11. Client Connection Defaults</A
></H1
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="RUNTIME-CONFIG-CLIENT-STATEMENT"
>18.11.1. Statement Behavior</A
></H2
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><A
NAME="GUC-SEARCH-PATH"
></A
><TT
CLASS="VARNAME"
>search_path</TT
> (<TT
CLASS="TYPE"
>string</TT
>)
</DT
><DD
><P
> 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 specified. 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.
</P
><P
> The value for <TT
CLASS="VARNAME"
>search_path</TT
> must be a comma-separated
list of schema names. Any name that is not an existing schema, or is
a schema for which the user does not have <TT
CLASS="LITERAL"
>USAGE</TT
>
permission, is silently ignored.
</P
><P
> If one of the list items is the special name
<TT
CLASS="LITERAL"
>$user</TT
>, then the schema having the name returned by
<CODE
CLASS="FUNCTION"
>SESSION_USER</CODE
> is substituted, if there is such a schema
and the user has <TT
CLASS="LITERAL"
>USAGE</TT
> permission for it.
(If not, <TT
CLASS="LITERAL"
>$user</TT
> is ignored.)
</P
><P
> The system catalog schema, <TT
CLASS="LITERAL"
>pg_catalog</TT
>, 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 <TT
CLASS="LITERAL"
>pg_catalog</TT
> is not in the path then it will
be searched <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>before</I
></SPAN
> searching any of the path items.
</P
><P
> Likewise, the current session's temporary-table schema,
<TT
CLASS="LITERAL"
>pg_temp_<TT
CLASS="REPLACEABLE"
><I
>nnn</I
></TT
></TT
>, is always searched if it
exists. It can be explicitly listed in the path by using the
alias <TT
CLASS="LITERAL"
>pg_temp</TT
>. If it is not listed in the path then
it is searched first (even before <TT
CLASS="LITERAL"
>pg_catalog</TT
>). However,
the temporary schema is only searched for relation (table, view,
sequence, etc) and data type names. It is never searched for
function or operator names.
</P
><P
> When objects are created without specifying a particular target
schema, they will be placed in the first valid schema named in
<TT
CLASS="VARNAME"
>search_path</TT
>. An error is reported if the search
path is empty.
</P
><P
> The default value for this parameter is
<TT
CLASS="LITERAL"
>"$user", public</TT
>.
This setting supports shared use of a database (where no users
have private schemas, and all share use of <TT
CLASS="LITERAL"
>public</TT
>),
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.
</P
><P
> The current effective value of the search path can be examined
via the <ACRONYM
CLASS="ACRONYM"
>SQL</ACRONYM
> function
<CODE
CLASS="FUNCTION"
>current_schemas</CODE
>
(see <A
HREF="functions-info.html"
>Section 9.25</A
>).
This is not quite the same as
examining the value of <TT
CLASS="VARNAME"
>search_path</TT
>, since
<CODE
CLASS="FUNCTION"
>current_schemas</CODE
> shows how the items
appearing in <TT
CLASS="VARNAME"
>search_path</TT
> were resolved.
</P
><P
> For more information on schema handling, see <A
HREF="ddl-schemas.html"
>Section 5.7</A
>.
</P
></DD
><DT
><A
NAME="GUC-DEFAULT-TABLESPACE"
></A
><TT
CLASS="VARNAME"
>default_tablespace</TT
> (<TT
CLASS="TYPE"
>string</TT
>)
</DT
><DD
><P
> This variable specifies the default tablespace in which to create
objects (tables and indexes) when a <TT
CLASS="COMMAND"
>CREATE</TT
> command does
not explicitly specify a tablespace.
</P
><P
> 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,
<SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> will automatically use the default
tablespace of the current database. If a nondefault tablespace
is specified, the user must have <TT
CLASS="LITERAL"
>CREATE</TT
> privilege
for it, or creation attempts will fail.
</P
><P
> This variable is not used for temporary tables; for them,
<A
HREF="runtime-config-client.html#GUC-TEMP-TABLESPACES"
>temp_tablespaces</A
> is consulted instead.
</P
><P
> This variable is also not used when creating databases.
By default, a new database inherits its tablespace setting from
the template database it is copied from.
</P
><P
> For more information on tablespaces,
see <A
HREF="manage-ag-tablespaces.html"
>Section 21.6</A
>.
</P
></DD
><DT
><A
NAME="GUC-TEMP-TABLESPACES"
></A
><TT
CLASS="VARNAME"
>temp_tablespaces</TT
> (<TT
CLASS="TYPE"
>string</TT
>)
</DT
><DD
><P
> This variable specifies tablespaces in which to create temporary
objects (temp tables and indexes on temp tables) when a
<TT
CLASS="COMMAND"
>CREATE</TT
> command does not explicitly specify a tablespace.
Temporary files for purposes such as sorting large data sets
are also created in these tablespaces.
</P
><P
> The value is a list of names of tablespaces. When there is more than
one name in the list, <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> chooses a random
member of the list each time a temporary object is to be created;
except that within a transaction, successively created temporary
objects are placed in successive tablespaces from the list.
If the selected element of the list is an empty string,
<SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> will automatically use the default
tablespace of the current database instead.
</P
><P
> When <TT
CLASS="VARNAME"
>temp_tablespaces</TT
> is set interactively, specifying a
nonexistent tablespace is an error, as is specifying a tablespace for
which the user does not have <TT
CLASS="LITERAL"
>CREATE</TT
> privilege. However,
when using a previously set value, nonexistent tablespaces are
ignored, as are tablespaces for which the user lacks
<TT
CLASS="LITERAL"
>CREATE</TT
> privilege. In particular, this rule applies when
using a value set in <TT
CLASS="FILENAME"
>postgresql.conf</TT
>.
</P
><P
> The default value is an empty string, which results in all temporary
objects being created in the default tablespace of the current
database.
</P
><P
> See also <A
HREF="runtime-config-client.html#GUC-DEFAULT-TABLESPACE"
>default_tablespace</A
>.
</P
></DD
><DT
><A
NAME="GUC-CHECK-FUNCTION-BODIES"
></A
><TT
CLASS="VARNAME"
>check_function_bodies</TT
> (<TT
CLASS="TYPE"
>boolean</TT
>)
</DT
><DD
><P
> This parameter is normally on. When set to <TT
CLASS="LITERAL"
>off</TT
>, it
disables validation of the function body string during <A
HREF="sql-createfunction.html"
>CREATE FUNCTION</A
>. Disabling validation avoids side
effects of the validation process and avoids false positives due
to problems such as forward references. Set this parameter
to <TT
CLASS="LITERAL"
>off</TT
> before loading functions on behalf of other
users; <SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
> does so automatically.
</P
></DD
><DT
><A
NAME="GUC-DEFAULT-TRANSACTION-ISOLATION"
></A
><TT
CLASS="VARNAME"
>default_transaction_isolation</TT
> (<TT
CLASS="TYPE"
>enum</TT
>)
</DT
><DD
><P
> Each SQL transaction has an isolation level, which can be
either <SPAN
CLASS="QUOTE"
>"read uncommitted"</SPAN
>, <SPAN
CLASS="QUOTE"
>"read
committed"</SPAN
>, <SPAN
CLASS="QUOTE"
>"repeatable read"</SPAN
>, or
<SPAN
CLASS="QUOTE"
>"serializable"</SPAN
>. This parameter controls the
default isolation level of each new transaction. The default
is <SPAN
CLASS="QUOTE"
>"read committed"</SPAN
>.
</P
><P
> Consult <A
HREF="mvcc.html"
>Chapter 13</A
> and <A
HREF="sql-set-transaction.html"
>SET TRANSACTION</A
> for more information.
</P
></DD
><DT
><A
NAME="GUC-DEFAULT-TRANSACTION-READ-ONLY"
></A
><TT
CLASS="VARNAME"
>default_transaction_read_only</TT
> (<TT
CLASS="TYPE"
>boolean</TT
>)
</DT
><DD
><P
> 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 <TT
CLASS="LITERAL"
>off</TT
> (read/write).
</P
><P
> Consult <A
HREF="sql-set-transaction.html"
>SET TRANSACTION</A
> for more information.
</P
></DD
><DT
><A
NAME="GUC-DEFAULT-TRANSACTION-DEFERRABLE"
></A
><TT
CLASS="VARNAME"
>default_transaction_deferrable</TT
> (<TT
CLASS="TYPE"
>boolean</TT
>)
</DT
><DD
><P
> When running at the <TT
CLASS="LITERAL"
>serializable</TT
> isolation level,
a deferrable read-only SQL transaction may be delayed before
it is allowed to proceed. However, once it begins executing
it does not incur any of the overhead required to ensure
serializability; so serialization code will have no reason to
force it to abort because of concurrent updates, making this
option suitable for long-running read-only transactions.
</P
><P
> This parameter controls the default deferrable status of each
new transaction. It currently has no effect on read-write
transactions or those operating at isolation levels lower
than <TT
CLASS="LITERAL"
>serializable</TT
>. The default is <TT
CLASS="LITERAL"
>off</TT
>.
</P
><P
> Consult <A
HREF="sql-set-transaction.html"
>SET TRANSACTION</A
> for more information.
</P
></DD
><DT
><A
NAME="GUC-SESSION-REPLICATION-ROLE"
></A
><TT
CLASS="VARNAME"
>session_replication_role</TT
> (<TT
CLASS="TYPE"
>enum</TT
>)
</DT
><DD
><P
> Controls firing of replication-related triggers and rules for the
current session. Setting this variable requires
superuser privilege and results in discarding any previously cached
query plans. Possible values are <TT
CLASS="LITERAL"
>origin</TT
> (the default),
<TT
CLASS="LITERAL"
>replica</TT
> and <TT
CLASS="LITERAL"
>local</TT
>.
See <A
HREF="sql-altertable.html"
>ALTER TABLE</A
> for
more information.
</P
></DD
><DT
><A
NAME="GUC-STATEMENT-TIMEOUT"
></A
><TT
CLASS="VARNAME"
>statement_timeout</TT
> (<TT
CLASS="TYPE"
>integer</TT
>)
</DT
><DD
><P
> Abort any statement that takes more than the specified number of
milliseconds, starting from the time the command arrives at the server
from the client. If <TT
CLASS="VARNAME"
>log_min_error_statement</TT
> is set to
<TT
CLASS="LITERAL"
>ERROR</TT
> or lower, the statement that timed out will also be
logged. A value of zero (the default) turns this off.
</P
><P
> Setting <TT
CLASS="VARNAME"
>statement_timeout</TT
> in
<TT
CLASS="FILENAME"
>postgresql.conf</TT
> is not recommended because it would
affect all sessions.
</P
></DD
><DT
><A
NAME="GUC-LOCK-TIMEOUT"
></A
><TT
CLASS="VARNAME"
>lock_timeout</TT
> (<TT
CLASS="TYPE"
>integer</TT
>)
</DT
><DD
><P
> Abort any statement that waits longer than the specified number of
milliseconds while attempting to acquire a lock on a table, index,
row, or other database object. The time limit applies separately to
each lock acquisition attempt. The limit applies both to explicit
locking requests (such as <TT
CLASS="COMMAND"
>LOCK TABLE</TT
>, or <TT
CLASS="COMMAND"
>SELECT
FOR UPDATE</TT
> without <TT
CLASS="LITERAL"
>NOWAIT</TT
>) and to implicitly-acquired
locks. If <TT
CLASS="VARNAME"
>log_min_error_statement</TT
> is set to
<TT
CLASS="LITERAL"
>ERROR</TT
> or lower, the statement that timed out will be
logged. A value of zero (the default) turns this off.
</P
><P
> Unlike <TT
CLASS="VARNAME"
>statement_timeout</TT
>, this timeout can only occur
while waiting for locks. Note that if <TT
CLASS="VARNAME"
>statement_timeout</TT
>
is nonzero, it is rather pointless to set <TT
CLASS="VARNAME"
>lock_timeout</TT
> to
the same or larger value, since the statement timeout would always
trigger first.
</P
><P
> Setting <TT
CLASS="VARNAME"
>lock_timeout</TT
> in
<TT
CLASS="FILENAME"
>postgresql.conf</TT
> is not recommended because it would
affect all sessions.
</P
></DD
><DT
><A
NAME="GUC-VACUUM-FREEZE-TABLE-AGE"
></A
><TT
CLASS="VARNAME"
>vacuum_freeze_table_age</TT
> (<TT
CLASS="TYPE"
>integer</TT
>)
</DT
><DD
><P
> <TT
CLASS="COMMAND"
>VACUUM</TT
> performs a whole-table scan if the table's
<TT
CLASS="STRUCTNAME"
>pg_class</TT
>.<TT
CLASS="STRUCTFIELD"
>relfrozenxid</TT
> field has reached
the age specified by this setting. The default is 150 million
transactions. Although users can set this value anywhere from zero to
two billions, <TT
CLASS="COMMAND"
>VACUUM</TT
> will silently limit the effective value
to 95% of <A
HREF="runtime-config-autovacuum.html#GUC-AUTOVACUUM-FREEZE-MAX-AGE"
>autovacuum_freeze_max_age</A
>, so that a
periodical manual <TT
CLASS="COMMAND"
>VACUUM</TT
> has a chance to run before an
anti-wraparound autovacuum is launched for the table. For more
information see
<A
HREF="routine-vacuuming.html#VACUUM-FOR-WRAPAROUND"
>Section 23.1.5</A
>.
</P
></DD
><DT
><A
NAME="GUC-VACUUM-FREEZE-MIN-AGE"
></A
><TT
CLASS="VARNAME"
>vacuum_freeze_min_age</TT
> (<TT
CLASS="TYPE"
>integer</TT
>)
</DT
><DD
><P
> Specifies the cutoff age (in transactions) that <TT
CLASS="COMMAND"
>VACUUM</TT
>
should use to decide whether to freeze row versions
while scanning a table.
The default is 50 million transactions. Although
users can set this value anywhere from zero to one billion,
<TT
CLASS="COMMAND"
>VACUUM</TT
> will silently limit the effective value to half
the value of <A
HREF="runtime-config-autovacuum.html#GUC-AUTOVACUUM-FREEZE-MAX-AGE"
>autovacuum_freeze_max_age</A
>, so
that there is not an unreasonably short time between forced
autovacuums. For more information see <A
HREF="routine-vacuuming.html#VACUUM-FOR-WRAPAROUND"
>Section 23.1.5</A
>.
</P
></DD
><DT
><A
NAME="GUC-VACUUM-MULTIXACT-FREEZE-TABLE-AGE"
></A
><TT
CLASS="VARNAME"
>vacuum_multixact_freeze_table_age</TT
> (<TT
CLASS="TYPE"
>integer</TT
>)
</DT
><DD
><P
> <TT
CLASS="COMMAND"
>VACUUM</TT
> performs a whole-table scan if the table's
<TT
CLASS="STRUCTNAME"
>pg_class</TT
>.<TT
CLASS="STRUCTFIELD"
>relminmxid</TT
> field has reached
the age specified by this setting. The default is 150 million multixacts.
Although users can set this value anywhere from zero to two billions,
<TT
CLASS="COMMAND"
>VACUUM</TT
> will silently limit the effective value to 95% of
<A
HREF="runtime-config-autovacuum.html#GUC-AUTOVACUUM-MULTIXACT-FREEZE-MAX-AGE"
>autovacuum_multixact_freeze_max_age</A
>, so that a
periodical manual <TT
CLASS="COMMAND"
>VACUUM</TT
> has a chance to run before an
anti-wraparound is launched for the table.
For more information see <A
HREF="routine-vacuuming.html#VACUUM-FOR-MULTIXACT-WRAPAROUND"
>Section 23.1.5.1</A
>.
</P
></DD
><DT
><A
NAME="GUC-VACUUM-MULTIXACT-FREEZE-MIN-AGE"
></A
><TT
CLASS="VARNAME"
>vacuum_multixact_freeze_min_age</TT
> (<TT
CLASS="TYPE"
>integer</TT
>)
</DT
><DD
><P
> Specifies the cutoff age (in multixacts) that <TT
CLASS="COMMAND"
>VACUUM</TT
>
should use to decide whether to replace multixact IDs with a newer
transaction ID or multixact ID while scanning a table. The default
is 5 million multixacts.
Although users can set this value anywhere from zero to one billion,
<TT
CLASS="COMMAND"
>VACUUM</TT
> will silently limit the effective value to half
the value of <A
HREF="runtime-config-autovacuum.html#GUC-AUTOVACUUM-MULTIXACT-FREEZE-MAX-AGE"
>autovacuum_multixact_freeze_max_age</A
>,
so that there is not an unreasonably short time between forced
autovacuums.
For more information see <A
HREF="routine-vacuuming.html#VACUUM-FOR-MULTIXACT-WRAPAROUND"
>Section 23.1.5.1</A
>.
</P
></DD
><DT
><A
NAME="GUC-BYTEA-OUTPUT"
></A
><TT
CLASS="VARNAME"
>bytea_output</TT
> (<TT
CLASS="TYPE"
>enum</TT
>)
</DT
><DD
><P
> Sets the output format for values of type <TT
CLASS="TYPE"
>bytea</TT
>.
Valid values are <TT
CLASS="LITERAL"
>hex</TT
> (the default)
and <TT
CLASS="LITERAL"
>escape</TT
> (the traditional PostgreSQL
format). See <A
HREF="datatype-binary.html"
>Section 8.4</A
> for more
information. The <TT
CLASS="TYPE"
>bytea</TT
> type always
accepts both formats on input, regardless of this setting.
</P
></DD
><DT
><A
NAME="GUC-XMLBINARY"
></A
><TT
CLASS="VARNAME"
>xmlbinary</TT
> (<TT
CLASS="TYPE"
>enum</TT
>)
</DT
><DD
><P
> Sets how binary values are to be encoded in XML. This applies
for example when <TT
CLASS="TYPE"
>bytea</TT
> values are converted to
XML by the functions <CODE
CLASS="FUNCTION"
>xmlelement</CODE
> or
<CODE
CLASS="FUNCTION"
>xmlforest</CODE
>. Possible values are
<TT
CLASS="LITERAL"
>base64</TT
> and <TT
CLASS="LITERAL"
>hex</TT
>, which
are both defined in the XML Schema standard. The default is
<TT
CLASS="LITERAL"
>base64</TT
>. For further information about
XML-related functions, see <A
HREF="functions-xml.html"
>Section 9.14</A
>.
</P
><P
> The actual choice here is mostly a matter of taste,
constrained only by possible restrictions in client
applications. Both methods support all possible values,
although the hex encoding will be somewhat larger than the
base64 encoding.
</P
></DD
><DT
><A
NAME="GUC-XMLOPTION"
></A
><TT
CLASS="VARNAME"
>xmloption</TT
> (<TT
CLASS="TYPE"
>enum</TT
>)
</DT
><DD
><P
> Sets whether <TT
CLASS="LITERAL"
>DOCUMENT</TT
> or
<TT
CLASS="LITERAL"
>CONTENT</TT
> is implicit when converting between
XML and character string values. See <A
HREF="datatype-xml.html"
>Section 8.13</A
> for a description of this. Valid
values are <TT
CLASS="LITERAL"
>DOCUMENT</TT
> and
<TT
CLASS="LITERAL"
>CONTENT</TT
>. The default is
<TT
CLASS="LITERAL"
>CONTENT</TT
>.
</P
><P
> According to the SQL standard, the command to set this option is
</P><PRE
CLASS="SYNOPSIS"
>SET XML OPTION { DOCUMENT | CONTENT };</PRE
><P>
This syntax is also available in PostgreSQL.
</P
></DD
></DL
></DIV
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="RUNTIME-CONFIG-CLIENT-FORMAT"
>18.11.2. Locale and Formatting</A
></H2
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><A
NAME="GUC-DATESTYLE"
></A
><TT
CLASS="VARNAME"
>DateStyle</TT
> (<TT
CLASS="TYPE"
>string</TT
>)
</DT
><DD
><P
> Sets the display format for date and time values, as well as the
rules for interpreting ambiguous date input values. For
historical reasons, this variable contains two independent
components: the output format specification (<TT
CLASS="LITERAL"
>ISO</TT
>,
<TT
CLASS="LITERAL"
>Postgres</TT
>, <TT
CLASS="LITERAL"
>SQL</TT
>, or <TT
CLASS="LITERAL"
>German</TT
>)
and the input/output specification for year/month/day ordering
(<TT
CLASS="LITERAL"
>DMY</TT
>, <TT
CLASS="LITERAL"
>MDY</TT
>, or <TT
CLASS="LITERAL"
>YMD</TT
>). These
can be set separately or together. The keywords <TT
CLASS="LITERAL"
>Euro</TT
>
and <TT
CLASS="LITERAL"
>European</TT
> are synonyms for <TT
CLASS="LITERAL"
>DMY</TT
>; the
keywords <TT
CLASS="LITERAL"
>US</TT
>, <TT
CLASS="LITERAL"
>NonEuro</TT
>, and
<TT
CLASS="LITERAL"
>NonEuropean</TT
> are synonyms for <TT
CLASS="LITERAL"
>MDY</TT
>. See
<A
HREF="datatype-datetime.html"
>Section 8.5</A
> for more information. The
built-in default is <TT
CLASS="LITERAL"
>ISO, MDY</TT
>, but
<SPAN
CLASS="APPLICATION"
>initdb</SPAN
> will initialize the
configuration file with a setting that corresponds to the
behavior of the chosen <TT
CLASS="VARNAME"
>lc_time</TT
> locale.
</P
></DD
><DT
><A
NAME="GUC-INTERVALSTYLE"
></A
><TT
CLASS="VARNAME"
>IntervalStyle</TT
> (<TT
CLASS="TYPE"
>enum</TT
>)
</DT
><DD
><P
> Sets the display format for interval values.
The value <TT
CLASS="LITERAL"
>sql_standard</TT
> will produce
output matching <ACRONYM
CLASS="ACRONYM"
>SQL</ACRONYM
> standard interval literals.
The value <TT
CLASS="LITERAL"
>postgres</TT
> (which is the default) will produce
output matching <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> releases prior to 8.4
when the <A
HREF="runtime-config-client.html#GUC-DATESTYLE"
>DateStyle</A
>
parameter was set to <TT
CLASS="LITERAL"
>ISO</TT
>.
The value <TT
CLASS="LITERAL"
>postgres_verbose</TT
> will produce output
matching <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> releases prior to 8.4
when the <TT
CLASS="VARNAME"
>DateStyle</TT
>
parameter was set to non-<TT
CLASS="LITERAL"
>ISO</TT
> output.
The value <TT
CLASS="LITERAL"
>iso_8601</TT
> will produce output matching the time
interval <SPAN
CLASS="QUOTE"
>"format with designators"</SPAN
> defined in section
4.4.3.2 of ISO 8601.
</P
><P
> The <TT
CLASS="VARNAME"
>IntervalStyle</TT
> parameter also affects the
interpretation of ambiguous interval input. See
<A
HREF="datatype-datetime.html#DATATYPE-INTERVAL-INPUT"
>Section 8.5.4</A
> for more information.
</P
></DD
><DT
><A
NAME="GUC-TIMEZONE"
></A
><TT
CLASS="VARNAME"
>TimeZone</TT
> (<TT
CLASS="TYPE"
>string</TT
>)
</DT
><DD
><P
> Sets the time zone for displaying and interpreting time stamps.
The built-in default is <TT
CLASS="LITERAL"
>GMT</TT
>, but that is typically
overridden in <TT
CLASS="FILENAME"
>postgresql.conf</TT
>; <SPAN
CLASS="APPLICATION"
>initdb</SPAN
>
will install a setting there corresponding to its system environment.
See <A
HREF="datatype-datetime.html#DATATYPE-TIMEZONES"
>Section 8.5.3</A
> for more information.
</P
></DD
><DT
><A
NAME="GUC-TIMEZONE-ABBREVIATIONS"
></A
><TT
CLASS="VARNAME"
>timezone_abbreviations</TT
> (<TT
CLASS="TYPE"
>string</TT
>)
</DT
><DD
><P
> Sets the collection of time zone abbreviations that will be accepted
by the server for datetime input. The default is <TT
CLASS="LITERAL"
>'Default'</TT
>,
which is a collection that works in most of the world; there are
also <TT
CLASS="LITERAL"
>'Australia'</TT
> and <TT
CLASS="LITERAL"
>'India'</TT
>,
and other collections can be defined for a particular installation.
See <A
HREF="datetime-config-files.html"
>Section B.3</A
> for more information.
</P
></DD
><DT
><A
NAME="GUC-EXTRA-FLOAT-DIGITS"
></A
><TT
CLASS="VARNAME"
>extra_float_digits</TT
> (<TT
CLASS="TYPE"
>integer</TT
>)
</DT
><DD
><P
> This parameter adjusts the number of digits displayed for
floating-point values, including <TT
CLASS="TYPE"
>float4</TT
>, <TT
CLASS="TYPE"
>float8</TT
>,
and geometric data types. The parameter value is added to the
standard number of digits (<TT
CLASS="LITERAL"
>FLT_DIG</TT
> or <TT
CLASS="LITERAL"
>DBL_DIG</TT
>
as appropriate). The value can be set as high as 3, to include
partially-significant digits; this is especially useful for dumping
float data that needs to be restored exactly. Or it can be set
negative to suppress unwanted digits.
See also <A
HREF="datatype-numeric.html#DATATYPE-FLOAT"
>Section 8.1.3</A
>.
</P
></DD
><DT
><A
NAME="GUC-CLIENT-ENCODING"
></A
><TT
CLASS="VARNAME"
>client_encoding</TT
> (<TT
CLASS="TYPE"
>string</TT
>)
</DT
><DD
><P
> Sets the client-side encoding (character set).
The default is to use the database encoding.
The character sets supported by the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>
server are described in <A
HREF="multibyte.html#MULTIBYTE-CHARSET-SUPPORTED"
>Section 22.3.1</A
>.
</P
></DD
><DT
><A
NAME="GUC-LC-MESSAGES"
></A
><TT
CLASS="VARNAME"
>lc_messages</TT
> (<TT
CLASS="TYPE"
>string</TT
>)
</DT
><DD
><P
> Sets the language in which messages are displayed. Acceptable
values are system-dependent; see <A
HREF="locale.html"
>Section 22.1</A
> for
more information. If this variable is set to the empty string
(which is the default) then the value is inherited from the
execution environment of the server in a system-dependent way.
</P
><P
> On some systems, this locale category does not exist. Setting
this variable will still work, but there will be no effect.
Also, there is a chance that no translated messages for the
desired language exist. In that case you will continue to see
the English messages.
</P
><P
> Only superusers can change this setting, because it affects the
messages sent to the server log as well as to the client, and
an improper value might obscure the readability of the server
logs.
</P
></DD
><DT
><A
NAME="GUC-LC-MONETARY"
></A
><TT
CLASS="VARNAME"
>lc_monetary</TT
> (<TT
CLASS="TYPE"
>string</TT
>)
</DT
><DD
><P
> Sets the locale to use for formatting monetary amounts, for
example with the <CODE
CLASS="FUNCTION"
>to_char</CODE
> family of
functions. Acceptable values are system-dependent; see <A
HREF="locale.html"
>Section 22.1</A
> for more information. If this variable is
set to the empty string (which is the default) then the value
is inherited from the execution environment of the server in a
system-dependent way.
</P
></DD
><DT
><A
NAME="GUC-LC-NUMERIC"
></A
><TT
CLASS="VARNAME"
>lc_numeric</TT
> (<TT
CLASS="TYPE"
>string</TT
>)
</DT
><DD
><P
> Sets the locale to use for formatting numbers, for example
with the <CODE
CLASS="FUNCTION"
>to_char</CODE
> family of
functions. Acceptable values are system-dependent; see <A
HREF="locale.html"
>Section 22.1</A
> for more information. If this variable is
set to the empty string (which is the default) then the value
is inherited from the execution environment of the server in a
system-dependent way.
</P
></DD
><DT
><A
NAME="GUC-LC-TIME"
></A
><TT
CLASS="VARNAME"
>lc_time</TT
> (<TT
CLASS="TYPE"
>string</TT
>)
</DT
><DD
><P
> Sets the locale to use for formatting dates and times, for example
with the <CODE
CLASS="FUNCTION"
>to_char</CODE
> family of
functions. Acceptable values are system-dependent; see <A
HREF="locale.html"
>Section 22.1</A
> for more information. If this variable is
set to the empty string (which is the default) then the value
is inherited from the execution environment of the server in a
system-dependent way.
</P
></DD
><DT
><A
NAME="GUC-DEFAULT-TEXT-SEARCH-CONFIG"
></A
><TT
CLASS="VARNAME"
>default_text_search_config</TT
> (<TT
CLASS="TYPE"
>string</TT
>)
</DT
><DD
><P
> Selects the text search configuration that is used by those variants
of the text search functions that do not have an explicit argument
specifying the configuration.
See <A
HREF="textsearch.html"
>Chapter 12</A
> for further information.
The built-in default is <TT
CLASS="LITERAL"
>pg_catalog.simple</TT
>, but
<SPAN
CLASS="APPLICATION"
>initdb</SPAN
> will initialize the
configuration file with a setting that corresponds to the
chosen <TT
CLASS="VARNAME"
>lc_ctype</TT
> locale, if a configuration
matching that locale can be identified.
</P
></DD
></DL
></DIV
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="RUNTIME-CONFIG-CLIENT-PRELOAD"
>18.11.3. Shared Library Preloading</A
></H2
><P
> Several settings are available for preloading shared libraries into the
server, in order to load additional functionality or achieve performance
benefits. For example, a setting of
<TT
CLASS="LITERAL"
>'$libdir/mylib'</TT
> would cause
<TT
CLASS="LITERAL"
>mylib.so</TT
> (or on some platforms,
<TT
CLASS="LITERAL"
>mylib.sl</TT
>) to be preloaded from the installation's standard
library directory. The differences between the settings are when they
take effect and what privileges are required to change them.
</P
><P
> <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> procedural language libraries can
be preloaded in this way, typically by using the
syntax <TT
CLASS="LITERAL"
>'$libdir/plXXX'</TT
> where
<TT
CLASS="LITERAL"
>XXX</TT
> is <TT
CLASS="LITERAL"
>pgsql</TT
>, <TT
CLASS="LITERAL"
>perl</TT
>,
<TT
CLASS="LITERAL"
>tcl</TT
>, or <TT
CLASS="LITERAL"
>python</TT
>.
</P
><P
> For each parameter, if more than one library is to be loaded, separate
their names with commas. All library names are converted to lower case
unless double-quoted.
</P
><P
> Only shared libraries specifically intended to be used with PostgreSQL
can be loaded this way. Every PostgreSQL-supported library has
a <SPAN
CLASS="QUOTE"
>"magic block"</SPAN
> that is checked to guarantee compatibility. For
this reason, non-PostgreSQL libraries cannot be loaded in this way. You
might be able to use operating-system facilities such
as <TT
CLASS="ENVAR"
>LD_PRELOAD</TT
> for that.
</P
><P
> In general, refer to the documentation of a specific module for the
recommended way to load that module.
</P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><A
NAME="GUC-LOCAL-PRELOAD-LIBRARIES"
></A
><TT
CLASS="VARNAME"
>local_preload_libraries</TT
> (<TT
CLASS="TYPE"
>string</TT
>)
</DT
><DD
><P
> This variable specifies one or more shared libraries that are to be
preloaded at connection start. This parameter cannot be changed after
the start of a particular session. If a specified library is not
found, the connection attempt will fail.
</P
><P
> This option can be set by any user. Because of that, the libraries
that can be loaded are restricted to those appearing in the
<TT
CLASS="FILENAME"
>plugins</TT
> subdirectory of the installation's
standard library directory. (It is the database administrator's
responsibility to ensure that only <SPAN
CLASS="QUOTE"
>"safe"</SPAN
> libraries
are installed there.) Entries in <TT
CLASS="VARNAME"
>local_preload_libraries</TT
>
can specify this directory explicitly, for example
<TT
CLASS="LITERAL"
>$libdir/plugins/mylib</TT
>, or just specify
the library name — <TT
CLASS="LITERAL"
>mylib</TT
> would have
the same effect as <TT
CLASS="LITERAL"
>$libdir/plugins/mylib</TT
>.
</P
><P
> Unless a module is specifically designed to be used in this way by
non-superusers, this is usually not the right setting to use. Look
at <A
HREF="runtime-config-client.html#GUC-SESSION-PRELOAD-LIBRARIES"
>session_preload_libraries</A
> instead.
</P
></DD
><DT
><A
NAME="GUC-SESSION-PRELOAD-LIBRARIES"
></A
><TT
CLASS="VARNAME"
>session_preload_libraries</TT
> (<TT
CLASS="TYPE"
>string</TT
>)
</DT
><DD
><P
> This variable specifies one or more shared libraries that are to be
preloaded at connection start. Only superusers can change this setting.
The parameter value only takes effect at the start of the connection.
Subsequent changes have no effect. If a specified library is not
found, the connection attempt will fail.
</P
><P
> The intent of this feature is to allow debugging or
performance-measurement libraries to be loaded into specific sessions
without an explicit
<TT
CLASS="COMMAND"
>LOAD</TT
> command being given. For
example, <A
HREF="auto-explain.html"
>auto_explain</A
> could be enabled for all
sessions under a given user name by setting this parameter
with <TT
CLASS="COMMAND"
>ALTER ROLE SET</TT
>. Also, this parameter can be changed
without restarting the server (but changes only take effect when a new
session is started), so it is easier to add new modules this way, even
if they should apply to all sessions.
</P
><P
> Unlike <A
HREF="runtime-config-client.html#GUC-SHARED-PRELOAD-LIBRARIES"
>shared_preload_libraries</A
>, there is no large
performance advantage to loading a library at session start rather than
when it is first used. There is some advantage, however, when
connection pooling is used.
</P
></DD
><DT
><A
NAME="GUC-SHARED-PRELOAD-LIBRARIES"
></A
><TT
CLASS="VARNAME"
>shared_preload_libraries</TT
> (<TT
CLASS="TYPE"
>string</TT
>)
</DT
><DD
><P
> This variable specifies one or more shared libraries to be preloaded at
server start. with commas. This parameter can only be set at server
start. If a specified library is not found, the server will fail to
start.
</P
><P
> Some libraries need to perform certain operations that can only take
place at postmaster start, such as allocating shared memory, reserving
light-weight locks, or starting background workers. Those libraries
must be loaded at server start through this parameter. See the
documentation of each library for details.
</P
><P
> Other libraries can also be preloaded. By preloading a shared library,
the library startup time is avoided when the library is first used.
However, the time to start each new server process might increase
slightly, even if that process never uses the library. So this
parameter is recommended only for libraries that will be used in most
sessions. Also, changing this parameter requires a server restart, so
this is not the right setting to use for short-term debugging tasks,
say. Use <A
HREF="runtime-config-client.html#GUC-SESSION-PRELOAD-LIBRARIES"
>session_preload_libraries</A
> for that
instead.
</P
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
> On Windows hosts, preloading a library at server start will not reduce
the time required to start each new server process; each server process
will re-load all preload libraries. However, <TT
CLASS="VARNAME"
>shared_preload_libraries
</TT
> is still useful on Windows hosts for libraries that need to
perform operations at postmaster start time.
</P
></BLOCKQUOTE
></DIV
></DD
></DL
></DIV
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="RUNTIME-CONFIG-CLIENT-OTHER"
>18.11.4. Other Defaults</A
></H2
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><A
NAME="GUC-DYNAMIC-LIBRARY-PATH"
></A
><TT
CLASS="VARNAME"
>dynamic_library_path</TT
> (<TT
CLASS="TYPE"
>string</TT
>)
</DT
><DD
><P
> If a dynamically loadable module needs to be opened and the
file name specified in the <TT
CLASS="COMMAND"
>CREATE FUNCTION</TT
> or
<TT
CLASS="COMMAND"
>LOAD</TT
> command
does not have a directory component (i.e., the
name does not contain a slash), the system will search this
path for the required file.
</P
><P
> The value for <TT
CLASS="VARNAME"
>dynamic_library_path</TT
> must be a
list of absolute directory paths separated by colons (or semi-colons
on Windows). If a list element starts
with the special string <TT
CLASS="LITERAL"
>$libdir</TT
>, the
compiled-in <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> package
library directory is substituted for <TT
CLASS="LITERAL"
>$libdir</TT
>; this
is where the modules provided by the standard
<SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> distribution are installed.
(Use <TT
CLASS="LITERAL"
>pg_config --pkglibdir</TT
> to find out the name of
this directory.) For example:
</P><PRE
CLASS="PROGRAMLISTING"
>dynamic_library_path = '/usr/local/lib/postgresql:/home/my_project/lib:$libdir'</PRE
><P>
or, in a Windows environment:
</P><PRE
CLASS="PROGRAMLISTING"
>dynamic_library_path = 'C:\tools\postgresql;H:\my_project\lib;$libdir'</PRE
><P>
</P
><P
> The default value for this parameter is
<TT
CLASS="LITERAL"
>'$libdir'</TT
>. If the value is set to an empty
string, the automatic path search is turned off.
</P
><P
> This parameter can be changed at run time by superusers, but a
setting done that way will only persist until the end of the
client connection, so this method should be reserved for
development purposes. The recommended way to set this parameter
is in the <TT
CLASS="FILENAME"
>postgresql.conf</TT
> configuration
file.
</P
></DD
><DT
><A
NAME="GUC-GIN-FUZZY-SEARCH-LIMIT"
></A
><TT
CLASS="VARNAME"
>gin_fuzzy_search_limit</TT
> (<TT
CLASS="TYPE"
>integer</TT
>)
</DT
><DD
><P
> Soft upper limit of the size of the set returned by GIN index scans. For more
information see <A
HREF="gin-tips.html"
>Section 58.5</A
>.
</P
></DD
></DL
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