Add the reverse_unordered_selects pragma. (CVS 6314)

FossilOrigin-Name: bc078e0007b6c3dc07722820bb53798b643212b3

diff --git a/manifest b/manifest
index 0af59bc7d2cbe32a26c5604e24f1a4d987348f2b..2d6a18ba595da6edce1c959e606b7c2b89a2b767 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Ensure\sthe\sreturn\svalue\sof\ssqlite3_errmsg16()\sis\saligned\son\sa\s2-byte\sboundary.\sTicket\s#3665.\s(CVS\s6313)
-D 2009-02-23T14:42:53
+C Add\sthe\sreverse_unordered_selects\spragma.\s(CVS\s6314)
+D 2009-02-23T16:52:08
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in d64baddbf55cdf33ff030e14da837324711a4ef7
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -148,7 +148,7 @@ F src/parse.y 5202dc712407fd6723f6639b88b86ddf8b33aef5
 F src/pcache.c fcf7738c83c4d3e9d45836b2334c8a368cc41274
 F src/pcache.h 9b927ccc5a538e31b4c3bc7eec4f976db42a1324
 F src/pcache1.c dabb8ab14827e090321f17150ce96fda172974e8
-F src/pragma.c 9ed2acb94efee8059efcc52c2e2140b43170831e
+F src/pragma.c 22ed04836aab8ce134c53be1ca896f3ad20fabdb
 F src/prepare.c d0bbb4b1a8b9c1db6d13788929839bb63764680e
 F src/printf.c 9866a9a9c4a90f6d4147407f373df3fd5d5f9b6f
 F src/random.c 676b9d7ac820fe81e6fb2394ac8c10cff7f38628
@@ -158,7 +158,7 @@ F src/select.c aa7328a23c0abe019f98bb7e1f4f63d62e20ba98
 F src/shell.c f109ebbb50132926ebbc173a6c2d8838d5d78527
 F src/sqlite.h.in 14f4d065bafed8500ea558a75a8e2be89c784d61
 F src/sqlite3ext.h 1db7d63ab5de4b3e6b83dd03d1a4e64fef6d2a17
-F src/sqliteInt.h 8bd8f5bb583832df68034525c1d763a35cd0365f
+F src/sqliteInt.h c682534d78d7af014c81b30d2c9e75661f4ef990
 F src/sqliteLimit.h ffe93f5a0c4e7bd13e70cd7bf84cfb5c3465f45d
 F src/status.c 237b193efae0cf6ac3f0817a208de6c6c6ef6d76
 F src/table.c 332ab0ea691e63862e2a8bdfe2c0617ee61062a3
@@ -208,7 +208,7 @@ F src/vdbeblob.c 08d6bac666c1f6a5d67452f5fbf808cf1311d2c9
 F src/vdbemem.c 543a79d722734d2f8b7ad70f08218c30bcc5bbf5
 F src/vtab.c e39e011d7443a8d574b1b9cde207a35522e6df43
 F src/walker.c 42bd3f00ca2ef5ae842304ec0d59903ef051412d
-F src/where.c de92174234ff56240df2b10bebe45466676ce7c3
+F src/where.c 72980baae14e7e71dc70c671b6cf34c4063dbd58
 F test/aggerror.test a867e273ef9e3d7919f03ef4f0e8c0d2767944f2
 F test/alias.test 597662c5d777a122f9a3df0047ea5c5bd383a911
 F test/all.test 14165b3e32715b700b5f0cbf8f6e3833dda0be45
@@ -674,6 +674,7 @@ F test/where7.test 2487cda68faabf5edeb524289913f00f8d64e223
 F test/where8.test 1b9152a086408ee789166d0a954abc597372f868
 F test/where8m.test c1010d61826412ff66abd29bfb32e5d6b37d965c
 F test/where9.test a46d394037a40b56e7855d29cce951f91108c353
+F test/whereA.test ef8d699d87934bd747119c75fbb4711b584a8b60
 F test/wherelimit.test 5e9fd41e79bb2b2d588ed999d641d9c965619b31
 F test/zeroblob.test 792124852ec61458a2eb527b5091791215e0be95
 F tool/diffdb.c 7524b1b5df217c20cd0431f6789851a4e0cb191b
@@ -700,7 +701,7 @@ F tool/speedtest16.c c8a9c793df96db7e4933f0852abb7a03d48f2e81
 F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
-P 5dcda154090e55a22b4d19f9def42beba8733f50
-R 995f5a3ef19f5c195500de164454e1d4
-U danielk1977
-Z a29e2652178988b1757076cd7ae15c3a
+P 9b8acf8319ec760713773407a4d5a33dea8d75e8
+R 41bbb1216086db2d528bb92c681c2add
+U drh
+Z 08cd8c8feaad5119cbc7d91cd8c2e6b1

diff --git a/manifest.uuid b/manifest.uuid
index f3e4c746ad1893b0042d4f7ba6b412fb12389ba6..c78d008e84537b068784837cd8f512b2b4cb3c3c 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-9b8acf8319ec760713773407a4d5a33dea8d75e8
\ No newline at end of file
+bc078e0007b6c3dc07722820bb53798b643212b3
\ No newline at end of file

diff --git a/src/pragma.c b/src/pragma.c
index 8497e69e20155f9843bf7a0f5fecb86aab9d0aab..496558e7a9fa48803e3c970f0b3c35f814557059 100644 (file)
--- a/src/pragma.c
+++ b/src/pragma.c
@@ -11,7 +11,7 @@
 *************************************************************************
 ** This file contains code used to implement the PRAGMA command.
 **
-** $Id: pragma.c,v 1.203 2009/02/19 14:39:25 danielk1977 Exp $
+** $Id: pragma.c,v 1.204 2009/02/23 16:52:08 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -172,6 +172,7 @@ static int flagPragma(Parse *pParse, const char *zLeft, const char *zRight){
     { "empty_result_callbacks",   SQLITE_NullCallback  },
     { "legacy_file_format",       SQLITE_LegacyFileFmt },
     { "fullfsync",                SQLITE_FullFSync     },
+    { "reverse_unordered_selects", SQLITE_ReverseOrder  },
 #ifdef SQLITE_DEBUG
     { "sql_trace",                SQLITE_SqlTrace      },
     { "vdbe_listing",             SQLITE_VdbeListing   },

diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 440771f9229b6067e417a7270242f5ba8abd2ead..98c3e364fd0644b395614051d0447eb21e353964 100644 (file)
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -11,7 +11,7 @@
 *************************************************************************
 ** Internal interface definitions for SQLite.
 **
-** @(#) $Id: sqliteInt.h,v 1.834 2009/02/19 14:39:25 danielk1977 Exp $
+** @(#) $Id: sqliteInt.h,v 1.835 2009/02/23 16:52:08 drh Exp $
 */
 #ifndef _SQLITEINT_H_
 #define _SQLITEINT_H_
@@ -847,6 +847,7 @@ struct sqlite3 {
 #define SQLITE_SharedCache    0x00080000  /* Cache sharing is enabled */
 #define SQLITE_Vtab           0x00100000  /* There exists a virtual table */
 #define SQLITE_CommitBusy     0x00200000  /* In the process of committing */
+#define SQLITE_ReverseOrder   0x00400000  /* Reverse unordered SELECTs */
 
 /*
 ** Possible values for the sqlite.magic field.

diff --git a/src/where.c b/src/where.c
index 858c5491212882b42926311daf811e254ed0083a..ea6e00a80225212cd958dc1800ed83e73607c140 100644 (file)
--- a/src/where.c
+++ b/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 1.370 2009/02/20 10:58:42 danielk1977 Exp $
+** $Id: where.c,v 1.371 2009/02/23 16:52:08 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -1837,7 +1837,15 @@ static void bestIndex(
         cost += cost*estLog(cost);
         WHERETRACE(("... sorting increases cost to %.9g\n", cost));
       }
+    }else if( pParse->db->flags & SQLITE_ReverseOrder ){
+      /* For application testing, randomly reverse the output order for
+      ** SELECT statements that omit the ORDER BY clause.  This will help
+      ** to find cases where
+      */
+      wsFlags |= WHERE_REVERSE;
     }
+
+    /* Remember this case if it is the best so far */
     if( cost<pCost->rCost ){
       pCost->rCost = cost;
       pCost->nRow = nRow;
@@ -1987,6 +1995,12 @@ static void bestIndex(
         cost += cost*estLog(cost);
         WHERETRACE(("...... orderby increases cost to %.9g\n", cost));
       }
+    }else if( pParse->db->flags & SQLITE_ReverseOrder ){
+      /* For application testing, randomly reverse the output order for
+      ** SELECT statements that omit the ORDER BY clause.  This will help
+      ** to find cases where
+      */
+      wsFlags |= WHERE_REVERSE;
     }
 
     /* Check to see if we can get away with using just the index without
@@ -2747,11 +2761,13 @@ static Bitmask codeOneLoopStart(
     /* Case 5:  There is no usable index.  We must do a complete
     **          scan of the entire table.
     */
+    static const u8 aStep[] = { OP_Next, OP_Prev };
+    static const u8 aStart[] = { OP_Rewind, OP_Last };
+    assert( bRev==0 || bRev==1 );
     assert( omitTable==0 );
-    assert( bRev==0 );
-    pLevel->op = OP_Next;
+    pLevel->op = aStep[bRev];
     pLevel->p1 = iCur;
-    pLevel->p2 = 1 + sqlite3VdbeAddOp2(v, OP_Rewind, iCur, addrBrk);
+    pLevel->p2 = 1 + sqlite3VdbeAddOp2(v, aStart[bRev], iCur, addrBrk);
     pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
     codeRowSetEarly = 0;
   }

diff --git a/test/whereA.test b/test/whereA.test
new file mode 100644 (file)
index 0000000..4f3780f
--- /dev/null
+++ b/test/whereA.test
@@ -0,0 +1,81 @@
+# 2009 February 23
+#
+# 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 the reverse_select_order pragma.
+#
+# $Id: whereA.test,v 1.1 2009/02/23 16:52:08 drh Exp $
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+
+do_test whereA-1.1 {
+  db eval {
+    CREATE TABLE t1(a INTEGER PRIMARY KEY, b UNIQUE, c);
+    INSERT INTO t1 VALUES(1,2,3);
+    INSERT INTO t1 values(2,'hello','world');
+    INSERT INTO t1 VALUES(3,4.53,NULL);
+    SELECT * FROM t1
+  }
+} {1 2 3 2 hello world 3 4.53 {}}
+do_test whereA-1.2 {
+  db eval {
+    PRAGMA reverse_unordered_selects=1;
+    SELECT * FROM t1;
+  }
+} {3 4.53 {} 2 hello world 1 2 3}
+
+do_test whereA-1.3 {
+  db eval {
+    PRAGMA reverse_unordered_selects=1;
+    SELECT * FROM t1 ORDER BY rowid;
+  }
+} {1 2 3 2 hello world 3 4.53 {}}
+
+do_test whereA-2.1 {
+  db eval {
+    PRAGMA reverse_unordered_selects=0;
+    SELECT * FROM t1 WHERE a>0;
+  }
+} {1 2 3 2 hello world 3 4.53 {}}
+do_test whereA-2.2 {
+  db eval {
+    PRAGMA reverse_unordered_selects=1;
+    SELECT * FROM t1 WHERE a>0;
+  }
+} {3 4.53 {} 2 hello world 1 2 3}
+
+do_test whereA-2.3 {
+  db eval {
+    PRAGMA reverse_unordered_selects=1;
+    SELECT * FROM t1 WHERE a>0 ORDER BY rowid;
+  }
+} {1 2 3 2 hello world 3 4.53 {}}
+
+do_test whereA-3.1 {
+  db eval {
+    PRAGMA reverse_unordered_selects=0;
+    SELECT * FROM t1 WHERE b>0;
+  }
+} {1 2 3 3 4.53 {} 2 hello world}
+do_test whereA-3.2 {
+  db eval {
+    PRAGMA reverse_unordered_selects=1;
+    SELECT * FROM t1 WHERE b>0;
+  }
+} {2 hello world 3 4.53 {} 1 2 3}
+do_test whereA-3.3 {
+  db eval {
+    PRAGMA reverse_unordered_selects=1;
+    SELECT * FROM t1 WHERE b>0 ORDER BY b;
+  }
+} {1 2 3 3 4.53 {} 2 hello world}
+
+finish_test