From 5e767c579344d6b980ec84940bbd9d72009a21bc Mon Sep 17 00:00:00 2001
From: drh <drh@noemail.net>
Date: Thu, 25 Feb 2010 04:15:47 +0000
Subject: [PATCH] Make sure the ON clause of a LEFT JOIN does not cause an
 index to be used to speed access to a table to the left of the join. Ticket
 [ebdbadade5]

FossilOrigin-Name: f0ae251abb9e8a8793f46a30b79b2ce541cf14d5
---
 manifest         | 20 ++++++++++----------
 manifest.uuid    |  2 +-
 src/where.c      |  5 +++--
 test/where6.test | 24 ++++++++++++++++++++++++
 4 files changed, 38 insertions(+), 13 deletions(-)

diff --git a/manifest b/manifest
index c7103b9a91..94a98d047e 100644
--- a/manifest
+++ b/manifest
@@ -1,8 +1,8 @@
 -----BEGIN PGP SIGNED MESSAGE-----
 Hash: SHA1
 
-C Add\stestcase()\smacros\sbeside\seach\ssqlite3_log()\scall\sto\smake\ssure\sit\sis\ntested\swith\sboth\slogging\senable\sand\sdisabled.
-D 2010-02-24T21:44:07
+C Make\ssure\sthe\sON\sclause\sof\sa\sLEFT\sJOIN\sdoes\snot\scause\san\sindex\sto\sbe\nused\sto\sspeed\saccess\sto\sa\stable\sto\sthe\sleft\sof\sthe\sjoin.\nTicket\s[ebdbadade5]
+D 2010-02-25T04:15:48
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 4f2f967b7e58a35bb74fb7ec8ae90e0f4ca7868b
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -224,7 +224,7 @@ F src/vdbemem.c aeba77b59f3553d3cc5b72c18a8267c6fba546b9
 F src/vdbetrace.c 864cef96919323482ebd9986f2132435115e9cc2
 F src/vtab.c 606adf51cd6d4ba51a8c6dccede06a6f7b0dd72d
 F src/walker.c 3112bb3afe1d85dc52317cb1d752055e9a781f8f
-F src/where.c 9269ec75e1e36e69748fd918ac5a636020c85e7e
+F src/where.c 399ea4c090284c9d16f76d685b9b44e8b9b4442b
 F test/aggerror.test a867e273ef9e3d7919f03ef4f0e8c0d2767944f2
 F test/alias.test 4529fbc152f190268a15f9384a5651bbbabc9d87
 F test/all.test 14165b3e32715b700b5f0cbf8f6e3833dda0be45
@@ -757,7 +757,7 @@ F test/where2.test 45eacc126aabb37959a387aa83e59ce1f1f03820
 F test/where3.test 97d3936e6a443b968f1a61cdcc0f673252000e94
 F test/where4.test e9b9e2f2f98f00379e6031db6a6fca29bae782a2
 F test/where5.test fdf66f96d29a064b63eb543e28da4dfdccd81ad2
-F test/where6.test 42c4373595f4409d9c6a9987b4a60000ad664faf
+F test/where6.test 5da5a98cec820d488e82708301b96cb8c18a258b
 F test/where7.test fdd58ab9dec9f97679e65d4414bf5e07d725d79f
 F test/where8.test 2bb8ea44b745fcc93db150fac9ce33d12e499760
 F test/where8m.test da346596e19d54f0aba35ebade032a7c47d79739
@@ -795,14 +795,14 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
-P dd480f62afa56ff85c2dd57ee7a16eee427e823f
-R c9523526f48a8860988dae54cadcdbf1
+P 1168763d2cd96acfa0488198e8bc82f0c4fa35a3
+R 1756ec34ec14812b999545b49c238389
 U drh
-Z 1dbd84d12743933d537cbe784ede4bca
+Z cef349c135ac8fde894db77ffb6c3cd3
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.6 (GNU/Linux)
 
-iD8DBQFLhZ2qoxKgR168RlERAtqjAJ9ekluC7QTqJi+Q6cIzjOZVf34HNACfUmiQ
-TteOSExg+iy0J6i1CF0ncys=
-=oaDc
+iD8DBQFLhfl5oxKgR168RlERAuYtAJ9UCQXaWqORFlTB8prfqFcd5VDUngCcDDwZ
+5GuaCQJQEFY+u7p5eZA7abU=
+=4lWh
 -----END PGP SIGNATURE-----
diff --git a/manifest.uuid b/manifest.uuid
index d00c919731..e4b48db311 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-1168763d2cd96acfa0488198e8bc82f0c4fa35a3
\ No newline at end of file
+f0ae251abb9e8a8793f46a30b79b2ce541cf14d5
\ No newline at end of file
diff --git a/src/where.c b/src/where.c
index f27ce66928..5f81ce0768 100644
--- a/src/where.c
+++ b/src/where.c
@@ -1096,7 +1096,7 @@ static void exprAnalyze(
   Expr *pExpr;                     /* The expression to be analyzed */
   Bitmask prereqLeft;              /* Prerequesites of the pExpr->pLeft */
   Bitmask prereqAll;               /* Prerequesites of pExpr */
-  Bitmask extraRight = 0;          /* */
+  Bitmask extraRight = 0;          /* Extra dependencies on LEFT JOIN */
   Expr *pStr1 = 0;                 /* RHS of LIKE/GLOB operator */
   int isComplete = 0;              /* RHS of LIKE/GLOB ends with wildcard */
   int noCase = 0;                  /* LIKE/GLOB distinguishes case */
@@ -1168,7 +1168,8 @@ static void exprAnalyze(
       pLeft = pDup->pLeft;
       pNew->leftCursor = pLeft->iTable;
       pNew->u.leftColumn = pLeft->iColumn;
-      pNew->prereqRight = prereqLeft;
+      testcase( (prereqLeft | extraRight) != prereqLeft );
+      pNew->prereqRight = prereqLeft | extraRight;
       pNew->prereqAll = prereqAll;
       pNew->eOperator = operatorMask(pDup->op);
     }
diff --git a/test/where6.test b/test/where6.test
index bcea6540a5..83e975b7dd 100644
--- a/test/where6.test
+++ b/test/where6.test
@@ -127,4 +127,28 @@ do_test where6-2.14 {
   }
 } {1 3 1 3}
 
+# Ticket [ebdbadade5b]:
+# If the ON close on a LEFT JOIN is of the form x=y where both x and y
+# are indexed columns on tables to left of the join, then do not use that 
+# term with indices to either table.
+#
+do_test where6-3.1 {
+  db eval {
+    CREATE TABLE t4(x UNIQUE);
+    INSERT INTO t4 VALUES('abc');
+    INSERT INTO t4 VALUES('def');
+    INSERT INTO t4 VALUES('ghi');
+    CREATE TABLE t5(a, b, c, PRIMARY KEY(a,b));
+    INSERT INTO t5 VALUES('abc','def',123);
+    INSERT INTO t5 VALUES('def','ghi',456);
+
+    SELECT t4a.x, t4b.x, t5.c, t6.v
+      FROM t4 AS t4a
+           INNER JOIN t4 AS t4b
+           LEFT JOIN t5 ON t5.a=t4a.x AND t5.b=t4b.x
+           LEFT JOIN (SELECT 1 AS v) AS t6 ON t4a.x=t4b.x
+     ORDER BY 1, 2, 3;
+  }
+} {abc abc {} 1 abc def 123 {} abc ghi {} {} def abc {} {} def def {} 1 def ghi 456 {} ghi abc {} {} ghi def {} {} ghi ghi {} 1}
+
 finish_test