<para>

As explained above, the environment of the operating system provides the

defaults for the locales of a newly initialized database cluster. In

many cases, this is enough:If the operating system is configured for

the desired language/territory,then

<productname>PostgreSQL</productname> willby defaultalso behave

accordingto that locale.

many cases, this is enough:if the operating system is configured for

the desired language/territory,by default

<productname>PostgreSQL</productname> will also behave according

to that locale.

</para>

</listitem>

<para>

The timeout is measured from the time a command arrives at the

server until it is completed by the server. If multiple SQL

statements appear in a single simple-Query message, the timeout

statements appear in a single simple-query message, the timeout

is applied to each statement separately.

(<productname>PostgreSQL</productname> versions before 13 usually

treated the timeout as applying to the whole query string.)

<para>

If you need to re-create a standby server while transactions are

waiting, make sure that thecommandspg_backup_start() and

pg_backup_stop() are run in a session with

waiting, make sure that thefunctions <function>pg_backup_start()</function>

and <function>pg_backup_stop()</function> are run in a session with

<varname>synchronous_commit</varname> = <literal>off</literal>, otherwise those

requests will wait forever for the standby to appear.

</para>

The cumulative statistics system is active during recovery. All scans,

reads, blocks, index usage, etc., will be recorded normally on the

standby. However, WAL replay will not increment relation and database

specific counters. I.e. replay will not increment pg_stat_all_tables

columns (like n_tup_ins), nor will reads or writes performed by the

startup process be tracked in the pg_statio views, nor will associated

pg_stat_database columns be incremented.

specific counters. I.e. replay will not increment

<structname>pg_stat_all_tables</structname> columns (like <structfield>n_tup_ins</structfield>),

nor will reads or writes performed by the startup process be tracked in the

<structname>pg_statio_</structname> views, nor will associated

<structname>pg_stat_database</structname> columns be incremented.

</para>

<para>

<para>

Index expressions are relatively expensive to maintain, because the

derived expression(s) must be computed for each row insertion

and <link linkend="storage-hot">non-HOT update.</link> However, the index expressions are

and <link linkend="storage-hot">non-HOT update</link>. However, the index expressions are

<emphasis>not</emphasis> recomputed during an indexed search, since they are

already stored in the index. In both examples above, the system

sees the query as just <literal>WHERE indexedcolumn = 'constant'</literal>

</programlisting>

<para>

The following examplesshows how logical decoding is controlled over the

The following examplesshow how logical decoding is controlled over the

streaming replication protocol, using the

program <xref linkend="app-pgrecvlogical"/> included in the PostgreSQL

distribution. This requires that client authentication is set up to allow

unnecessary and can be avoided by setting

<varname>stats_fetch_consistency</varname> to <literal>none</literal>.

You can invoke <function>pg_stat_clear_snapshot</function>() to discard the

You can invoke <function>pg_stat_clear_snapshot()</function> to discard the

current transaction's statistics snapshot or cached values (if any). The

next use of statistical information will (when in snapshot mode) cause a

new snapshot to be built or (when in cache mode) accessed statistics to be

An expression to assign to the column. If used in a

<literal>WHEN MATCHED</literal> clause, the expression can use values

from the original row in the target table, and values from the

<literal>data_source</literal> row.

<replaceable>data_source</replaceable> row.

If used in a <literal>WHEN NOT MATCHED</literal> clause, the

expression can use values from the <literal>data_source</literal>.

expression can use values from the <replaceable>data_source</replaceable>.

</para>

</listitem>

</varlistentry>

A compression detail string can optionally be specified.

If the detail string is an integer, it specifies the compression

level. Otherwise, it should be a comma-separated list of items,

each of the form <literal>keyword</literal> or

<literal>keyword=value</literal>.

each of the form

<replaceable>keyword</replaceable> or

<replaceable>keyword=value</replaceable>.

Currently, the supported keywords are <literal>level</literal>,

<literal>long</literal>, and <literal>workers</literal>.

The detail string cannot be used when the compression method

</screen></para>

<para>

To create a backup ofa local server with one tar file for each tablespace

To create a backup ofthe local server with one tar file for each tablespace

compressed with <application>gzip</application> at level 9, stored in the

directory <filename>backup</filename>:

<screen>

A compression detail string can optionally be specified. If the

detail string is an integer, it specifies the compression level.

Otherwise, it should be a comma-separated list of items, each of the

form <literal>keyword</literal> or <literal>keyword=value</literal>.

form <replaceable>keyword</replaceable> or

<replaceable>keyword=value</replaceable>.

Currently, the only supported keyword is <literal>level</literal>.

</para>

<para>

<listitem>

<para>

Enables decoding of prepared transactions. This option may only be specified with

<option>--create-slot</option>

<option>--create-slot</option>.

</para>

</listitem>

</varlistentry>

<para>

Do not output commands to select table access methods.

With this option, all objects will be created with whichever

access method is the default during restore.

tableaccess method is the default during restore.

</para>

</listitem>

</varlistentry>

<term><option>--fork=<replaceable>fork</replaceable></option></term>

<listitem>

<para>

If provided, only display records that modify blocks in the given fork.

Only display records that modify blocks in the given fork.

The valid values are <literal>main</literal> for the main fork,

<literal>fsm</literal> for the free space map,

<literal>vm</literal> for the visibility map,

names, and exit.

</para>

<para>

Extensions may define custom resource managers, but pg_waldump does

Extensions may define custom resource managers, but

<application>pg_waldump</application> does

not load the extension module and therefore does not recognize custom

resource managers by name. Instead, you can specify the custom

resource managers as <literal>custom###</literal> where

"<literal>###</literal>" is the three-digit resource manager ID. Names

of this form will always be considered valid.

<replaceable>###</replaceable> is the three-digit resource manager ID.

Namesof this form will always be considered valid.

</para>

</listitem>

</varlistentry>

data is generated in <command>pgbench</command> client and then

sent to the server. This uses the client/server bandwidth

extensively through a <command>COPY</command>.

<command>pgbench</command> uses the FREEZE option with version 14 or later

<command>pgbench</command> uses the <option>FREEZE</option> option

with version 14 or later

of <productname>PostgreSQL</productname> to speed up

subsequent <command>VACUUM</command>, except on the

<literal>pgbench_accounts</literal> table if partitions are

each SQL command on a single line ending with a semicolon.

</para>

<para>

It is assumed that pgbench scripts do not contain incomplete blocks of SQL

It is assumed that <application>pgbench</application> scripts do not contain

incomplete blocks of SQL

transactions. If at runtime the client reaches the end of the script without

completing the last transaction block, it will be aborted.

</para>

</para>

<para>

Here is some example output generated withthese options:

Here is some example output generated withthis option:

<screen>

<userinput>pgbench --aggregate-interval=10 --time=20 --client=10 --log --rate=1000 --latency-limit=10 --failures-detailed --max-tries=10 test</userinput>