I wrote:
> Anyway, here is a patch set teased apart into committable bites,
> and with your other points addressed.
Oh, maybe some docs would be a good thing too ...
regards, tom lane
diff --git a/doc/src/sgml/spgist.sgml b/doc/src/sgml/spgist.sgml
index cfb2b3c836..18f1f3cdbd 100644
--- a/doc/src/sgml/spgist.sgml
+++ b/doc/src/sgml/spgist.sgml
@@ -978,6 +978,18 @@ LANGUAGE C STRICT;
fails to do that, the <acronym>SP-GiST</acronym> core resorts to
extraordinary measures described in <xref linkend="spgist-all-the-same"/>.
</para>
+
+ <para>
+ When <structfield>longValuesOK</structfield> is true, it is expected
+ that successive levels of the <acronym>SP-GiST</acronym> tree will
+ absorb more and more information into the prefixes and node labels of
+ the inner tuples, making the required leaf datum smaller and smaller,
+ so that eventually it will fit on a page.
+ To prevent bugs in operator classes from causing infinite insertion
+ loops, the <acronym>SP-GiST</acronym> core will raise an error if the
+ leaf datum does not become any smaller within ten cycles
+ of <function>choose</function> method calls.
+ </para>
</sect2>
<sect2 id="spgist-null-labels">
