From: drh <drh@noemail.net>
Date: Wed, 18 Jul 2007 18:17:11 +0000 (+0000)
Subject: Get the min/max optimization working with descending indices.  Ticket #2514. (CVS... 
X-Git-Tag: version-3.6.10~2013
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=309be024833400571e3bf836187737053455c98f;p=thirdparty%2Fsqlite.git

Get the min/max optimization working with descending indices.  Ticket #2514. (CVS 4161)

FossilOrigin-Name: a80a3c9d0a5e0a8a3d67bd841e2076893fd5e9aa
---

diff --git a/manifest b/manifest
index 998a0299ac..1df201fdf6 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Additional\sdiagnostics\sadded\sto\sthe\s"out"\sfile\sgenerated\sby\slemon.\s(CVS\s4160)
-D 2007-07-18T18:16:30
+C Get\sthe\smin/max\soptimization\sworking\swith\sdescending\sindices.\s\sTicket\s#2514.\s(CVS\s4161)
+D 2007-07-18T18:17:12
 F Makefile.in 0c0e53720f658c7a551046442dd7afba0b72bfbe
 F Makefile.linux-gcc 65241babba6faf1152bf86574477baab19190499
 F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028
@@ -104,7 +104,7 @@ F src/pragma.c 7914a6b9ea05f158800116dfcae11e52ab8e39c4
 F src/prepare.c 609bb27860ce98ab39889fecc0998dfd8220891b
 F src/printf.c 9b3048d270e8bb2f8b910b491ac3aadece6cfab2
 F src/random.c 6119474a6f6917f708c1dee25b9a8e519a620e88
-F src/select.c e363327d0eba8d758ab00055de962a3bb0bc213e
+F src/select.c 3b167744fc375bddfddcef87feb18f5171737677
 F src/server.c 087b92a39d883e3fa113cae259d64e4c7438bc96
 F src/shell.c e7534cce78398bc1cac4a643e931fc6221c2897e
 F src/sqlite.h.in bbcc5481af9f40ce5762c323cf555581a025f3de
@@ -315,6 +315,7 @@ F test/manydb.test 8de36b8d33aab5ef295b11d9e95310aeded31af8
 F test/memdb.test a67bda4ff90a38f2b19f6c7f95aa7289e051d893
 F test/memleak.test d2d2a1ff7105d32dc3fdf691458cf6cba58c7217
 F test/minmax.test 66434d8ee04869fe4c220b665b73748accbb9163
+F test/minmax2.test 8294b6728819608861ba0e06ac1d9a87c4d815b5
 F test/misc1.test 27a6ad11ba6e4b73aeee650ab68053ad7dfd0433
 F test/misc2.test d35faf7df27750d25ab656ca92dceebbd89f7368
 F test/misc3.test 7bd937e2c62bcc6be71939faf068d506467b1e03
@@ -517,7 +518,7 @@ F www/tclsqlite.tcl 8be95ee6dba05eabcd27a9d91331c803f2ce2130
 F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
 F www/version3.tcl 890248cf7b70e60c383b0e84d77d5132b3ead42b
 F www/whentouse.tcl fc46eae081251c3c181bd79c5faef8195d7991a5
-P 4daadf659afe6b2524e1b37347247f233a211950
-R 5d58fd77215d6d5adff31f6d536d8ece
+P 7ef2aaf72a8a953df7a763dd94657bb4ff05294f
+R ff608d553175a9b0892b61edd3a60768
 U drh
-Z cf03852661dc72cf4141c4def40720dd
+Z 2ad3f38523c32921466d9249c05ca115
diff --git a/manifest.uuid b/manifest.uuid
index 176c17a2e8..8652c03424 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-7ef2aaf72a8a953df7a763dd94657bb4ff05294f
\ No newline at end of file
+a80a3c9d0a5e0a8a3d67bd841e2076893fd5e9aa
\ No newline at end of file
diff --git a/src/select.c b/src/select.c
index 4b78d9e4c0..8c29b57dbb 100644
--- 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 1.353 2007/06/26 10:38:55 danielk1977 Exp $
+** $Id: select.c,v 1.354 2007/07/18 18:17:12 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -2514,6 +2514,16 @@ static int simpleMinMaxQuery(Parse *pParse, Select *p, int eDest, int iParm){
       sqlite3VdbeAddOp(v, OP_MakeRecord, 1, 0);
       seekOp = OP_MoveGt;
     }
+    if( pIdx->aSortOrder[0]==SQLITE_SO_DESC ){
+      /* Ticket #2514: invert the seek operator if we are using
+      ** a descending index. */
+      if( seekOp==OP_Last ){
+        seekOp = OP_Rewind;
+      }else{
+        assert( seekOp==OP_MoveGt );
+        seekOp = OP_MoveLt;
+      }
+    }
     sqlite3VdbeAddOp(v, seekOp, iIdx, 0);
     sqlite3VdbeAddOp(v, OP_IdxRowid, iIdx, 0);
     sqlite3VdbeAddOp(v, OP_Close, iIdx, 0);
diff --git a/test/minmax2.test b/test/minmax2.test
new file mode 100644
index 0000000000..a3049408c0
--- /dev/null
+++ b/test/minmax2.test
@@ -0,0 +1,387 @@
+# 2007 July 17
+#
+# 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.  The
+# focus of this file is testing SELECT statements that contain
+# aggregate min() and max() functions and which are handled as
+# as a special case.  This file makes sure that the min/max
+# optimization works right in the presence of descending
+# indices.  Ticket #2514.
+#
+# $Id: minmax2.test,v 1.1 2007/07/18 18:17:12 drh Exp $
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+
+do_test minmax2-1.0 {
+  execsql {
+    PRAGMA legacy_file_format=0;
+    BEGIN;
+    CREATE TABLE t1(x, y);
+    INSERT INTO t1 VALUES(1,1);
+    INSERT INTO t1 VALUES(2,2);
+    INSERT INTO t1 VALUES(3,2);
+    INSERT INTO t1 VALUES(4,3);
+    INSERT INTO t1 VALUES(5,3);
+    INSERT INTO t1 VALUES(6,3);
+    INSERT INTO t1 VALUES(7,3);
+    INSERT INTO t1 VALUES(8,4);
+    INSERT INTO t1 VALUES(9,4);
+    INSERT INTO t1 VALUES(10,4);
+    INSERT INTO t1 VALUES(11,4);
+    INSERT INTO t1 VALUES(12,4);
+    INSERT INTO t1 VALUES(13,4);
+    INSERT INTO t1 VALUES(14,4);
+    INSERT INTO t1 VALUES(15,4);
+    INSERT INTO t1 VALUES(16,5);
+    INSERT INTO t1 VALUES(17,5);
+    INSERT INTO t1 VALUES(18,5);
+    INSERT INTO t1 VALUES(19,5);
+    INSERT INTO t1 VALUES(20,5);
+    COMMIT;
+    SELECT DISTINCT y FROM t1 ORDER BY y;
+  }
+} {1 2 3 4 5}
+
+do_test minmax2-1.1 {
+  set sqlite_search_count 0
+  execsql {SELECT min(x) FROM t1}
+} {1}
+do_test minmax2-1.2 {
+  set sqlite_search_count
+} {19}
+do_test minmax2-1.3 {
+  set sqlite_search_count 0
+  execsql {SELECT max(x) FROM t1}
+} {20}
+do_test minmax2-1.4 {
+  set sqlite_search_count
+} {19}
+do_test minmax2-1.5 {
+  execsql {CREATE INDEX t1i1 ON t1(x DESC)}
+  set sqlite_search_count 0
+  execsql {SELECT min(x) FROM t1}
+} {1}
+do_test minmax2-1.6 {
+  set sqlite_search_count
+} {2}
+do_test minmax2-1.7 {
+  set sqlite_search_count 0
+  execsql {SELECT max(x) FROM t1}
+} {20}
+do_test minmax2-1.8 {
+  set sqlite_search_count
+} {1}
+do_test minmax2-1.9 {
+  set sqlite_search_count 0
+  execsql {SELECT max(y) FROM t1}
+} {5}
+do_test minmax2-1.10 {
+  set sqlite_search_count
+} {19}
+
+do_test minmax2-2.0 {
+  execsql {
+    CREATE TABLE t2(a INTEGER PRIMARY KEY, b);
+    INSERT INTO t2 SELECT * FROM t1;
+  }
+  set sqlite_search_count 0
+  execsql {SELECT min(a) FROM t2}
+} {1}
+do_test minmax2-2.1 {
+  set sqlite_search_count
+} {0}
+do_test minmax2-2.2 {
+  set sqlite_search_count 0
+  execsql {SELECT max(a) FROM t2}
+} {20}
+do_test minmax2-2.3 {
+  set sqlite_search_count
+} {0}
+
+do_test minmax2-3.0 {
+  ifcapable subquery {
+    execsql {INSERT INTO t2 VALUES((SELECT max(a) FROM t2)+1,999)}
+  } else {
+    db function max_a_t2 {execsql {SELECT max(a) FROM t2}}
+    execsql {INSERT INTO t2 VALUES(max_a_t2()+1,999)}
+  }
+  set sqlite_search_count 0
+  execsql {SELECT max(a) FROM t2}
+} {21}
+do_test minmax2-3.1 {
+  set sqlite_search_count
+} {0}
+do_test minmax2-3.2 {
+  ifcapable subquery {
+    execsql {INSERT INTO t2 VALUES((SELECT max(a) FROM t2)+1,999)}
+  } else {
+    db function max_a_t2 {execsql {SELECT max(a) FROM t2}}
+    execsql {INSERT INTO t2 VALUES(max_a_t2()+1,999)}
+  }
+  set sqlite_search_count 0
+  ifcapable subquery {
+    execsql { SELECT b FROM t2 WHERE a=(SELECT max(a) FROM t2) }
+  } else {
+    execsql { SELECT b FROM t2 WHERE a=max_a_t2() }
+  }
+} {999}
+do_test minmax2-3.3 {
+  set sqlite_search_count
+} {0}
+
+ifcapable {compound && subquery} {
+  do_test minmax2-4.1 {
+    execsql {
+      SELECT coalesce(min(x+0),-1), coalesce(max(x+0),-1) FROM
+        (SELECT * FROM t1 UNION SELECT NULL as 'x', NULL as 'y')
+    }
+  } {1 20}
+  do_test minmax2-4.2 {
+    execsql {
+      SELECT y, coalesce(sum(x),0) FROM
+        (SELECT null AS x, y+1 AS y FROM t1 UNION SELECT * FROM t1)
+      GROUP BY y ORDER BY y;
+    }
+  } {1 1 2 5 3 22 4 92 5 90 6 0}
+  do_test minmax2-4.3 {
+    execsql {
+      SELECT y, count(x), count(*) FROM
+        (SELECT null AS x, y+1 AS y FROM t1 UNION SELECT * FROM t1)
+      GROUP BY y ORDER BY y;
+    }
+  } {1 1 1 2 2 3 3 4 5 4 8 9 5 5 6 6 0 1}
+} ;# ifcapable compound
+
+# Make sure the min(x) and max(x) optimizations work on empty tables
+# including empty tables with indices. Ticket #296.
+#
+do_test minmax2-5.1 {
+  execsql {
+    CREATE TABLE t3(x INTEGER UNIQUE NOT NULL);
+    SELECT coalesce(min(x),999) FROM t3;
+  }
+} {999}
+do_test minmax2-5.2 {
+  execsql {
+    SELECT coalesce(min(rowid),999) FROM t3;
+  }
+} {999}
+do_test minmax2-5.3 {
+  execsql {
+    SELECT coalesce(max(x),999) FROM t3;
+  }
+} {999}
+do_test minmax2-5.4 {
+  execsql {
+    SELECT coalesce(max(rowid),999) FROM t3;
+  }
+} {999}
+do_test minmax2-5.5 {
+  execsql {
+    SELECT coalesce(max(rowid),999) FROM t3 WHERE rowid<25;
+  }
+} {999}
+
+# Make sure the min(x) and max(x) optimizations work when there
+# is a LIMIT clause.  Ticket #396.
+#
+do_test minmax2-6.1 {
+  execsql {
+    SELECT min(a) FROM t2 LIMIT 1
+  }
+} {1}
+do_test minmax2-6.2 {
+  execsql {
+    SELECT max(a) FROM t2 LIMIT 3
+  }
+} {22}
+do_test minmax2-6.3 {
+  execsql {
+    SELECT min(a) FROM t2 LIMIT 0,100
+  }
+} {1}
+do_test minmax2-6.4 {
+  execsql {
+    SELECT max(a) FROM t2 LIMIT 1,100
+  }
+} {}
+do_test minmax2-6.5 {
+  execsql {
+    SELECT min(x) FROM t3 LIMIT 1
+  }
+} {{}}
+do_test minmax2-6.6 {
+  execsql {
+    SELECT max(x) FROM t3 LIMIT 0
+  }
+} {}
+do_test minmax2-6.7 {
+  execsql {
+    SELECT max(a) FROM t2 LIMIT 0
+  }
+} {}
+
+# Make sure the max(x) and min(x) optimizations work for nested
+# queries.  Ticket #587.
+#
+do_test minmax2-7.1 {
+  execsql {
+    SELECT max(x) FROM t1;
+  }
+} 20
+ifcapable subquery {
+  do_test minmax2-7.2 {
+    execsql {
+      SELECT * FROM (SELECT max(x) FROM t1);
+    }
+  } 20
+}
+do_test minmax2-7.3 {
+  execsql {
+    SELECT min(x) FROM t1;
+  }
+} 1
+ifcapable subquery {
+  do_test minmax2-7.4 {
+    execsql {
+      SELECT * FROM (SELECT min(x) FROM t1);
+    }
+  } 1
+}
+
+# Make sure min(x) and max(x) work correctly when the datatype is
+# TEXT instead of NUMERIC.  Ticket #623.
+#
+do_test minmax2-8.1 {
+  execsql {
+    CREATE TABLE t4(a TEXT);
+    INSERT INTO t4 VALUES('1234');
+    INSERT INTO t4 VALUES('234');
+    INSERT INTO t4 VALUES('34');
+    SELECT min(a), max(a) FROM t4;
+  }
+} {1234 34}
+do_test minmax2-8.2 {
+  execsql {
+    CREATE TABLE t5(a INTEGER);
+    INSERT INTO t5 VALUES('1234');
+    INSERT INTO t5 VALUES('234');
+    INSERT INTO t5 VALUES('34');
+    SELECT min(a), max(a) FROM t5;
+  }
+} {34 1234}
+
+# Ticket #658:  Test the min()/max() optimization when the FROM clause
+# is a subquery.
+#
+ifcapable {compound && subquery} {
+  do_test minmax2-9.1 {
+    execsql {
+      SELECT max(rowid) FROM (
+        SELECT max(rowid) FROM t4 UNION SELECT max(rowid) FROM t5
+      )
+    }
+  } {1}
+  do_test minmax2-9.2 {
+    execsql {
+      SELECT max(rowid) FROM (
+        SELECT max(rowid) FROM t4 EXCEPT SELECT max(rowid) FROM t5
+      )
+    }
+  } {{}}
+} ;# ifcapable compound&&subquery
+
+# If there is a NULL in an aggregate max() or min(), ignore it.  An
+# aggregate min() or max() will only return NULL if all values are NULL.
+#
+do_test minmax2-10.1 {
+  execsql {
+    CREATE TABLE t6(x);
+    INSERT INTO t6 VALUES(1);
+    INSERT INTO t6 VALUES(2);
+    INSERT INTO t6 VALUES(NULL);
+    SELECT coalesce(min(x),-1) FROM t6;
+  }
+} {1}
+do_test minmax2-10.2 {
+  execsql {
+    SELECT max(x) FROM t6;
+  }
+} {2}
+do_test minmax2-10.3 {
+  execsql {
+    CREATE INDEX i6 ON t6(x DESC);
+    SELECT coalesce(min(x),-1) FROM t6;
+  }
+} {1}
+do_test minmax2-10.4 {
+  execsql {
+    SELECT max(x) FROM t6;
+  }
+} {2}
+do_test minmax2-10.5 {
+  execsql {
+    DELETE FROM t6 WHERE x NOT NULL;
+    SELECT count(*) FROM t6;
+  }
+} 1
+do_test minmax2-10.6 {
+  execsql {
+    SELECT count(x) FROM t6;
+  }
+} 0
+ifcapable subquery {
+  do_test minmax2-10.7 {
+    execsql {
+      SELECT (SELECT min(x) FROM t6), (SELECT max(x) FROM t6);
+    }
+  } {{} {}}
+}
+do_test minmax2-10.8 {
+  execsql {
+    SELECT min(x), max(x) FROM t6;
+  }
+} {{} {}}
+do_test minmax2-10.9 {
+  execsql {
+    INSERT INTO t6 SELECT * FROM t6;
+    INSERT INTO t6 SELECT * FROM t6;
+    INSERT INTO t6 SELECT * FROM t6;
+    INSERT INTO t6 SELECT * FROM t6;
+    INSERT INTO t6 SELECT * FROM t6;
+    INSERT INTO t6 SELECT * FROM t6;
+    INSERT INTO t6 SELECT * FROM t6;
+    INSERT INTO t6 SELECT * FROM t6;
+    INSERT INTO t6 SELECT * FROM t6;
+    INSERT INTO t6 SELECT * FROM t6;
+    SELECT count(*) FROM t6;
+  }
+} 1024
+do_test minmax2-10.10 {
+  execsql {
+    SELECT count(x) FROM t6;
+  }
+} 0
+ifcapable subquery {
+  do_test minmax2-10.11 {
+    execsql {
+      SELECT (SELECT min(x) FROM t6), (SELECT max(x) FROM t6);
+    }
+  } {{} {}}
+}
+do_test minmax2-10.12 {
+  execsql {
+    SELECT min(x), max(x) FROM t6;
+  }
+} {{} {}}
+
+
+finish_test