From 6e6bd5658f1fa8ab3780a309b42acab4de00e7d9 Mon Sep 17 00:00:00 2001
From: dan <dan@noemail.net>
Date: Wed, 2 Jun 2010 18:59:03 +0000
Subject: [PATCH] Fix a problem with rolling back to a savepoint opened before
 the writer decided to wrap the log file.

FossilOrigin-Name: 6b4aed6aae7dc9e92807d27375cbe1e83c15841b
---
 manifest      | 16 ++++++++--------
 manifest.uuid |  2 +-
 src/wal.c     | 18 +++++++++++++++---
 src/wal.h     |  2 +-
 test/wal.test | 31 +++++++++++++++++++++++++++++++
 5 files changed, 56 insertions(+), 13 deletions(-)

diff --git a/manifest b/manifest
index 7719de6b69..755d8d1743 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C If\san\serror\soccurs\swhile\swriting\sframes\sto\sthe\slog\sto\scommit\sa\stransaction,\sdo\snot\smark\sthe\spages\sas\sclean\sin\sthe\scache.\sOtherwise,\sthe\ssubsequent\srollback\sdoes\snot\sroll\sthem\sback\s(leaving\sthe\sclient\sto\scontinue\swith\sa\scache\sthat\smakes\sit\sappear\sthat\sthe\stransaction\swas\scommitted\s-\sinconsistent\swith\sthe\sdatabase\son\sdisk).
-D 2010-06-02T17:15:25
+C Fix\sa\sproblem\swith\srolling\sback\sto\sa\ssavepoint\sopened\sbefore\sthe\swriter\sdecided\sto\swrap\sthe\slog\sfile.
+D 2010-06-02T18:59:03
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in a5cad1f8f3e021356bfcc6c77dc16f6f1952bbc3
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -224,8 +224,8 @@ F src/vdbeblob.c 5327132a42a91e8b7acfb60b9d2c3b1c5c863e0e
 F src/vdbemem.c 2a82f455f6ca6f78b59fb312f96054c04ae0ead1
 F src/vdbetrace.c 864cef96919323482ebd9986f2132435115e9cc2
 F src/vtab.c a0f8a40274e4261696ef57aa806de2776ab72cda
-F src/wal.c 125cc67e8e5c091ef78f3a499524701bcddbb8f4
-F src/wal.h 1c1c9feb629b7f4afcbe0b47f80f47c5551d3a02
+F src/wal.c 82da8997bccdf229edc192aede6e00a3454321e4
+F src/wal.h 4ace25262452d17e7d3ec970c89ee17794004008
 F src/walker.c 3112bb3afe1d85dc52317cb1d752055e9a781f8f
 F src/where.c 75fee9e255b62f773fcadd1d1f25b6f63ac7a356
 F test/aggerror.test a867e273ef9e3d7919f03ef4f0e8c0d2767944f2
@@ -761,7 +761,7 @@ F test/vtabE.test 7c4693638d7797ce2eda17af74292b97e705cc61
 F test/vtab_alter.test 9e374885248f69e251bdaacf480b04a197f125e5
 F test/vtab_err.test 0d4d8eb4def1d053ac7c5050df3024fd47a3fbd8
 F test/vtab_shared.test 0eff9ce4f19facbe0a3e693f6c14b80711a4222d
-F test/wal.test a54d9be9e82eede1653f7998723ead8ce8a1a580
+F test/wal.test bfec61450b47cdf09f7d2269f9e9967683b8b0fc
 F test/wal2.test a2146846c4dd940252f18ec1e00431346286bcb3
 F test/walbak.test e7650a26eb4b8abeca9b145b1af1e63026dde432
 F test/walcksum.test 4efa8fb88c32bed8288ea4385a9cc113a5c8f0bf
@@ -815,7 +815,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
-P b3109f85bde0b24bfbcfe6c0f7bbe973be196c1d
-R 830ef9967206d6e34b488a57bc115b0c
+P cb571c1b71a37b3a10d640987c77a6eec508235d
+R 958f6d0fb0d51651adb74690506f1284
 U dan
-Z 189de0d7978aa94a58fbada93d61bb5d
+Z 8958cafc220d9bcfdae765c6216ea4c7
diff --git a/manifest.uuid b/manifest.uuid
index fea9134b6c..ce9427a633 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-cb571c1b71a37b3a10d640987c77a6eec508235d
\ No newline at end of file
+6b4aed6aae7dc9e92807d27375cbe1e83c15841b
\ No newline at end of file
diff --git a/src/wal.c b/src/wal.c
index 8076227740..bc2d6ff46e 100644
--- a/src/wal.c
+++ b/src/wal.c
@@ -2110,6 +2110,7 @@ void sqlite3WalSavepoint(Wal *pWal, u32 *aWalData){
   aWalData[0] = pWal->hdr.mxFrame;
   aWalData[1] = pWal->hdr.aFrameCksum[0];
   aWalData[2] = pWal->hdr.aFrameCksum[1];
+  aWalData[3] = pWal->nCkpt;
 }
 
 /* 
@@ -2120,9 +2121,19 @@ void sqlite3WalSavepoint(Wal *pWal, u32 *aWalData){
 */
 int sqlite3WalSavepointUndo(Wal *pWal, u32 *aWalData){
   int rc = SQLITE_OK;
-  assert( pWal->writeLock );
 
-  assert( aWalData[0]<=pWal->hdr.mxFrame );
+  assert( pWal->writeLock );
+  assert( aWalData[3]!=pWal->nCkpt || aWalData[0]<=pWal->hdr.mxFrame );
+
+  if( aWalData[3]!=pWal->nCkpt ){
+    /* This savepoint was opened immediately after the write-transaction
+    ** was started. Right after that, the writer decided to wrap around
+    ** to the start of the log. Update the savepoint values to match.
+    */
+    aWalData[0] = 0;
+    aWalData[3] = pWal->nCkpt;
+  }
+
   if( aWalData[0]<pWal->hdr.mxFrame ){
     rc = walIndexMap(pWal, walMappingSize(pWal->hdr.mxFrame));
     pWal->hdr.mxFrame = aWalData[0];
@@ -2130,9 +2141,10 @@ int sqlite3WalSavepointUndo(Wal *pWal, u32 *aWalData){
     pWal->hdr.aFrameCksum[1] = aWalData[2];
     if( rc==SQLITE_OK ){
       walCleanupHash(pWal);
-      walIndexUnmap(pWal);
     }
   }
+
+  walIndexUnmap(pWal);
   return rc;
 }
 
diff --git a/src/wal.h b/src/wal.h
index 32aade1d0d..34710a4082 100644
--- a/src/wal.h
+++ b/src/wal.h
@@ -36,7 +36,7 @@
 # define sqlite3WalCallback(z)                 0
 #else
 
-#define WAL_SAVEPOINT_NDATA 3
+#define WAL_SAVEPOINT_NDATA 4
 
 /* Connection to a write-ahead log (WAL) file. 
 ** There is one object of this type for each pager. 
diff --git a/test/wal.test b/test/wal.test
index 1c5f556309..ca8ad2ad8f 100644
--- a/test/wal.test
+++ b/test/wal.test
@@ -1460,5 +1460,36 @@ integrity_check wal-20.5
 
 catch { db2 close }
 catch { db close }
+file delete -force test.db test.db-wal test.db-journal
+
+do_test wal-21.1 {
+  sqlite3 db test.db
+  execsql { 
+    PRAGMA journal_mode = WAL;
+    CREATE TABLE t1(a, b);
+    INSERT INTO t1 VALUES(1, 2);
+    INSERT INTO t1 VALUES(3, 4);
+    INSERT INTO t1 VALUES(5, 6);
+    INSERT INTO t1 VALUES(7, 8);
+    INSERT INTO t1 VALUES(9, 10);
+    INSERT INTO t1 VALUES(11, 12);
+  }
+} {wal}
+do_test wal-21.2 {
+  execsql { 
+    PRAGMA cache_size = 10;
+    PRAGMA wal_checkpoint;
+    BEGIN;
+      SAVEPOINT s;
+        INSERT INTO t1 SELECT randomblob(900), randomblob(900) FROM t1;
+      ROLLBACK TO s;
+    COMMIT;
+    SELECT * FROM t1;
+  }
+} {1 2 3 4 5 6 7 8 9 10 11 12}
+do_test wal-21.3 {
+  execsql { PRAGMA integrity_check }
+} {ok}
+
 
 finish_test