From: Paul Ramsey <pramsey@cleverelephant.ca>
Date: Sun, 12 Oct 2008 17:47:37 +0000 (+0000)
Subject: Performance boost: only detoast the front of the tuple first and
X-Git-Tag: 1.4.0b1~634
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=57586b2893de193801692710e08f133a0cb4ff87;p=postgis

Performance boost: only detoast the front of the tuple first and
extract the bbox from that.


git-svn-id: http://svn.osgeo.org/postgis/trunk@3091 b70326c6-7e19-0410-871a-916f4a2858ee
---

diff --git a/lwgeom/lwgeom_gist.c b/lwgeom/lwgeom_gist.c
index 880983e17..924e0513e 100644
--- a/lwgeom/lwgeom_gist.c
+++ b/lwgeom/lwgeom_gist.c
@@ -551,6 +551,7 @@ Datum LWGEOM_gist_consistent(PG_FUNCTION_ARGS)
 	PG_LWGEOM *query ; /* lwgeom serialized form */
 	StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);
 	bool result;
+	uchar *serialized_lwgeom;
 	BOX2DFLOAT4  box;
 
 #if POSTGIS_PGSQL_VERSION >= 84
@@ -571,7 +572,11 @@ Datum LWGEOM_gist_consistent(PG_FUNCTION_ARGS)
 		PG_RETURN_BOOL(false); /* null query - this is screwy! */
 	}
 
-	query = (PG_LWGEOM*)PG_DETOAST_DATUM(PG_GETARG_DATUM(1));
+	/* 
+	** First pull only a small amount of the tuple, enough to 
+	** get the bounding box, if one exists.
+	*/
+	query = (PG_LWGEOM*)PG_DETOAST_DATUM_SLICE(PG_GETARG_DATUM(1), 0, VARHDRSZ + 1 + sizeof(BOX2DFLOAT4) );
 
 	if ( ! (DatumGetPointer(entry->key) != NULL && query) )
 	{
@@ -580,10 +585,24 @@ Datum LWGEOM_gist_consistent(PG_FUNCTION_ARGS)
 		PG_RETURN_BOOL(FALSE);
 	}
 
-	if ( ! getbox2d_p(SERIALIZED_FORM(query), &box) )
+	/*
+	** If the bounding box exists, copy it into the working variable.
+	** If not, pull the full toasted data out, and call the standard box 
+	** retrieval function, which will calculate the box from scratch.
+	*/
+	serialized_lwgeom = SERIALIZED_FORM(query);
+	if( lwgeom_hasBBOX(serialized_lwgeom[0]) ) 
 	{
-		PG_FREE_IF_COPY(query, 1);
-		PG_RETURN_BOOL(FALSE);
+		memcpy(&box, serialized_lwgeom + 1, sizeof(BOX2DFLOAT4));
+	} 
+	else 
+	{
+		query = (PG_LWGEOM*)PG_DETOAST_DATUM(PG_GETARG_DATUM(1)); 
+		if ( ! getbox2d_p(SERIALIZED_FORM(query), &box) )
+		{
+			PG_FREE_IF_COPY(query, 1);
+			PG_RETURN_BOOL(FALSE);
+		}
 	}
 
 	if (GIST_LEAF(entry))