index 93d96f2f5669090db46d81ae5aadd5547fb6ff48..cd989e7d3c466e438f92f7ff84d9924208b0f19b 100644 (file)
by <literal>nodeToString</literal>, so that debugging routines that attempt to
print the custom path will work as designed. <structfield>methods</structfield> must
point to a (usually statically allocated) object implementing the required
- custom path methods, of which there is currently only one.
+ custom path methods, which are further detailed below.
</para>
<para>
be a <literal>CustomScan</literal> object, which the callback must allocate and
initialize. See <xref linkend="custom-scan-plan"/> for more details.
</para>
+
+ <para>
+<programlisting>
+List *(*ReparameterizeCustomPathByChild) (PlannerInfo *root,
+ List *custom_private,
+ RelOptInfo *child_rel);
+</programlisting>
+ This callback is called while converting a path parameterized by the
+ top-most parent of the given child relation <literal>child_rel</literal>
+ to be parameterized by the child relation. The callback is used to
+ reparameterize any paths or translate any expression nodes saved in the
+ given <literal>custom_private</literal> member of a
+ <structname>CustomPath</structname>. The callback may use
+ <literal>reparameterize_path_by_child</literal>,
+ <literal>adjust_appendrel_attrs</literal> or
+ <literal>adjust_appendrel_attrs_multilevel</literal> as required.
+ </para>
</sect2>
</sect1>