Add the SQLITE_FCNTL_OVERWRITE file-control. Used by SQLite to indicate to the OS layer that the current transaction will overwrite the entire file.

FossilOrigin-Name: 1da87fcdacfa7d277c3ee98e410a9ea8b529c368

manifest

@@ -1,5 +1,5 @@
-C Enhance\sthe\ssqlite3_data_count()\sroutine\sso\sthat\sit\scan\sbe\sused\sto\sdetermine\nif\sSQLITE_DONE\shas\sbeen\sseen\son\sthe\sprepared\sstatement.
-D 2011-10-07T12:59:23.182
+C Add\sthe\sSQLITE_FCNTL_OVERWRITE\sfile-control.\sUsed\sby\sSQLite\sto\sindicate\sto\sthe\sOS\slayer\sthat\sthe\scurrent\stransaction\swill\soverwrite\sthe\sentire\sfile.
+D 2011-10-07T16:57:59.355
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in a162fe39e249b8ed4a65ee947c30152786cfe897
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -121,7 +121,7 @@ F src/alter.c ac80a0f31189f8b4a524ebf661e47e84536ee7f5
 F src/analyze.c 775421ced0bd78181cc206fbc63063658066c1da
 F src/attach.c 12c6957996908edc31c96d7c68d4942c2474405f
 F src/auth.c 523da7fb4979469955d822ff9298352d6b31de34
-F src/backup.c 28a4fe55327ff708bfaf9d4326d02686f7a553c3
+F src/backup.c 4fd4440c8f81339d8eb8e5d2df54b68d79e94f2f
 F src/bitvec.c af50f1c8c0ff54d6bdb7a80e2fceca5a93670bef
 F src/btmutex.c 976f45a12e37293e32cae0281b15a21d48a8aaa7
 F src/btree.c 77b09c69d4849a90361e6fe5db36d167f20600c0
@@ -181,7 +181,7 @@ F src/resolve.c 36368f44569208fa074e61f4dd0b6c4fb60ca2b4
 F src/rowset.c 69afa95a97c524ba6faf3805e717b5b7ae85a697
 F src/select.c d9b7d20b0365f80761846f00ef3638d4b33eeaf2
 F src/shell.c e8fe1251aee84baa2fb232ce83d938de25aa650f
-F src/sqlite.h.in 1865923bdb9deb8dde42da5862aca0071adb6061
+F src/sqlite.h.in b22e3187e048661d98a748ad54099c69dccfe497
 F src/sqlite3ext.h 1a1a4f784aa9c3b00edd287940197de52487cd93
 F src/sqliteInt.h 28cca77ebdaf6025ae5df52717dff429c7c6d4ef
 F src/sqliteLimit.h 164b0e6749d31e0daa1a4589a169d31c0dec7b3d
@@ -237,7 +237,7 @@ F src/trigger.c 1cfb80e2290ef66ea89cb4e821caae65a02c0d56
 F src/update.c 74a6cfb34e9732c1e2a86278b229913b4b51eeec
 F src/utf.c 890c67dcfcc7a74623c95baac7535aadfe265e84
 F src/util.c 06302ffd2b80408d4f6c7af71f7090e0cf8d8ff7
-F src/vacuum.c 297f39745e05d7a6ed7def7929451474d570a31e
+F src/vacuum.c 0c0ba2242355c6048d65e2b333abe0f7c06348fa
 F src/vdbe.c 60340bfb23f456ea0791cb28262a887363773371
 F src/vdbe.h f0725ee997db869ecae5bb70a71612aabeca7755
 F src/vdbeInt.h 693d6ac6810298fc6b4c503cfbe3f99a240f40af
@@ -967,7 +967,7 @@ F tool/symbols.sh caaf6ccc7300fd43353318b44524853e222557d5
 F tool/tostr.awk e75472c2f98dd76e06b8c9c1367f4ab07e122d06
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
 F tool/warnings.sh fbc018d67fd7395f440c28f33ef0f94420226381
-P baa80c7bc31900decae0d8e6090b30fcde377492
-R 1223a474d1e5cea6170a2af45d3f0303
-U drh
-Z 7e8fd93d23ec7d2fecbdff0e025997fa
+P 9913996e7b0f94ba1c51200b61433193002f3638
+R 95c2b529419f78d1f0a0f16ca9ea56e3
+U dan
+Z 751eeeee5e1f94cafba63c56e2ffa2f0

manifest.uuid

@@ -1 +1 @@
-9913996e7b0f94ba1c51200b61433193002f3638
+1da87fcdacfa7d277c3ee98e410a9ea8b529c368

src/backup.c

@@ -669,10 +669,18 @@ void sqlite3BackupRestart(sqlite3_backup *pBackup){
 */
 int sqlite3BtreeCopyFile(Btree *pTo, Btree *pFrom){
   int rc;
+  sqlite3_file *pFd;              /* File descriptor for database pTo */
   sqlite3_backup b;
   sqlite3BtreeEnter(pTo);
   sqlite3BtreeEnter(pFrom);
 
+  assert( sqlite3BtreeIsInTrans(pTo) );
+  pFd = sqlite3PagerFile(sqlite3BtreePager(pTo));
+  if( pFd->pMethods ){
+    i64 nByte = sqlite3BtreeGetPageSize(pFrom)*(i64)sqlite3BtreeLastPage(pFrom);
+    sqlite3OsFileControl(pFd, SQLITE_FCNTL_OVERWRITE, &nByte);
+  }
+
   /* Set up an sqlite3_backup object. sqlite3_backup.pDestDb must be set
   ** to 0. This is used by the implementations of sqlite3_backup_step()
   ** and sqlite3_backup_finish() to detect that they are being called
@@ -698,6 +706,7 @@ int sqlite3BtreeCopyFile(Btree *pTo, Btree *pFrom){
     pTo->pBt->pageSizeFixed = 0;
   }
 
+  assert( sqlite3BtreeIsInTrans(pTo)==0 );
   sqlite3BtreeLeave(pFrom);
   sqlite3BtreeLeave(pTo);
   return rc;

src/sqlite.h.in

@@ -767,6 +767,10 @@ struct sqlite3_io_methods {
 ** WAL mode.  If the integer is -1, then it is overwritten with the current
 ** WAL persistence setting.
 **
+** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
+** a write transaction to indicate that, unless it is rolled back for some
+** reason, the entire database file will be overwritten by the current 
+** transaction. This is used by VACUUM operations.
 */
 #define SQLITE_FCNTL_LOCKSTATE        1
 #define SQLITE_GET_LOCKPROXYFILE      2
@@ -778,6 +782,7 @@ struct sqlite3_io_methods {
 #define SQLITE_FCNTL_SYNC_OMITTED     8
 #define SQLITE_FCNTL_WIN32_AV_RETRY   9
 #define SQLITE_FCNTL_PERSIST_WAL     10
+#define SQLITE_FCNTL_OVERWRITE       11
 
 /*
 ** CAPI3REF: Mutex Handle

src/vacuum.c

@@ -263,13 +263,11 @@ int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db){
   );
   if( rc ) goto end_of_vacuum;
 
-  /* At this point, unless the main db was completely empty, there is now a
-  ** transaction open on the vacuum database, but not on the main database.
-  ** Open a btree level transaction on the main database. This allows a
-  ** call to sqlite3BtreeCopyFile(). The main database btree level
-  ** transaction is then committed, so the SQL level never knows it was
-  ** opened for writing. This way, the SQL transaction used to create the
-  ** temporary database never needs to be committed.
+  /* At this point, there is a write transaction open on both the 
+  ** vacuum database and the main database. Assuming no error occurs,
+  ** both transactions are closed by this block - the main database
+  ** transaction by sqlite3BtreeCopyFile() and the other by an explicit
+  ** call to sqlite3BtreeCommit().
   */
   {
     u32 meta;