Skip flattening if subquery has LIMIT and outer query is DISTINCT. Fix for ticket 752e1646fc.

FossilOrigin-Name: 559739998833643f589fa76d8360080691f83c18

manifest

@@ -1,8 +1,5 @@
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-C Fix\sa\sbug\sin\sthe\snew\sWHERE-clause\sprocessing\sthat\stries\sto\suse\san\nindex\sto\sresolve\sIS\sNOT\sNULL\sconstraints\swhen\sSQLITE_ENABLE_STAT2\sis\ndefined.\s\sThe\sbug\scould\scause\smemory\soverruns\sand\ssegfaults.\s\sThe\sbug\nwas\snew\sto\sthe\scode\sand\shas\snot\sappeared\sin\san\sofficial\srelease.\nFound\sduring\sstructural\stesting.
-D 2011-02-11T06:59:02.077
+C Skip\sflattening\sif\ssubquery\shas\sLIMIT\sand\souter\squery\sis\sDISTINCT.\sFix\sfor\sticket\s752e1646fc.
+D 2011-02-11T20:52:21
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 27701a1653595a1f2187dc61c8117e00a6c1d50f
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -25,7 +22,7 @@ F art/src_logo.gif 9341ef09f0e53cd44c0c9b6fc3c16f7f3d6c2ad9
 F config.guess 226d9a188c6196f3033ffc651cbc9dcee1a42977
 F config.h.in 868fdb48c028421a203470e15c69ada15b9ba673
 F config.sub 9ebe4c3b3dab6431ece34f16828b594fb420da55
-F configure c38c1947db7ed4adaed2affcb09cea9d3acd5a9a x
+F configure c38c1947db7ed4adaed2affcb09cea9d3acd5a9a
 F configure.ac 87a3c71bbe9c925381c154413eea7f3cdc397244
 F contrib/sqlitecon.tcl 210a913ad63f9f991070821e599d600bd913e0ad
 F doc/lemon.html f0f682f50210928c07e562621c3b7e8ab912a538
@@ -101,7 +98,7 @@ F ext/rtree/rtree_util.tcl 06aab2ed5b826545bf215fff90ecb9255a8647ea
 F ext/rtree/sqlite3rtree.h 1af0899c63a688e272d69d8e746f24e76f10a3f0
 F ext/rtree/tkt3363.test 142ab96eded44a3615ec79fba98c7bde7d0f96de
 F ext/rtree/viewrtree.tcl eea6224b3553599ae665b239bd827e182b466024
-F install-sh 9d4de14ab9fb0facae2f48780b874848cbf2f895 x
+F install-sh 9d4de14ab9fb0facae2f48780b874848cbf2f895
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 F main.mk 54190fab7cdba523e311c274c95ea480f32abfb5
 F mkdll.sh 7d09b23c05d56532e9d44a50868eb4b12ff4f74a
@@ -178,7 +175,7 @@ F src/printf.c df2ff3bb5409e8958136933342c46464fbd017e7
 F src/random.c cd4a67b3953b88019f8cd4ccd81394a8ddfaba50
 F src/resolve.c 1c0f32b64f8e3f555fe1f732f9d6f501a7f05706
 F src/rowset.c 69afa95a97c524ba6faf3805e717b5b7ae85a697
-F src/select.c 8a7ba246b0b4bb45df7fbc52681728a0e3deaaa7
+F src/select.c ae2f38effc99cfb9d8ebce36249d938487b3230d
 F src/shell.c 649c51979812f77f97507024a4cea480c6862b8b
 F src/sqlite.h.in 388fca88d54577f671dc98bd805ff16085eabac1
 F src/sqlite3ext.h c90bd5507099f62043832d73f6425d8d5c5da754
@@ -697,6 +694,7 @@ F test/tkt-4a03edc4c8.test 2865e4edbc075b954daa82f8da7cc973033ec76e
 F test/tkt-5d863f876e.test 884072c2de496ddbb90c387c9ebc0d4f44a91b8e
 F test/tkt-5e10420e8d.test 904d1687b3c06d43e5b3555bbcf6802e7c0ffd84
 F test/tkt-5ee23731f.test 3581260f2a71e51db94e1506ba6b0f7311d002a9
+F test/tkt-752e1646fc.test ea78d88d14fe9866bdd991c634483334639e13bf
 F test/tkt-78e04e52ea.test ab52f0c1e2de6e46c910f4cc16b086bba05952b7
 F test/tkt-80ba201079.test a09684db1a0bd55b8838f606adccee456a51ddbf
 F test/tkt-80e031a00f.test 9a154173461a4dbe2de49cda73963e04842d52f7
@@ -909,14 +907,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
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manifest.uuid

@@ -1 +1 @@
-a5c36b9f39ab9629b857ec9c550f3892c0d94fb4
+559739998833643f589fa76d8360080691f83c18

src/select.c

@@ -2652,6 +2652,9 @@ static void substSelect(
 **        appear as unmodified result columns in the outer query.  But
 **        have other optimizations in mind to deal with that case.
 **
+**  (21)  The subquery does not use LIMIT or the outer query is not
+**        DISTINCT.  (See ticket [752e1646fc]).
+**
 ** In this routine, the "p" parameter is a pointer to the outer query.
 ** The subquery is p->pSrc->a[iFrom].  isAgg is true if the outer query
 ** uses aggregates and subqueryIsAgg is true if the subquery uses aggregates.
@@ -2720,6 +2723,9 @@ static int flattenSubquery(
   }
   if( isAgg && pSub->pOrderBy ) return 0;                /* Restriction (16) */
   if( pSub->pLimit && p->pWhere ) return 0;              /* Restriction (19) */
+  if( pSub->pLimit && (p->selFlags & SF_Distinct)!=0 ){
+     return 0;         /* Restriction (21) */
+  }
 
   /* OBSOLETE COMMENT 1:
   ** Restriction 3:  If the subquery is a join, make sure the subquery is 

test/tkt-752e1646fc.test

@@ -0,0 +1,30 @@
+# 2010 April 15
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+# This file implements regression tests for SQLite library.
+#
+# This file implements tests to verify that ticket [752e1646fc] has been
+# fixed.  
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+
+do_test tkt-752e1646fc-1.1 {
+  execsql {
+    CREATE TABLE "test" ("letter" VARCHAR(1) PRIMARY KEY, "number" INTEGER NOT NULL);
+    INSERT INTO "test" ("letter", "number") VALUES('b', 1); 
+    INSERT INTO "test" ("letter", "number") VALUES('a', 2); 
+    INSERT INTO "test" ("letter", "number") VALUES('c', 2); 
+    SELECT DISTINCT "number" FROM (SELECT "letter", "number" FROM "test" ORDER BY "letter", "number" LIMIT 1) AS "test";
+  }
+} {2}
+
+finish_test