Enhance the processing of ORDER BY clauses on compound queries to better

match terms of the order by against expressions in the result set, in order
to enable better query optimization.

FossilOrigin-Name: a49e909c8738317c8383ce93771c0a9c4cf270bc

manifest

@@ -1,5 +1,5 @@
-C Enhance\sthe\sdo_test\sproc\sin\sthe\stest\ssuite\sso\sthat\sif\sthe\sexpected\sresult\nis\sof\sthe\sform\s"/.../"\sor\s"~/.../"\sthen\sregular\sexpression\smatching\sis\sdone\nbetween\sresult\sand\sthe\s"..."\spart\sof\sthe\sexpectation.\s\sIn\sthe\s~/.../\scase,\nwe\sexpect\sthere\sto\sbe\sno\smatch.
-D 2012-04-27T01:08:02.413
+C Enhance\sthe\sprocessing\sof\sORDER\sBY\sclauses\son\scompound\squeries\sto\sbetter\nmatch\sterms\sof\sthe\sorder\sby\sagainst\sexpressions\sin\sthe\sresult\sset,\sin\sorder\nto\senable\sbetter\squery\soptimization.
+D 2012-04-27T01:09:06.388
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 2f37e468503dbe79d35c9f6dffcf3fae1ae9ec20
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -171,7 +171,7 @@ F src/pragma.c e708b3bb5704605816f617e0b1d63a5488060715
 F src/prepare.c ec4989f7f480544bdc4192fe663470d2a2d7d61e
 F src/printf.c 7ffb4ebb8b341f67e049695ba031da717b3d2699
 F src/random.c cd4a67b3953b88019f8cd4ccd81394a8ddfaba50
-F src/resolve.c 969ec2bc52db1b068054ecf5ddc74f244102a71d
+F src/resolve.c 748e75299faff345f34f0e5bd02a2bac8aa69fcd
 F src/rowset.c f6a49f3e9579428024662f6e2931832511f831a1
 F src/select.c d7b9018b7dd2e821183d69477ab55c39b8272335
 F src/shell.c 04399b2f9942bd02ed5ffee3b84bcdb39c52a1e6
@@ -676,7 +676,7 @@ F test/select5.test e758b8ef94f69b111df4cb819008856655dcd535
 F test/select6.test cc25a8650cf9a4d4f74e586c45a75f9836516b18
 F test/select7.test dad6f00f0d49728a879d6eb6451d4752db0b0abe
 F test/select8.test 391de11bdd52339c30580dabbbbe97e3e9a3c79d
-F test/select9.test 74c0fb2c6eecb0219cbed0cbe3df136f8fbf9343
+F test/select9.test c0ca3cd87a8ebb04de2cb1402c77df55d911a0ea
 F test/selectA.test 06d1032fa9009314c95394f2ca2e60d9f7ae8532
 F test/selectB.test 954e4e49cf1f896d61794e440669e03a27ceea25
 F test/selectC.test 871fb55d884d3de5943c4057ebd22c2459e71977
@@ -995,7 +995,7 @@ F tool/tostr.awk e75472c2f98dd76e06b8c9c1367f4ab07e122d06
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
 F tool/warnings-clang.sh a8a0a3babda96dfb1ff51adda3cbbf3dfb7266c2
 F tool/warnings.sh fbc018d67fd7395f440c28f33ef0f94420226381
-P 696a5a40bb28c4a54c9951f877b67015dc00bf55
-R cec8a879e3e3cce3faf837e46a46ad14
+P c9a734406c016329e80d887f7438206e41c52ce7
+R 726c49ce225b59d324679d0a91302d23
 U drh
-Z 3ce2501ea7e4d58e039b2073955afa3e
+Z fb90c7a1a92b2c585d3a7791f60ba9a6

manifest.uuid

@@ -1 +1 @@
-c9a734406c016329e80d887f7438206e41c52ce7
+a49e909c8738317c8383ce93771c0a9c4cf270bc

src/resolve.c

@@ -883,7 +883,7 @@ static int resolveOrderGroupBy(
   ExprList *pOrderBy,   /* An ORDER BY or GROUP BY clause to resolve */
   const char *zType     /* Either "ORDER" or "GROUP", as appropriate */
 ){
-  int i;                         /* Loop counter */
+  int i, j;                      /* Loop counters */
   int iCol;                      /* Column number */
   struct ExprList_item *pItem;   /* A term of the ORDER BY clause */
   Parse *pParse;                 /* Parsing context */
@@ -920,6 +920,11 @@ static int resolveOrderGroupBy(
     if( sqlite3ResolveExprNames(pNC, pE) ){
       return 1;
     }
+    for(j=0; j<pSelect->pEList->nExpr; j++){
+      if( sqlite3ExprCompare(pE, pSelect->pEList->a[j].pExpr)==0 ){
+        pItem->iOrderByCol = j+1;
+      }
+    }
   }
   return sqlite3ResolveOrderGroupBy(pParse, pSelect, pOrderBy, zType);
 }

test/select9.test

@@ -415,5 +415,40 @@ do_test select9-4.X {
   }
 } {}
 
+# Testing to make sure that queries involving a view of a compound select
+# are planned efficiently.  This detects a problem reported on the mailing
+# list on 2012-04-26.  See
+#
+#  http://www.mail-archive.com/sqlite-users%40sqlite.org/msg69746.html
+#
+# For additional information.
+#
+do_test select9-5.1 {
+  db eval {
+    CREATE TABLE t51(x, y);
+    CREATE TABLE t52(x, y);
+    CREATE VIEW v5 as
+       SELECT x, y FROM t51
+       UNION ALL
+       SELECT x, y FROM t52;
+    CREATE INDEX t51x ON t51(x);
+    CREATE INDEX t52x ON t52(x);
+    EXPLAIN QUERY PLAN
+       SELECT * FROM v5 WHERE x='12345' ORDER BY y;
+  }
+} {~/SCAN TABLE/}  ;# Uses indices with "*"
+do_test select9-5.2 {
+  db eval {
+    EXPLAIN QUERY PLAN
+       SELECT x, y FROM v5 WHERE x='12345' ORDER BY y;
+  }
+} {~/SCAN TABLE/}  ;# Uses indices with "x, y"
+do_test select9-5.3 {
+  db eval {
+    EXPLAIN QUERY PLAN
+       SELECT x, y FROM v5 WHERE +x='12345' ORDER BY y;
+  }
+} {/SCAN TABLE/}   ;# Full table scan if the "+x" prevents index usage.
+
 
 finish_test