Disable an overzealous optimization the omitted sorting on a join if the first

table gave a unique result.  The sort can only be omitted if all tables in
the join are unique.  Ticket #1358. (CVS 2589)

FossilOrigin-Name: 4f07661279fb11a06b3ddffeda672f077c0d306a

manifest

@@ -1,5 +1,5 @@
-C Fix\sa\scomment\sin\sprintf.\s(CVS\s2588)
+C Disable\san\soverzealous\soptimization\sthe\somitted\ssorting\son\sa\sjoin\sif\sthe\sfirst\ntable\sgave\sa\sunique\sresult.\s\sThe\ssort\scan\sonly\sbe\somitted\sif\sall\stables\sin\nthe\sjoin\sare\sunique.\s\sTicket\s#1358.\s(CVS\s2589)
-D 2005-08-13T13:40:42
+D 2005-08-13T16:13:05
 F Makefile.in 22ea9c0fe748f591712d8fe3c6d972c6c173a165
 F Makefile.linux-gcc 06be33b2a9ad4f005a5f42b22c4a19dab3cbb5c7
 F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028
@@ -86,7 +86,7 @@ F src/vdbeapi.c dc5b78cabf8d6e33318bd3d4ed25307d2aadce9a
 F src/vdbeaux.c d53139d819b887dac608ac4ae9a501baee3cd311
 F src/vdbefifo.c b8805850afe13b43f1de78d58088cb5d66f88e1e
 F src/vdbemem.c 89154caae3b8d4d0397e1235390fc4ff8aba4233
-F src/where.c ac754c021f716e17337f45ffdc2436c6d5109fd3
+F src/where.c 27d6432ea5fa255008ef80cb1d8e5e58ea8d615f
 F tclinstaller.tcl 046e3624671962dc50f0481d7c25b38ef803eb42
 F test/all.test 7f0988442ab811dfa41793b5b550f5828ce316f3
 F test/alter.test 9d6837a3d946b73df692b7cef2a7644d2e2f6bc6
@@ -198,7 +198,7 @@ F test/select4.test c239f516aa31f42f2ef7c6d7cd01105f08f934ca
 F test/select5.test 2d414f712bff8e590091e08f9b7287600731be00
 F test/select6.test 6559d16ad16edb7d6864f7e74a3d204d0af72486
 F test/select7.test 1bf795b948c133a15a2a5e99d3270e652ec58ce6
-F test/sort.test 131787aadaa0eca8bc97eaf244bbde2380a4bb77
+F test/sort.test 3b871d6e032f0a6c84d9f3d2d4b226e8fda97de0
 F test/subquery.test 0df3de0dbb65165b96ebe895550f1549d5439856
 F test/subselect.test 3f3f7a940dc3195c3139f4d530385cb54665d614
 F test/table.test d0e05ede3f6e5a8b79f8661ddcc4618cf7e69f8a
@@ -228,7 +228,7 @@ F test/vacuum2.test 5d77e98c458bcdbeecc6327de5107179ba1aa095
 F test/varint.test ab7b110089a08b9926ed7390e7e97bdefeb74102
 F test/view.test 3c79232a2ee45918c62a0cf90411525899404a76
 F test/where.test b6ab0f64adc5fbb4259f284b19da6cd9aeadc711
-F test/where2.test 3432fc9c24af9120df65a9a4cc8dad3bb9285633
+F test/where2.test 503e2e2b6abe14c5c10222e72d08ef84c1bf1ffb
 F tool/diffdb.c 7524b1b5df217c20cd0431f6789851a4e0cb191b
 F tool/lemon.c c88936c67f6411608db8fa4254d254f509fa40f6
 F tool/lempar.c f0c30abcae762a7d1eb37cd88b2232ab8dd625fb
@@ -291,7 +291,7 @@ F www/tclsqlite.tcl 3df553505b6efcad08f91e9b975deb2e6c9bb955
 F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
 F www/version3.tcl a99cf5f6d8bd4d5537584a2b342f0fb9fa601d8b
 F www/whentouse.tcl 528299b8316726dbcc5548e9aa0648c8b1bd055b
-P 240bb049001b0d1419d72b6ef909236e12bd5949
+P 1054685f15095ef147d9e9a32bd56b0eaaf9fa54
-R c4c4f129cf45073166872f89ead87e29
+R d225fbaf33bc549b919b820e573eeddf
 U drh
-Z 355afc4615017b256e4a9bb53eaadeae
+Z ca2afe75bb06779be079d2484ddb7fa4

manifest.uuid

@@ -1 +1 @@
-1054685f15095ef147d9e9a32bd56b0eaaf9fa54
+4f07661279fb11a06b3ddffeda672f077c0d306a

src/where.c

@@ -16,7 +16,7 @@
 ** so is applicable.  Because this module is responsible for selecting
 ** indices, you might also think of this module as the "query optimizer".
 **
-** $Id: where.c,v 1.160 2005/08/12 22:56:09 drh Exp $
+** $Id: where.c,v 1.161 2005/08/13 16:13:05 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -719,10 +719,6 @@ or_not_possible:
 ** constraints.  Any of these columns may be missing from the ORDER BY
 ** clause and the match can still be a success.
 **
-** If the index is UNIQUE, then the ORDER BY clause is allowed to have
-** additional terms past the end of the index and the match will still
-** be a success.
-**
 ** All terms of the ORDER BY that match against the index must be either
 ** ASC or DESC.  (Terms of the ORDER BY clause past the end of a UNIQUE
 ** index do not need to satisfy this constraint.)  The *pbRev value is
@@ -791,10 +787,9 @@ static int isSortingIndex(
   }
 
   /* The index can be used for sorting if all terms of the ORDER BY clause
-  ** or covered or if we ran out of index columns and the it is a UNIQUE
+  ** are covered.
-  ** index.
   */
-  if( j>=nTerm || (i>=pIdx->nColumn && pIdx->onError!=OE_None) ){
+  if( j>=nTerm ){
     *pbRev = sortOrder==SQLITE_SO_DESC;
     return 1;
   }
@@ -829,14 +824,12 @@ static int sortableByRowid(
 ** the total cost of performing operatings with O(logN) or O(NlogN)
 ** complexity.  Because N is just a guess, it is no great tragedy if
 ** logN is a little off.
-**
-** We can assume N>=1.0;
 */
 static double estLog(double N){
   double logN = 1.0;
   double x = 10.0;
   while( N>x ){
-    logN = logN+1.0;
+    logN += 1.0;
     x *= 10;
   }
   return logN;
@@ -1013,7 +1006,7 @@ static double bestIndex(
     */
     if( pOrderBy ){
       if( (flags & WHERE_COLUMN_IN)==0 &&
-        isSortingIndex(pParse, pProbe, pSrc->pTab, iCur, pOrderBy, nEq, &rev) ){
+           isSortingIndex(pParse,pProbe,pSrc->pTab,iCur,pOrderBy,nEq,&rev) ){
         if( flags==0 ){
           flags = WHERE_COLUMN_RANGE;
         }

test/sort.test

@@ -11,7 +11,7 @@
 # This file implements regression tests for SQLite library.  The
 # focus of this file is testing the CREATE TABLE statement.
 #
-# $Id: sort.test,v 1.21 2005/08/13 12:59:16 drh Exp $
+# $Id: sort.test,v 1.22 2005/08/13 16:13:06 drh Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -431,4 +431,20 @@ do_test sort-10.3 {
   }
 } {2 1}
 
+# ticket #1358.  Just because one table in a join gives a unique
+# result does not mean they all do.  We cannot disable sorting unless
+# all tables in the join give unique results.
+#
+do_test sort-11.1 {
+  execsql {
+    create table t8(a unique, b, c);
+    insert into t8 values(1,2,3);
+    insert into t8 values(2,3,4);
+    create table t9(x,y);
+    insert into t9 values(2,4);
+    insert into t9 values(2,3);
+    select y from t8, t9 where a=1 order by a, y;
+  }
+} {3 4}
+
 finish_test

test/where2.test

@@ -12,7 +12,7 @@
 # focus of this file is testing the use of indices in WHERE clauses
 # based on recent changes to the optimizer.
 #
-# $Id: where2.test,v 1.4 2005/07/29 19:43:59 drh Exp $
+# $Id: where2.test,v 1.5 2005/08/13 16:13:06 drh Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -238,6 +238,37 @@ do_test where2-6.6 {
   }
 } {1 0 4 4 2 1 9 10 sort a i1w b i1zyx}
 
-
+# Unique queries (queries that are guaranteed to return only a single
+# row of result) do not call the sorter.  But all tables must give
+# a unique result.  If any one table in the join does not give a unique
+# result then sorting is necessary.
+#
+do_test where2-7.1 {
+  cksort {
+    create table t8(a unique, b, c);
+    insert into t8 values(1,2,3);
+    insert into t8 values(2,3,4);
+    create table t9(x,y);
+    insert into t9 values(2,4);
+    insert into t9 values(2,3);
+    select y from t8, t9 where a=1 order by a, y;
+  }
+} {3 4 sort}
+do_test where2-7.2 {
+  cksort {
+    select * from t8 where a=1 order by b, c
+  }
+} {1 2 3 nosort}
+do_test where2-7.3 {
+  cksort {
+    select * from t8, t9 where a=1 and y=3 order by b, x
+  }
+} {1 2 3 2 3 sort}
+do_test where2-7.4 {
+  cksort {
+    create unique index i9y on t9(y);
+    select * from t8, t9 where a=1 and y=3 order by b, x
+  }
+} {1 2 3 2 3 nosort}
 
 finish_test