Update the sessions branch to include the SQLLOG enhancement, the

SQLITE_IOERR_DELETE_NOENT fix, and a fix for the number-of-documents
bug in FTS4.

FossilOrigin-Name: ba8d08b67021a32fda069c18b7eb93523e6f0d1f

8 files changed, 584 insertions, 5 deletions

diff --git a/src/global.c b/src/global.c
index dc86e1e08..f5da7e7f1 100644
--- a/src/global.c
+++ b/src/global.c
@@ -175,6 +175,10 @@ SQLITE_WSD struct Sqlite3Config sqlite3Config = {
    0,                         /* xLog */
    0,                         /* pLogArg */
    0,                         /* bLocaltimeFault */
+#ifdef SQLITE_ENABLE_SQLLOG
+   0,                         /* xSqllog */
+   0                          /* pSqllogArg */
+#endif
 };
 
 
diff --git a/src/main.c b/src/main.c
index 5778f8780..b8de24576 100644
--- a/src/main.c
+++ b/src/main.c
@@ -132,6 +132,13 @@ int sqlite3_initialize(void){
   */
   if( sqlite3GlobalConfig.isInit ) return SQLITE_OK;
 
+#ifdef SQLITE_ENABLE_SQLLOG
+  {
+    extern void sqlite3_init_sqllog(void);
+    sqlite3_init_sqllog();
+  }
+#endif
+
   /* Make sure the mutex subsystem is initialized.  If unable to 
   ** initialize the mutex subsystem, return early with the error.
   ** If the system is so sick that we are unable to allocate a mutex,
@@ -480,6 +487,15 @@ int sqlite3_config(int op, ...){
       break;
     }
 
+#ifdef SQLITE_ENABLE_SQLLOG
+    case SQLITE_CONFIG_SQLLOG: {
+      typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
+      sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
+      sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
+      break;
+    }
+#endif
+
     default: {
       rc = SQLITE_ERROR;
       break;
@@ -819,6 +835,13 @@ static int sqlite3Close(sqlite3 *db, int forceZombie){
     return SQLITE_BUSY;
   }
 
+#ifdef SQLITE_ENABLE_SQLLOG
+  if( sqlite3GlobalConfig.xSqllog ){
+    /* Closing the handle. Fourth parameter is passed the value 2. */
+    sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
+  }
+#endif
+
   /* Convert the connection into a zombie and then close it.
   */
   db->magic = SQLITE_MAGIC_ZOMBIE;
@@ -2472,6 +2495,13 @@ opendb_out:
     db->magic = SQLITE_MAGIC_SICK;
   }
   *ppDb = db;
+#ifdef SQLITE_ENABLE_SQLLOG
+  if( sqlite3GlobalConfig.xSqllog ){
+    /* Opening a db handle. Fourth parameter is passed 0. */
+    void *pArg = sqlite3GlobalConfig.pSqllogArg;
+    sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
+  }
+#endif
   return sqlite3ApiExit(0, rc);
 }
 
diff --git a/src/os_unix.c b/src/os_unix.c
index ca6213943..a3a012126 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -46,6 +46,13 @@
 #include "sqliteInt.h"
 #if SQLITE_OS_UNIX              /* This file is used on unix only */
 
+/* Use posix_fallocate() if it is available
+*/
+#if !defined(HAVE_POSIX_FALLOCATE) \
+      && (_XOPEN_SOURCE >= 600 || _POSIX_C_SOURCE >= 200112L)
+# define HAVE_POSIX_FALLOCATE 1
+#endif
+
 /*
 ** There are various methods for file locking used for concurrency
 ** control:
@@ -4168,11 +4175,19 @@ static int unixShmMap(
         ** the requested memory region.
         */
         if( !bExtend ) goto shmpage_out;
+#if defined(HAVE_POSIX_FALLOCATE) && HAVE_POSIX_FALLOCATE
+        if( osFallocate(pShmNode->h, sStat.st_size, nByte)!=0 ){
+          rc = unixLogError(SQLITE_IOERR_SHMSIZE, "fallocate",
+                            pShmNode->zFilename);
+          goto shmpage_out;
+        }
+#else
         if( robust_ftruncate(pShmNode->h, nByte) ){
           rc = unixLogError(SQLITE_IOERR_SHMSIZE, "ftruncate",
                             pShmNode->zFilename);
           goto shmpage_out;
         }
+#endif
       }
     }
 
diff --git a/src/os_win.c b/src/os_win.c
index 3c92b43d4..6f4925770 100644
--- a/src/os_win.c
+++ b/src/os_win.c
@@ -3888,14 +3888,24 @@ static int winDelete(
                                   &sAttrData) ){
         attr = sAttrData.dwFileAttributes;
       }else{
-        rc = SQLITE_OK; /* Already gone? */
+        lastErrno = osGetLastError();
+        if( lastErrno==ERROR_FILE_NOT_FOUND || lastErrno==ERROR_PATH_NOT_FOUND ){
+          rc = SQLITE_IOERR_DELETE_NOENT; /* Already gone? */
+        }else{
+          rc = SQLITE_ERROR;
+        }
         break;
       }
 #else
       attr = osGetFileAttributesW(zConverted);
 #endif
       if ( attr==INVALID_FILE_ATTRIBUTES ){
-        rc = SQLITE_OK; /* Already gone? */
+        lastErrno = osGetLastError();
+        if( lastErrno==ERROR_FILE_NOT_FOUND || lastErrno==ERROR_PATH_NOT_FOUND ){
+          rc = SQLITE_IOERR_DELETE_NOENT; /* Already gone? */
+        }else{
+          rc = SQLITE_ERROR;
+        }
         break;
       }
       if ( attr&FILE_ATTRIBUTE_DIRECTORY ){
@@ -3917,7 +3927,12 @@ static int winDelete(
     do {
       attr = osGetFileAttributesA(zConverted);
       if ( attr==INVALID_FILE_ATTRIBUTES ){
-        rc = SQLITE_OK; /* Already gone? */
+        lastErrno = osGetLastError();
+        if( lastErrno==ERROR_FILE_NOT_FOUND || lastErrno==ERROR_PATH_NOT_FOUND ){
+          rc = SQLITE_IOERR_DELETE_NOENT; /* Already gone? */
+        }else{
+          rc = SQLITE_ERROR;
+        }
         break;
       }
       if ( attr&FILE_ATTRIBUTE_DIRECTORY ){
@@ -3935,7 +3950,7 @@ static int winDelete(
     } while(1);
   }
 #endif
-  if( rc ){
+  if( rc && rc!=SQLITE_IOERR_DELETE_NOENT ){
     rc = winLogError(SQLITE_IOERR_DELETE, lastErrno,
              "winDelete", zFilename);
   }else{
diff --git a/src/sqlite.h.in b/src/sqlite.h.in
index 0522973f8..95fb0190b 100644
--- a/src/sqlite.h.in
+++ b/src/sqlite.h.in
@@ -1593,6 +1593,22 @@ struct sqlite3_mem_methods {
 ** <dd> These options are obsolete and should not be used by new code.
 ** They are retained for backwards compatibility but are now no-ops.
 ** </dl>
+**
+** [[SQLITE_CONFIG_SQLLOG]]
+** <dt>SQLITE_CONFIG_SQLLOG
+** <dd>This option is only available if sqlite is compiled with the
+** SQLITE_ENABLE_SQLLOG pre-processor macro defined. The first argument should
+** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
+** The second should be of type (void*). The callback is invoked by the library
+** in three separate circumstances, identified by the value passed as the
+** fourth parameter. If the fourth parameter is 0, then the database connection
+** passed as the second argument has just been opened. The third argument
+** points to a buffer containing the name of the main database file. If the
+** fourth parameter is 1, then the SQL statement that the third parameter
+** points to has just been executed. Or, if the fourth parameter is 2, then
+** the connection being passed as the second parameter is being closed. The
+** third parameter is passed NULL In this case.
+** </dl>
 */
 #define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
 #define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
@@ -1614,6 +1630,7 @@ struct sqlite3_mem_methods {
 #define SQLITE_CONFIG_PCACHE2      18  /* sqlite3_pcache_methods2* */
 #define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */
 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
+#define SQLITE_CONFIG_SQLLOG       21  /* xSqllog, void* */
 
 /*
 ** CAPI3REF: Database Connection Configuration Options
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 658b67ba4..c3085ffd8 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -2527,6 +2527,10 @@ struct Sqlite3Config {
   void (*xLog)(void*,int,const char*); /* Function for logging */
   void *pLogArg;                       /* First argument to xLog() */
   int bLocaltimeFault;              /* True to fail localtime() calls */
+#ifdef SQLITE_ENABLE_SQLLOG
+  void(*xSqllog)(void*,sqlite3*,const char*, int);
+  void *pSqllogArg;
+#endif
 };
 
 /*
diff --git a/src/test_sqllog.c b/src/test_sqllog.c
new file mode 100644
index 000000000..49569a39f
--- /dev/null
+++ b/src/test_sqllog.c
@@ -0,0 +1,472 @@
+/*
+** 2012 November 26
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** OVERVIEW
+**
+**   This file contains experimental code used to record data from live
+**   SQLite applications that may be useful for offline analysis. Specifically:
+**
+**     1) The initial contents of all database files opened by the 
+**        application, and
+**
+**     2) All SQL statements executed by the application.
+**
+** USAGE
+**
+**   To use this module, SQLite must be compiled with the SQLITE_ENABLE_SQLLOG
+**   pre-processor symbol defined and this file linked into the application
+**   somehow.
+**
+**   At runtime, logging is enabled by setting environment variable
+**   SQLITE_SQLLOG_DIR to the name of a directory in which to store logged 
+**   data. The directory must already exist.
+**
+**   Usually, if the application opens the same database file more than once
+**   (either by attaching it or by using more than one database handle), only
+**   a single copy is made. This behaviour may be overridden (so that a 
+**   separate copy is taken each time the database file is opened or attached)
+**   by setting the environment variable SQLITE_SQLLOG_REUSE_FILES to 0.
+**
+** OUTPUT:
+**
+**   The SQLITE_SQLLOG_DIR is populated with three types of files:
+**
+**      sqllog_N.db   - Copies of database files. N may be any integer.
+**
+**      sqllog_N.sql  - A list of SQL statements executed by a single
+**                      connection. N may be any integer.
+**
+**      sqllog.idx    - An index mapping from integer N to a database
+**                      file name - indicating the full path of the
+**                      database from which sqllog_N.db was copied.
+**
+** ERROR HANDLING:
+**
+**   This module attempts to make a best effort to continue logging if an
+**   IO or other error is encountered. For example, if a log file cannot 
+**   be opened logs are not collected for that connection, but other
+**   logging proceeds as expected. Errors are logged by calling sqlite3_log().
+*/
+
+#include "sqlite3.h"
+#include "stdio.h"
+#include "stdlib.h"
+#include "string.h"
+#include "assert.h"
+
+#include "sys/types.h"
+#include "unistd.h"
+static int getProcessId(void){
+#if SQLITE_OS_WIN
+  return (int)_getpid();
+#else
+  return (int)getpid();
+#endif
+}
+
+
+#define ENVIRONMENT_VARIABLE1_NAME "SQLITE_SQLLOG_DIR"
+#define ENVIRONMENT_VARIABLE2_NAME "SQLITE_SQLLOG_REUSE_FILES"
+
+/* Assume that all database and database file names are shorted than this. */
+#define SQLLOG_NAMESZ 512
+
+/* Maximum number of simultaneous database connections the process may
+** open (if any more are opened an error is logged using sqlite3_log()
+** and processing is halted).
+*/
+#define MAX_CONNECTIONS 256
+
+struct SLConn {
+  int isErr;                      /* True if an error has occurred */
+  sqlite3 *db;                    /* Connection handle */
+  int iLog;                       /* First integer value used in file names */
+  FILE *fd;                       /* File descriptor for log file */
+};
+
+struct SLGlobal {
+  /* Protected by MUTEX_STATIC_MASTER */
+  sqlite3_mutex *mutex;           /* Recursive mutex */
+  int nConn;                      /* Size of aConn[] array */
+
+  /* Protected by SLGlobal.mutex */
+  int bReuse;                     /* True to avoid extra copies of db files */
+  char zPrefix[SQLLOG_NAMESZ];    /* Prefix for all created files */
+  char zIdx[SQLLOG_NAMESZ];       /* Full path to *.idx file */
+  int iNextLog;                   /* Used to allocate file names */
+  int iNextDb;                    /* Used to allocate database file names */
+  int bRec;                       /* True if testSqllog() is called rec. */
+  int iClock;                     /* Clock value */
+  struct SLConn aConn[MAX_CONNECTIONS];
+} sqllogglobal;
+
+/*
+** Return true if c is an ASCII whitespace character.
+*/
+static int sqllog_isspace(char c){
+  return (c==' ' || c=='\t' || c=='\n' || c=='\v' || c=='\f' || c=='\r');
+}
+
+/*
+** The first argument points to a nul-terminated string containing an SQL
+** command. Before returning, this function sets *pz to point to the start
+** of the first token in this command, and *pn to the number of bytes in 
+** the token. This is used to check if the SQL command is an "ATTACH" or 
+** not.
+*/
+static void sqllogTokenize(const char *z, const char **pz, int *pn){
+  const char *p = z;
+  int n;
+
+  /* Skip past any whitespace */
+  while( sqllog_isspace(*p) ){
+    p++;
+  }
+
+  /* Figure out how long the first token is */
+  *pz = p;
+  n = 0;
+  while( (p[n]>='a' && p[n]<='z') || (p[n]>='A' && p[n]<='Z') ) n++;
+  *pn = n;
+}
+
+/*
+** Check if the logs directory already contains a copy of database file 
+** zFile. If so, return a pointer to the full path of the copy. Otherwise,
+** return NULL.
+**
+** If a non-NULL value is returned, then the caller must arrange to 
+** eventually free it using sqlite3_free().
+*/
+static char *sqllogFindFile(const char *zFile){
+  char *zRet = 0;
+  FILE *fd = 0;
+
+  /* Open the index file for reading */
+  fd = fopen(sqllogglobal.zIdx, "r");
+  if( fd==0 ){
+    sqlite3_log(SQLITE_IOERR, "sqllogFindFile(): error in fopen()");
+    return 0;
+  }
+
+  /* Loop through each entry in the index file. If zFile is not NULL and the
+  ** entry is a match, then set zRet to point to the filename of the existing
+  ** copy and break out of the loop.  */
+  while( feof(fd)==0 ){
+    char zLine[SQLLOG_NAMESZ*2+5];
+    if( fgets(zLine, sizeof(zLine), fd) ){
+      int n;
+      char *z;
+
+      zLine[sizeof(zLine)-1] = '\0';
+      z = zLine;
+      while( *z>='0' && *z<='9' ) z++;
+      while( *z==' ' ) z++;
+
+      n = strlen(z);
+      while( n>0 && sqllog_isspace(z[n-1]) ) n--;
+
+      if( n==strlen(zFile) && 0==memcmp(zFile, z, n) ){
+        char zBuf[16];
+        memset(zBuf, 0, sizeof(zBuf));
+        z = zLine;
+        while( *z>='0' && *z<='9' ){
+          zBuf[z-zLine] = *z;
+          z++;
+        }
+        zRet = sqlite3_mprintf("%s_%s.db", sqllogglobal.zPrefix, zBuf);
+        break;
+      }
+    }
+  }
+
+  if( ferror(fd) ){
+    sqlite3_log(SQLITE_IOERR, "sqllogFindFile(): error reading index file");
+  }
+
+  fclose(fd);
+  return zRet;
+}
+
+static int sqllogFindAttached(
+  struct SLConn *p,               /* Database connection */
+  const char *zSearch,            /* Name to search for (or NULL) */
+  char *zName,                    /* OUT: Name of attached database */
+  char *zFile                     /* OUT: Name of attached file */
+){
+  sqlite3_stmt *pStmt;
+  int rc;
+
+  /* The "PRAGMA database_list" command returns a list of databases in the
+  ** order that they were attached. So a newly attached database is 
+  ** described by the last row returned.  */
+  assert( sqllogglobal.bRec==0 );
+  sqllogglobal.bRec = 1;
+  rc = sqlite3_prepare_v2(p->db, "PRAGMA database_list", -1, &pStmt, 0);
+  if( rc==SQLITE_OK ){
+    while( SQLITE_ROW==sqlite3_step(pStmt) ){
+      const char *zVal1; int nVal1;
+      const char *zVal2; int nVal2;
+
+      zVal1 = (const char*)sqlite3_column_text(pStmt, 1);
+      nVal1 = sqlite3_column_bytes(pStmt, 1);
+      memcpy(zName, zVal1, nVal1+1);
+
+      zVal2 = (const char*)sqlite3_column_text(pStmt, 2);
+      nVal2 = sqlite3_column_bytes(pStmt, 2);
+      memcpy(zFile, zVal2, nVal2+1);
+
+      if( zSearch && strlen(zSearch)==nVal1 
+       && 0==sqlite3_strnicmp(zSearch, zVal1, nVal1)
+      ){
+        break;
+      }
+    }
+    rc = sqlite3_finalize(pStmt);
+  }
+  sqllogglobal.bRec = 0;
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_log(rc, "sqllogFindAttached(): error in \"PRAGMA database_list\"");
+  }
+  return rc;
+}
+
+
+/*
+** Parameter zSearch is the name of a database attached to the database 
+** connection associated with the first argument. This function creates
+** a backup of this database in the logs directory.
+**
+** The name used for the backup file is automatically generated. Call
+** it zFile.
+**
+** If the bLog parameter is true, then a statement of the following form
+** is written to the log file associated with *p:
+**
+**    ATTACH 'zFile' AS 'zName';
+**
+** Otherwise, if bLog is false, a comment is added to the log file:
+**
+**    -- Main database file is 'zFile'
+**
+** The SLGlobal.mutex mutex is always held when this function is called.
+*/
+static void sqllogCopydb(struct SLConn *p, const char *zSearch, int bLog){
+  char zName[SQLLOG_NAMESZ];      /* Attached database name */
+  char zFile[SQLLOG_NAMESZ];      /* Database file name */
+  char *zFree;
+  char *zInit = 0;
+  int rc;
+
+  rc = sqllogFindAttached(p, zSearch, zName, zFile);
+  if( rc!=SQLITE_OK ) return;
+
+  if( zFile[0]=='\0' ){
+    zInit = sqlite3_mprintf("");
+  }else{
+    if( sqllogglobal.bReuse ){
+      zInit = sqllogFindFile(zFile);
+    }else{
+      zInit = 0;
+    }
+    if( zInit==0 ){
+      int rc;
+      sqlite3 *copy = 0;
+      int iDb;
+
+      /* Generate a file-name to use for the copy of this database */
+      iDb = sqllogglobal.iNextDb++;
+      zInit = sqlite3_mprintf("%s_%d.db", sqllogglobal.zPrefix, iDb);
+
+      /* Create the backup */
+      assert( sqllogglobal.bRec==0 );
+      sqllogglobal.bRec = 1;
+      rc = sqlite3_open(zInit, &copy);
+      if( rc==SQLITE_OK ){
+        sqlite3_backup *pBak;
+        sqlite3_exec(copy, "PRAGMA synchronous = 0", 0, 0, 0);
+        pBak = sqlite3_backup_init(copy, "main", p->db, zName);
+        if( pBak ){
+          sqlite3_backup_step(pBak, -1);
+          rc = sqlite3_backup_finish(pBak);
+        }else{
+          rc = sqlite3_errcode(copy);
+        }
+        sqlite3_close(copy);
+      }
+      sqllogglobal.bRec = 0;
+
+      if( rc==SQLITE_OK ){
+        /* Write an entry into the database index file */
+        FILE *fd = fopen(sqllogglobal.zIdx, "a");
+        if( fd ){
+          fprintf(fd, "%d %s\n", iDb, zFile);
+          fclose(fd);
+        }
+      }else{
+        sqlite3_log(rc, "sqllogCopydb(): error backing up database");
+      }
+    }
+  }
+
+  if( bLog ){
+    zFree = sqlite3_mprintf("ATTACH '%q' AS '%q'; -- clock=%d\n", 
+        zInit, zName, sqllogglobal.iClock++
+    );
+  }else{
+    zFree = sqlite3_mprintf("-- Main database is '%q'\n", zInit);
+  }
+  fprintf(p->fd, "%s", zFree);
+  sqlite3_free(zFree);
+
+  sqlite3_free(zInit);
+}
+
+/*
+** If it is not already open, open the log file for connection *p. 
+**
+** The SLGlobal.mutex mutex is always held when this function is called.
+*/
+static void sqllogOpenlog(struct SLConn *p){
+  /* If the log file has not yet been opened, open it now. */
+  if( p->fd==0 ){
+    char *zLog;
+
+    /* If it is still NULL, have global.zPrefix point to a copy of 
+    ** environment variable $ENVIRONMENT_VARIABLE1_NAME.  */
+    if( sqllogglobal.zPrefix[0]==0 ){
+      FILE *fd;
+      char *zVar = getenv(ENVIRONMENT_VARIABLE1_NAME);
+      if( zVar==0 || strlen(zVar)+10>=(sizeof(sqllogglobal.zPrefix)) ) return;
+      sprintf(sqllogglobal.zPrefix, "%s/sqllog_%d", zVar, getProcessId());
+      sprintf(sqllogglobal.zIdx, "%s.idx", sqllogglobal.zPrefix);
+      if( getenv(ENVIRONMENT_VARIABLE2_NAME) ){
+        sqllogglobal.bReuse = atoi(getenv(ENVIRONMENT_VARIABLE2_NAME));
+      }
+      fd = fopen(sqllogglobal.zIdx, "w");
+      if( fd ) fclose(fd);
+    }
+
+    /* Open the log file */
+    zLog = sqlite3_mprintf("%s_%d.sql", sqllogglobal.zPrefix, p->iLog);
+    p->fd = fopen(zLog, "w");
+    sqlite3_free(zLog);
+    if( p->fd==0 ){
+      sqlite3_log(SQLITE_IOERR, "sqllogOpenlog(): Failed to open log file");
+    }
+  }
+}
+
+/*
+** This function is called if the SQLLOG callback is invoked to report
+** execution of an SQL statement. Parameter p is the connection the statement
+** was executed by and parameter zSql is the text of the statement itself.
+*/
+static void testSqllogStmt(struct SLConn *p, const char *zSql){
+  const char *zFirst;             /* Pointer to first token in zSql */
+  int nFirst;                     /* Size of token zFirst in bytes */
+
+  sqllogTokenize(zSql, &zFirst, &nFirst);
+  if( nFirst!=6 || 0!=sqlite3_strnicmp("ATTACH", zFirst, 6) ){
+    /* Not an ATTACH statement. Write this directly to the log. */
+    fprintf(p->fd, "%s; -- clock=%d\n", zSql, sqllogglobal.iClock++);
+  }else{
+    /* This is an ATTACH statement. Copy the database. */
+    sqllogCopydb(p, 0, 1);
+  }
+}
+
+/*
+** The SQLITE_CONFIG_SQLLOG callback registered by sqlite3_init_sqllog().
+*/
+static void testSqllog(void *pCtx, sqlite3 *db, const char *zSql, int eType){
+  struct SLConn *p;
+  sqlite3_mutex *master = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER);
+
+  assert( eType==0 || eType==1 || eType==2 );
+  assert( (eType==2)==(zSql==0) );
+
+  /* This is a database open command. */
+  if( eType==0 ){
+    sqlite3_mutex_enter(master);
+    if( sqllogglobal.mutex==0 ){
+      sqllogglobal.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_RECURSIVE);
+    }
+    p = &sqllogglobal.aConn[sqllogglobal.nConn++];
+    p->fd = 0;
+    p->db = db;
+    p->iLog = sqllogglobal.iNextLog++;
+    sqlite3_mutex_leave(master);
+
+    /* Open the log and take a copy of the main database file */
+    sqlite3_mutex_enter(sqllogglobal.mutex);
+    if( sqllogglobal.bRec==0 ){
+      sqllogOpenlog(p);
+      if( p->fd ) sqllogCopydb(p, "main", 0);
+    }
+    sqlite3_mutex_leave(sqllogglobal.mutex);
+  }
+
+  else{
+
+    int i;
+    for(i=0; i<sqllogglobal.nConn; i++){
+      p = &sqllogglobal.aConn[i];
+      if( p->db==db ) break;
+    }
+    if( i==sqllogglobal.nConn ) return;
+
+    /* A database handle close command */
+    if( eType==2 ){
+      sqlite3_mutex_enter(master);
+      if( p->fd ) fclose(p->fd);
+      p->db = 0;
+      p->fd = 0;
+
+      sqllogglobal.nConn--;
+      if( sqllogglobal.nConn==0 ){
+        sqlite3_mutex_free(sqllogglobal.mutex);
+        sqllogglobal.mutex = 0;
+      }else{
+        int nShift = &sqllogglobal.aConn[sqllogglobal.nConn] - p;
+        if( nShift>0 ){
+          memmove(p, &p[1], nShift*sizeof(struct SLConn));
+        }
+      }
+      sqlite3_mutex_leave(master);
+
+    /* An ordinary SQL command. */
+    }else if( p->fd ){
+      sqlite3_mutex_enter(sqllogglobal.mutex);
+      if( sqllogglobal.bRec==0 ){
+        testSqllogStmt(p, zSql);
+      }
+      sqlite3_mutex_leave(sqllogglobal.mutex);
+    }
+  }
+}
+
+/*
+** This function is called either before sqlite3_initialized() or by it.
+** It checks if the SQLITE_SQLLOG_DIR variable is defined, and if so 
+** registers an SQLITE_CONFIG_SQLLOG callback to record the applications
+** database activity.
+*/
+void sqlite3_init_sqllog(void){
+  if( getenv(ENVIRONMENT_VARIABLE1_NAME) ){
+    if( SQLITE_OK==sqlite3_config(SQLITE_CONFIG_SQLLOG, testSqllog, 0) ){
+      memset(&sqllogglobal, 0, sizeof(sqllogglobal));
+      sqllogglobal.bReuse = 1;
+    }
+  }
+}
diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index c37a0c566..7170f982e 100644
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -53,7 +53,7 @@ Vdbe *sqlite3VdbeCreate(sqlite3 *db){
 void sqlite3VdbeSetSql(Vdbe *p, const char *z, int n, int isPrepareV2){
   assert( isPrepareV2==1 || isPrepareV2==0 );
   if( p==0 ) return;
-#ifdef SQLITE_OMIT_TRACE
+#if defined(SQLITE_OMIT_TRACE) && !defined(SQLITE_ENABLE_SQLLOG)
   if( !isPrepareV2 ) return;
 #endif
   assert( p->zSql==0 );
@@ -2327,6 +2327,27 @@ int sqlite3VdbeTransferError(Vdbe *p){
   return rc;
 }
 
+#ifdef SQLITE_ENABLE_SQLLOG
+/*
+** If an SQLITE_CONFIG_SQLLOG hook is registered and the VM has been run, 
+** invoke it.
+*/
+static void vdbeInvokeSqllog(Vdbe *v){
+  if( sqlite3GlobalConfig.xSqllog && v->rc==SQLITE_OK && v->zSql && v->pc>=0 ){
+    char *zExpanded = sqlite3VdbeExpandSql(v, v->zSql);
+    assert( v->db->init.busy==0 );
+    if( zExpanded ){
+      sqlite3GlobalConfig.xSqllog(
+          sqlite3GlobalConfig.pSqllogArg, v->db, zExpanded, 1
+      );
+      sqlite3DbFree(v->db, zExpanded);
+    }
+  }
+}
+#else
+# define vdbeInvokeSqllog(x)
+#endif
+
 /*
 ** Clean up a VDBE after execution but do not delete the VDBE just yet.
 ** Write any error messages into *pzErrMsg.  Return the result code.
@@ -2354,6 +2375,7 @@ int sqlite3VdbeReset(Vdbe *p){
   ** instructions yet, leave the main database error information unchanged.
   */
   if( p->pc>=0 ){
+    vdbeInvokeSqllog(p);
     sqlite3VdbeTransferError(p);
     sqlite3DbFree(db, p->zErrMsg);
     p->zErrMsg = 0;