<para><emphasis role="strong">Contents</emphasis></para>

<para><link linkend="pg-pathman-choosing-partitioning-strategies">Choosing Partitioning Strategies</link></para>

<para><link linkend="pg-pathman-running-non-blocking-data-migration">Running Non-Blocking Data Migration</link></para>

<para><link linkend="pg-pathman-partitioning-by-expression">Partitioning by Expression</link></para>

<para><link linkend="pg-pathman-partitioning-by-expression">Partitioning bya SingleExpression</link></para>

<para><link linkend="pg-pathman-partitioning-by-comp-key">Partitioning by Composite Key</link></para>

<para>

As your database grows, indexing mechanisms may become inefficient

when you insert data outside of the already covered range.</para>

<programlisting>

create_range_partitions(relation REGCLASS,

expressionTEXT,

expression TEXT,

start_value ANYELEMENT,

p_interval ANYELEMENT | INTERVAL,

p_count INTEGER DEFAULT NULL,

</para></tip>

</sect3>

<sect3 id="pg-pathman-partitioning-by-expression">

<title>Partitioning by Expression</title>

<title>Partitioning bya SingleExpression</title>

<para>

For both range and hash partitioning strategies, <filename>pg_pathman</filename>

supports partitioning by expression that returns a single scalar value. The partitioning expression

supports partitioning by expression that returns a single scalar value.

The partitioning expression

can reference a table column, as well as calculate the partitioning key

based on one or more column values.

</para>

To enable automatic partition naming, run the <literal>create_naming_sequence()</literal>

function passing the table name as an argument:

<programlisting>

select create_naming_sequence('test');

SELECT create_naming_sequence('test');

</programlisting>

</para>

<para>

Register the <structname>test</structname> table with

<filename>pg_pathman</filename>, specifying the partitioning key you are going to use:

<programlisting>

select add_to_pathman_config('test',

SELECT add_to_pathman_config('test',

'( extract(year from logdate),

extract(month from logdate) )::test_key',

NULL);

<para>Create a partition that includes all the data in the range of ten years,

starting from January of the current year:

<programlisting>

select add_range_partition('test',

SELECT add_range_partition('test',

(extract(year from current_date), 1)::test_key,

(extract(year from current_date + '10 years'::interval), 1)::test_key);

</programlisting>