Added the new FULL option to the SYNCHRONOUS pragma. Still need to test it. (CVS 863)

FossilOrigin-Name: 792a9e157dd066fcaffd4f5b373010151fb4ca61

manifest

@@ -1,5 +1,5 @@
-C Fix\sa\sbug\sin\sthe\slegacy\sjournal\sformat\swriting\slogic.\s(CVS\s862)
-D 2003-02-12T02:10:15
+C Added\sthe\snew\sFULL\soption\sto\sthe\sSYNCHRONOUS\spragma.\s\sStill\sneed\sto\stest\sit.\s(CVS\s863)
+D 2003-02-12T14:09:43
 F Makefile.in 6606854b1512f185b8e8c779b8d7fc2750463d64
 F Makefile.linux-gcc b86a99c493a5bfb402d1d9178dcdc4bd4b32f906
 F README f1de682fbbd94899d50aca13d387d1b3fd3be2dd
@@ -19,9 +19,9 @@ F publish.sh ce0bf7e235984bc156dc5d1a0c8092db4c8442f3
 F spec.template 238f7db425a78dc1bb7682e56e3834c7270a3f5e
 F sqlite.1 83f4a9d37bdf2b7ef079a82d54eaf2e3509ee6ea
 F src/auth.c f37bfc9451b8c1fa52f34adff474560018892729
-F src/btree.c 668402ca441592d85da521309625bd1bcc6f010e
-F src/btree.h 17710339f7a8f46e3c7d6d0d4648ef19c584ffda
-F src/build.c f13728865b6de5eb1ecc61827d334dc881ca1fb5
+F src/btree.c 2a0305ccbe617266ac3524805e0c6ef55a9f9cb7
+F src/btree.h 36a7a26a29382c2b1a519b42bb125880d46d00d4
+F src/build.c 757b1a37436b55b43c8eb41436a23a0ce8cad447
 F src/delete.c cbd499f3f9297504c42e328af89bef1a2113d04c
 F src/encode.c faf03741efe921755ec371cf4a6984536de00042
 F src/expr.c bd690b3a6174e97a0f16800e78c8aeae749a4e71
@@ -29,12 +29,12 @@ F src/func.c 90c583f0b91220f7cd411a2407deaf9327245d63
 F src/hash.c 4fc39feb7b7711f6495ee9f2159559bedb043e1f
 F src/hash.h cd0433998bc1a3759d244e1637fe5a3c13b53bf8
 F src/insert.c 13c2ef8984ce0f38701a8af89e4ba7a3c86c0701
-F src/main.c 764a72e6a4f021ae1d3db7e82dab625075f4fedb
+F src/main.c f88dfe09ed79588899cb4013836dd940f73a17fa
 F src/md5.c fe4f9c9c6f71dfc26af8da63e4d04489b1430565
 F src/os.c ed27e178e0c4b71f2807da81b8851f0fadc50778
 F src/os.h afa3e096213bad86845f8bdca81a9e917505e401
-F src/pager.c 1748a01ed18d7507c4c4dd54985c4aa613583a52
-F src/pager.h ce264d558c8ec289f5a9c50ca4ad499e3522a67e
+F src/pager.c f7658e5d07ef66c966443a3f4420510ce640442b
+F src/pager.h e5b8e301a732007766dc04880c764d7ee1aa34dd
 F src/parse.y cdaed5009423d851708848bd279147c268e6022e
 F src/printf.c f8fd911a8738f9b2eb07aca2870473d34707055d
 F src/random.c 19e8e00fe0df32a742f115773f57651be327cabe
@@ -42,7 +42,7 @@ F src/select.c d12d4c12d6536deccdede90b482d24f0590f5dc8
 F src/shell.c 0d260a007e0668fc7dda2b0c89bd597ef2966ec6
 F src/shell.tcl 27ecbd63dd88396ad16d81ab44f73e6c0ea9d20e
 F src/sqlite.h.in 6f648803f2ffb9beb35cb1cfa42b323d55519171
-F src/sqliteInt.h 8beea34db78e1452569e22b020934002da5debee
+F src/sqliteInt.h 2ae2c24fde8f7bb8040db964223d6e551e979358
 F src/table.c eed2098c9b577aa17f8abe89313a9c4413f57d63
 F src/tclsqlite.c 8167d40fd34036701e07492d07a6f9e5c4015241
 F src/test1.c eb05abd3ec6822f800476c04aed4db112690b144
@@ -60,7 +60,7 @@ F test/all.test 873d30e25a41b3aa48fec5633a7ec1816e107029
 F test/auth.test 33e8b9680eb0ce521c54096fff1c9ab506c7dfb8
 F test/bigfile.test 1cd8256d4619c39bea48147d344f348823e78678
 F test/bigrow.test 8ab252dba108f12ad64e337b0f2ff31a807ac578
-F test/btree.test 10e75aec120ecefc0edc4c912a0980a43db1b6c2
+F test/btree.test 1e3463c7838e7e71bbf37c9c6e45beee9c8975ba
 F test/btree2.test e3b81ec33dc2f89b3e6087436dfe605b870c9080
 F test/btree3.test e597fb59be2ac0ea69c62aaa2064e998e528b665
 F test/btree4.test fa955a3d7a8bc91d6084b7f494f9e5d1bdfb15b6
@@ -142,7 +142,7 @@ F www/datatypes.tcl 0cb28565580554fa7e03e8fcb303e87ce57757ae
 F www/download.tcl 0932d7f4f0e8b2adbbd22fac73132f86e43ab4a9
 F www/dynload.tcl 02eb8273aa78cfa9070dd4501dca937fb22b466c
 F www/faq.tcl 06276ff6c3e369374bb83034cc9d4a7d3a2a34a1
-F www/fileformat.tcl a4b5c2c6e89b7d42d09f97fd4d7bbd39cbf24936
+F www/fileformat.tcl 5e3009b1451364602916da986501b94d8516bbb4
 F www/formatchng.tcl b4449e065d2da38b6563bdf12cf46cfe1d4d765e
 F www/index.tcl b5265ca54a5124ec40bffb7c7943e072e074d61a
 F www/lang.tcl 7ad51d873059368a98bcc2afec60d6ba4bb5688a
@@ -155,7 +155,7 @@ F www/speed.tcl 4d463e2aea41f688ed320a937f93ff885be918c3
 F www/sqlite.tcl ae3dcfb077e53833b59d4fcc94d8a12c50a44098
 F www/tclsqlite.tcl 1db15abeb446aad0caf0b95b8b9579720e4ea331
 F www/vdbe.tcl 2013852c27a02a091d39a766bc87cff329f21218
-P 8ec5632536eea31197a3b1fd6abc57881a0cf1d7
-R b30735c88387ed3f8675a36136884368
+P 6c927dd36c19ebb8bb8222b4d18ed67f4fe733e8
+R 4c767e05bbbde68a52aa488a93a1a8fd
 U drh
-Z b9a60900a465cbc97d661e720b92ed2b
+Z c4a4b24e4cf8bd7a0ea9e8a1c854d6c7

manifest.uuid

@@ -1 +1 @@
-6c927dd36c19ebb8bb8222b4d18ed67f4fe733e8
+792a9e157dd066fcaffd4f5b373010151fb4ca61

src/btree.c

@@ -9,7 +9,7 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-** $Id: btree.c,v 1.82 2003/01/29 22:58:26 drh Exp $
+** $Id: btree.c,v 1.83 2003/02/12 14:09:43 drh Exp $
 **
 ** This file implements a external (disk-based) database using BTrees.
 ** For a detailed discussion of BTrees, refer to
@@ -745,6 +745,19 @@ int sqliteBtreeSetCacheSize(Btree *pBt, int mxPage){
   return SQLITE_OK;
 }
 
+/*
+** Change the way data is synced to disk in order to increase or decrease
+** how well the database resists damage due to OS crashes and power
+** failures.  Level 1 is the same as asynchronous (no syncs() occur and
+** there is a high probability of damage)  Level 2 is the default.  There
+** is a very low but non-zero probability of damage.  Level 3 reduces the
+** probability of damage to near zero but with a write performance reduction.
+*/
+int sqliteBtreeSetSafetyLevel(Btree *pBt, int level){
+  sqlitepager_set_safety_level(pBt->pPager, level);
+  return SQLITE_OK;
+}
+
 /*
 ** Get a reference to page1 of the database file.  This will
 ** also acquire a readlock on that file.

src/btree.h

@@ -13,7 +13,7 @@
 ** subsystem.  See comments in the source code for a detailed description
 ** of what each interface routine does.
 **
-** @(#) $Id: btree.h,v 1.26 2002/12/04 13:40:26 drh Exp $
+** @(#) $Id: btree.h,v 1.27 2003/02/12 14:09:44 drh Exp $
 */
 #ifndef _BTREE_H_
 #define _BTREE_H_
@@ -24,6 +24,7 @@ typedef struct BtCursor BtCursor;
 int sqliteBtreeOpen(const char *zFilename, int mode, int nPg, Btree **ppBtree);
 int sqliteBtreeClose(Btree*);
 int sqliteBtreeSetCacheSize(Btree*, int);
+int sqliteBtreeSetSafetyLevel(Btree*, int);
 
 int sqliteBtreeBeginTrans(Btree*);
 int sqliteBtreeCommit(Btree*);
@@ -54,7 +55,7 @@ int sqliteBtreeDataSize(BtCursor*, int *pSize);
 int sqliteBtreeData(BtCursor*, int offset, int amt, char *zBuf);
 int sqliteBtreeCloseCursor(BtCursor*);
 
-#define SQLITE_N_BTREE_META 4
+#define SQLITE_N_BTREE_META 10
 int sqliteBtreeGetMeta(Btree*, int*);
 int sqliteBtreeUpdateMeta(Btree*, int*);
 

src/build.c

@@ -25,7 +25,7 @@
 **     ROLLBACK
 **     PRAGMA
 **
-** $Id: build.c,v 1.128 2003/02/01 13:53:28 drh Exp $
+** $Id: build.c,v 1.129 2003/02/12 14:09:44 drh Exp $
 */
 #include "sqliteInt.h"
 #include <ctype.h>
@@ -2141,6 +2141,39 @@ static int getBoolean(char *z){
   return 0;
 }
 
+/*
+** Interpret the given string as a safety level.  Return 0 for OFF,
+** 1 for ON or NORMAL and 2 for FULL.
+**
+** Note that the values returned are one less that the values that
+** should be passed into sqliteBtreeSetSafetyLevel().  The is done
+** to support legacy SQL code.  The safety level used to be boolean
+** and older scripts may have used numbers 0 for OFF and 1 for ON.
+*/
+static int getSafetyLevel(char *z){
+  static const struct {
+    const char *zWord;
+    int val;
+  } aKey[] = {
+    { "no",    0 },
+    { "off",   0 },
+    { "false", 0 },
+    { "yes",   1 },
+    { "on",    1 },
+    { "true",  1 },
+    { "full",  2 },
+  };
+  int i;
+  if( z[0]==0 ) return 1;
+  if( isdigit(z[0]) || (z[0]=='-' && isdigit(z[1])) ){
+    return atoi(z);
+  }
+  for(i=0; i<sizeof(aKey)/sizeof(aKey[0]); i++){
+    if( sqliteStrICmp(z,aKey[i].zWord)==0 ) return aKey[i].val;
+  }
+  return 1;
+}
+
 /*
 ** Process a pragma statement.  
 **
@@ -2257,7 +2290,7 @@ void sqlitePragma(Parse *pParse, Token *pLeft, Token *pRight, int minusFlag){
 
   /*
   **  PRAGMA default_synchronous
-  **  PRAGMA default_synchronous=BOOLEAN
+  **  PRAGMA default_synchronous=ON|OFF|NORMAL|FULL
   **
   ** The first form returns the persistent value of the "synchronous" setting
   ** that is stored in the database.  This is the synchronous setting that
@@ -2265,33 +2298,35 @@ void sqlitePragma(Parse *pParse, Token *pLeft, Token *pRight, int minusFlag){
   ** "synchronous" pragma.  The second form changes the persistent and the
   ** local synchronous setting to the value given.
   **
-  ** If synchronous is on, SQLite will do an fsync() system call at strategic
-  ** points to insure that all previously written data has actually been
-  ** written onto the disk surface before continuing.  This mode insures that
-  ** the database will always be in a consistent state event if the operating
-  ** system crashes or power to the computer is interrupted unexpectedly.
-  ** When synchronous is off, SQLite will not wait for changes to actually
-  ** be written to the disk before continuing.  As soon as it hands changes
-  ** to the operating system, it assumes that the changes are permanent and
-  ** it continues going.  The database cannot be corrupted by a program crash
-  ** even with synchronous off, but an operating system crash or power loss
-  ** could potentially corrupt data.  On the other hand, synchronous off is
-  ** faster than synchronous on.
+  ** If synchronous is OFF, SQLite does not attempt any fsync() systems calls
+  ** to make sure data is committed to disk.  Write operations are very fast,
+  ** but a power failure can leave the database in an inconsistent state.
+  ** If synchronous is ON or NORMAL, SQLite will do an fsync() system call to
+  ** make sure data is being written to disk.  The risk of corruption due to
+  ** a power loss in this mode is negligible but non-zero.  If synchronous
+  ** is FULL, extra fsync()s occur to reduce the risk of corruption to near
+  ** zero, but with a write performance penalty.  The default mode is NORMAL.
   */
   if( sqliteStrICmp(zLeft,"default_synchronous")==0 ){
     static VdbeOp getSync[] = {
-      { OP_Integer,     0, 0,        0},
+      { OP_ColumnName,  0, 0,        "synchronous"},
+      { OP_ReadCookie,  0, 3,        0},
+      { OP_Dup,         0, 0,        0},
+      { OP_If,          0, 0,        0},  /* 3 */
       { OP_ReadCookie,  0, 2,        0},
       { OP_Integer,     0, 0,        0},
       { OP_Lt,          0, 5,        0},
       { OP_AddImm,      1, 0,        0},
-      { OP_ColumnName,  0, 0,        "synchronous"},
       { OP_Callback,    1, 0,        0},
+      { OP_Halt,        0, 0,        0},
+      { OP_AddImm,     -1, 0,        0},  /* 10 */
+      { OP_Callback,    1, 0,        0}
     };
     Vdbe *v = sqliteGetVdbe(pParse);
     if( v==0 ) return;
     if( pRight->z==pLeft->z ){
-      sqliteVdbeAddOpList(v, ArraySize(getSync), getSync);
+      int addr = sqliteVdbeAddOpList(v, ArraySize(getSync), getSync);
+      sqliteVdbeChangeP2(v, addr+3, addr+10);
     }else{
       int addr;
       int size = db->cache_size;
@@ -2303,20 +2338,24 @@ void sqlitePragma(Parse *pParse, Token *pLeft, Token *pRight, int minusFlag){
       sqliteVdbeAddOp(v, OP_Ne, 0, addr+3);
       sqliteVdbeAddOp(v, OP_AddImm, MAX_PAGES, 0);
       sqliteVdbeAddOp(v, OP_AbsValue, 0, 0);
-      if( !getBoolean(zRight) ){
+      db->safety_level = getSafetyLevel(zRight)+1;
+      if( db->safety_level==1 ){
         sqliteVdbeAddOp(v, OP_Negative, 0, 0);
         size = -size;
       }
       sqliteVdbeAddOp(v, OP_SetCookie, 0, 2);
+      sqliteVdbeAddOp(v, OP_Integer, db->safety_level, 0);
+      sqliteVdbeAddOp(v, OP_SetCookie, 0, 3);
       sqliteEndWriteOperation(pParse);
       db->cache_size = size;
       sqliteBtreeSetCacheSize(db->pBe, db->cache_size);
+      sqliteBtreeSetSafetyLevel(db->pBe, db->safety_level);
     }
   }else
 
   /*
   **   PRAGMA synchronous
-  **   PRAGMA synchronous=BOOLEAN
+  **   PRAGMA synchronous=OFF|ON|NORMAL|FULL
   **
   ** Return or set the local value of the synchronous flag.  Changing
   ** the local value does not make changes to the disk file and the
@@ -2331,14 +2370,16 @@ void sqlitePragma(Parse *pParse, Token *pLeft, Token *pRight, int minusFlag){
     Vdbe *v = sqliteGetVdbe(pParse);
     if( v==0 ) return;
     if( pRight->z==pLeft->z ){
-      sqliteVdbeAddOp(v, OP_Integer, db->cache_size>=0, 0);
+      sqliteVdbeAddOp(v, OP_Integer, db->safety_level-1, 0);
       sqliteVdbeAddOpList(v, ArraySize(getSync), getSync);
     }else{
       int size = db->cache_size;
       if( size<0 ) size = -size;
-      if( !getBoolean(zRight) ) size = -size;
+      db->safety_level = getSafetyLevel(zRight)+1;
+      if( db->safety_level==1 ) size = -size;
       db->cache_size = size;
       sqliteBtreeSetCacheSize(db->pBe, db->cache_size);
+      sqliteBtreeSetSafetyLevel(db->pBe, db->safety_level);
     }
   }else
 

src/main.c

@@ -14,7 +14,7 @@
 ** other files are for internal use by SQLite and should not be
 ** accessed by users of the library.
 **
-** $Id: main.c,v 1.112 2003/01/29 18:46:53 drh Exp $
+** $Id: main.c,v 1.113 2003/02/12 14:09:44 drh Exp $
 */
 #include "sqliteInt.h"
 #include "os.h"
@@ -273,6 +273,9 @@ int sqliteInit(sqlite *db, char **pzErrMsg){
   if( size==0 ){ size = MAX_PAGES; }
   db->cache_size = size;
   sqliteBtreeSetCacheSize(db->pBe, size);
+  db->safety_level = meta[4];
+  if( db->safety_level==0 ) db->safety_level = 2;
+  sqliteBtreeSetSafetyLevel(db->pBe, db->safety_level);
 
   /*
   **     file_format==1    Version 2.1.0.

src/pager.c

@@ -18,7 +18,7 @@
 ** file simultaneously, or one process from reading the database while
 ** another is writing.
 **
-** @(#) $Id: pager.c,v 1.74 2003/02/12 02:10:15 drh Exp $
+** @(#) $Id: pager.c,v 1.75 2003/02/12 14:09:44 drh Exp $
 */
 #include "os.h"         /* Must be first to enable large file support */
 #include "sqliteInt.h"
@@ -101,7 +101,7 @@ struct PgHdr {
   u8 alwaysRollback;             /* Disable dont_rollback() for this page */
   PgHdr *pDirty;                 /* Dirty pages sorted by PgHdr.pgno */
   /* SQLITE_PAGE_SIZE bytes of page data follow this header */
-  /* Pager.nExtra bytes of local data follow the page data and checksum */
+  /* Pager.nExtra bytes of local data follow the page data */
 };
 
 /*
@@ -470,10 +470,6 @@ static int pager_unwritelock(Pager *pPager){
 */
 static u32 pager_cksum(Pager *pPager, Pgno pgno, const char *aData){
   u32 cksum = pPager->cksumInit + pgno;
-  /* const u8 *a = (const u8*)aData;
-  int i;
-  for(i=0; i<SQLITE_PAGE_SIZE; i++){ cksum += a[i]; } */
-  /* fprintf(stderr,"CKSUM for %p(%08x) page %d: %08x\n", pPager, pPager->cksumInit, pgno, cksum); */
   return cksum;
 }
 
@@ -770,6 +766,36 @@ void sqlitepager_set_cachesize(Pager *pPager, int mxPage){
   }
 }
 
+/*
+** Adjust the robustness of the database to damage due to OS crashes
+** or power failures by changing the number of syncs()s when writing
+** the rollback journal.  There are three levels:
+**
+**    OFF       sqliteOsSync() is never called.  This is the default
+**              for temporary and transient files.
+**
+**    NORMAL    The journal is synced once before writes begin on the
+**              database.  This is normally adequate protection, but
+**              it is theoretically possible, though very unlikely,
+**              that an inopertune power failure could leave the journal
+**              in a state which would cause damage to the database
+**              when it is rolled back.
+**
+**    FULL      The journal is synced twice before writes begin on the
+**              database (with some additional information being written
+**              in between the two syncs.  If we assume that writing a
+**              single disk sector is atomic, then this mode provides
+**              assurance that the journal will not be corrupted to the
+**              point of causing damage to the database during rollback.
+**
+** Numeric values associated with these states are OFF==1, NORMAL=2,
+** and FULL=3.
+*/
+void sqlitepager_set_safety_level(Pager *pPager, int level){
+  pPager->noSync =  level==1 || pPager->tempFile;
+  pPager->fullSync = level==3 && !pPager->tempFile;
+}
+
 /*
 ** Open a temporary file.  Write the name of the file into zName
 ** (zName must be at least SQLITE_TEMPNAME_SIZE bytes long.)  Write

src/pager.h

@@ -13,7 +13,7 @@
 ** subsystem.  The page cache subsystem reads and writes a file a page
 ** at a time and provides a journal for rollback.
 **
-** @(#) $Id: pager.h,v 1.19 2003/02/11 14:55:41 drh Exp $
+** @(#) $Id: pager.h,v 1.20 2003/02/12 14:09:44 drh Exp $
 */
 
 /*
@@ -70,6 +70,7 @@ int sqlitepager_ckpt_rollback(Pager*);
 void sqlitepager_dont_rollback(void*);
 void sqlitepager_dont_write(Pager*, Pgno);
 int *sqlitepager_stats(Pager*);
+void sqlitepager_set_safety_level(Pager*,int);
 
 #ifdef SQLITE_TEST
 void sqlitepager_refdump(Pager*);

src/sqliteInt.h

@@ -11,7 +11,7 @@
 *************************************************************************
 ** Internal interface definitions for SQLite.
 **
-** @(#) $Id: sqliteInt.h,v 1.160 2003/02/11 14:55:41 drh Exp $
+** @(#) $Id: sqliteInt.h,v 1.161 2003/02/12 14:09:44 drh Exp $
 */
 #include "config.h"
 #include "sqlite.h"
@@ -207,7 +207,8 @@ struct sqlite {
   Btree *pBe;                   /* The B*Tree backend */
   Btree *pBeTemp;               /* Backend for session temporary tables */
   int flags;                    /* Miscellanous flags. See below */
-  int file_format;              /* What file format version is this database? */
+  u8 file_format;               /* What file format version is this database? */
+  u8 safety_level;              /* How aggressive at synching data to disk */
   int schema_cookie;            /* Magic number that changes with the schema */
   int next_cookie;              /* Value of schema_cookie after commit */
   int cache_size;               /* Number of pages to use in the cache */

test/btree.test

@@ -11,7 +11,7 @@
 # This file implements regression tests for SQLite library.  The
 # focus of this script is btree database backend
 #
-# $Id: btree.test,v 1.13 2002/09/02 12:14:51 drh Exp $
+# $Id: btree.test,v 1.14 2003/02/12 14:09:45 drh Exp $
 
 
 set testdir [file dirname $argv0]
@@ -359,30 +359,30 @@ do_test btree-4.9 {
 #
 do_test btree-5.1 {
   btree_get_meta $::b1
-} {0 0 0 0}
+} {0 0 0 0 0 0 0 0 0 0}
 do_test btree-5.2 {
-  set rc [catch {btree_update_meta $::b1 1 2 3 4} msg]
+  set rc [catch {btree_update_meta $::b1 1 2 3 4 5 6 7 8 9 10} msg]
   lappend rc $msg
 } {1 SQLITE_ERROR}
 do_test btree-5.3 {
   btree_begin_transaction $::b1
-  set rc [catch {btree_update_meta $::b1 1 2 3 4} msg]
+  set rc [catch {btree_update_meta $::b1 1 2 3 4 5 6 7 8 9 10} msg]
   lappend rc $msg
 } {0 {}}
 do_test btree-5.4 {
   btree_get_meta $::b1
-} {0 2 3 4}
+} {0 2 3 4 5 6 7 8 9 10}
 do_test btree-5.5 {
   btree_close_cursor $::c1
   btree_rollback $::b1
   btree_get_meta $::b1
-} {0 0 0 0}
+} {0 0 0 0 0 0 0 0 0 0}
 do_test btree-5.6 {
   btree_begin_transaction $::b1
-  btree_update_meta $::b1 999 10 20 30
+  btree_update_meta $::b1 999 10 20 30 40 50 60 70 80 90
   btree_commit $::b1
   btree_get_meta $::b1
-} {0 10 20 30}
+} {0 10 20 30 40 50 60 70 80 90}
 
 proc select_all {cursor} {
   set r {}

www/fileformat.tcl

@@ -1,7 +1,7 @@
 #
 # Run this script to generated a fileformat.html output file
 #
-set rcsid {$Id: fileformat.tcl,v 1.6 2002/08/18 19:09:24 drh Exp $}
+set rcsid {$Id: fileformat.tcl,v 1.7 2003/02/12 14:09:45 drh Exp $}
 
 puts {<html>
 <head>
@@ -687,17 +687,18 @@ name change, it works exactly the same.
 <h3>4.4 &nbsp; Schema Version Numbering And Other Meta-Information</h3>
 
 <p>
-The four 32-bit integers that are stored beginning at byte offset
+The nine 32-bit integers that are stored beginning at byte offset
 60 of Page 1 in the b-tree layer are passed up into the schema layer
 and used for versioning and configuration information.  The meaning
-of these four integers is as follows:
+of the first four integers is shown below.  The other five are currently
+unused.
 </p>
 
 <ol>
 <li>The schema version number</li>
 <li>The format version number</li>
 <li>The recommended pager cache size</li>
-<li>Unused</li>
+<li>The safety level</li>
 </ol>
 
 <p>