Index: Makefile.in
==================================================================
--- Makefile.in
+++ Makefile.in
@@ -375,10 +375,12 @@
   parse.c \
   parse.h \
   config.h \
   shell.c \
   sqlite3.h
+
+SRC += $(TOP)/src/test_osinst.c
 
 # Source code to the test files.
 #
 TESTSRC = \
   $(TOP)/src/test1.c \
@@ -679,10 +681,13 @@
 sessionfuzz$(TEXE):	$(TOP)/test/sessionfuzz.c sqlite3.c sqlite3.h
 	$(LTLINK) -o $@ $(TOP)/test/sessionfuzz.c $(TLIBS)
 
 dbfuzz$(TEXE):	$(TOP)/test/dbfuzz.c sqlite3.c sqlite3.h
 	$(LTLINK) -o $@ $(DBFUZZ_OPT) $(TOP)/test/dbfuzz.c sqlite3.c $(TLIBS)
+
+osinst2sql$(TEXE):	$(TOP)/tool/osinst2sql.c sqlite3.c sqlite3.h
+	$(LTLINK) -o $@ $(TOP)/tool/osinst2sql.c sqlite3.c $(TLIBS)
 
 DBFUZZ2_OPTS = \
   -DSQLITE_THREADSAFE=0 \
   -DSQLITE_OMIT_LOAD_EXTENSION \
   -DSQLITE_ENABLE_DESERIALIZE \

Index: Makefile.msc
==================================================================
--- Makefile.msc
+++ Makefile.msc
@@ -1468,11 +1468,11 @@
 SRC12 =
 !ENDIF
 
 # All source code files.
 #
-SRC = $(SRC00) $(SRC01) $(SRC03) $(SRC04) $(SRC05) $(SRC06) $(SRC07) $(SRC08) $(SRC09) $(SRC10) $(SRC11)
+SRC = $(SRC00) $(SRC01) $(SRC03) $(SRC04) $(SRC05) $(SRC06) $(SRC07) $(SRC08) $(SRC09) $(SRC10) $(SRC11) $(TOP)\src\test_osinst.c
 
 # Source code to the test files.
 #
 TESTSRC = \
   $(TOP)\src\test1.c \
@@ -1770,10 +1770,13 @@
 	$(LTLINK) $(NO_WARN) $(FUZZERSHELL_COMPILE_OPTS) $(TOP)\tool\fuzzershell.c $(SQLITE3C) /link $(LDFLAGS) $(LTLINKOPTS)
 
 dbfuzz.exe:	$(TOP)\test\dbfuzz.c $(SQLITE3C) $(SQLITE3H)
 	$(LTLINK) $(NO_WARN) $(DBFUZZ_COMPILE_OPTS) $(TOP)\test\dbfuzz.c $(SQLITE3C) /link $(LDFLAGS) $(LTLINKOPTS)
 
+osinst2sql.exe:	$(TOP)\tool\osinst2sql.c $(SQLITE3C) $(SQLITE3H)
+	$(LTLINK) $(NO_WARN) $(TOP)\tool\osinst2sql.c $(SQLITE3C) /link $(LDFLAGS) $(LTLINKOPTS)
+
 fuzzcheck.exe:	$(FUZZCHECK_SRC) $(SQLITE3C) $(SQLITE3H)
 	$(LTLINK) $(NO_WARN) $(FUZZCHECK_OPTS) $(FUZZCHECK_SRC) $(SQLITE3C) /link $(LDFLAGS) $(LTLINKOPTS)
 
 ossshell.exe:	$(OSSSHELL_SRC) $(SQLITE3C) $(SQLITE3H)
 	$(LTLINK) $(NO_WARN) $(FUZZCHECK_OPTS) $(OSSSHELL_SRC) $(SQLITE3C) /link $(LDFLAGS) $(LTLINKOPTS)

Index: main.mk
==================================================================
--- main.mk
+++ main.mk
@@ -295,10 +295,12 @@
   parse.c \
   parse.h \
   shell.c \
   sqlite3.h
 
+SRC += $(TOP)/src/test_osinst.c
+
 
 # Source code to the test files.
 #
 TESTSRC = \
   $(TOP)/ext/expert/sqlite3expert.c \
@@ -577,10 +579,15 @@
 
 dbfuzz$(EXE):	$(TOP)/test/dbfuzz.c sqlite3.c sqlite3.h
 	$(TCCX) -o dbfuzz$(EXE) -DSQLITE_THREADSAFE=0 -DSQLITE_OMIT_LOAD_EXTENSION \
 	  $(DBFUZZ_OPT) $(TOP)/test/dbfuzz.c sqlite3.c \
 	  $(TLIBS) $(THREADLIB)
+
+osinst2sql$(EXE): $(TOP)/tool/osinst2sql.c sqlite3.c sqlite3.h
+	$(TCCX) -o osinst2sql$(EXE) -DSQLITE_THREADSAFE=0 -DSQLITE_OMIT_LOAD_EXTENSION \
+	  $(DBFUZZ_OPT) $(TOP)/tool/osinst2sql.c sqlite3.c \
+	  $(TLIBS) $(THREADLIB)
 
 DBFUZZ2_OPTS = \
   -DSQLITE_THREADSAFE=0 \
   -DSQLITE_OMIT_LOAD_EXTENSION \
   -DSQLITE_ENABLE_DESERIALIZE \

Index: src/main.c
==================================================================
--- src/main.c
+++ src/main.c
@@ -1145,10 +1145,15 @@
 ** prepare statement or sqlite3_backup closes.
 */
 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
 
+#ifdef SQLITE_ENABLE_OSINST
+int sqlite3_vfslog_new(const char*,const char*,const char*,sqlite3_vfs**);
+int sqlite3_vfslog_finalize(const char*);
+#endif
+
 
 /*
 ** Close the mutex on database connection db.
 **
 ** Furthermore, if database connection db is a zombie (meaning that there
@@ -1249,10 +1254,17 @@
   sqlite3_free(db->auth.zAuthUser);
   sqlite3_free(db->auth.zAuthPW);
 #endif
 
   db->magic = SQLITE_MAGIC_ERROR;
+
+#ifdef SQLITE_ENABLE_OSINST
+  if( db->pOsinstVfs ){
+    sqlite3_vfslog_finalize(db->pOsinstVfs->zName);
+    db->pOsinstVfs = 0;
+  }
+#endif
 
   /* The temp-database schema is allocated differently from the other schema
   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
   ** So it needs to be freed here. Todo: Why not roll the temp schema into
   ** the same sqliteMalloc() as the one that allocates the database 
@@ -3185,16 +3197,36 @@
   if( ((1<<(flags&7)) & 0x46)==0 ){
     rc = SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
   }else{
     rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
   }
+#ifdef SQLITE_ENABLE_OSINST
+  /* If this is not a temporary or ":memory:" database, create an osinst
+  ** VFS to use. */
+  assert( db->pVfs );
+  if( rc==SQLITE_OK && zOpen && zOpen[0] && strcmp(":memory:", zOpen) ){
+    u32 iVal = 0;
+    char *zLog = 0;
+    sqlite3_randomness(sizeof(iVal), (void*)&iVal);
+    zLog = sqlite3_mprintf("%s-osinst-%08x", zOpen, iVal);
+    if( zLog==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+    }else{
+      sqlite3_vfs *pVfs = 0;
+      rc = sqlite3_vfslog_new(zLog, db->pVfs->zName, zLog, &pVfs);
+      sqlite3_free(zLog);
+      db->pOsinstVfs = db->pVfs = pVfs;
+    }
+  }
+#endif
   if( rc!=SQLITE_OK ){
     if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
     sqlite3_free(zErrMsg);
     goto opendb_out;
   }
+
 
   /* Open the backend database driver */
   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
                         flags | SQLITE_OPEN_MAIN_DB);
   if( rc!=SQLITE_OK ){

Index: src/sqliteInt.h
==================================================================
--- src/sqliteInt.h
+++ src/sqliteInt.h
@@ -13,10 +13,12 @@
 **
 */
 #ifndef SQLITEINT_H
 #define SQLITEINT_H
 
+#define SQLITE_ENABLE_OSINST 1
+
 /* Special Comments:
 **
 ** Some comments have special meaning to the tools that measure test
 ** coverage:
 **
@@ -1485,10 +1487,13 @@
   sqlite3 *pNextBlocked;        /* Next in list of all blocked connections */
 #endif
 #ifdef SQLITE_USER_AUTHENTICATION
   sqlite3_userauth auth;        /* User authentication information */
 #endif
+#ifdef SQLITE_ENABLE_OSINST
+  sqlite3_vfs *pOsinstVfs;      /* osinst VFS to finalize, if any */
+#endif
 };
 
 /*
 ** A macro to discover the encoding of a database.
 */

Index: src/test_osinst.c
==================================================================
--- src/test_osinst.c
+++ src/test_osinst.c
@@ -640,11 +640,11 @@
   sqlite3_io_error_persist = persist;
   sqlite3_diskfull_pending = diskfull;
 #endif
 }
 
-static void put32bits(unsigned char *p, unsigned int v){
+static void vfslogPut32bits(unsigned char *p, unsigned int v){
   p[0] = v>>24;
   p[1] = (unsigned char)(v>>16);
   p[2] = (unsigned char)(v>>8);
   p[3] = (unsigned char)v;
 }
@@ -662,16 +662,16 @@
   unsigned char *zRec;
   if( (24+p->nBuf)>sizeof(p->aBuf) ){
     vfslog_flush(p);
   }
   zRec = (unsigned char *)&p->aBuf[p->nBuf];
-  put32bits(&zRec[0], eEvent);
-  put32bits(&zRec[4], iFileid);
-  put32bits(&zRec[8], (unsigned int)(nClick&0xffff));
-  put32bits(&zRec[12], return_code);
-  put32bits(&zRec[16], size);
-  put32bits(&zRec[20], offset);
+  vfslogPut32bits(&zRec[0], eEvent);
+  vfslogPut32bits(&zRec[4], iFileid);
+  vfslogPut32bits(&zRec[8], (unsigned int)(nClick&0xffffffff));
+  vfslogPut32bits(&zRec[12], return_code);
+  vfslogPut32bits(&zRec[16], size);
+  vfslogPut32bits(&zRec[20], offset);
   p->nBuf += 24;
 }
 
 static void vfslog_string(sqlite3_vfs *pVfs, const char *zStr){
   VfslogVfs *p = (VfslogVfs *)pVfs;
@@ -679,11 +679,11 @@
   int nStr = zStr ? (int)strlen(zStr) : 0;
   if( (4+nStr+p->nBuf)>sizeof(p->aBuf) ){
     vfslog_flush(p);
   }
   zRec = (unsigned char *)&p->aBuf[p->nBuf];
-  put32bits(&zRec[0], nStr);
+  vfslogPut32bits(&zRec[0], nStr);
   if( zStr ){
     memcpy(&zRec[4], zStr, nStr);
   }
   p->nBuf += (4 + nStr);
 }
@@ -708,11 +708,12 @@
 }
 
 int sqlite3_vfslog_new(
   const char *zVfs,               /* New VFS name */
   const char *zParentVfs,         /* Parent VFS name (or NULL) */
-  const char *zLog                /* Log file name */
+  const char *zLog,               /* Log file name */
+  sqlite3_vfs **ppVfs             /* OUT: New VFS object */
 ){
   VfslogVfs *p;
   sqlite3_vfs *pParent;
   int nByte;
   int flags;
@@ -745,11 +746,12 @@
   rc = pParent->xOpen(pParent, zFile, p->pLog, flags, &flags);
   if( rc==SQLITE_OK ){
     memcpy(p->aBuf, "sqlite_ostrace1.....", 20);
     p->iOffset = 0;
     p->nBuf = 20;
-    rc = sqlite3_vfs_register((sqlite3_vfs *)p, 1);
+    rc = sqlite3_vfs_register((sqlite3_vfs *)p, 0);
+    if( ppVfs ) *ppVfs = (sqlite3_vfs*)p;
   }
   if( rc ){
     vfslog_finalize(p);
   }
   return rc;
@@ -1178,15 +1180,16 @@
       }
       zVfs = Tcl_GetString(objv[2]);
       zParent = Tcl_GetString(objv[3]);
       zLog = Tcl_GetString(objv[4]);
       if( *zParent=='\0' ) zParent = 0;
-      rc = sqlite3_vfslog_new(zVfs, zParent, zLog);
+      rc = sqlite3_vfslog_new(zVfs, zParent, zLog, 0);
       if( rc!=SQLITE_OK ){
         Tcl_AppendResult(interp, "failed", 0);
         return TCL_ERROR;
       }
+      sqlite3_vfs_register(sqlite3_vfs_find(zVfs), 1);
       break;
     };
 
     case VL_REGISTER: {
       char *zDb;

Index: tool/mksqlite3c.tcl
==================================================================
--- tool/mksqlite3c.tcl
+++ tool/mksqlite3c.tcl
@@ -401,10 +401,12 @@
    dbstat.c
    dbpage.c
    sqlite3session.c
    fts5.c
    stmt.c
+
+   test_osinst.c
 } {
   copy_file tsrc/$file
 }
 
 # Synthesize an alternative sqlite3_sourceid() implementation that