Add some tests for the atomic-write optimization. (CVS 4275)

FossilOrigin-Name: e2cc7b4a3476a733b2701546f6b4ec9abc18152b

manifest

@@ -1,5 +1,5 @@
-C Change\snames\sof\sconstants\sin\slemon.c\sto\swork\saround\sname\sconflicts\non\sSolaris.\s\sTicket\s#2583.\s(CVS\s4274)
+C Add\ssome\stests\sfor\sthe\satomic-write\soptimization.\s(CVS\s4275)
-D 2007-08-23T02:50:56
+D 2007-08-23T08:06:45
 F Makefile.in 0c0e53720f658c7a551046442dd7afba0b72bfbe
 F Makefile.linux-gcc 65241babba6faf1152bf86574477baab19190499
 F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028
@@ -94,7 +94,7 @@ F src/func.c aa8a3a8db571c46e5197664ddbc2784006ee5525
 F src/hash.c 2f322979071dd2bdba7503b5276d66f028744382
 F src/hash.h 3ad3da76bfb954978d227bf495568b0e6da2c19e
 F src/insert.c 633322aef1799f6604fa805e12488bc628570b0c
-F src/journal.c 5ba2a1443b181741d3f2984d9d49e730073d74d1
+F src/journal.c 03d6b5cc1afe7c5e3cd0af55415f5168eb094398
 F src/legacy.c 7e1b1c57694e49cbadf561e2a7d9cd984dc743b5
 F src/limits.h 71ab25f17e35e0a9f3f6f234b8ed49cc56731d35
 F src/loadext.c 8b31e2e0e961918fa045515459aee1c122d8c266
@@ -104,7 +104,7 @@ F src/md5.c c5fdfa5c2593eaee2e32a5ce6c6927c986eaf217
 F src/mem1.c 7b023d45dd71944414db469c742457239e24d74d
 F src/mem2.c 48919353f72b8f6e957a0021eb9deaf863998189
 F src/mutex.c 9cf641f556a4119ef90ed41b82f2d5647f81686e
-F src/os.c d8f029317c95dcd2887b9f0f154281cdfbd303ad
+F src/os.c 86593b6e8cc22304d7c2d24b06c0aae49254b181
 F src/os.h 399c89cafa93b9ef35c3dc70f77644d10936b535
 F src/os_common.h a5c446d3b93f09f369d13bf217de4bed3437dd1c
 F src/os_os2.c 8769301bff502de642ad2634cedcb77d967ce199
@@ -136,7 +136,7 @@ F src/test2.c 4f742e99ed1bea5c14692f627bdb59a146f30504
 F src/test3.c a7d011c51d6b2e2a73c43983d5c2b731d69c74d7
 F src/test4.c c2c0f5dc907f1346f5d4b65eb5799f11eb9e4071
 F src/test5.c 3a6a5717a149d7ca2e6d14f5be72cf7555d54dc4
-F src/test6.c 1191c2305c85aa192f04186b59b05a4fb40018cc
+F src/test6.c 2c141f367ba483eef99a7f4d00f07431caff791e
 F src/test7.c a9d509d0e9ad214b4772696f49f6e61be26213d1
 F src/test8.c e6a543c8b248efe120ae33a6859fcd55dcf46a96
 F src/test9.c b46c8fe02ac7cca1a7316436d8d38d50c66f4b2f
@@ -318,7 +318,7 @@ F test/insert3.test 72ea6056811fd234f80d923f977c196089947381
 F test/insert4.test 1e27f0a3e5670d5f03c1636f699aa44270945bca
 F test/interrupt.test 81555fb0f8179bb2d0dc7151fd75428223f93cf2
 F test/intpkey.test af4fd826c4784ec5c93b444de07adea0254d0d30
-F test/io.test 6b7ee16f78560c4b81b52da2ea1051b8a2a93ce3
+F test/io.test ca9db7cd57a1b02cd983863c1be1153e1900e68b
 F test/ioerr.test 491d42c49bbec598966d26b01ed7901f55e5ee2d
 F test/ioerr2.test f938eadb12108048813869b86beee4a2f98e34b8
 F test/join.test af0443185378b64878750aa1cf4b83c216f246b4
@@ -559,7 +559,7 @@ F www/tclsqlite.tcl 8be95ee6dba05eabcd27a9d91331c803f2ce2130
 F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
 F www/version3.tcl 890248cf7b70e60c383b0e84d77d5132b3ead42b
 F www/whentouse.tcl fc46eae081251c3c181bd79c5faef8195d7991a5
-P 21f6b31097692171c6493e6ca6de6acbd62dc595
+P e4e74cd0f9343448ea38e57f08bb4f0616825f31
-R eedd9c3af3e8b7da02c2c75af15e1919
+R 630334db112909a8743c928d15787556
-U drh
+U danielk1977
-Z e69a56f3f634fc877bc9bea036855b24
+Z 01e41e90624e3bb8ea0ae5e4ad13b9f8

manifest.uuid

@@ -1 +1 @@
-e4e74cd0f9343448ea38e57f08bb4f0616825f31
+e2cc7b4a3476a733b2701546f6b4ec9abc18152b

src/journal.c

@@ -10,7 +10,7 @@
 **
 *************************************************************************
 **
-** @(#) $Id: journal.c,v 1.1 2007/08/22 11:22:04 danielk1977 Exp $
+** @(#) $Id: journal.c,v 1.2 2007/08/23 08:06:45 danielk1977 Exp $
 */
 
 #ifdef SQLITE_ENABLE_ATOMIC_WRITE
@@ -54,11 +54,14 @@ typedef struct JournalFile JournalFile;
 static int createFile(JournalFile *p){
   int rc = SQLITE_OK;
   if( !p->pReal ){
-    p->pReal = (sqlite3_file *)&p[1];
+    sqlite3_file *pReal = (sqlite3_file *)&p[1];
-    rc = sqlite3OsOpen(p->pVfs, p->zJournal, p->pReal, p->flags, 0);
+    rc = sqlite3OsOpen(p->pVfs, p->zJournal, pReal, p->flags, 0);
-    if( rc==SQLITE_OK && p->iSize>0 ){
+    if( rc==SQLITE_OK ){
-      assert(p->iSize<=p->nBuf);
+      p->pReal = pReal;
-      rc = sqlite3OsWrite(p->pReal, p->zBuf, p->iSize, 0);
+      if( p->iSize>0 ){
+        assert(p->iSize<=p->nBuf);
+        rc = sqlite3OsWrite(p->pReal, p->zBuf, p->iSize, 0);
+      }
     }
   }
   return rc;

src/os.c

@@ -58,13 +58,35 @@ int sqlite3OsBreakLock(sqlite3_file *id){
 int sqlite3OsCheckReservedLock(sqlite3_file *id){
   return id->pMethods->xCheckReservedLock(id);
 }
-int sqlite3OsSectorSize(sqlite3_file *id){
+
-  int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
+#ifdef SQLITE_TEST
-  return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
+  /* The following two variables are used to override the values returned
-}
+  ** by the xSectorSize() and xDeviceCharacteristics() vfs methods for
-int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
+  ** testing purposes. They are usually set by a test command implemented
-  return id->pMethods->xDeviceCharacteristics(id);
+  ** in test6.c.
-}
+  */
+  int sqlite3_test_sector_size = 0;
+  int sqlite3_test_device_characteristics = 0;
+  int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
+    int dc = id->pMethods->xDeviceCharacteristics(id);
+    return dc | sqlite3_test_device_characteristics;
+  }
+  int sqlite3OsSectorSize(sqlite3_file *id){
+    if( sqlite3_test_sector_size==0 ){
+      int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
+      return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
+    }
+    return sqlite3_test_sector_size;
+  }
+#else
+  int sqlite3OsSectorSize(sqlite3_file *id){
+    int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
+    return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
+  }
+  int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
+    return id->pMethods->xDeviceCharacteristics(id);
+  }
+#endif
 
 #if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)
   /* These methods are currently only used for testing and debugging. */

src/test6.c

@@ -540,6 +540,98 @@ static int cfCurrentTime(void *pAppData, double *pTimeOut){
   return pVfs->xCurrentTime(pVfs->pAppData, pTimeOut);
 }
 
+static int processDevSymArgs(
+  Tcl_Interp *interp,
+  int objc,
+  Tcl_Obj *CONST objv[],
+  int *piDeviceChar,
+  int *piSectorSize
+){
+  struct DeviceFlag {
+    char *zName;
+    int iValue;
+  } aFlag[] = {
+    { "atomic",      SQLITE_IOCAP_ATOMIC      },
+    { "atomic512",   SQLITE_IOCAP_ATOMIC512   },
+    { "atomic1k",    SQLITE_IOCAP_ATOMIC1K    },
+    { "atomic2k",    SQLITE_IOCAP_ATOMIC2K    },
+    { "atomic4k",    SQLITE_IOCAP_ATOMIC4K    },
+    { "atomic8k",    SQLITE_IOCAP_ATOMIC8K    },
+    { "atomic16k",   SQLITE_IOCAP_ATOMIC16K   },
+    { "atomic32k",   SQLITE_IOCAP_ATOMIC32K   },
+    { "atomic64k",   SQLITE_IOCAP_ATOMIC64K   },
+    { "sequential",  SQLITE_IOCAP_SEQUENTIAL  },
+    { "safe_append", SQLITE_IOCAP_SAFE_APPEND },
+    { 0, 0 }
+  };
+
+  int i;
+  int iDc = 0;
+  int iSectorSize = 0;
+  int setSectorsize = 0;
+  int setDeviceChar = 0;
+
+  for(i=0; i<objc; i+=2){
+    int nOpt;
+    char *zOpt = Tcl_GetStringFromObj(objv[i], &nOpt);
+
+    if( (nOpt>11 || nOpt<2 || strncmp("-sectorsize", zOpt, nOpt)) 
+     && (nOpt>16 || nOpt<2 || strncmp("-characteristics", zOpt, nOpt))
+    ){
+      Tcl_AppendResult(interp, 
+        "Bad option: \"", zOpt, 
+        "\" - must be \"-characteristics\" or \"-sectorsize\"", 0
+      );
+      return TCL_ERROR;
+    }
+    if( i==objc-1 ){
+      Tcl_AppendResult(interp, "Option requires an argument: \"", zOpt, "\"",0);
+      return TCL_ERROR;
+    }
+
+    if( zOpt[1]=='s' ){
+      if( Tcl_GetIntFromObj(interp, objv[i+1], &iSectorSize) ){
+        return TCL_ERROR;
+      }
+      setSectorsize = 1;
+    }else{
+      int j;
+      Tcl_Obj **apObj;
+      int nObj;
+      if( Tcl_ListObjGetElements(interp, objv[i+1], &nObj, &apObj) ){
+        return TCL_ERROR;
+      }
+      for(j=0; j<nObj; j++){
+        int rc;
+        int iChoice;
+        Tcl_Obj *pFlag = Tcl_DuplicateObj(apObj[j]);
+        Tcl_IncrRefCount(pFlag);
+        Tcl_UtfToLower(Tcl_GetString(pFlag));
+ 
+        rc = Tcl_GetIndexFromObjStruct(
+            interp, pFlag, aFlag, sizeof(aFlag[0]), "no such flag", 0, &iChoice
+        );
+        Tcl_DecrRefCount(pFlag);
+        if( rc ){
+          return TCL_ERROR;
+        }
+
+        iDc |= aFlag[iChoice].iValue;
+      }
+      setDeviceChar = 1;
+    }
+  }
+
+  if( setDeviceChar ){
+    *piDeviceChar = iDc;
+  }
+  if( setSectorsize ){
+    *piSectorSize = iSectorSize;
+  }
+
+  return TCL_OK;
+}
+
 /*
 ** tclcmd:   sqlite_crashparams ?OPTIONS? DELAY CRASHFILE
 **
@@ -564,7 +656,6 @@ static int crashParamsObjCmd(
   int objc,
   Tcl_Obj *CONST objv[]
 ){
-  int i;
   int iDelay;
   const char *zCrashFile;
   int nCrashFile;
@@ -606,29 +697,9 @@ static int crashParamsObjCmd(
     sqlite3_vfs_register(&crashVfs, 1);
   }
 
-  int iDc = 0;
+  int iDc = -1;
-  int iSectorSize = 0;
+  int iSectorSize = -1;
-  int setSectorsize = 0;
-  int setDeviceChar = 0;
 
-  struct DeviceFlag {
-    char *zName;
-    int iValue;
-  } aFlag[] = {
-    { "atomic",      SQLITE_IOCAP_ATOMIC      },
-    { "atomic512",   SQLITE_IOCAP_ATOMIC512   },
-    { "atomic1k",    SQLITE_IOCAP_ATOMIC1K    },
-    { "atomic2k",    SQLITE_IOCAP_ATOMIC2K    },
-    { "atomic4k",    SQLITE_IOCAP_ATOMIC4K    },
-    { "atomic8k",    SQLITE_IOCAP_ATOMIC8K    },
-    { "atomic16k",   SQLITE_IOCAP_ATOMIC16K   },
-    { "atomic32k",   SQLITE_IOCAP_ATOMIC32K   },
-    { "atomic64k",   SQLITE_IOCAP_ATOMIC64K   },
-    { "sequential",  SQLITE_IOCAP_SEQUENTIAL  },
-    { "safe_append", SQLITE_IOCAP_SAFE_APPEND },
-    { 0, 0 }
-  };
-  
   if( objc<3 ){
     Tcl_WrongNumArgs(interp, 1, objv, "?OPTIONS? DELAY CRASHFILE");
     goto error;
@@ -643,63 +714,17 @@ static int crashParamsObjCmd(
     goto error;
   }
 
-  for(i=1; i<(objc-2); i+=2){
+  if( processDevSymArgs(interp, objc-3, &objv[1], &iDc, &iSectorSize) ){
-    int nOpt;
+    return TCL_ERROR;
-    char *zOpt = Tcl_GetStringFromObj(objv[i], &nOpt);
-
-    if( (nOpt>11 || nOpt<2 || strncmp("-sectorsize", zOpt, nOpt)) 
-     && (nOpt>16 || nOpt<2 || strncmp("-characteristics", zOpt, nOpt))
-    ){
-      Tcl_AppendResult(interp, 
-        "Bad option: \"", zOpt, 
-        "\" - must be \"-characteristics\" or \"-sectorsize\"", 0
-      );
-      goto error;
-    }
-    if( i==objc-3 ){
-      Tcl_AppendResult(interp, "Option requires an argument: \"", zOpt, "\"",0);
-      goto error;
-    }
-
-    if( zOpt[1]=='s' ){
-      if( Tcl_GetIntFromObj(interp, objv[i+1], &iSectorSize) ){
-        goto error;
-      }
-      setSectorsize = 1;
-    }else{
-      int j;
-      Tcl_Obj **apObj;
-      int nObj;
-      if( Tcl_ListObjGetElements(interp, objv[i+1], &nObj, &apObj) ){
-        goto error;
-      }
-      for(j=0; j<nObj; j++){
-        int rc;
-        int iChoice;
-        Tcl_Obj *pFlag = Tcl_DuplicateObj(apObj[j]);
-        Tcl_IncrRefCount(pFlag);
-        Tcl_UtfToLower(Tcl_GetString(pFlag));
- 
-        rc = Tcl_GetIndexFromObjStruct(
-            interp, pFlag, aFlag, sizeof(aFlag[0]), "no such flag", 0, &iChoice
-        );
-        Tcl_DecrRefCount(pFlag);
-        if( rc ){
-          goto error;
-        }
-
-        iDc |= aFlag[iChoice].iValue;
-      }
-      setDeviceChar = 1;
-    }
   }
 
-  if( setDeviceChar ){
+  if( iDc>=0 ){
     g.iDeviceCharacteristics = iDc;
   }
-  if( setSectorsize ){
+  if( iSectorSize>=0 ){
     g.iSectorSize = iSectorSize;
   }
+
   g.iCrash = iDelay;
   memcpy(g.zCrashFile, zCrashFile, nCrashFile+1);
   sqlite3CrashTestEnable = 1;
@@ -709,6 +734,32 @@ error:
   return TCL_ERROR;
 }
 
+static int devSymObjCmd(
+  void * clientData,
+  Tcl_Interp *interp,
+  int objc,
+  Tcl_Obj *CONST objv[]
+){
+
+  extern int sqlite3_test_device_characteristics;
+  extern int sqlite3_test_sector_size;
+
+  int iDc = -1;
+  int iSectorSize = -1;
+  if( processDevSymArgs(interp, objc-1, &objv[1], &iDc, &iSectorSize) ){
+    return TCL_ERROR;
+  }
+
+  if( iDc>=0 ){
+    sqlite3_test_device_characteristics = iDc;
+  }
+  if( iSectorSize>=0 ){
+    sqlite3_test_sector_size = iSectorSize;
+  }
+
+  return TCL_OK;
+}
+
 #endif /* SQLITE_OMIT_DISKIO */
 
 /*
@@ -717,6 +768,7 @@ error:
 int Sqlitetest6_Init(Tcl_Interp *interp){
 #ifndef SQLITE_OMIT_DISKIO
   Tcl_CreateObjCommand(interp, "sqlite3_crashparams", crashParamsObjCmd, 0, 0);
+  Tcl_CreateObjCommand(interp, "sqlite3_simulate_device", devSymObjCmd, 0, 0);
 #endif
   return TCL_OK;
 }

test/io.test

@@ -13,11 +13,18 @@
 # IO traffic generated by SQLite (making sure SQLite is not writing out
 # more database pages than it has to, stuff like that).
 #
-# $Id: io.test,v 1.2 2007/08/22 02:56:44 drh Exp $
+# $Id: io.test,v 1.3 2007/08/23 08:06:45 danielk1977 Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
 
+# Test summary:
+#
+# io-1.* -  Test that quick-balance does not journal pages unnecessarily.
+# io-2.* -  Test that when the atomic-write optimisation is used no
+#           journal file is created.
+#           
+
 set ::nWrite 0
 proc nWrite {db} {
   set bt [btree_from_db $db]
@@ -29,6 +36,13 @@ proc nWrite {db} {
   set res
 }
 
+set ::nSync 0
+proc nSync {} {
+  set res [expr {$::sqlite_sync_count - $::nSync}]
+  set ::nSync $::sqlite_sync_count
+  set res
+}
+
 do_test io-1.1 {
   execsql {
     PRAGMA page_size = 1024;
@@ -75,8 +89,6 @@ do_test io-1.4 {
   lappend ret [nWrite db]
 } {2 2 2}
 
-#db eval {select * from sqlite_master} {btree_tree_dump [btree_from_db db] 2}
-
 # This insert should use the quick-balance trick to add a third leaf
 # to the b-tree used to store table abc. It should only be necessary to
 # write to 3 pages to do this: the change-counter, the root-page and
@@ -86,6 +98,174 @@ do_test io-1.5 {
   nWrite db
 } {3}
 
-#db eval {select * from sqlite_master} {btree_tree_dump [btree_from_db db] 2}
+
+
+#----------------------------------------------------------------------
+# Test cases io-2.* test the atomic-write optimization.
+#
+do_test io-2.1 {
+  execsql { DELETE FROM abc; VACUUM; }
+} {}
+
+# Clear the write and sync counts.
+nWrite db ; nSync
+
+# The following INSERT updates 2 pages and requires 4 calls to fsync():
+#
+#   1) The directory in which the journal file is created,
+#   2) The journal file (to sync the page data),
+#   3) The journal file (to sync the journal file header),
+#   4) The database file.
+#
+do_test io-2.2 {
+  execsql { INSERT INTO abc VALUES(1, 2) }
+  list [nWrite db] [nSync]
+} {2 4}
+
+# Set the device-characteristic mask to include the SQLITE_IOCAP_ATOMIC,
+# then do another INSERT similar to the one in io-2.2. This should
+# only write 1 page and require a single fsync().
+# 
+# The single fsync() is the database file. Only one page is reported as
+# written because page 1 - the change-counter page - is written using
+# an out-of-band method that bypasses the write counter.
+#
+sqlite3_simulate_device -char atomic
+do_test io-2.3 {
+  execsql { INSERT INTO abc VALUES(3, 4) }
+  list [nWrite db] [nSync]
+} {1 1}
+
+# Test that the journal file is not created and the change-counter is
+# updated when the atomic-write optimization is used.
+#
+do_test io-2.4.1 {
+  execsql {
+    BEGIN;
+    INSERT INTO abc VALUES(5, 6);
+  }
+  sqlite3 db2 test.db
+  execsql { SELECT * FROM abc } db2
+} {1 2 3 4}
+do_test io-2.4.2 {
+  file exists test.db-journal
+} {0}
+do_test io-2.4.3 {
+  execsql { COMMIT }
+  execsql { SELECT * FROM abc } db2
+} {1 2 3 4 5 6}
+db2 close
+
+# Test that the journal file is created and sync()d if the transaction
+# modifies more than one database page, even if the IOCAP_ATOMIC flag
+# is set.
+#
+do_test io-2.5.1 {
+  execsql { CREATE TABLE def(d, e) }
+  nWrite db ; nSync
+  execsql {
+    BEGIN;
+    INSERT INTO abc VALUES(7, 8);
+  }
+  file exists test.db-journal
+} {0}
+do_test io-2.5.2 {
+  execsql { INSERT INTO def VALUES('a', 'b'); }
+  file exists test.db-journal
+} {1}
+do_test io-2.5.3 {
+  execsql { COMMIT }
+  list [nWrite db] [nSync]
+} {3 4}
+
+# Test that the journal file is created and sync()d if the transaction
+# modifies a single database page and also appends a page to the file.
+# Internally, this case is handled differently to the one above. The
+# journal file is not actually created until the 'COMMIT' statement
+# is executed.
+#
+do_test io-2.6.1 {
+  execsql {
+    BEGIN;
+    INSERT INTO abc VALUES(9, randstr(1000,1000));
+  }
+  file exists test.db-journal
+} {0}
+do_test io-2.6.2 {
+  # Create a file at "test.db-journal". This will prevent SQLite from
+  # opening the journal for exclusive access. As a result, the COMMIT
+  # should fail with SQLITE_CANTOPEN and the transaction rolled back.
+  #
+  set fd [open test.db-journal w]
+  puts $fd "This is not a journal file"
+  close $fd
+  catchsql { COMMIT }
+} {1 {unable to open database file}}
+do_test io-2.6.3 {
+  file delete -force test.db-journal
+  catchsql { COMMIT }
+} {1 {cannot commit - no transaction is active}}
+do_test io-2.6.4 {
+  execsql { SELECT * FROM abc }
+} {1 2 3 4 5 6 7 8}
+
+
+# Test that if the database modification is part of multi-file commit,
+# the journal file is always created. In this case, the journal file
+# is created during execution of the COMMIT statement, so we have to
+# use the same technique to check that it is created as in the above 
+# block.
+file delete -force test2.db test2.db-journal
+do_test io-2.7.1 {
+  execsql {
+    ATTACH 'test2.db' AS aux;
+    CREATE TABLE aux.abc2(a, b);
+    BEGIN;
+    INSERT INTO abc VALUES(9, 10);
+  }
+  file exists test.db-journal
+} {0}
+do_test io-2.7.2 {
+  execsql { INSERT INTO abc2 SELECT * FROM abc }
+  file exists test2.db-journal
+} {0}
+do_test io-2.7.3 {
+  execsql { SELECT * FROM abc UNION ALL SELECT * FROM abc2 }
+} {1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10}
+do_test io-2.7.4 {
+  set fd [open test2.db-journal w]
+  puts $fd "This is not a journal file"
+  close $fd
+  catchsql { COMMIT }
+} {1 {unable to open database file}}
+do_test io-2.7.5 {
+  file delete -force test2.db-journal
+  catchsql { COMMIT }
+} {1 {cannot commit - no transaction is active}}
+do_test io-2.7.6 {
+  execsql { SELECT * FROM abc UNION ALL SELECT * FROM abc2 }
+} {1 2 3 4 5 6 7 8}
+
+# Try an explicit ROLLBACK before the journal file is created.
+#
+do_test io-2.8.1 {
+  execsql {
+    BEGIN;
+    DELETE FROM abc;
+  }
+  file exists test.db-journal
+} {0}
+do_test io-2.8.2 {
+  execsql { SELECT * FROM abc }
+} {}
+do_test io-2.8.3 {
+  execsql {
+    ROLLBACK;
+    SELECT * FROM abc;
+  }
+} {1 2 3 4 5 6 7 8}
+
+sqlite3_simulate_device -char {} -sectorsize 0
 
 finish_test
+