From e576521d96c07b18d21c11eb94856be126f171e8 Mon Sep 17 00:00:00 2001
From: danielk1977 <danielk1977@noemail.net>
Date: Wed, 17 Jun 2009 11:13:28 +0000
Subject: [PATCH] Fix for #3918. Also, fix the TRACE macros in
 balance_nonroot(). (CVS 6772)

FossilOrigin-Name: 368e44ec2e648b04f3b817f82586ccd864e60c89
---
 manifest          | 15 ++++++------
 manifest.uuid     |  2 +-
 src/btree.c       | 21 ++++++++++-------
 test/tkt3918.test | 60 +++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 82 insertions(+), 16 deletions(-)
 create mode 100644 test/tkt3918.test

diff --git a/manifest b/manifest
index 81fa5a6b5b..4f691b9024 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C A\sminor\ssimplification\sto\sthe\stokenizer.\s(CVS\s6771)
-D 2009-06-17T01:17:13
+C Fix\sfor\s#3918.\sAlso,\sfix\sthe\sTRACE\smacros\sin\sbalance_nonroot().\s(CVS\s6772)
+D 2009-06-17T11:13:28
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 8b8fb7823264331210cddf103831816c286ba446
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -106,7 +106,7 @@ F src/auth.c 98db07c2088455797678eb1031f42d4d94d18a71
 F src/backup.c ff50af53184a5fd7bdee4d620b5dabef74717c79
 F src/bitvec.c 0ef0651714728055d43de7a4cdd95e703fac0119
 F src/btmutex.c 9b899c0d8df3bd68f527b0afe03088321b696d3c
-F src/btree.c 1edede2a80d466679754453794df2d9070bd14a8
+F src/btree.c 371458438e6436e02b50796edb124a8d0e51299f
 F src/btree.h f70b694e8c163227369a66863b01fbff9009f323
 F src/btreeInt.h df64030d632f8c8ac217ed52e8b6b3eacacb33a5
 F src/build.c 75b57e3f4de1b34d4e1e49d350dc87febff48ba0
@@ -653,6 +653,7 @@ F test/tkt3841.test fe7451fb899bc31c5fbcee53362c621d0271e25f
 F test/tkt3871.test 43ecbc8d90dc83908e2a454aef345acc9d160c6f
 F test/tkt3879.test 2ad5bef2c87e9991ce941e054c31abe26ef7fb90
 F test/tkt3911.test 74cd324f3ba653040cc6d94cc4857b290d12d633
+F test/tkt3918.test e6cdf6bfcfe9ba939d86a4238a9dc55d6eec5d42
 F test/tokenize.test ce430a7aed48fc98301611429595883fdfcab5d7
 F test/trace.test 19ffbc09885c3321d56358a5738feae8587fb377
 F test/trans.test d887cb07630dc39879a322d958ad8b006137485c
@@ -734,7 +735,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl 672f81d693a03f80f5ae60bfefacd8a349e76746
-P 08cca219f16efab93cb00f04d2e2f8033893e5f1
-R 7849aa14ee9aea370d50947a30a5b469
-U drh
-Z 7a86c39b397e7cb764e22053087fdcff
+P 18f2076ac21dd0ab343a79461837f5591f9d4d87
+R e09f9b7c30f5fb6a040ae5f6d3595072
+U danielk1977
+Z fa0237a4a1ebff673136562f4d6dd1cb
diff --git a/manifest.uuid b/manifest.uuid
index d62860e8ad..876cc839f6 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-18f2076ac21dd0ab343a79461837f5591f9d4d87
\ No newline at end of file
+368e44ec2e648b04f3b817f82586ccd864e60c89
\ No newline at end of file
diff --git a/src/btree.c b/src/btree.c
index c7688fd016..68c28214d9 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -9,7 +9,7 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-** $Id: btree.c,v 1.630 2009/06/16 16:50:22 danielk1977 Exp $
+** $Id: btree.c,v 1.631 2009/06/17 11:13:28 danielk1977 Exp $
 **
 ** This file implements a external (disk-based) database using BTrees.
 ** See the header comment on "btreeInt.h" for additional information.
@@ -4525,7 +4525,7 @@ static int allocateBtreePage(
         pTrunk = 0;
         TRACE(("ALLOCATE: %d trunk - %d free pages left\n", *pPgno, n-1));
 #endif
-      }else{
+      }else if( k>0 ){
         /* Extract a leaf from the trunk */
         int closest;
         Pgno iPage;
@@ -5412,7 +5412,9 @@ static int balance_nonroot(
   assert( sqlite3_mutex_held(pBt->mutex) );
   assert( sqlite3PagerIswriteable(pParent->pDbPage) );
 
+#if 0
   TRACE(("BALANCE: begin page %d child of %d\n", pPage->pgno, pParent->pgno));
+#endif
 
   /* At this point pParent may have at most one overflow cell. And if
   ** this overflow cell is present, it must be the cell with 
@@ -5640,6 +5642,12 @@ static int balance_nonroot(
   */
   assert( cntNew[0]>0 || (pParent->pgno==1 && pParent->nCell==0) );
 
+  TRACE(("BALANCE: old: %d %d %d  ",
+    apOld[0]->pgno, 
+    nOld>=2 ? apOld[1]->pgno : 0,
+    nOld>=3 ? apOld[2]->pgno : 0
+  ));
+
   /*
   ** Allocate k new pages.  Reuse old pages where possible.
   */
@@ -5715,10 +5723,7 @@ static int balance_nonroot(
       apNew[minI] = pT;
     }
   }
-  TRACE(("BALANCE: old: %d %d %d  new: %d(%d) %d(%d) %d(%d) %d(%d) %d(%d)\n",
-    apOld[0]->pgno, 
-    nOld>=2 ? apOld[1]->pgno : 0,
-    nOld>=3 ? apOld[2]->pgno : 0,
+  TRACE(("new: %d(%d) %d(%d) %d(%d) %d(%d) %d(%d)\n",
     apNew[0]->pgno, szNew[0],
     nNew>=2 ? apNew[1]->pgno : 0, nNew>=2 ? szNew[1] : 0,
     nNew>=3 ? apNew[2]->pgno : 0, nNew>=3 ? szNew[2] : 0,
@@ -5914,8 +5919,8 @@ static int balance_nonroot(
   }
 
   assert( pParent->isInit );
-  TRACE(("BALANCE: finished with %d: old=%d new=%d cells=%d\n",
-          pPage->pgno, nOld, nNew, nCell));
+  TRACE(("BALANCE: finished: old=%d new=%d cells=%d\n",
+          nOld, nNew, nCell));
  
   /*
   ** Cleanup before returning.
diff --git a/test/tkt3918.test b/test/tkt3918.test
new file mode 100644
index 0000000000..c46ad8f6c1
--- /dev/null
+++ b/test/tkt3918.test
@@ -0,0 +1,60 @@
+# 2009 June 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.
+#
+#***********************************************************************
+#
+# $Id: tkt3918.test,v 1.1 2009/06/17 11:13:28 danielk1977 Exp $
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+
+do_test tkt3918.1 {
+  execsql {
+    PRAGMA page_size = 1024;
+    PRAGMA auto_vacuum = incremental;
+    CREATE TABLE t1(i, x);
+  }
+} {}
+do_test tkt3918.2 {
+  execsql {
+    INSERT INTO t1 VALUES(1, randstr(1000,1000));
+    INSERT INTO t1 VALUES(2, zeroblob(248*1020 + 100));
+    INSERT INTO t1 VALUES(3, zeroblob(2*1020 + 100));
+  }
+} {}
+
+# This set of statements sets up the free list so that the
+# first free-list trunk page contains only a single leaf.
+# The leaf page is also the last page in the database. The
+# second free-list trunk page contains, amongst other things,
+# page number 4.
+do_test tkt3918.3 {
+  execsql {
+    DELETE FROM t1 WHERE i = 2;
+    DELETE FROM t1 WHERE i = 1;
+    DELETE FROM t1 WHERE i = 3;
+  }
+} {}
+
+# Incrementally vacuum the database to reduce its size by a single
+# page. This will remove the single leaf from the first page in
+# the linked list of free-list trunk pages.
+do_test tkt3918.4 {
+  execsql { PRAGMA incremental_vacuum = 1 }
+} {}
+
+# Create another table. This operation will attempt to extract 
+# page 4 from the database free-list. Bug 3918 caused sqlite to
+# incorrectly report corruption here.
+do_test tkt3918.5 {
+  execsql { CREATE TABLE t2(a, b) }
+} {}
+
+finish_test
+