<para>

The <filename>dump_stat</> module provides functions that allow you to

backup and recover the contents of the pg_statistic table. The

<function>dump_statistic</> function generates <literal>INSERT</> statements which

can later be applied to a compatible PostgreSQL server. The extension

backup and recover the contents of the

<link linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link>

table. The <function>dump_statistic</> function generates <literal>INSERT</>

statements which can later be applied to a compatible database. The extension

should be installed on the recipient server in order to successfuly restore

statistical data since these statements rely on the provided functions.

statistical data since these statements heavily rely on the provided functions.

</para>

<para>

Note that the definition of the

<link linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link>

table might change occasionally, which means that generated dump might be incompatible

with future releases of PostgreSQL.

</para>

<sect2>

<function>dump_statistic</function> dumps the contents of the

<link linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link>

system catalog. It produces an <literal>INSERT</> statement

per each tuple of the <literal>pg_statistic</>, excluding

the ones that contain statistical data for tables in

<literal>information_schema</> and <literal>pg_catalog</>

schemas.

per each tuple of the

<link linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link>,

excluding the ones that contain statistical data for tables in the

<literal>information_schema</> and <literal>pg_catalog</> schemas.

</para>

<para>

The <literal>INSERT</> statement takes form of

<screen>

WITH upsert as (

UPDATE pg_catalog.pg_statistic SET %s

WHERE to_schema_qualified_relation(starelid) = relname

AND to_attname(relname, staattnum) = attname

AND to_atttype(relname, staattnum) = atttype

AND stainherit = r.stainherit

RETURNING *)

ins as (

SELECT %s

WHERE NOT EXISTS (SELECT * FROM upsert)

AND to_attnum(relname, attname) IS NOT NULL

AND to_atttype(relname, attname) = atttype)

INSERT INTO pg_catalog.pg_statistic SELECT * FROM ins;

</screen>

</para>

</listitem>

</varlistentry>

<function>dump_statistic</function> dumps the contents of the

<link linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link>

system catalog. It produces an <literal>INSERT</> statement

per each tuple of the <literal>pg_statistic</>, excluding

schemas.

per each tuple of the

<literal>schema_name</> schema.

</para>

</listitem>

</varlistentry>

<function>dump_statistic</function> dumps the contents of the

<link linkend="catalog-pg-statistic"><structname>pg_statistic</structname></link>

system catalog. It produces an <literal>INSERT</> statement

per each tuple of the <literal>pg_statistic</>, excluding

schemas.

per each tuple of the

<literal>"schema_name.table_name"</> table.

</para>

</listitem>

</varlistentry>

<listitem>

<para>

Returns the element type of the given array as oid.

Returns the element type of the given array as<literal>oid</>.

</para>

</listitem>

</varlistentry>

<listitem>

<para>

Given a relation name and a column number, returns the column name as text.

Given a relation name and a column number, returns the column name

as <literal>text</>.

</para>

</listitem>

</varlistentry>

<listitem>

<para>

Given a relation name and a column name, returns the column number as int2.

Given a relation name and a column name, returns the column number

as <literal>int2</>.

</para>

</listitem>

</varlistentry>

<listitem>

<para>

Given a relation name and a column name, returns the column type as text.

Given a relation name and a column name, returns the column type

as <literal>text</>.

</para>

</listitem>

</varlistentry>

<function>to_namespace</function> duplicates the behavior of

the cast to <literal>regnamespace</> type, which is not

present in the 9.4 release (and prior releases). This

function returns the oid of the givennamespace.

function returns the<literal>oid</> of the givenschema.

</para>

</listitem>

</varlistentry>

<listitem>

<para>

<function>get_namespace</function> returns thenamespace

of the given relation as oid.

<function>get_namespace</function> returns theschema

of the given relation as<literal>oid</>.

</para>

</listitem>

</varlistentry>