Disable the query flattening optimization when the subquery is a compound

query with an ORDER BY clause.  Ticket #3773 shows why that combination
does not work. (CVS 6437)

FossilOrigin-Name: 23f90d50737a36ebd17152dd4667948ce7049967

diff --git a/manifest b/manifest
index 59561aa6d104b3d48fde8361211ff3bfec591446..8fcc3d2fc13c895997987e086fe1163bcdd61169 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Change\sthe\sway\sthat\sthe\srandom()\sSQL\sfunction\sprevents\sthe\smaximum\nnegative\sinteger\sso\sthat\sit\sis\stestable.\s(CVS\s6436)
-D 2009-04-02T14:05:22
+C Disable\sthe\squery\sflattening\soptimization\swhen\sthe\ssubquery\sis\sa\scompound\nquery\swith\san\sORDER\sBY\sclause.\s\sTicket\s#3773\sshows\swhy\sthat\scombination\ndoes\snot\swork.\s(CVS\s6437)
+D 2009-04-02T16:59:47
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 583e87706abc3026960ed759aff6371faf84c211
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -155,7 +155,7 @@ F src/printf.c 9866a9a9c4a90f6d4147407f373df3fd5d5f9b6f
 F src/random.c 676b9d7ac820fe81e6fb2394ac8c10cff7f38628
 F src/resolve.c 094e44450371fb27869eb8bf679aacbe51fdc56d
 F src/rowset.c badb9f36b3a2ced9ee9551f4ce730f5fab442791
-F src/select.c bd494b68a54a51de3df94ecdd6d24fa7598929d1
+F src/select.c 462d9671e91accd983110fa38674be0d2a3daa66
 F src/shell.c 0a11f831603f17fea20ca97133c0f64e716af4a7
 F src/sqlite.h.in 0db1e59d89aeacb8fe64a19fd14c13a796060ccb
 F src/sqlite3ext.h 1db7d63ab5de4b3e6b83dd03d1a4e64fef6d2a17
@@ -525,7 +525,7 @@ F test/select7.test 7906735805cfbee4dddc0bed4c14e68d7f5f9c5f
 F test/select8.test 391de11bdd52339c30580dabbbbe97e3e9a3c79d
 F test/select9.test b4007b15396cb7ba2615cab31e1973b572e43210
 F test/selectA.test 06d1032fa9009314c95394f2ca2e60d9f7ae8532
-F test/selectB.test 31e81ac9af7d224850e0706350f070ecb92fcbc7
+F test/selectB.test f305cc6660804cb239aab4e2f26b0e288b59958b
 F test/selectC.test ae49d258c875bc1712898f1632062bc5c01a7470
 F test/server1.test f5b790d4c0498179151ca8a7715a65a7802c859c
 F test/shared.test 3b448dc0f7a9356e641894ed81c27599f39d809d
@@ -635,6 +635,7 @@ F test/tkt3731.test 8a6e3732f5a8a24eb875a6faf287ef77bb8c0579
 F test/tkt3757.test 8f2208930655bbd4f92c14e19e72303a43e098ef
 F test/tkt3761.test b95ea9c98f21cf91325f18a984887e62caceab33
 F test/tkt3762.test 2a9f3b03df44ec49ec0cfa8d5da6574c2a7853df
+F test/tkt3773.test 430b06567ce40285dfd2c4834a2a61816403efeb
 F test/tokenize.test ce430a7aed48fc98301611429595883fdfcab5d7
 F test/trace.test 951cd0f5f571e7f36bf7bfe04be70f90fb16fb00
 F test/trans.test 8b79967a7e085289ec64890c6fdf9d089e1b4a5f
@@ -714,7 +715,7 @@ F tool/speedtest16.c c8a9c793df96db7e4933f0852abb7a03d48f2e81
 F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
-P eb65e64e7ed5edbe506365971d4d81ea037098d3
-R 8df4d225606e2ef05ef65f87475b71e8
+P 995f2b9b1031fadc85e179701536b9dd4153654b
+R 46fe8bc037aad00af46b1a5a3fe7667b
 U drh
-Z 5cdbeb238444c4b2ca5bad90a2a75082
+Z e4c9dcb4224dad890dcbd3f746876a28

diff --git a/manifest.uuid b/manifest.uuid
index 8035b62021742dab97f92a1bd3b82a2f3a1114d8..fa10f36f7b39ee4c864996dd7b843b00715cce7c 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-995f2b9b1031fadc85e179701536b9dd4153654b
\ No newline at end of file
+23f90d50737a36ebd17152dd4667948ce7049967
\ No newline at end of file

diff --git a/src/select.c b/src/select.c
index b7f3c638289c3cfbd8d7169704c302b091ca4806..08d9e416f753e884cee1933cba37fb5520b79a3f 100644 (file)
--- a/src/select.c
+++ b/src/select.c
@@ -12,7 +12,7 @@
 ** This file contains C code routines that are called by the parser
 ** to handle SELECT statements in SQLite.
 **
-** $Id: select.c,v 1.506 2009/03/31 03:41:57 shane Exp $
+** $Id: select.c,v 1.507 2009/04/02 16:59:47 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -2555,6 +2555,12 @@ static void substSelect(
 **  (19)  The subquery does not use LIMIT or the outer query does not
 **        have a WHERE clause.
 **
+**  (20)  If the sub-query is a compound select, then it must not use
+**        an ORDER BY clause.  Ticket #3773.  We could relax this constraint
+**        somewhat by saying that the terms of the ORDER BY clause must
+**        appear as unmodified result columns in the outer query.  But
+**        have other optimizations in mind to deal with that case.
+**
 ** 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.
@@ -2665,6 +2671,9 @@ static int flattenSubquery(
   ** queries.
   */
   if( pSub->pPrior ){
+    if( pSub->pOrderBy ){
+      return 0;  /* Restriction 20 */
+    }
     if( isAgg || (p->selFlags & SF_Distinct)!=0 || pSrc->nSrc!=1 ){
       return 0;
     }

diff --git a/test/selectB.test b/test/selectB.test
index 9f5261e91edda3507ef4190f33375c62e8d8f9c9..3fdf85c0f9fc92b47b02bb2215b55b22702db470 100644 (file)
--- a/test/selectB.test
+++ b/test/selectB.test
@@ -10,7 +10,7 @@
 #***********************************************************************
 # This file implements regression tests for SQLite library. 
 #
-# $Id: selectB.test,v 1.9 2008/08/04 03:51:24 danielk1977 Exp $
+# $Id: selectB.test,v 1.10 2009/04/02 16:59:47 drh Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -122,7 +122,7 @@ for {set ii 1} {$ii <= 2} {incr ii} {
   } {
     SELECT a FROM t1 UNION ALL SELECT d FROM t2 ORDER BY 1 LIMIT 2 OFFSET 3
   } {12 14}
-  
+
   test_transform selectB-$ii.9 {
     SELECT * FROM (
       SELECT a FROM t1 UNION ALL SELECT d FROM t2 UNION ALL SELECT c FROM t1
@@ -156,33 +156,35 @@ for {set ii 1} {$ii <= 2} {incr ii} {
     SELECT a FROM t1 UNION ALL SELECT d FROM t2 LIMIT 2
   } {2 8}
 
-  test_transform selectB-$ii.13 {
-    SELECT * FROM (SELECT a FROM t1 UNION ALL SELECT d FROM t2 ORDER BY a ASC)
-  } {
-    SELECT a FROM t1 UNION ALL SELECT d FROM t2 ORDER BY 1 ASC
-  } {2 3 8 12 14 21}
-
-  test_transform selectB-$ii.14 {
-    SELECT * FROM (SELECT a FROM t1 UNION ALL SELECT d FROM t2 ORDER BY a DESC)
-  } {
-    SELECT a FROM t1 UNION ALL SELECT d FROM t2 ORDER BY 1 DESC
-  } {21 14 12 8 3 2}
-
-  test_transform selectB-$ii.14 {
-    SELECT * FROM (
-      SELECT a FROM t1 UNION ALL SELECT d FROM t2 ORDER BY a DESC
-    ) LIMIT 2 OFFSET 2
-  } {
-    SELECT a FROM t1 UNION ALL SELECT d FROM t2 ORDER BY 1 DESC LIMIT 2 OFFSET 2
-  } {12 8}
-
-  test_transform selectB-$ii.15 {
-    SELECT * FROM (
-      SELECT a, b FROM t1 UNION ALL SELECT d, e FROM t2 ORDER BY a ASC, e DESC
-    )
-  } {
-    SELECT a, b FROM t1 UNION ALL SELECT d, e FROM t2 ORDER BY a ASC, e DESC
-  } {2 4 3 6 8 10 12 15 14 16 21 24}
+  # An ORDER BY in a compound subqueries defeats flattening.  Ticket #3773
+  # test_transform selectB-$ii.13 {
+  #   SELECT * FROM (SELECT a FROM t1 UNION ALL SELECT d FROM t2 ORDER BY a ASC)
+  # } {
+  #   SELECT a FROM t1 UNION ALL SELECT d FROM t2 ORDER BY 1 ASC
+  # } {2 3 8 12 14 21}
+  # 
+  # test_transform selectB-$ii.14 {
+  #  SELECT * FROM (SELECT a FROM t1 UNION ALL SELECT d FROM t2 ORDER BY a DESC)
+  # } {
+  #  SELECT a FROM t1 UNION ALL SELECT d FROM t2 ORDER BY 1 DESC
+  # } {21 14 12 8 3 2}
+  #
+  # test_transform selectB-$ii.14 {
+  #   SELECT * FROM (
+  #     SELECT a FROM t1 UNION ALL SELECT d FROM t2 ORDER BY a DESC
+  #   ) LIMIT 2 OFFSET 2
+  # } {
+  #   SELECT a FROM t1 UNION ALL SELECT d FROM t2 ORDER BY 1 DESC
+  #    LIMIT 2 OFFSET 2
+  # } {12 8}
+  #
+  # test_transform selectB-$ii.15 {
+  #   SELECT * FROM (
+  #     SELECT a, b FROM t1 UNION ALL SELECT d, e FROM t2 ORDER BY a ASC, e DESC
+  #  )
+  # } {
+  #   SELECT a, b FROM t1 UNION ALL SELECT d, e FROM t2 ORDER BY a ASC, e DESC
+  # } {2 4 3 6 8 10 12 15 14 16 21 24}
 }
 
 do_test selectB-3.0 {

diff --git a/test/tkt3773.test b/test/tkt3773.test
new file mode 100644 (file)
index 0000000..0dc414e
--- /dev/null
+++ b/test/tkt3773.test
@@ -0,0 +1,38 @@
+# 2009 April 2
+#
+# 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.
+#
+#***********************************************************************
+#
+# Ticket #3773:  Be careful not to over-optimize when a compound
+# subquery contains an ORDER BY clause.
+#
+#
+# $Id: tkt3773.test,v 1.1 2009/04/02 16:59:47 drh Exp $
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+
+do_test tkt3773-1.1 {
+  db eval {
+    CREATE TABLE t1(a,b);
+    INSERT INTO t1 VALUES(2,1);
+    INSERT INTO t1 VALUES(33,3);
+    CREATE TABLE t2(x,y);
+    INSERT INTO t2 VALUES(123,2);
+    INSERT INTO t2 VALUES(4,4);
+    SELECT a FROM (
+      SELECT a, b FROM t1
+      UNION ALL
+      SELECT x, y FROM t2
+      ORDER BY 2
+    );
+  }
+} {2 123 33 4}
+
+finish_test