From 05bba3d176e0adc1a032d5c8c6ea2a7622c7dd0d Mon Sep 17 00:00:00 2001
From: Tom Lane
Date: Wed, 29 Oct 2008 00:00:39 +0000
Subject: Be more tense about not creating tuplestores with randomAccess = true
 unless backwards scan could actually happen.  In particular, pass a flag to
 materialize-mode SRFs that tells them whether they need to require random
 access.  In passing, also suppress unneeded backward-scan overhead for a
 Portal's holdStore tuplestore.  Per my proposal about reducing I/O costs for
 tuplestores.

---
 contrib/xml2/xpath.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

(limited to 'contrib/xml2/xpath.c')

diff --git a/contrib/xml2/xpath.c b/contrib/xml2/xpath.c
index 39908494f3e..b2f3342f737 100644
--- a/contrib/xml2/xpath.c
+++ b/contrib/xml2/xpath.c
@@ -1,5 +1,5 @@
 /*
- * $PostgreSQL: pgsql/contrib/xml2/xpath.c,v 1.20 2008/05/17 01:28:22 adunstan Exp $ 
+ * $PostgreSQL: pgsql/contrib/xml2/xpath.c,v 1.21 2008/10/29 00:00:38 tgl Exp $ 
  *
  * Parser interface for DOM-based parser (libxml) rather than
    stream-based SAX-type parser */
@@ -688,7 +688,9 @@ xpath_table(PG_FUNCTION_ARGS)
 	 * Create the tuplestore - work_mem is the max in-memory size before a
 	 * file is created on disk to hold it.
 	 */
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	tupstore =
+		tuplestore_begin_heap(rsinfo->allowedModes & SFRM_Materialize_Random,
+							  false, work_mem);
 
 	MemoryContextSwitchTo(oldcontext);
 
-- 
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