Robert Haas <robertmhaas@gmail.com> writes:
> On Mon, Jun 1, 2009 at 3:34 PM, Selena Deckelmann <selena@endpoint.com> wrote:
>> Suggested revision of Robert's prose:
>>
>> Because genetic query optimization may be triggered, increasing
>> from_collapse_limit should be considered relative to <xref
>> linkend="guc-geqo-threshold">.
> Here's my attempt.
I applied the attached, along with some other wordsmithing.
regards, tom lane
***************
*** 2252,2261 **** The planner will merge sub-queries into upper queries if the resulting
<literal>FROM</literal>list would have no more than this many items. Smaller values reduce planning time but
might
! yield inferior query plans. The default is eight. It is usually
! wise to keep this less than <xref linkend="guc-geqo-threshold">. For more information see <xref
linkend="explicit-joins">. </para> </listitem> </varlistentry>
--- 2261,2275 ---- The planner will merge sub-queries into upper queries if the resulting
<literal>FROM</literal>list would have no more than this many items. Smaller values reduce planning time but
might
! yield inferior query plans. The default is eight. For more information see <xref
linkend="explicit-joins">. </para>
+
+ <para>
+ Setting this value to <xref linkend="guc-geqo-threshold"> or more
+ may trigger use of the GEQO planner, resulting in nondeterministic
+ plans. See <xref linkend="runtime-config-query-geqo">.
+ </para> </listitem> </varlistentry>