the write-ahead log stream. It is printed as two hexadecimal numbers of

up to 8 digits each, separated by a slash; for example,

<literal>16/B374D848</>. The <type>pg_lsn</type> type supports the

standard comparison operators, like <literal>=</literal> and

standard comparison operators, like <literal>=</literal> and

<literal>&gt;</literal>. Two LSNs can be subtracted using the

<literal>-</literal> operator; the result is the number of bytes separating

those write-ahead log positions.

</note>

<para>

The standard comparison operators shown in <xref

linkend="functions-comparison-table"> are available for

<type>jsonb</type>, but not for <type>json</type>. They follow the

linkend="functions-comparison-table"> are available for

<type>jsonb</type>, but not for <type>json</type>. They follow the

ordering rules for btree operations outlined at <xref

linkend="json-indexing">.

</para>

<entry><literal>select * from json_to_record('{"a":1,"b":[1,2,3],"c":"bar"}') as x(a int, b text, d text) </literal></entry>

<entry>

<programlisting>

a | b | d

a | b | d

---+---------+---

1 | [1,2,3] |

1 | [1,2,3] |

</programlisting>

</entry>

</row>

<literal>*&gt;=</>.

These operators compare the internal binary representation of the two

rows. Two rows might have a different binary representation even

though comparisons of the two rows with the equality operator is true.

though comparisons of the two rows with the equality operator is true.

The ordering of rows under these comparision operators is deterministic

but not otherwise meaningful. These operators are used internally for

materialized views and might be useful for other specialized purposes

triConsistent alone is sufficient. However, if the boolean variant is

significantly cheaper to calculate, it can be advantageous to provide both.

If only the boolean variant is provided, some optimizations that depend on

refuting index items before fetching all the keys are disabled.

refuting index items before fetching all the keys are disabled.

<variablelist>

<varlistentry>

When <literal>GIN_MAYBE</> values are present, the function should only

return GIN_TRUE if the item matches whether or not the index item

contains the corresponding query keys. Likewise, the function must

return GIN_FALSE only if the item does not match, whether or not it

return GIN_FALSE only if the item does not match, whether or not it

contains the GIN_MAYBE keys. If the result depends on the GIN_MAYBE

entries, i.e. the match cannot be confirmed or refuted based on the

known query keys, the function must return GIN_MAYBE.

</para>

<para>

Note that the client's <filename>~/.postgresql/root.crt</> lists the top-level CAs

Note that the client's <filename>~/.postgresql/root.crt</> lists the top-level CAs

that are considered trusted for signing server certificates. In principle it need

not list the CA that signed the client's certificate, though in most cases

that CA would also be trusted for server certificates.

</para>

<para>

The algorithms in <function>crypt()</> differ from the usual

The algorithms in <function>crypt()</> differ from the usual

MD5 or SHA1 hashing algorithms in the following respects:

</para>

<para>

The first argument is the relation to be prewarmed. The second argument

is the prewarming method to be used, as further discussed below; the third

is the relation fork to be prewarmed, usually <literal>main</literal>.

is the relation fork to be prewarmed, usually <literal>main</literal>.

The fourth argument is the first block number to prewarm

(<literal>NULL</literal> is accepted as a synonym for zero). The fifth

argument is the last block number to prewarm (<literal>NULL</literal>

<para>

These additional checks are enabled through the configuration variables

<varname>plpgsql.extra_warnings</> for warnings and

<varname>plpgsql.extra_warnings</> for warnings and

<varname>plpgsql.extra_errors</> for errors. Both can be set either to

a comma-separated list of checks, <literal>"none"</> or <literal>"all"</>.

The default is <literal>"none"</>. Currently the list of available checks

<term><varname>shadowed_variables</varname></term>

<listitem>

<para>

Checks if a declaration shadows a previously defined variable.

Checks if a declaration shadows a previously defined variable.

</para>

</listitem>

</varlistentry>

following parameters can be used to specify an earlier stopping point.

At most one of <varname>recovery_target</>,

<varname>recovery_target_name</>, <varname>recovery_target_time</>, or

<varname>recovery_target_xid</> can be specified.

<varname>recovery_target_xid</> can be specified.

</para>

<variablelist>

values to the <filename>postgresql.auto.conf</filename> file. With

<literal>DEFAULT</literal>, it removes a configuration entry from

<filename>postgresql.auto.conf</filename> file. The values will be

effective after reload of server configuration (SIGHUP) or in next

effective after reload of server configuration (SIGHUP) or in next

server start based on the type of configuration parameter modified.

</para>

<para>

This command is not allowed inside transaction block or function.

</para>

<para>

See <xref linkend="config-setting"> for other ways to set the parameters and

See <xref linkend="config-setting"> for other ways to set the parameters and

how they become effective.

</para>

</refsect1>

<listitem>

<para>

The approximate average size (in bytes) of the aggregate's state

value, when using moving-aggregate mode. This works the same as

value, when using moving-aggregate mode. This works the same as

<replaceable>state_data_size</>.

</para>

</listitem>