Change the mmap_limit pragma to report the new limit, or to report the

existing limit if called with no arguments. Report the default mmap_limit as part of PRAGMA compile_options. Set the default mmmap_limit to 0 for all systems other than linux, mac, windows, and solaris.
xiexiemanyou · Apr 3, 2013 · e76909d · e76909d
1 parent cf5344e
commit e76909d
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Showing 8 changed files with 28 additions and 18 deletions.
diff --git a/src/ctime.c b/src/ctime.c
@@ -57,6 +57,9 @@ static const char * const azCompileOpt[] = {
 #ifdef SQLITE_DEFAULT_LOCKING_MODE
   "DEFAULT_LOCKING_MODE=" CTIMEOPT_VAL(SQLITE_DEFAULT_LOCKING_MODE),
 #endif
+#ifdef SQLITE_DEFAULT_MMAP_LIMIT
+  "DEFAULT_MMAP_LIMIT=" CTIMEOPT_VAL(SQLITE_DEFAULT_MMAP_LIMIT),
+#endif
 #ifdef SQLITE_DISABLE_DIRSYNC
   "DISABLE_DIRSYNC",
 #endif

diff --git a/src/os_unix.c b/src/os_unix.c
@@ -3710,7 +3710,9 @@ static int unixFileControl(sqlite3_file *id, int op, void *pArg){
       return SQLITE_OK;
     }
     case SQLITE_FCNTL_MMAP_LIMIT: {
-      pFile->mmapLimit = *(i64*)pArg;
+      i64 newLimit = *(i64*)pArg;
+      *(i64*)pArg = pFile->mmapLimit;
+      if( newLimit>=0 ) pFile->mmapLimit = newLimit;
       return SQLITE_OK;
     }
 #ifdef SQLITE_DEBUG

diff --git a/src/os_win.c b/src/os_win.c
@@ -2837,7 +2837,9 @@ static int winFileControl(sqlite3_file *id, int op, void *pArg){
       return SQLITE_OK;
     }
     case SQLITE_FCNTL_MMAP_LIMIT: {
-      pFile->mmapLimit = *(i64*)pArg;
+      i64 newLimit = *(i64*)pArg;
+      *(i64*) = pFile->mmapLimit;
+      if( newLimit>=0 ) pFile->mmapLimit = newLimit;
       return SQLITE_OK;
     }
   }

diff --git a/src/pager.c b/src/pager.c
@@ -3358,9 +3358,10 @@ void sqlite3PagerSetCachesize(Pager *pPager, int mxPage){
 static void pagerFixMaplimit(Pager *pPager){
   sqlite3_file *fd = pPager->fd;
   if( isOpen(fd) ){
+    sqlite3_int64 mx;
     pPager->bUseFetch = (fd->pMethods->iVersion>=3) && pPager->mxMmap>0;
-    sqlite3OsFileControlHint(pPager->fd, SQLITE_FCNTL_MMAP_LIMIT,
-                             (void*)&pPager->mxMmap);
+    mx = pPager->mxMmap;
+    sqlite3OsFileControlHint(pPager->fd, SQLITE_FCNTL_MMAP_LIMIT, &mx);
   }
 }
 

diff --git a/src/pragma.c b/src/pragma.c
@@ -759,19 +759,23 @@ void sqlite3Pragma(
   ** upper layers will never invoke the xFetch interfaces to the VFS.
   */
   if( sqlite3StrICmp(zLeft,"mmap_limit")==0 ){
+    sqlite3_int64 mx;
     assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
     if( zRight ){
-      sqlite3_int64 size;
       int ii;
-      sqlite3Atoi64(zRight, &size, 1000, SQLITE_UTF8);
-      if( size<0 ) size = sqlite3GlobalConfig.mxMmap;
-      if( pId2->n==0 ) db->mxMmap = size;
+      sqlite3Atoi64(zRight, &mx, 1000, SQLITE_UTF8);
+      if( mx<0 ) mx = sqlite3GlobalConfig.mxMmap;
+      if( pId2->n==0 ) db->mxMmap = mx;
       for(ii=db->nDb-1; ii>=0; ii--){
         if( db->aDb[ii].pBt && (ii==iDb || pId2->n==0) ){
-          sqlite3BtreeSetMmapLimit(db->aDb[ii].pBt, size);
+          sqlite3BtreeSetMmapLimit(db->aDb[ii].pBt, mx);
         }
       }
     }
+    mx = -1;
+    if( sqlite3_file_control(db,zDb,SQLITE_FCNTL_MMAP_LIMIT,&mx)==SQLITE_OK ){
+      returnSingleInt(pParse, "mmap_limit", mx);
+    }
   }else
 
   /*

diff --git a/src/sqlite.h.in b/src/sqlite.h.in
@@ -888,7 +888,9 @@ struct sqlite3_io_methods {
 **
 ** <li>[[SQLITE_FCNTL_MMAP_LIMIT]]
 ** The argument is assumed to pointer to a value of type sqlite3_int64 that
-** is an advisory maximum number of bytes in the file to memory map.
+** is an advisory maximum number of bytes in the file to memory map.  The
+** pointer is overwritten with the old value.  The limit is not changed if
+** the original value pointed to is negative.
 **
 ** </ul>
 */

diff --git a/src/sqliteLimit.h b/src/sqliteLimit.h
@@ -219,13 +219,9 @@
 #ifndef SQLITE_DEFAULT_MMAP_LIMIT
 # if defined(__linux__) \
   || defined(_WIN32) \
-  || (defined(__APPLE__) && defined(__MACH__)  && !defined(TARGET_OS_IPHONE)) \
-  || defined(__sun) \
-  || defined(__DragonFly__) \
-  || defined(__FreeBSD__) \
-  || defined(__NetBSD__) \
-  || defined(__OpenBSD__)
-#   define SQLITE_DEFAULT_MMAP_LIMIT (256*1024*1024)
+  || (defined(__APPLE__) && defined(__MACH__)) \
+  || defined(__sun)
+#   define SQLITE_DEFAULT_MMAP_LIMIT 268435456 /* = 256*1024*1024 */
 # else
 #   define SQLITE_DEFAULT_MMAP_LIMIT 0
 # endif

diff --git a/test/mmap1.test b/test/mmap1.test
@@ -108,7 +108,7 @@ do_execsql_test 2.1 {
   INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --   16
   INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --   32
   PRAGMA wal_checkpoint;
-} {wal 0 103 103}
+} {67108864 wal 0 103 103}
 
 do_execsql_test 2.2 {
   PRAGMA auto_vacuum;