SQLite

test:	testfixture$(EXE) sqlite3$(EXE)
	./testfixture$(EXE) $(TOP)/test/veryquick.test

# The next two rules are used to support the "threadtest" target. Building
# threadtest runs a few thread-safety tests that are implemented in C. This
# target is invoked by the releasetest.tcl script.
# 
THREADTEST3_SRC = $(TOP)/test/threadtest3.c    \
                  $(TOP)/test/tt3_checkpoint.c \
                  $(TOP)/test/tt3_index.c      \
                  $(TOP)/test/tt3_vacuum.c      \
                  $(TOP)/test/tt3_stress.c      \
                  $(TOP)/test/tt3_lookaside1.c

threadtest3$(EXE): sqlite3.o $(THREADTEST3_SRC)
	$(TCCX) $(TOP)/test/threadtest3.c sqlite3.o -o $@ $(THREADLIB)

threadtest: threadtest3$(EXE)
	./threadtest3$(EXE)

TEST_EXTENSION = $(SHPREFIX)testloadext.$(SO)
$(TEST_EXTENSION): $(TOP)/src/test_loadext.c
	$(MKSHLIB) $(TOP)/src/test_loadext.c -o $(TEST_EXTENSION)

    if( !aNew->pSchema ){
      rc = SQLITE_NOMEM;
    }else if( aNew->pSchema->file_format && aNew->pSchema->enc!=ENC(db) ){
      zErrDyn = sqlite3MPrintf(db, 
        "attached databases must use the same text encoding as main database");
      rc = SQLITE_ERROR;
    }
    sqlite3BtreeEnter(aNew->pBt);
    pPager = sqlite3BtreePager(aNew->pBt);
    sqlite3PagerLockingMode(pPager, db->dfltLockMode);
    sqlite3BtreeSecureDelete(aNew->pBt,
                             sqlite3BtreeSecureDelete(db->aDb[0].pBt,-1) );
#ifndef SQLITE_OMIT_PAGER_PRAGMAS
    sqlite3BtreeSetPagerFlags(aNew->pBt, 3 | (db->flags & PAGER_FLAGS_MASK));
#endif
    sqlite3BtreeLeave(aNew->pBt);
  }
  aNew->safety_level = 3;
  aNew->zName = sqlite3DbStrDup(db, zName);
  if( rc==SQLITE_OK && aNew->zName==0 ){
    rc = SQLITE_NOMEM;
  }

    if( pCur->pNext ){
      pCur->pNext->pPrev = pCur->pPrev;
    }
    for(i=0; i<=pCur->iPage; i++){
      releasePage(pCur->apPage[i]);
    }
    unlockBtreeIfUnused(pBt);
    sqlite3_free(pCur->aOverflow);
    /* sqlite3_free(pCur); */
    sqlite3BtreeLeave(pBtree);
  }
  return SQLITE_OK;
}

/*

    rc = copyPayload(&aPayload[offset], pBuf, a, (eOp & 0x01), pPage->pDbPage);
    offset = 0;
    pBuf += a;
    amt -= a;
  }else{
    offset -= pCur->info.nLocal;
  }


  if( rc==SQLITE_OK && amt>0 ){
    const u32 ovflSize = pBt->usableSize - 4;  /* Bytes content per ovfl page */
    Pgno nextPage;

    nextPage = get4byte(&aPayload[pCur->info.nLocal]);

    /* If the BtCursor.aOverflow[] has not been allocated, allocate it now.
    ** Except, do not allocate aOverflow[] for eOp==2.
    **
    ** The aOverflow[] array is sized at one entry for each overflow page
    ** in the overflow chain. The page number of the first overflow page is
    ** stored in aOverflow[0], etc. A value of 0 in the aOverflow[] array
    ** means "not yet known" (the cache is lazily populated).
    */
    if( eOp!=2 && (pCur->curFlags & BTCF_ValidOvfl)==0 ){
      int nOvfl = (pCur->info.nPayload-pCur->info.nLocal+ovflSize-1)/ovflSize;
      if( nOvfl>pCur->nOvflAlloc ){
        Pgno *aNew = (Pgno*)sqlite3Realloc(
            pCur->aOverflow, nOvfl*2*sizeof(Pgno)
        );
        if( aNew==0 ){
          rc = SQLITE_NOMEM;
        }else{
          pCur->nOvflAlloc = nOvfl*2;
          pCur->aOverflow = aNew;
        }

        ** function.
        **
        ** Note that the aOverflow[] array must be allocated because eOp!=2
        ** here.  If eOp==2, then offset==0 and this branch is never taken.
        */
        assert( eOp!=2 );
        assert( pCur->curFlags & BTCF_ValidOvfl );
        assert( pCur->pBtree->db==pBt->db );
        if( pCur->aOverflow[iIdx+1] ){
          nextPage = pCur->aOverflow[iIdx+1];
        }else{
          rc = getOverflowPage(pBt, nextPage, 0, &nextPage);
        }
        offset -= ovflSize;
      }else{

    ** caller.
    */
    if( pPage->leaf ){
      do {
        if( pCur->iPage==0 ){
          /* All pages of the b-tree have been visited. Return successfully. */
          *pnEntry = nEntry;
          return moveToRoot(pCur);
        }
        moveToParent(pCur);
      }while ( pCur->aiIdx[pCur->iPage]>=pCur->apPage[pCur->iPage]->nCell );

      pCur->aiIdx[pCur->iPage]++;
      pPage = pCur->apPage[pCur->iPage];
    }

/*
** Reclaim the memory used by an index
*/
static void freeIndex(sqlite3 *db, Index *p){
#ifndef SQLITE_OMIT_ANALYZE
  sqlite3DeleteIndexSamples(db, p);
#endif

  sqlite3ExprDelete(db, p->pPartIdxWhere);
  sqlite3DbFree(db, p->zColAff);
  if( p->isResized ) sqlite3DbFree(db, p->azColl);
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
  sqlite3_free(p->aiRowEst);
#endif
  sqlite3DbFree(db, p);

** So there might be multiple references to the returned pointer.  The
** caller should not try to modify the KeyInfo object.
**
** The caller should invoke sqlite3KeyInfoUnref() on the returned object
** when it has finished using it.
*/
KeyInfo *sqlite3KeyInfoOfIndex(Parse *pParse, Index *pIdx){








  int i;
  int nCol = pIdx->nColumn;
  int nKey = pIdx->nKeyCol;
  KeyInfo *pKey;
  if( pParse->nErr ) return 0;
  if( pIdx->uniqNotNull ){
    pKey = sqlite3KeyInfoAlloc(pParse->db, nKey, nCol-nKey);
  }else{
    pKey = sqlite3KeyInfoAlloc(pParse->db, nCol, 0);
  }
  if( pKey ){
    assert( sqlite3KeyInfoIsWriteable(pKey) );
    for(i=0; i<nCol; i++){
      char *zColl = pIdx->azColl[i];
      assert( zColl!=0 );
      pKey->aColl[i] = strcmp(zColl,"BINARY")==0 ? 0 :
                        sqlite3LocateCollSeq(pParse, zColl);
      pKey->aSortOrder[i] = pIdx->aSortOrder[i];
    }
    if( pParse->nErr ){
      sqlite3KeyInfoUnref(pKey);

      pKey = 0;
    }
  }

  return pKey;
}

#ifndef SQLITE_OMIT_CTE
/* 
** This routine is invoked once per CTE by the parser while parsing a 
** WITH clause. 
*/

#ifndef SQLITE_ENABLE_COLUMN_METADATA
# define sqlite3_column_database_name   0
# define sqlite3_column_database_name16 0
# define sqlite3_column_table_name      0
# define sqlite3_column_table_name16    0
# define sqlite3_column_origin_name     0
# define sqlite3_column_origin_name16   0

#endif

#ifdef SQLITE_OMIT_AUTHORIZATION
# define sqlite3_set_authorizer         0
#endif

#ifdef SQLITE_OMIT_UTF16

  /* Free any outstanding Savepoint structures. */
  sqlite3CloseSavepoints(db);

  /* Close all database connections */
  for(j=0; j<db->nDb; j++){
    struct Db *pDb = &db->aDb[j];
    if( pDb->pBt ){










      sqlite3BtreeClose(pDb->pBt);
      pDb->pBt = 0;
      if( j!=1 ){
        pDb->pSchema = 0;
      }
    }
  }

** argument.  For now, this simply calls the internal sqlite3ErrStr()
** function.
*/
const char *sqlite3_errstr(int rc){
  return sqlite3ErrStr(rc);
}



























/*
** Create a new collating function for database "db".  The name is zName
** and the encoding is enc.
*/
static int createCollation(
  sqlite3* db,
  const char *zName, 

  if( pColl && pColl->xCmp ){
    if( db->nVdbeActive ){
      sqlite3ErrorWithMsg(db, SQLITE_BUSY, 
        "unable to delete/modify collation sequence due to active statements");
      return SQLITE_BUSY;
    }
    sqlite3ExpirePreparedStatements(db);


    /* If collation sequence pColl was created directly by a call to
    ** sqlite3_create_collation, and not generated by synthCollSeq(),
    ** then any copies made by synthCollSeq() need to be invalidated.
    ** Also, collation destructor - CollSeq.xDel() - function may need
    ** to be called.
    */ 

#endif
#if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
                 | SQLITE_RecTriggers
#endif
#if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
                 | SQLITE_ForeignKeys
#endif
#if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
                 | SQLITE_ReverseOrder
#endif
      ;
  sqlite3HashInit(&db->aCollSeq);
#ifndef SQLITE_OMIT_VIRTUALTABLE
  sqlite3HashInit(&db->aModule);
#endif

  /* Add the default collation sequence BINARY. BINARY works for both UTF-8

      rc = SQLITE_NOMEM;
    }
    sqlite3Error(db, rc);
    goto opendb_out;
  }
  sqlite3BtreeEnter(db->aDb[0].pBt);
  db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
  if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
  sqlite3BtreeLeave(db->aDb[0].pBt);
  db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);

  /* The default safety_level for the main database is 'full'; for the temp
  ** database it is 'NONE'. This matches the pager layer defaults.  
  */
  db->aDb[0].zName = "main";

  sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
  zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
  if( zFilename8 ){
    rc = openDatabase(zFilename8, ppDb,
                      SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
    assert( *ppDb || rc==SQLITE_NOMEM );
    if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
      SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
    }
  }else{
    rc = SQLITE_NOMEM;
  }
  sqlite3ValueFree(pVal);

  return sqlite3ApiExit(0, rc);

}
#endif

/*
** Return meta information about a specific column of a database table.
** See comment in sqlite3.h (sqlite.h.in) for details.
*/

int sqlite3_table_column_metadata(
  sqlite3 *db,                /* Connection handle */
  const char *zDbName,        /* Database name or NULL */
  const char *zTableName,     /* Table name */
  const char *zColumnName,    /* Column name */
  char const **pzDataType,    /* OUTPUT: Declared data type */
  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */

  pTab = sqlite3FindTable(db, zTableName, zDbName);
  if( !pTab || pTab->pSelect ){
    pTab = 0;
    goto error_out;
  }

  /* Find the column for which info is requested */
  if( zColumnName==0 ){
    /* Query for existance of table only */



  }else{
    for(iCol=0; iCol<pTab->nCol; iCol++){
      pCol = &pTab->aCol[iCol];
      if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
        break;
      }
    }
    if( iCol==pTab->nCol ){
      if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
        iCol = pTab->iPKey;
        pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
      }else{
        pTab = 0;
        goto error_out;
      }
    }
  }

  /* The following block stores the meta information that will be returned
  ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
  ** and autoinc. At this point there are two possibilities:
  ** 

  }
  sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
  sqlite3DbFree(db, zErrMsg);
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}


/*
** Sleep for a little while.  Return the amount of time slept.
*/
int sqlite3_sleep(int ms){
  sqlite3_vfs *pVfs;
  int rc;

** the sqlite3_memory_used() function does not return zero, SQLITE_BUSY will
** be returned and no changes will be made to the Win32 native heap.
*/
int sqlite3_win32_reset_heap(){
  int rc;
  MUTEX_LOGIC( sqlite3_mutex *pMaster; ) /* The main static mutex */
  MUTEX_LOGIC( sqlite3_mutex *pMem; )    /* The memsys static mutex */
  MUTEX_LOGIC( pMaster = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MASTER); )
  MUTEX_LOGIC( pMem = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM); )
  sqlite3_mutex_enter(pMaster);
  sqlite3_mutex_enter(pMem);
  winMemAssertMagic();
  if( winMemGetHeap()!=NULL && winMemGetOwned() && sqlite3_memory_used()==0 ){
    /*
    ** At this point, there should be no outstanding memory allocations on
    ** the heap.  Also, since both the master and memsys locks are currently

      */
      if( 
        !(DbHasProperty(db, 0, DB_SchemaLoaded)) || 
        DbHasProperty(db, 0, DB_Empty) 
      ){
        for(pEnc=&encnames[0]; pEnc->zName; pEnc++){
          if( 0==sqlite3StrICmp(zRight, pEnc->zName) ){
            SCHEMA_ENC(db) = ENC(db) =
                pEnc->enc ? pEnc->enc : SQLITE_UTF16NATIVE;
            break;
          }
        }
        if( !pEnc->zName ){
          sqlite3ErrorMsg(pParse, "unsupported encoding: %s", zRight);
        }
      }

** file was of zero-length, then the DB_Empty flag is also set.
*/
int sqlite3Init(sqlite3 *db, char **pzErrMsg){
  int i, rc;
  int commit_internal = !(db->flags&SQLITE_InternChanges);
  
  assert( sqlite3_mutex_held(db->mutex) );
  assert( sqlite3BtreeHoldsMutex(db->aDb[0].pBt) );
  assert( db->init.busy==0 );
  rc = SQLITE_OK;
  db->init.busy = 1;
  ENC(db) = SCHEMA_ENC(db);
  for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
    if( DbHasProperty(db, i, DB_SchemaLoaded) || i==1 ) continue;
    rc = sqlite3InitOne(db, i, pzErrMsg);
    if( rc ){
      sqlite3ResetOneSchema(db, i);
    }
  }

** the desired setting of the [SQLITE_THREADSAFE] macro.
**
** This interface only reports on the compile-time mutex setting
** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
** can be fully or partially disabled using a call to [sqlite3_config()]
** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
** or [SQLITE_CONFIG_SERIALIZED].  ^(The return value of the
** sqlite3_threadsafe() function shows only the compile-time setting of
** thread safety, not any run-time changes to that setting made by
** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
** is unchanged by calls to sqlite3_config().)^
**
** See the [threading mode] documentation for additional information.
*/

*/
SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);


/*
** CAPI3REF: Extract Metadata About A Column Of A Table
**
** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
** information about column C of table T in database D
** on [database connection] X.)^  ^The sqlite3_table_column_metadata()
** interface returns SQLITE_OK and fills in the non-NULL pointers in
** the final five arguments with appropriate values if the specified
** column exists.  ^The sqlite3_table_column_metadata() interface returns
** SQLITE_ERROR and if the specified column does not exist.
** ^If the column-name parameter to sqlite3_table_column_metadata() is a
** NULL pointer, then this routine simply checks for the existance of the
** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
** does not.
**
** ^The column is identified by the second, third and fourth parameters to
** this function. ^(The second parameter is either the name of the database
** (i.e. "main", "temp", or an attached database) containing the specified
** table or NULL.)^ ^If it is NULL, then all attached databases are searched
** for the table using the same algorithm used by the database engine to
** resolve unqualified table references.
**
** ^The third and fourth parameters to this function are the table and column
** name of the desired column, respectively.

**
** ^Metadata is returned by writing to the memory locations passed as the 5th
** and subsequent parameters to this function. ^Any of these arguments may be
** NULL, in which case the corresponding element of metadata is omitted.
**
** ^(<blockquote>
** <table border="1">
** <tr><th> Parameter <th> Output<br>Type <th>  Description
**
** <tr><td> 5th <td> const char* <td> Data type
** <tr><td> 6th <td> const char* <td> Name of default collation sequence
** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
** </table>
** </blockquote>)^
**
** ^The memory pointed to by the character pointers returned for the
** declaration type and collation sequence is valid until the next
** call to any SQLite API function.
**
** ^If the specified table is actually a view, an [error code] is returned.
**
** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 
** is not a [WITHOUT ROWID] table and an
** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
** parameters are set for the explicitly declared column. ^(If there is no
** [INTEGER PRIMARY KEY] column, then the outputs
** for the [rowid] are set as follows:
**
** <pre>
**     data type: "INTEGER"
**     collation sequence: "BINARY"
**     not null: 0
**     primary key: 1
**     auto increment: 0
** </pre>)^
**
** ^This function causes all database schemas to be read from disk and
** parsed, if that has not already been done, and returns an error if
** any errors are encountered while loading the schema.




*/
int sqlite3_table_column_metadata(
  sqlite3 *db,                /* Connection handle */
  const char *zDbName,        /* Database name or NULL */
  const char *zTableName,     /* Table name */
  const char *zColumnName,    /* Column name */
  char const **pzDataType,    /* OUTPUT: Declared data type */

*/
void sqlite3_log(int iErrCode, const char *zFormat, ...);

/*
** CAPI3REF: Write-Ahead Log Commit Hook
**
** ^The [sqlite3_wal_hook()] function is used to register a callback that
** is invoked each time data is committed to a database in wal mode.


**
** ^(The callback is invoked by SQLite after the commit has taken place and 
** the associated write-lock on the database released)^, so the implementation 
** may read, write or [checkpoint] the database as required.
**
** ^The first parameter passed to the callback function when it is invoked
** is a copy of the third parameter passed to sqlite3_wal_hook() when
** registering the callback. ^The second is a copy of the database handle.
** ^The third parameter is the name of the database that was written to -
** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter

  int flags;                    /* Miscellaneous flags. See below */
  i64 lastRowid;                /* ROWID of most recent insert (see above) */
  i64 szMmap;                   /* Default mmap_size setting */
  unsigned int openFlags;       /* Flags passed to sqlite3_vfs.xOpen() */
  int errCode;                  /* Most recent error code (SQLITE_*) */
  int errMask;                  /* & result codes with this before returning */
  u16 dbOptFlags;               /* Flags to enable/disable optimizations */
  u8 enc;                       /* Text encoding */
  u8 autoCommit;                /* The auto-commit flag. */
  u8 temp_store;                /* 1: file 2: memory 0: default */
  u8 mallocFailed;              /* True if we have seen a malloc failure */
  u8 dfltLockMode;              /* Default locking-mode for attached dbs */
  signed char nextAutovac;      /* Autovac setting after VACUUM if >=0 */
  u8 suppressErr;               /* Do not issue error messages if true */
  u8 vtabOnConflict;            /* Value to return for s3_vtab_on_conflict() */

  sqlite3_userauth auth;        /* User authentication information */
#endif
};

/*
** A macro to discover the encoding of a database.
*/
#define SCHEMA_ENC(db) ((db)->aDb[0].pSchema->enc)
#define ENC(db)        ((db)->enc)

/*
** Possible values for the sqlite3.flags.
*/
#define SQLITE_VdbeTrace      0x00000001  /* True to trace VDBE execution */
#define SQLITE_InternChanges  0x00000002  /* Uncommitted Hash table changes */
#define SQLITE_FullFSync      0x00000004  /* Use full fsync on the backend */

  Table *pTable;           /* The SQL table being indexed */
  char *zColAff;           /* String defining the affinity of each column */
  Index *pNext;            /* The next index associated with the same table */
  Schema *pSchema;         /* Schema containing this index */
  u8 *aSortOrder;          /* for each column: True==DESC, False==ASC */
  char **azColl;           /* Array of collation sequence names for index */
  Expr *pPartIdxWhere;     /* WHERE clause for partial indices */

  int tnum;                /* DB Page containing root of this index */
  LogEst szIdxRow;         /* Estimated average row size in bytes */
  u16 nKeyCol;             /* Number of columns forming the key */
  u16 nColumn;             /* Number of columns stored in the index */
  u8 onError;              /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
  unsigned idxType:2;      /* 1==UNIQUE, 2==PRIMARY KEY, 0==CREATE INDEX */
  unsigned bUnordered:1;   /* Use this index for == or IN queries only */

){
  int ret = SQLITE_OK;
  Tcl_Obj *p;
  SqliteDb *pDb = (SqliteDb*)clientData;
  Tcl_Interp *interp = pDb->interp;
  assert(pDb->pWalHook);

  assert( db==pDb->db );
  p = Tcl_DuplicateObj(pDb->pWalHook);
  Tcl_IncrRefCount(p);
  Tcl_ListObjAppendElement(interp, p, Tcl_NewStringObj(zDb, -1));
  Tcl_ListObjAppendElement(interp, p, Tcl_NewIntObj(nEntry));
  if( TCL_OK!=Tcl_EvalObjEx(interp, p, 0) 
   || TCL_OK!=Tcl_GetIntFromObj(interp, Tcl_GetObjResult(interp), &ret)
  ){

  return TCL_OK;
}

/*
** Usage: sqlite3_table_column_metadata DB dbname tblname colname
**
*/

static int test_table_column_metadata(
  ClientData clientData, /* Pointer to sqlite3_enable_XXX function */
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int objc,              /* Number of arguments */
  Tcl_Obj *CONST objv[]  /* Command arguments */
){
  sqlite3 *db;
  const char *zDb;
  const char *zTbl;
  const char *zCol;
  int rc;
  Tcl_Obj *pRet;

  const char *zDatatype;
  const char *zCollseq;
  int notnull;
  int primarykey;
  int autoincrement;

  if( objc!=5 && objc!=4 ){
    Tcl_WrongNumArgs(interp, 1, objv, "DB dbname tblname colname");
    return TCL_ERROR;
  }
  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;
  zDb = Tcl_GetString(objv[2]);
  zTbl = Tcl_GetString(objv[3]);
  zCol = objc==5 ? Tcl_GetString(objv[4]) : 0;

  if( strlen(zDb)==0 ) zDb = 0;

  rc = sqlite3_table_column_metadata(db, zDb, zTbl, zCol, 
      &zDatatype, &zCollseq, &notnull, &primarykey, &autoincrement);

  if( rc!=SQLITE_OK ){

  Tcl_ListObjAppendElement(0, pRet, Tcl_NewIntObj(notnull));
  Tcl_ListObjAppendElement(0, pRet, Tcl_NewIntObj(primarykey));
  Tcl_ListObjAppendElement(0, pRet, Tcl_NewIntObj(autoincrement));
  Tcl_SetObjResult(interp, pRet);

  return TCL_OK;
}


#ifndef SQLITE_OMIT_INCRBLOB

static int blobHandleFromObj(
  Tcl_Interp *interp, 
  Tcl_Obj *pObj,
  sqlite3_blob **ppBlob

  )){
    return TCL_ERROR;
  }

  rc = sqlite3_wal_checkpoint_v2(db, zDb, eMode, &nLog, &nCkpt);
  if( rc!=SQLITE_OK && rc!=SQLITE_BUSY ){
    const char *zErrCode = sqlite3ErrName(rc);
    Tcl_ResetResult(interp);
    Tcl_AppendResult(interp, zErrCode, " - ", (char *)sqlite3_errmsg(db), 0);
    return TCL_ERROR;
  }

  pRet = Tcl_NewObj();
  Tcl_ListObjAppendElement(interp, pRet, Tcl_NewIntObj(rc==SQLITE_BUSY?1:0));
  Tcl_ListObjAppendElement(interp, pRet, Tcl_NewIntObj(nLog));
  Tcl_ListObjAppendElement(interp, pRet, Tcl_NewIntObj(nCkpt));
  Tcl_SetObjResult(interp, pRet);

  return TCL_OK;
}

/*
** tclcmd:  sqlite3_wal_autocheckpoint db VALUE
*/
static int test_wal_autocheckpoint(
  ClientData clientData, /* Unused */
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int objc,              /* Number of arguments */
  Tcl_Obj *CONST objv[]  /* Command arguments */
){
  sqlite3 *db;
  int rc;
  int iVal;


  if( objc!=3 ){
    Tcl_WrongNumArgs(interp, 1, objv, "DB VALUE");
    return TCL_ERROR;
  }

  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) 
   || Tcl_GetIntFromObj(0, objv[2], &iVal)
  ){
    return TCL_ERROR;
  }

  rc = sqlite3_wal_autocheckpoint(db, iVal);
  Tcl_ResetResult(interp);
  if( rc!=SQLITE_OK ){
    const char *zErrCode = sqlite3ErrName(rc);
    Tcl_SetObjResult(interp, Tcl_NewStringObj(zErrCode, -1));
    return TCL_ERROR;
  }

  return TCL_OK;
}


/*
** tclcmd:  test_sqlite3_log ?SCRIPT?
*/
static struct LogCallback {
  Tcl_Interp *pInterp;
  Tcl_Obj *pObj;

     { "sqlite3_test_errstr",     test_errstr, 0             },
     { "tcl_variable_type",       tcl_variable_type, 0       },
#ifndef SQLITE_OMIT_SHARED_CACHE
     { "sqlite3_enable_shared_cache", test_enable_shared, 0  },
     { "sqlite3_shared_cache_report", sqlite3BtreeSharedCacheReport, 0},
#endif
     { "sqlite3_libversion_number", test_libversion_number, 0  },

     { "sqlite3_table_column_metadata", test_table_column_metadata, 0  },

#ifndef SQLITE_OMIT_INCRBLOB
     { "sqlite3_blob_reopen", test_blob_reopen, 0  },
#endif
     { "pcache_stats",       test_pcache_stats, 0  },
#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
     { "sqlite3_unlock_notify", test_unlock_notify, 0  },
#endif
     { "sqlite3_wal_checkpoint",   test_wal_checkpoint, 0  },
     { "sqlite3_wal_checkpoint_v2",test_wal_checkpoint_v2, 0  },
     { "sqlite3_wal_autocheckpoint",test_wal_autocheckpoint, 0  },
     { "test_sqlite3_log",         test_sqlite3_log, 0  },
#ifndef SQLITE_OMIT_EXPLAIN
     { "print_explain_query_plan", test_print_eqp, 0  },
#endif
     { "sqlite3_test_control", test_test_control },
#if SQLITE_OS_UNIX
     { "getrusage", test_getrusage },

static int doWalCallbacks(sqlite3 *db){
  int rc = SQLITE_OK;
#ifndef SQLITE_OMIT_WAL
  int i;
  for(i=0; i<db->nDb; i++){
    Btree *pBt = db->aDb[i].pBt;
    if( pBt ){
      int nEntry;
      sqlite3BtreeEnter(pBt);
      nEntry = sqlite3PagerWalCallback(sqlite3BtreePager(pBt));
      sqlite3BtreeLeave(pBt);
      if( db->xWalCallback && nEntry>0 && rc==SQLITE_OK ){
        rc = db->xWalCallback(db->pWalArg, db, db->aDb[i].zName, nEntry);
      }
    }
  }
#endif
  return rc;

    ** into the database handle. This block copies the error message 
    ** from the database handle into the statement and sets the statement
    ** program counter to 0 to ensure that when the statement is 
    ** finalized or reset the parser error message is available via
    ** sqlite3_errmsg() and sqlite3_errcode().
    */
    const char *zErr = (const char *)sqlite3_value_text(db->pErr); 

    sqlite3DbFree(db, v->zErrMsg);
    if( !db->mallocFailed ){
      v->zErrMsg = sqlite3DbStrDup(db, zErr);
      v->rc = rc2;
    } else {
      v->zErrMsg = 0;
      v->rc = rc = SQLITE_NOMEM;

**   void *SRVAL(SorterRecord *p) { return (void*)&p[1]; }
*/
#define SRVAL(p) ((void*)((SorterRecord*)(p) + 1))

/* The minimum PMA size is set to this value multiplied by the database
** page size in bytes.  */
#ifndef SQLITE_SORTER_PMASZ
# define SQLITE_SORTER_PMASZ 10
#endif

/* Maximum number of PMAs that a single MergeEngine can merge */
#define SORTER_MAX_MERGE_COUNT 16

static int vdbeIncrSwap(IncrMerger*);
static void vdbeIncrFree(IncrMerger *);

  if( p->wsFlags & (WHERE_VIRTUALTABLE|WHERE_AUTO_INDEX) ){
    if( (p->wsFlags & WHERE_VIRTUALTABLE)!=0 && p->u.vtab.needFree ){
      sqlite3_free(p->u.vtab.idxStr);
      p->u.vtab.needFree = 0;
      p->u.vtab.idxStr = 0;
    }else if( (p->wsFlags & WHERE_AUTO_INDEX)!=0 && p->u.btree.pIndex!=0 ){
      sqlite3DbFree(db, p->u.btree.pIndex->zColAff);

      sqlite3DbFree(db, p->u.btree.pIndex);
      p->u.btree.pIndex = 0;
    }
  }
}

/*

# focus of this script is the sqlite3_table_column_metadata() API.
#
# $Id: colmeta.test,v 1.4 2008/01/23 12:52:41 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl






# Set up a schema in the main and temp test databases.
do_test colmeta-0 {
  execsql {
    CREATE TABLE abc(a, b, c);
    CREATE TABLE abc2(a PRIMARY KEY COLLATE NOCASE, b VARCHAR(32), c);
    CREATE TABLE abc3(a NOT NULL, b INTEGER PRIMARY KEY, c);
    CREATE TABLE abc5(w,x,y,z,PRIMARY KEY(x,z)) WITHOUT ROWID;
    CREATE TABLE abc6(rowid TEXT COLLATE rtrim, oid REAL, _rowid_ BLOB);
  }
  ifcapable autoinc {
    execsql {
      CREATE TABLE abc4(a, b INTEGER PRIMARY KEY AUTOINCREMENT, c);
    }
  }
  ifcapable view {

  4  {main abc2 b}               {0 {VARCHAR(32) BINARY 0 0 0}}
  5  {{} abc2 a}                 {0 {{} NOCASE 0 1 0}}
  6  {{} abc3 a}                 {0 {{} BINARY 1 0 0}}
  7  {{} abc3 b}                 {0 {INTEGER BINARY 0 1 0}}
  13 {main abc rowid}            {0 {INTEGER BINARY 0 1 0}}
  14 {main abc3 rowid}           {0 {INTEGER BINARY 0 1 0}}
  16 {main abc d}                {1 {no such table column: abc.d}}
  20 {main abc5 w}               {0 {{} BINARY 0 0 0}}
  21 {main abc5 x}               {0 {{} BINARY 1 1 0}}
  22 {main abc5 y}               {0 {{} BINARY 0 0 0}}
  23 {main abc5 z}               {0 {{} BINARY 1 1 0}}
  24 {main abc5 rowid}           {1 {no such table column: abc5.rowid}}
  30 {main abc6 rowid}           {0 {TEXT rtrim 0 0 0}}
  31 {main abc6 oid}             {0 {REAL BINARY 0 0 0}}
  32 {main abc6 _rowid_}         {0 {BLOB BINARY 0 0 0}}
}
ifcapable autoinc {
  set tests [concat $tests {
    100 {{} abc4 b}              {0 {INTEGER BINARY 0 1 1}}
    101 {main abc4 rowid}        {0 {INTEGER BINARY 0 1 1}}
  }]
}
ifcapable view {
  set tests [concat $tests {
    200 {{} v1 a}                {1 {no such table column: v1.a}}
    201 {main v1 b}              {1 {no such table column: v1.b}}
    202 {main v1 badname}        {1 {no such table column: v1.badname}}
    203 {main v1 rowid}          {1 {no such table column: v1.rowid}}
  }]
}

foreach {tn params results} $tests {
  set ::DB [sqlite3_connection_pointer db]

  set tstbody [concat sqlite3_table_column_metadata $::DB $params] 
  do_test colmeta-$tn.1 {
    list [catch $tstbody msg] [set msg]
  } $results

  db close
  sqlite3 db test.db

  set ::DB [sqlite3_connection_pointer db]
  set tstbody [concat sqlite3_table_column_metadata $::DB $params] 
  do_test colmeta-$tn.2 {
    list [catch $tstbody msg] [set msg]
  } $results
}

# Calling sqlite3_table_column_metadata with a NULL column name merely
# checks for the existance of the table.
#
do_test colmeta-300 {
  catch {sqlite3_table_column_metadata $::DB main xyzzy} res
} {1}
do_test colmeta-301 {
  catch {sqlite3_table_column_metadata $::DB main abc} res
} {0}


finish_test

# 2014 December 04
#
# 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.
#
#***********************************************************************
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/wal_common.tcl
set testprefix e_walauto


proc read_nbackfill {} {
  seek $::shmfd 96
  binary scan [read $::shmfd 4] i nBackfill
  set nBackfill
}
proc read_mxframe {} {
  seek $::shmfd 16
  binary scan [read $::shmfd 4] i mxFrame
  set mxFrame
}

# Assuming that the main db for database handle
#
proc do_autocommit_threshold_test {tn value} {

  set nBackfillSaved [read_nbackfill]
  while {1} {
    db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }
    if {[read_mxframe] >= $value} break
  }
  
  set nBackfillNew [read_nbackfill]
  uplevel [list do_test $tn "expr $nBackfillNew > $nBackfillSaved" 1]
}

# EVIDENCE-OF: R-30135-06439 The wal_autocheckpoint pragma can be used
# to invoke this interface from SQL.
#
#   All tests in this file are run twice - once using the
#   sqlite3_wal_autocheckpoint() API, and once using "PRAGMA
#   wal_autocheckpoint".
#
foreach {tn code} {
  1 {
    proc autocheckpoint {db value} {
      uplevel [list $db eval "PRAGMA wal_autocheckpoint = $value"]
    }
  }

  2 {
    proc autocheckpoint {db value} {
      uplevel [list sqlite3_wal_autocheckpoint $db $value]
      return $value
    }
  }
} {

  eval $code

  reset_db
  do_execsql_test 1.$tn.0 { PRAGMA journal_mode = WAL } {wal}
  do_execsql_test 1.$tn.1 { CREATE TABLE t1(a, b) }
  set shmfd [open "test.db-shm"]

  # EVIDENCE-OF: R-41531-51083 Every new database connection defaults to
  # having the auto-checkpoint enabled with a threshold of 1000 or
  # SQLITE_DEFAULT_WAL_AUTOCHECKPOINT pages.
  #
  do_autocommit_threshold_test 1.$tn.2 1000
  db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }
  do_autocommit_threshold_test 1.$tn.3 1000

  # EVIDENCE-OF: R-38128-34102 The sqlite3_wal_autocheckpoint(D,N) is a
  # wrapper around sqlite3_wal_hook() that causes any database on database
  # connection D to automatically checkpoint after committing a
  # transaction if there are N or more frames in the write-ahead log file.
  #
  do_test 1.$tn.4 {
    db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }
    autocheckpoint db 100
  } {100}
  do_autocommit_threshold_test 1.$tn.5 100

  do_test 1.$tn.6 {
    db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }
    autocheckpoint db 500
  } {500}
  do_autocommit_threshold_test 1.$tn.7 500

  # EVIDENCE-OF: R-26993-43540 Passing zero or a negative value as the
  # nFrame parameter disables automatic checkpoints entirely.
  #
  do_test 1.$tn.7 {
    autocheckpoint db 0    ;# Set to zero
    for {set i 0} {$i < 10000} {incr i} {
      db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }
    }
    expr {[file size test.db-wal] > (5 * 1024 * 1024)}
  } 1
  do_test 1.$tn.8 {
    sqlite3_wal_checkpoint_v2 db truncate
    file size test.db-wal
  } 0
  do_test 1.$tn.9 {
    autocheckpoint db -4    ;# Set to a negative value
    for {set i 0} {$i < 10000} {incr i} {
      db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }
    }
    expr {[file size test.db-wal] > (5 * 1024 * 1024)}
  } 1

  # EVIDENCE-OF: R-10203-42688 The callback registered by this function
  # replaces any existing callback registered using sqlite3_wal_hook().
  #
  set ::wal_hook_callback 0
  proc wal_hook_callback {args} { incr ::wal_hook_callback ; return 0 }
  do_test 1.$tn.10.1 {
    db wal_hook wal_hook_callback
    db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }
    db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }
    set ::wal_hook_callback
  } 2
  do_test 1.$tn.10.2 {
    autocheckpoint db 100
    db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }
    db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }
    set ::wal_hook_callback
  } 2

  # EVIDENCE-OF: R-17497-43474 Likewise, registering a callback using
  # sqlite3_wal_hook() disables the automatic checkpoint mechanism
  # configured by this function.
  do_test 1.$tn.11.1 {
    sqlite3_wal_checkpoint_v2 db truncate
    file size test.db-wal
  } 0
  do_test 1.$tn.11.2 {
    autocheckpoint db 100 
    for {set i 0} {$i < 1000} {incr i} {
      db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }
    }
    expr {[file size test.db-wal] < (1 * 1024 * 1024)}
  } 1
  do_test 1.$tn.11.3 {
    db wal_hook wal_hook_callback
    for {set i 0} {$i < 1000} {incr i} {
      db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }
    }
    expr {[file size test.db-wal] < (1 * 1024 * 1024)}
  } 0

  # EVIDENCE-OF: R-33080-59193 Checkpoints initiated by this mechanism 
  # are PASSIVE.
  #
  set ::busy_callback_count 0
  proc busy_callback {args} {
  puts Hello
    incr ::busy_callback_count
    return 0
  }
  do_test 1.$tn.12.1 {
    sqlite3_wal_checkpoint_v2 db truncate
    autocheckpoint db 100 
    db busy busy_callback
    db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }
    db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }
  } {}
  do_test 1.$tn.12.2 {
    sqlite3 db2 test.db
    db2 eval { BEGIN; SELECT * FROM t1 LIMIT 10; }
    read_nbackfill
  } {0}
  do_test 1.$tn.12.3 {
    for {set i 0} {$i < 1000} {incr i} {
      db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }
    }
    read_nbackfill
  } {2}
  do_test 1.$tn.12.4 {
    set ::busy_callback_count
  } {0}
  db2 close

  do_test 1.$tn.12.5 {
    db eval { INSERT INTO t1 VALUES(randomblob(100), randomblob(100)) }
    read_nbackfill
  } {1559}

  db close
  close $shmfd
}

finish_test

    set expect 0
    catch { set expect [md5file $f] }
    if {$H($f) != $expect} { lappend ret $f }
  }
  set ret
}

#-------------------------------------------------------------------------
# All calls to the [sqlite3_wal_checkpoint_v2] command made within this
# file use this wrapper. It's sole purpose is to throw an error if the
# following requirement is violated:
#
# EVIDENCE-OF: R-60567-47780 Unless it returns SQLITE_MISUSE, the
# sqlite3_wal_checkpoint_v2() interface sets the error information that
# is queried by sqlite3_errcode() and sqlite3_errmsg().
#
proc wal_checkpoint_v2 {db args} {
  set rc [catch {
    uplevel sqlite3_wal_checkpoint_v2 $db $args
  } msg]

  set errcode "SQLITE_OK"
  if {$rc} {
    set errcode [lindex [split $msg " "] 0]
  } elseif { [lindex $msg 0] } {
    set errcode "SQLITE_BUSY"
  }

  if {$errcode != "SQLITE_MISUSE" && [sqlite3_errcode $db] != $errcode} {
    error "sqlite3_errcode mismatch! (1) $errcode!=[sqlite3_errcode $db]"
  }

  if {$rc==0} {
    return $msg
  } else {
    error $msg
  }
}


# The following tests are run 3 times, each using a different method of 
# invoking a checkpoint:
#
#   1) Using sqlite3_wal_checkpoint_v2()
#   2) Using "PRAGMA wal_checkpoint"
#   3) Using sqlite3_wal_checkpoint() in place of checkpoint_v2(PASSIVE)

# EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is
# equivalent to
# sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0).
# 
foreach {tn script} {
  1 {
    proc checkpoint {db mode args} {
      eval wal_checkpoint_v2 [list $db] [list $mode] $args
    }
  }

  2 {
    proc checkpoint {db mode args} {
      set sql "PRAGMA wal_checkpoint = $mode"
      if {[llength $args] && [lindex $args 0]!=""} {

    proc checkpoint {db mode args} {
      if {$mode == "passive"} {
        set rc [eval sqlite3_wal_checkpoint [list $db] $args]
        if {$rc != "SQLITE_OK"} {
          error "$rc - [sqlite3_errmsg $db]"
        }
      } else {
        eval wal_checkpoint_v2 [list $db] [list $mode] $args
      }
    }
  }

} {

  eval $script

    switch -- $busy_handler_mode {
      1 {
        # Do nothing. Do not block.
        return 1
      }

      2 {
        # Close first the reader, then later the writer. Give up before
        # closing the [db6] reader.
        if {$n==5}  { catch {db2 eval commit} }
        if {$n==10} { catch {db3 eval commit} }
        if {$n==15} { return 1 }
        return 0
      }

      3 {
        # Close first the writer, then later the reader. And finally the 
        # [db6] reader.
        if {$n==5}  { catch {db2 eval commit} }
        if {$n==10} { catch {db3 eval commit} }
        if {$n==15} { catch {db6 eval commit} }
        return 0
      }
    }
  }

  foreach {mode busy_handler_mode} { 
    passive  1
    full     1       full     2       full    3
    restart  1       restart  2       restart  3
    truncate 1       truncate 2       truncate 3
  } {
    set tp "$tn.$mode.$busy_handler_mode"

    set ::sync_counter 0

    # Set up a callback function for xSync and xWrite calls made during
    # the checkpoint.
    #
    set ::checkpoint_ongoing 0
    proc tvfs_callback {method args} {
      if {$::checkpoint_ongoing==0} return

      set tail [file tail [lindex $args 0]]
      if {$method == "xSync" && $tail == "test.db"} {
        incr ::sync_counter
      }

      if {$method == "xWrite" && $tail=="test.db"} {
        if {$::write_ok < 0} {
          set ::write_ok [expr ![catch {db5 eval { BEGIN IMMEDIATE }}]]
          catch { db5 eval ROLLBACK }
        }
        if {$::read_ok < 0} {
          set ::read_ok [expr ![catch {db5 eval { SELECT * FROM t1 }}]]
        }

        # If one has not already been opened, open a read-transaction using
        # connection [db6]
        catch { db6 eval { BEGIN ; SELECT * FROM sqlite_master } } msg
      }
      if {$method == "xShmLock" } {
        set details [lindex $args 2]
        if {$details == "0 1 lock exclusive"} { set ::seen_writer_lock 1 }
      }
    }

    catch { db close }
    forcedelete test.db
    testvfs tvfs
    sqlite3 db test.db -vfs tvfs
    #tvfs filter xSync
    tvfs script tvfs_callback

    do_execsql_test $tp.0 {
      CREATE TABLE t1(a, b);
      CREATE TABLE t2(a, b);
      PRAGMA journal_mode = wal;
      INSERT INTO t1 VALUES(1, 2);
      INSERT INTO t1 VALUES(3, 4);
      INSERT INTO t1 VALUES(5, 6);
    } {wal}

    # Open a reader on the current database snapshot.
    do_test $tp.1 {
      sqlite3 db2 test.db -vfs tvfs
      execsql {
        BEGIN;
          SELECT * FROM t1 UNION ALL SELECT * FROM t2;
      } db2
    } {1 2 3 4 5 6}

    # Open a writer. Write a transaction. Then begin, but do not commit,
    # a second transaction.
    do_test $tp.2 {
      sqlite3 db3 test.db -vfs tvfs
      execsql {
        INSERT INTO t2 VALUES(7, 8);
        BEGIN;
          INSERT INTO t2 VALUES(9, 10);
          SELECT * FROM t1 UNION ALL SELECT * FROM t2;
      } db3
    } {1 2 3 4 5 6 7 8 9 10}

    sqlite3 db5 test.db -vfs tvfs
    sqlite3 db6 test.db -vfs tvfs

    # Register a busy-handler with connection [db].
    #
    db busy [list busy_handler $mode $busy_handler_mode]
    set ::sync_counter 0
    set ::busy_handler_counter 0
    set ::read_ok -1
    set ::write_ok -1
    set ::seen_writer_lock 0
    
    set ::checkpoint_ongoing 1
    do_test $tp.3 {
      checkpoint db $mode main
      set {} {}
    } {}
    set ::checkpoint_ongoing 0
    set ::did_restart_blocking [expr {[catch {db6 eval commit}]}]

    if { $mode=="passive" } {
      # EVIDENCE-OF: R-16333-64433 Checkpoint as many frames as possible
      # without waiting for any database readers or writers to finish, then
      # sync the database file if all frames in the log were checkpointed.
      #
      #   "As many frames as possible" means all but the last two transactions
      #   (the two that write to table t2, of which the scond is unfinished).
      #   So copying the db file only we see the t1 change, but not the t2
      #   modifications.
      #
      #   The busy handler is not invoked (see below) and the db reader and
      #   writer are still active - so the checkpointer did not wait for either
      #   readers or writers. As a result the checkpoint was not finished and
      #   so the db file is not synced.
      #
      # EVIDENCE-OF: R-62920-47450 The busy-handler callback is never invoked
      # in the SQLITE_CHECKPOINT_PASSIVE mode.
      #
      #   It's not. Test case "$tp.6".
      #
      do_test $tp.4 {
        forcecopy test.db abc.db
        sqlite3 db4 abc.db
        db4 eval { SELECT * FROM t1 UNION ALL SELECT * FROM t2 }
      } {1 2 3 4 5 6}
      do_test $tp.5 { set ::sync_counter } 0
      do_test $tp.6 { set ::busy_handler_counter } 0
      db4 close
  
      db2 eval COMMIT
      db3 eval COMMIT
  
      # EVIDENCE-OF: R-65499-53765 On the other hand, passive mode might leave
      # the checkpoint unfinished if there are concurrent readers or writers.
      #
      #   The reader and writer have now dropped their locks. And so a 
      #   checkpoint now is able to checkpoint more frames. Showing that the
      #   attempt above was left "unfinished".
      #
      #   Also, because the checkpoint finishes this time, the db is synced.
      #   Which is part of R-16333-64433 above.
      #
      set ::checkpoint_ongoing 1
      do_test $tp.7 {
        checkpoint db $mode main
        forcecopy test.db abc.db
        sqlite3 db4 abc.db
        db4 eval { SELECT * FROM t1 UNION ALL SELECT * FROM t2 }
      } {1 2 3 4 5 6 7 8 9 10}
      set ::checkpoint_ongoing 0
      do_test $tp.7 { set ::sync_counter } 1
      do_test $tp.8 { set ::busy_handler_counter } 0
      db4 close
    }

    if { $mode=="full" || $mode=="restart" || $mode=="truncate" } {

      # EVIDENCE-OF: R-59782-36818 The SQLITE_CHECKPOINT_FULL, RESTART and
      # TRUNCATE modes also obtain the exclusive "writer" lock on the 
      # database file.
      #
      #   Or at least attempts to obtain.
      #
      do_test $tp.9 {
        set ::seen_writer_lock
      } {1}

      if {$busy_handler_mode==2 || $busy_handler_mode==3} {
        # EVIDENCE-OF: R-59171-47567 This mode blocks (it invokes the
        # busy-handler callback) until there is no database writer and all
        # readers are reading from the most recent database snapshot.
        #
        #   The test below shows that both the reader and writer have 
        #   finished:
        #
        #   Also restated by the following two. That both busy_handler_mode
        #   values 2 and 3 work show that both of the following are true - as
        #   they release the reader and writer transactions in different
        #   orders.
        #
        # EVIDENCE-OF: R-60642-04082 If the writer lock cannot be obtained
        # immediately, and a busy-handler is configured, it is invoked and the
        # writer lock retried until either the busy-handler returns 0 or the
        # lock is successfully obtained.
        #
        # EVIDENCE-OF: R-48107-00250 The busy-handler is also invoked while
        # waiting for database readers as described above.
        #
        do_test $tp.7 {
          list [catchsql COMMIT db2] [catchsql COMMIT db3]
        } [list                                             \
            {1 {cannot commit - no transaction is active}}  \
            {1 {cannot commit - no transaction is active}}  \
        ]

        # EVIDENCE-OF: R-29177-48281 It then checkpoints all frames in the log
        # file and syncs the database file.
        #
        do_test $tp.8 {
          forcecopy test.db abc.db
          sqlite3 db4 abc.db
          db4 eval { SELECT * FROM t1 UNION ALL SELECT * FROM t2 }
        } {1 2 3 4 5 6 7 8 9 10}
        do_test $tp.9 { set ::sync_counter } 1
        db4 close

        # EVIDENCE-OF: R-51867-44713 This mode blocks new database writers
        # while it is pending, but new database readers are allowed to continue
        # unimpeded.
        #
        # EVIDENCE-OF: R-47276-58266 Like SQLITE_CHECKPOINT_FULL, this mode
        # blocks new database writer attempts while it is pending, but does not
        # impede readers.
        #
        #   The first of the above two refers to "full" mode. The second
        #   to "restart".
        #
        do_test $tp.10.1 {
          list $::write_ok $::read_ok
        } {0 1}

        # EVIDENCE-OF: R-12410-31217 This mode works the same way as
        # SQLITE_CHECKPOINT_FULL with the addition that after checkpointing the
        # log file it blocks (calls the busy-handler callback) until all
        # readers are reading from the database file only.
        #
        #     The stuff above passed, so the first part of this requirement
        #     is met. The second part is tested below. If the checkpoint mode
        #     was "restart" or "truncate", then the busy-handler will have
        #     been called to block on wal-file readers.
        #
        do_test $tp.11 {
          set ::did_restart_blocking
        } [expr {($mode=="restart"||$mode=="truncate")&&$busy_handler_mode==3}]

        # EVIDENCE-OF: R-44699-57140 This mode works the same way as
        # SQLITE_CHECKPOINT_RESTART with the addition that it also truncates
        # the log file to zero bytes just prior to a successful return.
        if {$mode=="truncate" && $busy_handler_mode==3} {
          do_test $tp.12 {
            file size test.db-wal
          } 0
        }
      } elseif {$busy_handler_mode==1} {

        # EVIDENCE-OF: R-34519-06271 SQLITE_BUSY is returned in this case.
        if {$tn!=2} {
          # ($tn==2) is the loop that uses "PRAGMA wal_checkpoint"
          do_test $tp.13 { sqlite3_errcode db } {SQLITE_BUSY}
        }

        # EVIDENCE-OF: R-49155-63541 If the busy-handler returns 0 before the
        # writer lock is obtained or while waiting for database readers, the
        # checkpoint operation proceeds from that point in the same way as
        # SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
        # without blocking any further.
        do_test $tp.14 {
          forcecopy test.db abc.db
            sqlite3 db4 abc.db
            db4 eval { SELECT * FROM t1 UNION ALL SELECT * FROM t2 }
        } {1 2 3 4 5 6}
        do_test $tp.15 { set ::sync_counter } 0
        do_test $tp.16 { set ::busy_handler_counter } 1
        db4 close
      }
    }

    db2 close
    db3 close
    db5 close
    db6 close
  }

  db close
  tvfs delete
}

#-----------------------------------------------------------------------

  4  2       {0 {0 -1 -1}}
  5  3       {0 {0 -1 -1}}
  6  4       {1 {SQLITE_MISUSE - not an error}}
  7  114     {1 {SQLITE_MISUSE - not an error}}
  8  1000000 {1 {SQLITE_MISUSE - not an error}}
} {
  do_test 4.$tn {
    list [catch "wal_checkpoint_v2 db $mode" msg] $msg
  } $res
}
db close

foreach tn {1 2 3} {
  forcedelete test.db test.db2 test.db3
  testvfs tvfs

  sqlite3 db test.db -vfs tvfs
  execsql {
    ATTACH 'test.db2' AS aux2;
    ATTACH 'test.db3' AS aux3;
    PRAGMA main.journal_mode = WAL;
    PRAGMA aux2.journal_mode = WAL;
    PRAGMA aux3.journal_mode = WAL;

    CREATE TABLE main.t1(x,y);
    CREATE TABLE aux2.t2(x,y);
    CREATE TABLE aux3.t3(x,y);

    INSERT INTO t1 VALUES('a', 'b');
    INSERT INTO t2 VALUES('a', 'b');
    INSERT INTO t3 VALUES('a', 'b');
  }
  sqlite3 db2 test.db2 -vfs tvfs

  switch -- $tn {
    1 {
      # EVIDENCE-OF: R-41299-52117 If no error (SQLITE_BUSY or otherwise) is
      # encountered while processing the attached databases, SQLITE_OK is
      # returned.
      do_test 5.$tn.1 {
        lindex [wal_checkpoint_v2 db truncate] 0
      } {0}    ;# 0 -> SQLITE_OK
      do_test 5.$tn.2 {
        list [expr [file size test.db-wal]==0]  \
             [expr [file size test.db2-wal]==0] \
             [expr [file size test.db3-wal]==0]
      } {1 1 1}
    }

    2 {
      # EVIDENCE-OF: R-38578-34175 If an SQLITE_BUSY error is encountered when
      # processing one or more of the attached WAL databases, the operation is
      # still attempted on any remaining attached databases and SQLITE_BUSY is
      # returned at the end.
      db2 eval { BEGIN; INSERT INTO t2 VALUES('d', 'e'); }
      do_test 5.$tn.1 {
        lindex [wal_checkpoint_v2 db truncate] 0
      } {1}    ;# 1 -> SQLITE_BUSY
      do_test 5.$tn.2 {
        list [expr [file size test.db-wal]==0]  \
             [expr [file size test.db2-wal]==0] \
             [expr [file size test.db3-wal]==0]
      } {1 0 1}
      db2 eval ROLLBACK
    }

    3 {
      # EVIDENCE-OF: R-38049-07913 If any other error occurs while processing
      # an attached database, processing is abandoned and the error code is
      # returned to the caller immediately.
      tvfs filter xWrite
      tvfs script inject_ioerr
      proc inject_ioerr {method file args} {
        if {[file tail $file]=="test.db2"} {
          return "SQLITE_IOERR"
        }
        return 0
      }
      do_test 5.$tn.1 {
        list [catch { wal_checkpoint_v2 db truncate } msg] $msg
      } {1 {SQLITE_IOERR - disk I/O error}}
      do_test 5.$tn.2 {
        list [expr [file size test.db-wal]==0]  \
             [expr [file size test.db2-wal]==0] \
             [expr [file size test.db3-wal]==0]
      } {1 0 0}
      tvfs script ""
    }
  }

  db close
  db2 close
}

reset_db
sqlite3 db2 test.db

do_test 6.1 {
  execsql {
    PRAGMA journal_mode = WAL;
    CREATE TABLE t1(a, b);
    INSERT INTO t1 VALUES(1, 2);
  }
  file size test.db-wal
} [wal_file_size 3 1024]

do_test 6.2 {
  db2 eval { BEGIN; SELECT * FROM t1; }
  db  eval { INSERT INTO t1 VALUES(3, 4) }
  file size test.db-wal
} [wal_file_size 4 1024]

#   At this point the log file contains 4 frames. 3 of which it should
#   be possible to checkpoint.
#
# EVIDENCE-OF: R-16642-42503 If pnLog is not NULL, then *pnLog is set to
# the total number of frames in the log file or to -1 if the checkpoint
# could not run because of an error or because the database is not in
# WAL mode.
#
# EVIDENCE-OF: R-10514-25250 If pnCkpt is not NULL,then *pnCkpt is set
# to the total number of checkpointed frames in the log file (including
# any that were already checkpointed before the function was called) or
# to -1 if the checkpoint could not run due to an error or because the
# database is not in WAL mode.
#
do_test 6.4 {
  lrange [wal_checkpoint_v2 db passive] 1 2
} {4 3} 

# EVIDENCE-OF: R-37257-17813 Note that upon successful completion of an
# SQLITE_CHECKPOINT_TRUNCATE, the log file will have been truncated to
# zero bytes and so both *pnLog and *pnCkpt will be set to zero.
#
do_test 6.5 {
  db2 eval COMMIT
  wal_checkpoint_v2 db truncate
} {0 0 0}



finish_test

# 2014 December 04
#
# 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.
#
#***********************************************************************
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/wal_common.tcl
set testprefix e_walhook


# EVIDENCE-OF: R-00752-43975 The sqlite3_wal_hook() function is used to
# register a callback that is invoked each time data is committed to a
# database in wal mode.
#
#   1.1: shows that the wal-hook is not invoked in rollback mode.
#   1.2: but is invoked in wal mode.
#
set ::wal_hook_count 0
proc my_wal_hook {args} {
  incr ::wal_hook_count
  return 0
}

do_test 1.1.1 {
  db wal_hook my_wal_hook
  execsql {
    CREATE TABLE t1(x);
    INSERT INTO t1 VALUES(1);
  }
  set ::wal_hook_count
} 0
do_test 1.1.2 {
  execsql { PRAGMA journal_mode = wal }
  set ::wal_hook_count
} 0

do_test 1.3 {
  execsql { INSERT INTO t1 VALUES(2) }
  set wal_hook_count
} 1

do_test 1.4 {
  execsql { 
    BEGIN;
      INSERT INTO t1 VALUES(3);
      INSERT INTO t1 VALUES(4);
    COMMIT;
  }
  set wal_hook_count
} 2

# EVIDENCE-OF: R-65366-15139 The callback is invoked by SQLite after the
# commit has taken place and the associated write-lock on the database
# released
#
set ::read_ok 0
proc my_wal_hook {args} {
  sqlite3 db2 test.db
  if {[db2 eval { SELECT * FROM t1 }] == "1 2 3 4 5"} {
    set ::read_ok 1
  }
  db2 close
}
do_test 2.1 {
  execsql { INSERT INTO t1 VALUES(5) }
  set ::read_ok
} 1

# EVIDENCE-OF: R-44294-52863 The third parameter is the name of the
# database that was written to - either "main" or the name of an
# ATTACH-ed database.
#
# EVIDENCE-OF: R-18913-19355 The fourth parameter is the number of pages
# currently in the write-ahead log file, including those that were just
# committed.
#
set ::wal_hook_args [list]
proc my_wal_hook {dbname nEntry} {
  set ::wal_hook_args [list $dbname $nEntry]
}
forcedelete test.db2
do_test 3.0 {
  execsql {
    ATTACH 'test.db2' AS aux;
    CREATE TABLE aux.t2(x);
    PRAGMA aux.journal_mode = wal;
  }
} {wal}

# Database "aux"
do_test 3.1.1 {
  set wal_hook_args [list]
  execsql { INSERT INTO t2 VALUES('a') }
} {}
do_test 3.1.2 {
  set wal_hook_args
} [list aux [wal_frame_count test.db2-wal 1024]]

# Database "main"
do_test 3.2.1 {
  set wal_hook_args [list]
  execsql { INSERT INTO t1 VALUES(6) }
} {}
do_test 3.1.2 {
  set wal_hook_args
} [list main [wal_frame_count test.db-wal 1024]]

# EVIDENCE-OF: R-14034-00929 If an error code is returned, that error
# will propagate back up through the SQLite code base to cause the
# statement that provoked the callback to report an error, though the
# commit will have still occurred.
#
proc my_wal_hook {args} { return 1 ;# SQLITE_ERROR }
do_catchsql_test 4.1 {
  INSERT INTO t1 VALUES(7)
} {1 {SQL logic error or missing database}}

proc my_wal_hook {args} { return 5 ;# SQLITE_BUSY }
do_catchsql_test 4.2 {
  INSERT INTO t1 VALUES(8)
} {1 {database is locked}}

proc my_wal_hook {args} { return 14 ;# SQLITE_CANTOPEN }
do_catchsql_test 4.3 {
  INSERT INTO t1 VALUES(9)
} {1 {unable to open database file}}

do_execsql_test 4.4 {
  SELECT * FROM t1
} {1 2 3 4 5 6 7 8 9}

# EVIDENCE-OF: R-10466-53920 Calling sqlite3_wal_hook() replaces any
# previously registered write-ahead log callback.
set ::old_wal_hook 0
proc my_old_wal_hook {args} {
  incr ::old_wal_hook 
  return 0
}
db wal_hook my_old_wal_hook
do_test 5.1 {
  execsql { INSERT INTO t1 VALUES(10) }
  set ::old_wal_hook
} {1}

# Replace old_wal_hook. Observe that it is not invoked after it has 
# been replaced.
proc my_new_wal_hook {args} { return 0 }
db wal_hook my_new_wal_hook
do_test 5.2 {
  execsql { INSERT INTO t1 VALUES(11) }
  set ::old_wal_hook
} {1}



# EVIDENCE-OF: R-42842-27162 Note that the sqlite3_wal_autocheckpoint()
# interface and the wal_autocheckpoint pragma both invoke
# sqlite3_wal_hook() and will those overwrite any prior
# sqlite3_wal_hook() settings.
#
set ::old_wal_hook 0
proc my_old_wal_hook {args} { incr ::old_wal_hook ; return 0 }
db wal_hook my_old_wal_hook
do_test 6.1.1 {
  execsql { INSERT INTO t1 VALUES(12) }
  set ::old_wal_hook
} {1}
do_test 6.1.2 {
  execsql { PRAGMA wal_autocheckpoint = 1000 }
  execsql { INSERT INTO t1 VALUES(12) }
  set ::old_wal_hook
} {1}

# EVIDENCE-OF: R-52629-38967 The first parameter passed to the callback
# function when it is invoked is a copy of the third parameter passed to
# sqlite3_wal_hook() when registering the callback.
#
#    This is tricky to test using the tcl interface. However, the
#    mechanism used to invoke the tcl script registered as a wal-hook
#    depends on the context pointer being correctly passed through. And
#    since multiple different wal-hook scripts have been successfully
#    invoked by this test script, consider this tested.
#
# EVIDENCE-OF: R-23378-42536 The second is a copy of the database
# handle.
#
#    There is an assert() in the C wal-hook used by tclsqlite.c to
#    prove this. And that hook has been invoked multiple times when
#    running this script. So consider this requirement tested as well.
#

finish_test

    execsql { 
      BEGIN;
      SELECT * FROM t1;
    } db2
  } {1 2}
  do_test lock5-none.5 {
    execsql COMMIT
  } {}
  do_test lock5-none.6 {
    sqlite3_release_memory 1000000
    execsql {SELECT * FROM t1} db2
  } {1 2}

  ifcapable memorymanage {
    do_test lock5-none.6 {

} {{non-unique entry in index t1a} {NULL value in t1x.a} {non-unique entry in index t1a} {NULL value in t1x.a}}
do_execsql_test pragma-3.21 {
  PRAGMA integrity_check(3);
} {{non-unique entry in index t1a} {NULL value in t1x.a} {non-unique entry in index t1a}}
do_execsql_test pragma-3.22 {
  PRAGMA integrity_check(2);
} {{non-unique entry in index t1a} {NULL value in t1x.a}}
do_execsql_test pragma-3.23 {
  PRAGMA integrity_check(1);
} {{non-unique entry in index t1a}}

# PRAGMA integrity check (or more specifically the sqlite3BtreeCount()
# interface) used to leave index cursors in an inconsistent state
# which could result in an assertion fault in sqlite3BtreeKey()
# called from saveCursorPosition() if content is removed from the
# index while the integrity_check is still running.  This test verifies
# that problem has been fixed.
#
do_test pragma-3.30 {
  db close
  delete_file test.db
  sqlite3 db test.db
  db eval {
    CREATE TABLE t1(a,b,c);
    WITH RECURSIVE
      c(i) AS (VALUES(1) UNION ALL SELECT i+1 FROM c WHERE i<100)
    INSERT INTO t1(a,b,c) SELECT i, printf('xyz%08x',i), 2000-i FROM c;
    CREATE INDEX t1a ON t1(a);
    CREATE INDEX t1bc ON t1(b,c);
  }
  db eval {PRAGMA integrity_check} {
     db eval {DELETE FROM t1}
  }
} {}

# Test modifying the cache_size of an attached database.
ifcapable pager_pragmas&&attach {
do_test pragma-4.1 {
  execsql {
    ATTACH 'test2.db' AS aux;
    pragma aux.cache_size;

/* Functions to execute SQL */
#define sql_script(x,y,z)       (SEL(x), sql_script_x(x,y,z))
#define integrity_check(x,y)    (SEL(x), integrity_check_x(x,y))
#define execsql_i64(x,y,...)    (SEL(x), execsql_i64_x(x,y,__VA_ARGS__))
#define execsql_text(x,y,z,...) (SEL(x), execsql_text_x(x,y,z,__VA_ARGS__))
#define execsql(x,y,...)        (SEL(x), (void)execsql_i64_x(x,y,__VA_ARGS__))
#define sql_script_printf(x,y,z,...) (                \
    SEL(x), sql_script_printf_x(x,y,z,__VA_ARGS__)    \
) 

/* Thread functions */
#define launch_thread(w,x,y,z)     (SEL(w), launch_thread_x(w,x,y,z))
#define join_all_threads(y,z)      (SEL(y), join_all_threads_x(y,z))

/* Timer functions */
#define setstoptime(y,z)        (SEL(y), setstoptime_x(y,z))
#define timetostop(z)           (SEL(z), timetostop_x(z))

/* Report/clear errors. */
#define test_error(z, ...)      test_error_x(z, sqlite3_mprintf(__VA_ARGS__))
#define clear_error(y,z)        clear_error_x(y, z)

/* File-system operations */
#define filesize(y,z)           (SEL(y), filesize_x(y,z))
#define filecopy(x,y,z)         (SEL(x), filecopy_x(x,y,z))

#define PTR2INT(x) ((int)((intptr_t)x))
#define INT2PTR(x) ((void*)((intptr_t)x))

/*
** End of test code/infrastructure interface macros.
*************************************************************************/

#  define uint32 unsigned int
#endif

struct MD5Context {
  int isInit;
  uint32 buf[4];
  uint32 bits[2];
  union {
    unsigned char in[64];
    uint32 in32[16];
  } u;
};
typedef struct MD5Context MD5Context;

/*
 * Note: this code is harmless on little-endian machines.
 */
static void byteReverse (unsigned char *buf, unsigned longs){

  ctx->bits[1] += len >> 29;

  t = (t >> 3) & 0x3f;    /* Bytes already in shsInfo->data */

  /* Handle any leading odd-sized chunks */

  if ( t ) {
    unsigned char *p = (unsigned char *)ctx->u.in + t;

    t = 64-t;
    if (len < t) {
      memcpy(p, buf, len);
      return;
    }
    memcpy(p, buf, t);
    byteReverse(ctx->u.in, 16);
    MD5Transform(ctx->buf, (uint32 *)ctx->u.in);
    buf += t;
    len -= t;
  }

  /* Process data in 64-byte chunks */

  while (len >= 64) {
    memcpy(ctx->u.in, buf, 64);
    byteReverse(ctx->u.in, 16);
    MD5Transform(ctx->buf, (uint32 *)ctx->u.in);
    buf += 64;
    len -= 64;
  }

  /* Handle any remaining bytes of data. */

  memcpy(ctx->u.in, buf, len);
}

/*
 * Final wrapup - pad to 64-byte boundary with the bit pattern 
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
static void MD5Final(unsigned char digest[16], MD5Context *ctx){
  unsigned count;
  unsigned char *p;

  /* Compute number of bytes mod 64 */
  count = (ctx->bits[0] >> 3) & 0x3F;

  /* Set the first char of padding to 0x80.  This is safe since there is
     always at least one byte free */
  p = ctx->u.in + count;
  *p++ = 0x80;

  /* Bytes of padding needed to make 64 bytes */
  count = 64 - 1 - count;

  /* Pad out to 56 mod 64 */
  if (count < 8) {
    /* Two lots of padding:  Pad the first block to 64 bytes */
    memset(p, 0, count);
    byteReverse(ctx->u.in, 16);
    MD5Transform(ctx->buf, (uint32 *)ctx->u.in);

    /* Now fill the next block with 56 bytes */
    memset(ctx->u.in, 0, 56);
  } else {
    /* Pad block to 56 bytes */
    memset(p, 0, count-8);
  }
  byteReverse(ctx->u.in, 14);

  /* Append length in bits and transform */
  ctx->u.in32[14] = ctx->bits[0];
  ctx->u.in32[15] = ctx->bits[1];

  MD5Transform(ctx->buf, (uint32 *)ctx->u.in);
  byteReverse((unsigned char *)ctx->buf, 4);
  memcpy(digest, ctx->buf, 16);
  memset(ctx, 0, sizeof(*ctx));    /* In case it is sensitive */
}

/*
** Convert a 128-bit MD5 digest into a 32-digit base-16 number.
*/
static void MD5DigestToBase16(unsigned char *digest, char *zBuf){
  static char const zEncode[] = "0123456789abcdef";

typedef struct Threadset Threadset;
typedef struct Thread Thread;

/* Total number of errors in this process so far. */
static int nGlobalErr = 0;




struct Error {
  int rc;
  int iLine;
  char *zErr;
};

struct Sqlite {
  sqlite3 *db;                    /* Database handle */
  Statement *pCache;              /* Linked list of cached statements */
  int nText;                      /* Size of array at aText[] */
  char **aText;                   /* Stored text results */
};

struct Statement {
  sqlite3_stmt *pStmt;            /* Pre-compiled statement handle */
  Statement *pNext;               /* Next statement in linked-list */
};

struct Thread {
  int iTid;                       /* Thread number within test */
  void* pArg;                     /* Pointer argument passed by caller */

  pthread_t tid;                  /* Thread id */
  char *(*xProc)(int, void*);     /* Thread main proc */
  Thread *pNext;                  /* Next in this list of threads */
};

struct Threadset {
  int iMaxTid;                    /* Largest iTid value allocated so far */
  Thread *pThread;                /* Linked list of threads */
};

  Error *pErr,                    /* IN/OUT: Error code */
  Sqlite *pDb,                    /* OUT: Database handle */
  const char *zFile,              /* Database file name */
  int bDelete                     /* True to delete db file before opening */
){
  if( pErr->rc==SQLITE_OK ){
    int rc;
    int flags = SQLITE_OPEN_CREATE | SQLITE_OPEN_READWRITE | SQLITE_OPEN_URI;
    if( bDelete ) unlink(zFile);
    rc = sqlite3_open_v2(zFile, &pDb->db, flags, 0);
    if( rc ){
      sqlite_error(pErr, pDb, "open");
      sqlite3_close(pDb->db);
      pDb->db = 0;
    }else{
      sqlite3_create_function(
          pDb->db, "md5sum", -1, SQLITE_UTF8, 0, 0, md5step, md5finalize

  Sqlite *pDb,                    /* Database handle */
  const char *zSql                /* SQL script to execute */
){
  if( pErr->rc==SQLITE_OK ){
    pErr->rc = sqlite3_exec(pDb->db, zSql, 0, 0, &pErr->zErr);
  }
}

static void sql_script_printf_x(
  Error *pErr,                    /* IN/OUT: Error code */
  Sqlite *pDb,                    /* Database handle */
  const char *zFormat,            /* SQL printf format string */
  ...                             /* Printf args */
){
  va_list ap;                     /* ... printf arguments */
  va_start(ap, zFormat);
  if( pErr->rc==SQLITE_OK ){
    char *zSql = sqlite3_vmprintf(zFormat, ap);
    pErr->rc = sqlite3_exec(pDb->db, zSql, 0, 0, &pErr->zErr);
    sqlite3_free(zSql);
  }
  va_end(ap);
}

static Statement *getSqlStatement(
  Error *pErr,                    /* IN/OUT: Error code */
  Sqlite *pDb,                    /* Database handle */
  const char *zSql                /* SQL statement */
){
  Statement *pRet;

  Sqlite *pDb,                    /* Database handle */
  ...                             /* SQL and pointers to parameter values */
){
  i64 iRet = 0;
  if( pErr->rc==SQLITE_OK ){
    sqlite3_stmt *pStmt;          /* SQL statement to execute */
    va_list ap;                   /* ... arguments */

    va_start(ap, pDb);
    pStmt = getAndBindSqlStatement(pErr, pDb, ap);
    if( pStmt ){

      int first = 1;
      while( SQLITE_ROW==sqlite3_step(pStmt) ){
        if( first && sqlite3_column_count(pStmt)>0 ){
          iRet = sqlite3_column_int64(pStmt, 0);
        }
        first = 0;
      }

    memset(&pDb->aText[pDb->nText], 0, sizeof(char*)*(iSlot+1-pDb->nText));
    pDb->nText = iSlot+1;
  }

  if( pErr->rc==SQLITE_OK ){
    sqlite3_stmt *pStmt;          /* SQL statement to execute */
    va_list ap;                   /* ... arguments */

    va_start(ap, iSlot);
    pStmt = getAndBindSqlStatement(pErr, pDb, ap);
    if( pStmt ){

      int first = 1;
      while( SQLITE_ROW==sqlite3_step(pStmt) ){
        if( first && sqlite3_column_count(pStmt)>0 ){
          zRet = sqlite3_mprintf("%s", sqlite3_column_text(pStmt, 0));
          sqlite3_free(pDb->aText[iSlot]);
          pDb->aText[iSlot] = zRet;
        }

static void integrity_check_x(
  Error *pErr,                    /* IN/OUT: Error code */
  Sqlite *pDb                     /* Database handle */
){
  if( pErr->rc==SQLITE_OK ){
    Statement *pStatement;        /* Statement to execute */

    char *zErr = 0;               /* Integrity check error */

    pStatement = getSqlStatement(pErr, pDb, "PRAGMA integrity_check");
    if( pStatement ){
      sqlite3_stmt *pStmt = pStatement->pStmt;
      while( SQLITE_ROW==sqlite3_step(pStmt) ){
        const char *z = (const char*)sqlite3_column_text(pStmt, 0);
        if( strcmp(z, "ok") ){
          if( zErr==0 ){
            zErr = sqlite3_mprintf("%s", z);
          }else{
            zErr = sqlite3_mprintf("%z\n%s", zErr, z);
          }
        }
      }
      sqlite3_reset(pStmt);

      if( zErr ){
        pErr->zErr = zErr;
        pErr->rc = 1;
      }
    }
  }
}

static void *launch_thread_main(void *pArg){
  Thread *p = (Thread *)pArg;
  return (void *)p->xProc(p->iTid, p->pArg);
}

static void launch_thread_x(
  Error *pErr,                    /* IN/OUT: Error code */
  Threadset *pThreads,            /* Thread set */
  char *(*xProc)(int, void*),     /* Proc to run */
  void *pArg                      /* Argument passed to thread proc */
){
  if( pErr->rc==SQLITE_OK ){
    int iTid = ++pThreads->iMaxTid;
    Thread *p;
    int rc;

    p = (Thread *)sqlite3_malloc(sizeof(Thread));
    memset(p, 0, sizeof(Thread));
    p->iTid = iTid;
    p->pArg = pArg;
    p->xProc = xProc;

    rc = pthread_create(&p->tid, NULL, launch_thread_main, (void *)p);
    if( rc!=0 ){
      system_error(pErr, rc);
      sqlite3_free(p);
    }else{

**************************************************************************
** End infrastructure. Begin tests.
*/

#define WALTHREAD1_NTHREAD  10
#define WALTHREAD3_NTHREAD  6

static char *walthread1_thread(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
  int nIter = 0;                  /* Iterations so far */

  opendb(&err, &db, "test.db", 0);
  while( !timetostop(&err) ){
    const char *azSql[] = {

  }
  closedb(&err, &db);

  print_and_free_err(&err);
  return sqlite3_mprintf("%d iterations", nIter);
}

static char *walthread1_ckpt_thread(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
  int nCkpt = 0;                  /* Checkpoints so far */

  opendb(&err, &db, "test.db", 0);
  while( !timetostop(&err) ){
    usleep(500*1000);

  }
  launch_thread(&err, &threads, walthread1_ckpt_thread, 0);
  join_all_threads(&err, &threads);

  print_and_free_err(&err);
}

static char *walthread2_thread(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
  int anTrans[2] = {0, 0};        /* Number of WAL and Rollback transactions */
  int iArg = PTR2INT(pArg);

  const char *zJournal = "PRAGMA journal_mode = WAL";
  if( iArg ){ zJournal = "PRAGMA journal_mode = DELETE"; }

  while( !timetostop(&err) ){
    int journal_exists = 0;
    int wal_exists = 0;

  opendb(&err, &db, "test.db", 1);
  sql_script(&err, &db, "CREATE TABLE t1(x INTEGER PRIMARY KEY, y UNIQUE)");
  closedb(&err, &db);

  setstoptime(&err, nMs);
  launch_thread(&err, &threads, walthread2_thread, 0);
  launch_thread(&err, &threads, walthread2_thread, 0);
  launch_thread(&err, &threads, walthread2_thread, (void*)1);
  launch_thread(&err, &threads, walthread2_thread, (void*)1);
  join_all_threads(&err, &threads);

  print_and_free_err(&err);
}

static char *walthread3_thread(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
  i64 iNextWrite;                 /* Next value this thread will write */
  int iArg = PTR2INT(pArg);

  opendb(&err, &db, "test.db", 0);
  sql_script(&err, &db, "PRAGMA wal_autocheckpoint = 10");

  iNextWrite = iArg+1;
  while( 1 ){
    i64 sum1;

      "CREATE INDEX i2 ON t1(sum2);"
      "INSERT INTO t1 VALUES(0, 0, 0);"
  );
  closedb(&err, &db);

  setstoptime(&err, nMs);
  for(i=0; i<WALTHREAD3_NTHREAD; i++){
    launch_thread(&err, &threads, walthread3_thread, INT2PTR(i));
  }
  join_all_threads(&err, &threads);

  print_and_free_err(&err);
}

static char *walthread4_reader_thread(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */

  opendb(&err, &db, "test.db", 0);
  while( !timetostop(&err) ){
    integrity_check(&err, &db);
  }
  closedb(&err, &db);

  print_and_free_err(&err);
  return 0;
}

static char *walthread4_writer_thread(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
  i64 iRow = 1;

  opendb(&err, &db, "test.db", 0);
  sql_script(&err, &db, "PRAGMA wal_autocheckpoint = 15;");
  while( !timetostop(&err) ){

  launch_thread(&err, &threads, walthread4_reader_thread, 0);
  launch_thread(&err, &threads, walthread4_writer_thread, 0);
  join_all_threads(&err, &threads);

  print_and_free_err(&err);
}

static char *walthread5_thread(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
  i64 nRow;

  opendb(&err, &db, "test.db", 0);
  nRow = execsql_i64(&err, &db, "SELECT count(*) FROM t1");
  closedb(&err, &db);

** Test case "dynamic_triggers"
**
**   Two threads executing statements that cause deeply nested triggers
**   to fire. And one thread busily creating and deleting triggers. This
**   is an attempt to find a bug reported to us.
*/

static char *dynamic_triggers_1(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
  int nDrop = 0;
  int nCreate = 0;

  opendb(&err, &db, "test.db", 0);
  while( !timetostop(&err) ){

    for(i=1; i<9; i++){
      char *zSql = sqlite3_mprintf("DROP TRIGGER dtr%d", i);
      execsql(&err, &db, zSql);
      sqlite3_free(zSql);
      nDrop++;
    }
  }
  closedb(&err, &db);

  print_and_free_err(&err);
  return sqlite3_mprintf("%d created, %d dropped", nCreate, nDrop);
}

static char *dynamic_triggers_2(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
  i64 iVal = 0;
  int nInsert = 0;
  int nDelete = 0;

  opendb(&err, &db, "test.db", 0);
  while( !timetostop(&err) ){
    do {
      iVal = (iVal+1)%100;
      execsql(&err, &db, "INSERT INTO t1 VALUES(:iX, :iY+1)", &iVal, &iVal);
      nInsert++;
    } while( iVal );

    do {
      iVal = (iVal+1)%100;
      execsql(&err, &db, "DELETE FROM t1 WHERE x = :iX", &iVal);
      nDelete++;
    } while( iVal );
  }
  closedb(&err, &db);

  print_and_free_err(&err);
  return sqlite3_mprintf("%d inserts, %d deletes", nInsert, nDelete);
}

static void dynamic_triggers(int nMs){
  Error err = {0};

      "CREATE TABLE t4(x, y);"
      "CREATE TABLE t5(x, y);"
      "CREATE TABLE t6(x, y);"
      "CREATE TABLE t7(x, y);"
      "CREATE TABLE t8(x, y);"
      "CREATE TABLE t9(x, y);"
  );
  closedb(&err, &db);

  setstoptime(&err, nMs);

  sqlite3_enable_shared_cache(1);
  launch_thread(&err, &threads, dynamic_triggers_2, 0);
  launch_thread(&err, &threads, dynamic_triggers_2, 0);


  sleep(2);
  sqlite3_enable_shared_cache(0);

  launch_thread(&err, &threads, dynamic_triggers_2, 0);
  launch_thread(&err, &threads, dynamic_triggers_1, 0);

  join_all_threads(&err, &threads);

  print_and_free_err(&err);
}



#include "tt3_checkpoint.c"
#include "tt3_index.c"
#include "tt3_lookaside1.c"
#include "tt3_vacuum.c"
#include "tt3_stress.c"

int main(int argc, char **argv){
  struct ThreadTest {
    void (*xTest)(int);
    const char *zTest;
    int nMs;
  } aTest[] = {

    { cgt_pager_1,      "cgt_pager_1", 0 },
    { dynamic_triggers, "dynamic_triggers", 20000 },

    { checkpoint_starvation_1, "checkpoint_starvation_1", 10000 },
    { checkpoint_starvation_2, "checkpoint_starvation_2", 10000 },

    { create_drop_index_1, "create_drop_index_1", 10000 },
    { lookaside1,          "lookaside1", 10000 },
    { vacuum1,             "vacuum1", 10000 },
    { stress1,             "stress1", 10000 },
    { stress2,             "stress2", 60000 },
  };

  int i;


  int bTestfound = 0;











  sqlite3_config(SQLITE_CONFIG_MULTITHREAD);
  sqlite3_config(SQLITE_CONFIG_MULTITHREAD);

  for(i=0; i<sizeof(aTest)/sizeof(aTest[0]); i++){
    char const *z = aTest[i].zTest;
    if( argc>1 ){
      int iArg;
      for(iArg=1; iArg<argc; iArg++){
        if( 0==sqlite3_strglob(argv[iArg], z) ) break;
      }
      if( iArg==argc ) continue;
    }

    printf("Running %s for %d seconds...\n", z, aTest[i].nMs/1000);
    aTest[i].xTest(aTest[i].nMs);
    bTestfound++;

  }
  if( bTestfound==0 ) goto usage;

  printf("Total of %d errors across all tests\n", nGlobalErr);
  return (nGlobalErr>0 ? 255 : 0);

 usage:
  printf("Usage: %s [testname|testprefix*]...\n", argv[0]);
  printf("Available tests are:\n");
  for(i=0; i<sizeof(aTest)/sizeof(aTest[0]); i++){
    printf("   %s\n", aTest[i].zTest);
  }

  return 254;
}

/*
** 2014-12-11
**
** 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.
**
*************************************************************************
** This file implements a simple standalone program used to stress the
** SQLite library when accessing the same set of databases simultaneously
** from multiple threads in shared-cache mode.
**
** This test program runs on unix-like systems only.  It uses pthreads.
** To compile:
**
**     gcc -g -Wall -I. threadtest4.c sqlite3.c -ldl -lpthread
**
** To run:
**
**     ./a.out 10
**
** The argument is the number of threads.  There are also options, such
** as -wal and -multithread and -serialized.
**
** Consider also compiling with clang instead of gcc and adding the
** -fsanitize=thread option.
*/
#include "sqlite3.h"
#include <pthread.h>
#include <sched.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdarg.h>

/*
** An instance of the following structure is passed into each worker
** thread.
*/
typedef struct WorkerInfo WorkerInfo;
struct WorkerInfo {
  int tid;                    /* Thread ID */
  int nWorker;                /* Total number of workers */
  unsigned wkrFlags;          /* Flags */
  sqlite3 *mainDb;            /* Database connection of the main thread */
  sqlite3 *db;                /* Database connection of this thread */
  int nErr;                   /* Number of errors seen by this thread */
  int nTest;                  /* Number of tests run by this thread */
  char *zMsg;                 /* Message returned by this thread */
  pthread_t id;               /* Thread id */
  pthread_mutex_t *pWrMutex;  /* Hold this mutex while writing */
};

/*
** Allowed values for WorkerInfo.wkrFlags
*/
#define TT4_SERIALIZED    0x0000001   /* The --serialized option is used */
#define TT4_WAL           0x0000002   /* WAL mode in use */
#define TT4_TRACE         0x0000004   /* Trace activity */


/*
** Report an OOM error and die if the argument is NULL
*/
static void check_oom(void *x){
  if( x==0 ){
    fprintf(stderr, "out of memory\n");
    exit(1);
  }
}

/*
** Allocate memory.  If the allocation fails, print an error message and
** kill the process.
*/
static void *safe_malloc(int sz){
  void *x = sqlite3_malloc(sz>0?sz:1);
  check_oom(x);
  return x;
}

/*
** Print a trace message for a worker
*/
static void worker_trace(WorkerInfo *p, const char *zFormat, ...){
  va_list ap;
  char *zMsg;
  if( (p->wkrFlags & TT4_TRACE)==0 ) return;
  va_start(ap, zFormat);
  zMsg = sqlite3_vmprintf(zFormat, ap);
  check_oom(zMsg);
  va_end(ap);
  fprintf(stderr, "TRACE(%02d): %s\n", p->tid, zMsg);
  sqlite3_free(zMsg);
}

/*
** Prepare a single SQL query
*/
static sqlite3_stmt *prep_sql(sqlite3 *db, const char *zFormat, ...){
  va_list ap;
  char *zSql;
  int rc;
  sqlite3_stmt *pStmt = 0;

  va_start(ap, zFormat);
  zSql = sqlite3_vmprintf(zFormat, ap);
  va_end(ap);
  check_oom(zSql);
  rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
  if( rc!=SQLITE_OK ){
    fprintf(stderr, "SQL error (%d,%d): %s\nWhile preparing: [%s]\n",
            rc, sqlite3_extended_errcode(db), sqlite3_errmsg(db), zSql);
    exit(1);
  }
  sqlite3_free(zSql);
  return pStmt;
}

/*
** Run a SQL statements.  Panic if unable.
*/
static void run_sql(WorkerInfo *p, const char *zFormat, ...){
  va_list ap;
  char *zSql;
  int rc;
  sqlite3_stmt *pStmt = 0;
  int nRetry = 0;

  va_start(ap, zFormat);
  zSql = sqlite3_vmprintf(zFormat, ap);
  va_end(ap);
  check_oom(zSql);
  rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0);
  if( rc!=SQLITE_OK ){
    fprintf(stderr, "SQL error (%d,%d): %s\nWhile preparing: [%s]\n",
            rc, sqlite3_extended_errcode(p->db), sqlite3_errmsg(p->db), zSql);
    exit(1);
  }
  worker_trace(p, "running [%s]", zSql);
  while( (rc = sqlite3_step(pStmt))!=SQLITE_DONE ){
    if( (rc&0xff)==SQLITE_BUSY || (rc&0xff)==SQLITE_LOCKED ){
      sqlite3_reset(pStmt);
      nRetry++;
      if( nRetry<10 ){
        worker_trace(p, "retry %d for [%s]", nRetry, zSql);
        sched_yield();
        continue;
      }else{
        fprintf(stderr, "Deadlock in thread %d while running [%s]\n",
                p->tid, zSql);
        exit(1);
      }
    }
    if( rc!=SQLITE_ROW ){
      fprintf(stderr, "SQL error (%d,%d): %s\nWhile running [%s]\n",
              rc, sqlite3_extended_errcode(p->db), sqlite3_errmsg(p->db), zSql);
      exit(1);
    }
  }
  sqlite3_free(zSql);
  sqlite3_finalize(pStmt);
}


/*
** Open the database connection for WorkerInfo.  The order in which
** the files are opened is a function of the tid value.
*/
static void worker_open_connection(WorkerInfo *p, int iCnt){
  char *zFile;
  int x;
  int rc;
  static const unsigned char aOrder[6][3] = {
    { 1, 2, 3},
    { 1, 3, 2},
    { 2, 1, 3},
    { 2, 3, 1},
    { 3, 1, 2},
    { 3, 2, 1}
  };
  x = (p->tid + iCnt) % 6;
  zFile = sqlite3_mprintf("tt4-test%d.db", aOrder[x][0]);
  check_oom(zFile);
  worker_trace(p, "open %s", zFile);
  rc = sqlite3_open_v2(zFile, &p->db,
                       SQLITE_OPEN_READWRITE|SQLITE_OPEN_SHAREDCACHE, 0);
  if( rc!=SQLITE_OK ){
    fprintf(stderr, "sqlite_open_v2(%s) failed on thread %d\n",
            zFile, p->tid);
    exit(1);
  }
  sqlite3_free(zFile);
  run_sql(p, "PRAGMA read_uncommitted=ON;");
  sqlite3_busy_timeout(p->db, 10000);
  run_sql(p, "PRAGMA synchronous=OFF;");
  run_sql(p, "ATTACH 'tt4-test%d.db' AS aux1", aOrder[x][1]);
  run_sql(p, "ATTACH 'tt4-test%d.db' AS aux2", aOrder[x][2]);
}

/*
** Close the worker database connection
*/
static void worker_close_connection(WorkerInfo *p){
  if( p->db ){
    worker_trace(p, "close");
    sqlite3_close(p->db);
    p->db = 0;
  }
}

/*
** Delete all content in the three databases associated with a
** single thread.  Make this happen all in a single transaction if
** inTrans is true, or separately for each database if inTrans is
** false.
*/
static void worker_delete_all_content(WorkerInfo *p, int inTrans){
  if( inTrans ){
    pthread_mutex_lock(p->pWrMutex);
    run_sql(p, "BEGIN");
    run_sql(p, "DELETE FROM t1 WHERE tid=%d", p->tid);
    run_sql(p, "DELETE FROM t2 WHERE tid=%d", p->tid);
    run_sql(p, "DELETE FROM t3 WHERE tid=%d", p->tid);
    run_sql(p, "COMMIT");
    pthread_mutex_unlock(p->pWrMutex);
    p->nTest++;
  }else{
    pthread_mutex_lock(p->pWrMutex);
    run_sql(p, "DELETE FROM t1 WHERE tid=%d", p->tid);
    pthread_mutex_unlock(p->pWrMutex);
    p->nTest++;
    pthread_mutex_lock(p->pWrMutex);
    run_sql(p, "DELETE FROM t2 WHERE tid=%d", p->tid);
    pthread_mutex_unlock(p->pWrMutex);
    p->nTest++;
    pthread_mutex_lock(p->pWrMutex);
    run_sql(p, "DELETE FROM t3 WHERE tid=%d", p->tid);
    pthread_mutex_unlock(p->pWrMutex);
    p->nTest++;
  }
}

/*
** Create rows mn through mx in table iTab for the given worker
*/
static void worker_add_content(WorkerInfo *p, int mn, int mx, int iTab){
  char *zTabDef;
  switch( iTab ){
    case 1:  zTabDef = "t1(tid,sp,a,b,c)";  break;
    case 2:  zTabDef = "t2(tid,sp,d,e,f)";  break;
    case 3:  zTabDef = "t3(tid,sp,x,y,z)";  break;
  }
  pthread_mutex_lock(p->pWrMutex);
  run_sql(p, 
     "WITH RECURSIVE\n"
     " c(i) AS (VALUES(%d) UNION ALL SELECT i+1 FROM c WHERE i<%d)\n"
     "INSERT INTO %s SELECT %d, zeroblob(3000), i, printf('%%d',i), i FROM c;",
     mn, mx, zTabDef, p->tid
  );
  pthread_mutex_unlock(p->pWrMutex);
  p->nTest++;
}

/*
** Set an error message on a worker
*/
static void worker_error(WorkerInfo *p, const char *zFormat, ...){
  va_list ap;
  p->nErr++;
  sqlite3_free(p->zMsg);
  va_start(ap, zFormat);
  p->zMsg = sqlite3_vmprintf(zFormat, ap);
  va_end(ap);
}

/*
** Each thread runs the following function.
*/
static void *worker_thread(void *pArg){
  WorkerInfo *p = (WorkerInfo*)pArg;
  int iOuter;
  int i;
  int rc;
  sqlite3_stmt *pStmt;

  printf("worker %d startup\n", p->tid);  fflush(stdout);
  for(iOuter=1; iOuter<=p->nWorker; iOuter++){
    worker_open_connection(p, iOuter);
    for(i=0; i<4; i++){
      worker_add_content(p, i*100+1, (i+1)*100, (p->tid+iOuter)%3 + 1);
      worker_add_content(p, i*100+1, (i+1)*100, (p->tid+iOuter+1)%3 + 1);
      worker_add_content(p, i*100+1, (i+1)*100, (p->tid+iOuter+2)%3 + 1);
    }

    pStmt = prep_sql(p->db, "SELECT count(a) FROM t1 WHERE tid=%d", p->tid);
    worker_trace(p, "query [%s]", sqlite3_sql(pStmt));
    rc = sqlite3_step(pStmt);
    if( rc!=SQLITE_ROW ){
      worker_error(p, "Failed to step: %s", sqlite3_sql(pStmt));
    }else if( sqlite3_column_int(pStmt, 0)!=400 ){
      worker_error(p, "Wrong result: %d", sqlite3_column_int(pStmt,0));
    }
    sqlite3_finalize(pStmt);
    if( p->nErr ) break;

    if( ((iOuter+p->tid)%3)==0 ){
      sqlite3_db_release_memory(p->db);
      p->nTest++;
    }

    pthread_mutex_lock(p->pWrMutex);
    run_sql(p, "BEGIN;");
    run_sql(p, "UPDATE t1 SET c=NULL WHERE a=55");
    run_sql(p, "UPDATE t2 SET f=NULL WHERE d=42");
    run_sql(p, "UPDATE t3 SET z=NULL WHERE x=31");
    run_sql(p, "ROLLBACK;");
    p->nTest++;
    pthread_mutex_unlock(p->pWrMutex);


    if( iOuter==p->tid ){
      pthread_mutex_lock(p->pWrMutex);
      run_sql(p, "VACUUM");
      pthread_mutex_unlock(p->pWrMutex);
    }

    pStmt = prep_sql(p->db,
       "SELECT t1.rowid, t2.rowid, t3.rowid"
       "  FROM t1, t2, t3"
       " WHERE t1.tid=%d AND t2.tid=%d AND t3.tid=%d"
       "   AND t1.a<>t2.d AND t2.d<>t3.x"
       " ORDER BY 1, 2, 3"
       ,p->tid, p->tid, p->tid);
    worker_trace(p, "query [%s]", sqlite3_sql(pStmt));
    for(i=0; i<p->nWorker; i++){
      rc = sqlite3_step(pStmt);
      if( rc!=SQLITE_ROW ){
        worker_error(p, "Failed to step: %s", sqlite3_sql(pStmt));
        break;
      }
      sched_yield();
    }
    sqlite3_finalize(pStmt);
    if( p->nErr ) break;

    worker_delete_all_content(p, (p->tid+iOuter)%2);
    worker_close_connection(p);
    p->db = 0;
  }
  worker_close_connection(p);
  printf("worker %d finished\n", p->tid); fflush(stdout);
  return 0;
}

int main(int argc, char **argv){
  int nWorker = 0;         /* Number of worker threads */
  int i;                   /* Loop counter */
  WorkerInfo *aInfo;       /* Information for each worker */
  unsigned wkrFlags = 0;   /* Default worker flags */
  int nErr = 0;            /* Number of errors */
  int nTest = 0;           /* Number of tests */
  int rc;                  /* Return code */
  sqlite3 *db = 0;         /* Main database connection */
  pthread_mutex_t wrMutex; /* The write serialization mutex */
  WorkerInfo infoTop;      /* WorkerInfo for the main thread */
  WorkerInfo *p;           /* Pointer to infoTop */

  sqlite3_config(SQLITE_CONFIG_MULTITHREAD);
  for(i=1; i<argc; i++){
    const char *z = argv[i];
    if( z[0]=='-' ){
      if( z[1]=='-' && z[2]!=0 ) z++;
      if( strcmp(z,"-multithread")==0 ){
        sqlite3_config(SQLITE_CONFIG_MULTITHREAD);
        wkrFlags &= ~TT4_SERIALIZED;
      }else if( strcmp(z,"-serialized")==0 ){
        sqlite3_config(SQLITE_CONFIG_SERIALIZED);
        wkrFlags |= TT4_SERIALIZED;
      }else if( strcmp(z,"-wal")==0 ){
        wkrFlags |= TT4_WAL;
      }else if( strcmp(z,"-trace")==0 ){
        wkrFlags |= TT4_TRACE;
      }else{
        fprintf(stderr, "unknown command-line option: %s\n", argv[i]);
        exit(1);
      }
    }else if( z[0]>='1' && z[0]<='9' && nWorker==0 ){
      nWorker = atoi(z);
      if( nWorker<2 ){
        fprintf(stderr, "minimum of 2 threads\n");
        exit(1);
      }
    }else{
      fprintf(stderr, "extra command-line argument: \"%s\"\n", argv[i]);
      exit(1);
    }
  }
  if( nWorker==0 ){ 
    fprintf(stderr,
       "usage:  %s ?OPTIONS? N\n"
       "N is the number of threads and must be at least 2.\n"
       "Options:\n"
       "  --serialized\n"
       "  --multithread\n"
       "  --wal\n"
       "  --trace\n"
       ,argv[0]
    );
    exit(1);
  }
  if( !sqlite3_threadsafe() ){
    fprintf(stderr, "requires a threadsafe build of SQLite\n");
    exit(1);
  }
  sqlite3_initialize();
  sqlite3_enable_shared_cache(1);
  pthread_mutex_init(&wrMutex, 0);

  /* Initialize the test database files */
  (void)unlink("tt4-test1.db");
  (void)unlink("tt4-test2.db");
  (void)unlink("tt4-test3.db");
  rc = sqlite3_open("tt4-test1.db", &db);
  if( rc!=SQLITE_OK ){
    fprintf(stderr, "Unable to open test database: tt4-test2.db\n");
    exit(1);
  }
  memset(&infoTop, 0, sizeof(infoTop));
  infoTop.db = db;
  infoTop.wkrFlags = wkrFlags;
  p = &infoTop;
  if( wkrFlags & TT4_WAL ){
    run_sql(p, "PRAGMA journal_mode=WAL");
  }
  run_sql(p, "PRAGMA synchronous=OFF");
  run_sql(p, "CREATE TABLE IF NOT EXISTS t1(tid INTEGER, sp, a, b, c)");
  run_sql(p, "CREATE INDEX t1tid ON t1(tid)");
  run_sql(p, "CREATE INDEX t1ab ON t1(a,b)");
  run_sql(p, "ATTACH 'tt4-test2.db' AS 'test2'");
  run_sql(p, "CREATE TABLE IF NOT EXISTS test2.t2(tid INTEGER, sp, d, e, f)");
  run_sql(p, "CREATE INDEX test2.t2tid ON t2(tid)");
  run_sql(p, "CREATE INDEX test2.t2de ON t2(d,e)");
  run_sql(p, "ATTACH 'tt4-test3.db' AS 'test3'");
  run_sql(p, "CREATE TABLE IF NOT EXISTS test3.t3(tid INTEGER, sp, x, y, z)");
  run_sql(p, "CREATE INDEX test3.t3tid ON t3(tid)");
  run_sql(p, "CREATE INDEX test3.t3xy ON t3(x,y)");
  aInfo = safe_malloc( sizeof(*aInfo)*nWorker );
  memset(aInfo, 0, sizeof(*aInfo)*nWorker);
  for(i=0; i<nWorker; i++){
    aInfo[i].tid = i+1;
    aInfo[i].nWorker = nWorker;
    aInfo[i].wkrFlags = wkrFlags;
    aInfo[i].mainDb = db;
    aInfo[i].pWrMutex = &wrMutex;
    rc = pthread_create(&aInfo[i].id, 0, worker_thread, &aInfo[i]);
    if( rc!=0 ){
      fprintf(stderr, "thread creation failed for thread %d\n", i+1);
      exit(1);
    }
    sched_yield();
  }
  for(i=0; i<nWorker; i++){
    pthread_join(aInfo[i].id, 0);
    printf("Joined thread %d: %d errors in %d tests",
           aInfo[i].tid, aInfo[i].nErr, aInfo[i].nTest);
    if( aInfo[i].zMsg ){
      printf(": %s\n", aInfo[i].zMsg);
    }else{
      printf("\n");
    }
    nErr += aInfo[i].nErr;
    nTest += aInfo[i].nTest;
    fflush(stdout);
  }
  sqlite3_close(db);
  sqlite3_free(aInfo);
  printf("Total %d errors in %d tests\n", nErr, nTest);
  return nErr;
}

  }
  if( nFrame>=CHECKPOINT_STARVATION_FRAMELIMIT ){
    sqlite3_wal_checkpoint_v2(db, zDb, p->eMode, 0, 0);
  }
  return SQLITE_OK;
}

static char *checkpoint_starvation_reader(int iTid, void *pArg){
  Error err = {0};
  Sqlite db = {0};

  opendb(&err, &db, "test.db", 0);
  while( !timetostop(&err) ){
    i64 iCount1, iCount2;
    sql_script(&err, &db, "BEGIN");

**
*************************************************************************
**
**     create_drop_index_1
*/


static char *create_drop_index_thread(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */

  while( !timetostop(&err) ){
    opendb(&err, &db, "test.db", 0);

    sql_script(&err, &db, 

      "DROP INDEX IF EXISTS i1;"
      "DROP INDEX IF EXISTS i2;"
      "DROP INDEX IF EXISTS i3;"
      "DROP INDEX IF EXISTS i4;"

      "CREATE INDEX IF NOT EXISTS i1 ON t11(a);"
      "CREATE INDEX IF NOT EXISTS i2 ON t11(b);"
      "CREATE INDEX IF NOT EXISTS i3 ON t11(c);"
      "CREATE INDEX IF NOT EXISTS i4 ON t11(d);"

      "SELECT * FROM t11 ORDER BY a;"
      "SELECT * FROM t11 ORDER BY b;"
      "SELECT * FROM t11 ORDER BY c;"
      "SELECT * FROM t11 ORDER BY d;"
    );
    clear_error(&err, SQLITE_LOCKED);

    closedb(&err, &db);
  }

  print_and_free_err(&err);
  return sqlite3_mprintf("ok");
}

static void create_drop_index_1(int nMs){
  Error err = {0};
  Sqlite db = {0};
  Threadset threads = {0};

  opendb(&err, &db, "test.db", 1);
  sql_script(&err, &db, 
     "CREATE TABLE t11(a, b, c, d);"
     "WITH data(x) AS (SELECT 1 UNION ALL SELECT x+1 FROM data WHERE x<100) "
     "INSERT INTO t11 SELECT x,x,x,x FROM data;"
  );
  closedb(&err, &db);

  setstoptime(&err, nMs);

  sqlite3_enable_shared_cache(1);
  launch_thread(&err, &threads, create_drop_index_thread, 0);
  launch_thread(&err, &threads, create_drop_index_thread, 0);
  launch_thread(&err, &threads, create_drop_index_thread, 0);
  launch_thread(&err, &threads, create_drop_index_thread, 0);
  launch_thread(&err, &threads, create_drop_index_thread, 0);


  join_all_threads(&err, &threads);
  sqlite3_enable_shared_cache(0);
  print_and_free_err(&err);
}

/*
** 2014 December 9
**
** 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.
**
*************************************************************************
**
**     lookaside1
*/

/*
** The test in this file attempts to expose a specific race condition
** that is suspected to exist at time of writing.
*/

static char *lookaside1_thread_reader(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */

  opendb(&err, &db, "test.db", 0);

  while( !timetostop(&err) ){
    sqlite3_stmt *pStmt = 0;
    int rc;

    sqlite3_prepare_v2(db.db, "SELECT 1 FROM t1", -1, &pStmt, 0);
    while( sqlite3_step(pStmt)==SQLITE_ROW ){
      execsql(&err, &db, "SELECT length(x||y||z) FROM t2");
    }
    rc = sqlite3_finalize(pStmt);
    if( err.rc==SQLITE_OK && rc!=SQLITE_OK ){
      sqlite_error(&err, &db, "finalize");
    }
  }

  closedb(&err, &db);
  print_and_free_err(&err);
  return sqlite3_mprintf("ok");
}

static char *lookaside1_thread_writer(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */

  opendb(&err, &db, "test.db", 0);

  do{
    sql_script(&err, &db, 
      "BEGIN;"
        "UPDATE t3 SET i=i+1 WHERE x=1;"
      "ROLLBACK;"
    );
  }while( !timetostop(&err) );

  closedb(&err, &db);
  print_and_free_err(&err);
  return sqlite3_mprintf("ok");
}


static void lookaside1(int nMs){
  Error err = {0};
  Sqlite db = {0};
  Threadset threads = {0};

  opendb(&err, &db, "test.db", 1);
  sql_script(&err, &db, 
     "CREATE TABLE t1(x PRIMARY KEY) WITHOUT ROWID;"
     "WITH data(x,y) AS ("
     "  SELECT 1, quote(randomblob(750)) UNION ALL "
     "  SELECT x*2, y||y FROM data WHERE x<5) "
     "INSERT INTO t1 SELECT y FROM data;"

     "CREATE TABLE t3(x PRIMARY KEY,i) WITHOUT ROWID;"
     "INSERT INTO t3 VALUES(1, 1);"

     "CREATE TABLE t2(x,y,z);"
     "INSERT INTO t2 VALUES(randomblob(50), randomblob(50), randomblob(50));"
  );
  closedb(&err, &db);

  setstoptime(&err, nMs);

  sqlite3_enable_shared_cache(1);
  launch_thread(&err, &threads, lookaside1_thread_reader, 0);
  launch_thread(&err, &threads, lookaside1_thread_reader, 0);
  launch_thread(&err, &threads, lookaside1_thread_reader, 0);
  launch_thread(&err, &threads, lookaside1_thread_reader, 0);
  launch_thread(&err, &threads, lookaside1_thread_reader, 0);
  launch_thread(&err, &threads, lookaside1_thread_writer, 0);
  join_all_threads(&err, &threads);
  sqlite3_enable_shared_cache(0);
  print_and_free_err(&err);
}

/*
** 2014 December 9
**
** 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.
**
*************************************************************************
**
**
*/


/*
** Thread 1. CREATE and DROP a table.
*/
static char *stress_thread_1(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */

  opendb(&err, &db, "test.db", 0);
  while( !timetostop(&err) ){
    sql_script(&err, &db, "CREATE TABLE IF NOT EXISTS t1(a PRIMARY KEY, b)");
    clear_error(&err, SQLITE_LOCKED);
    sql_script(&err, &db, "DROP TABLE IF EXISTS t1");
    clear_error(&err, SQLITE_LOCKED);
  }
  closedb(&err, &db);
  print_and_free_err(&err);
  return sqlite3_mprintf("ok");
}

/*
** Thread 2. Open and close database connections.
*/
static char *stress_thread_2(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
  while( !timetostop(&err) ){
    opendb(&err, &db, "test.db", 0);
    sql_script(&err, &db, "SELECT * FROM sqlite_master;");
    clear_error(&err, SQLITE_LOCKED);
    closedb(&err, &db);
  }
  print_and_free_err(&err);
  return sqlite3_mprintf("ok");
}

/*
** Thread 3. Attempt many small SELECT statements.
*/
static char *stress_thread_3(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */

  int i1 = 0;
  int i2 = 0;

  opendb(&err, &db, "test.db", 0);
  while( !timetostop(&err) ){
    sql_script(&err, &db, "SELECT * FROM t1 ORDER BY a;");
    i1++;
    if( err.rc ) i2++;
    clear_error(&err, SQLITE_LOCKED);
    clear_error(&err, SQLITE_ERROR);
  }
  closedb(&err, &db);
  print_and_free_err(&err);
  return sqlite3_mprintf("read t1 %d/%d attempts", i2, i1);
}

/*
** Thread 5. Attempt INSERT statements.
*/
static char *stress_thread_4(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
  int i1 = 0;
  int i2 = 0;
  int iArg = PTR2INT(pArg);

  opendb(&err, &db, "test.db", 0);
  while( !timetostop(&err) ){
    if( iArg ){
      closedb(&err, &db);
      opendb(&err, &db, "test.db", 0);
    }
    sql_script(&err, &db, 
        "WITH loop(i) AS (SELECT 1 UNION ALL SELECT i+1 FROM loop LIMIT 200) "
        "INSERT INTO t1 VALUES(randomblob(60), randomblob(60));"
    );
    i1++;
    if( err.rc ) i2++;
    clear_error(&err, SQLITE_LOCKED);
    clear_error(&err, SQLITE_ERROR);
  }
  closedb(&err, &db);
  print_and_free_err(&err);
  return sqlite3_mprintf("wrote t1 %d/%d attempts", i2, i1);
}

/*
** Thread 6. Attempt DELETE operations.
*/
static char *stress_thread_5(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
  int iArg = PTR2INT(pArg);

  int i1 = 0;
  int i2 = 0;

  opendb(&err, &db, "test.db", 0);
  while( !timetostop(&err) ){
    i64 i = (i1 % 4);
    if( iArg ){
      closedb(&err, &db);
      opendb(&err, &db, "test.db", 0);
    }
    execsql(&err, &db, "DELETE FROM t1 WHERE (rowid % 4)==:i", &i);
    i1++;
    if( err.rc ) i2++;
    clear_error(&err, SQLITE_LOCKED);
  }
  closedb(&err, &db);
  print_and_free_err(&err);
  return sqlite3_mprintf("deleted from t1 %d/%d attempts", i2, i1);
}


static void stress1(int nMs){
  Error err = {0};
  Threadset threads = {0};

  setstoptime(&err, nMs);
  sqlite3_enable_shared_cache(1);

  launch_thread(&err, &threads, stress_thread_1, 0);
  launch_thread(&err, &threads, stress_thread_1, 0);

  launch_thread(&err, &threads, stress_thread_2, 0);
  launch_thread(&err, &threads, stress_thread_2, 0);

  launch_thread(&err, &threads, stress_thread_3, 0);
  launch_thread(&err, &threads, stress_thread_3, 0);

  launch_thread(&err, &threads, stress_thread_4, 0);
  launch_thread(&err, &threads, stress_thread_4, 0);

  launch_thread(&err, &threads, stress_thread_5, 0);
  launch_thread(&err, &threads, stress_thread_5, (void*)1);

  join_all_threads(&err, &threads);
  sqlite3_enable_shared_cache(0);

  print_and_free_err(&err);
}

/**************************************************************************
***************************************************************************
** Start of test case "stress2"
*/



/*
** 1.  CREATE TABLE statements.
** 2.  DROP TABLE statements.
** 3.  Small SELECT statements.
** 4.  Big SELECT statements.
** 5.  Small INSERT statements.
** 6.  Big INSERT statements.
** 7.  Small UPDATE statements.
** 8.  Big UPDATE statements.
** 9.  Small DELETE statements.
** 10. Big DELETE statements.
** 11. VACUUM.
** 14. Integrity-check.
** 17. Switch the journal mode from delete to wal and back again.
** 19. Open and close database connections rapidly.
*/

#define STRESS2_TABCNT 5          /* count1 in SDS test */

#define STRESS2_COUNT2 200        /* count2 in SDS test */
#define STRESS2_COUNT3  57        /* count2 in SDS test */

static void stress2_workload1(Error *pErr, Sqlite *pDb, int i){
  int iTab = (i % (STRESS2_TABCNT-1)) + 1;
  sql_script_printf(pErr, pDb, 
      "CREATE TABLE IF NOT EXISTS t%d(x PRIMARY KEY, y, z);", iTab
  );
}

static void stress2_workload2(Error *pErr, Sqlite *pDb, int i){
  int iTab = (i % (STRESS2_TABCNT-1)) + 1;
  sql_script_printf(pErr, pDb, "DROP TABLE IF EXISTS t%d;", iTab);
}

static void stress2_workload3(Error *pErr, Sqlite *pDb, int i){
  sql_script(pErr, pDb, "SELECT * FROM t0 WHERE z = 'small'");
}

static void stress2_workload4(Error *pErr, Sqlite *pDb, int i){
  sql_script(pErr, pDb, "SELECT * FROM t0 WHERE z = 'big'");
}

static void stress2_workload5(Error *pErr, Sqlite *pDb, int i){
  sql_script(pErr, pDb,
      "INSERT INTO t0 VALUES(hex(random()), hex(randomblob(200)), 'small');"
  );
}

static void stress2_workload6(Error *pErr, Sqlite *pDb, int i){
  sql_script(pErr, pDb,
      "INSERT INTO t0 VALUES(hex(random()), hex(randomblob(57)), 'big');"
  );
}

static void stress2_workload7(Error *pErr, Sqlite *pDb, int i){
  sql_script_printf(pErr, pDb,
      "UPDATE t0 SET y = hex(randomblob(200)) "
      "WHERE x LIKE hex((%d %% 5)) AND z='small';"
      ,i
  );
}
static void stress2_workload8(Error *pErr, Sqlite *pDb, int i){
  sql_script_printf(pErr, pDb,
      "UPDATE t0 SET y = hex(randomblob(57)) "
      "WHERE x LIKE hex(%d %% 5) AND z='big';"
      ,i
  );
}

static void stress2_workload9(Error *pErr, Sqlite *pDb, int i){
  sql_script_printf(pErr, pDb,
      "DELETE FROM t0 WHERE x LIKE hex(%d %% 5) AND z='small';", i
  );
}
static void stress2_workload10(Error *pErr, Sqlite *pDb, int i){
  sql_script_printf(pErr, pDb,
      "DELETE FROM t0 WHERE x LIKE hex(%d %% 5) AND z='big';", i
  );
}

static void stress2_workload11(Error *pErr, Sqlite *pDb, int i){
  sql_script(pErr, pDb, "VACUUM");
}

static void stress2_workload14(Error *pErr, Sqlite *pDb, int i){
  sql_script(pErr, pDb, "PRAGMA integrity_check");
}

static void stress2_workload17(Error *pErr, Sqlite *pDb, int i){
  sql_script_printf(pErr, pDb, 
      "PRAGMA journal_mode = %q", (i%2) ? "delete" : "wal"
  );
}

static char *stress2_workload19(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
  const char *zDb = (const char*)pArg;
  while( !timetostop(&err) ){
    opendb(&err, &db, zDb, 0);
    sql_script(&err, &db, "SELECT * FROM sqlite_master;");
    clear_error(&err, SQLITE_LOCKED);
    closedb(&err, &db);
  }
  print_and_free_err(&err);
  return sqlite3_mprintf("ok");
}


typedef struct Stress2Ctx Stress2Ctx;
struct Stress2Ctx {
  const char *zDb;
  void (*xProc)(Error*, Sqlite*, int);
};

static char *stress2_thread_wrapper(int iTid, void *pArg){
  Stress2Ctx *pCtx = (Stress2Ctx*)pArg;
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
  int i1 = 0;
  int i2 = 0;

  while( !timetostop(&err) ){
    int cnt;
    opendb(&err, &db, pCtx->zDb, 0);
    for(cnt=0; err.rc==SQLITE_OK && cnt<STRESS2_TABCNT; cnt++){
      pCtx->xProc(&err, &db, i1);
      i2 += (err.rc==SQLITE_OK);
      clear_error(&err, SQLITE_LOCKED);
      i1++;
    }
    closedb(&err, &db);
  }

  print_and_free_err(&err);
  return sqlite3_mprintf("ok %d/%d", i2, i1);
}

static void stress2_launch_thread_loop(
  Error *pErr,                    /* IN/OUT: Error code */
  Threadset *pThreads,            /* Thread set */
  const char *zDb,                /* Database name */
  void (*x)(Error*,Sqlite*,int)   /* Run this until error or timeout */
){
  Stress2Ctx *pCtx = sqlite3_malloc(sizeof(Stress2Ctx));
  pCtx->zDb = zDb;
  pCtx->xProc = x;
  launch_thread(pErr, pThreads, stress2_thread_wrapper, (void*)pCtx);
}

static void stress2(int nMs){
  struct Stress2Task {
    void (*x)(Error*,Sqlite*,int);
  } aTask[] = {
    { stress2_workload1 },
    { stress2_workload2 },
    { stress2_workload3 },
    { stress2_workload4 },
    { stress2_workload5 },
    { stress2_workload6 },
    { stress2_workload7 },
    { stress2_workload8 },
    { stress2_workload9 },
    { stress2_workload10 },
    { stress2_workload11 },
    { stress2_workload14 },
    { stress2_workload17 },
  };
  const char *zDb = "test.db";

  int i;
  Error err = {0};
  Sqlite db = {0};
  Threadset threads = {0};

  /* To make sure the db file is empty before commencing */
  opendb(&err, &db, zDb, 1);
  sql_script(&err, &db, 
      "CREATE TABLE IF NOT EXISTS t0(x PRIMARY KEY, y, z);"
      "CREATE INDEX IF NOT EXISTS i0 ON t0(y);"
  );
  closedb(&err, &db);

  setstoptime(&err, nMs);
  sqlite3_enable_shared_cache(1);

  for(i=0; i<sizeof(aTask)/sizeof(aTask[0]); i++){
    stress2_launch_thread_loop(&err, &threads, zDb, aTask[i].x);
  }
  launch_thread(&err, &threads, stress2_workload19, (void*)zDb);
  launch_thread(&err, &threads, stress2_workload19, (void*)zDb);

  join_all_threads(&err, &threads);
  sqlite3_enable_shared_cache(0);
  print_and_free_err(&err);
}

/*
** 2014 December 9
**
** 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.
**
*************************************************************************
**
** This file contains multi-threaded tests that use shared-cache and 
** the VACUUM command.
**
** Tests:
**
**     vacuum1
**
*/


static char *vacuum1_thread_writer(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
  opendb(&err, &db, "test.db", 0);
  i64 i = 0;

  while( !timetostop(&err) ){
    i++;

    /* Insert lots of rows. Then delete some. */
    execsql(&err, &db, 
        "WITH loop(i) AS (SELECT 1 UNION ALL SELECT i+1 FROM loop WHERE i<100) "
        "INSERT INTO t1 SELECT randomblob(50), randomblob(2500) FROM loop"
    );

    /* Delete lots of rows */
    execsql(&err, &db, "DELETE FROM t1 WHERE rowid = :i", &i);
    clear_error(&err, SQLITE_LOCKED);

    /* Select the rows */
    execsql(&err, &db, "SELECT * FROM t1 ORDER BY x");
    clear_error(&err, SQLITE_LOCKED);
  }

  closedb(&err, &db);
  print_and_free_err(&err);
  return sqlite3_mprintf("ok");
}

static char *vacuum1_thread_vacuumer(int iTid, void *pArg){
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
  opendb(&err, &db, "test.db", 0);

  do{
    sql_script(&err, &db, "VACUUM");
    clear_error(&err, SQLITE_LOCKED);
  }while( !timetostop(&err) );

  closedb(&err, &db);
  print_and_free_err(&err);
  return sqlite3_mprintf("ok");
}

static void vacuum1(int nMs){
  Error err = {0};
  Sqlite db = {0};
  Threadset threads = {0};

  opendb(&err, &db, "test.db", 1);
  sql_script(&err, &db, 
     "CREATE TABLE t1(x PRIMARY KEY, y BLOB);"
     "CREATE INDEX i1 ON t1(y);"
  );
  closedb(&err, &db);

  setstoptime(&err, nMs);

  sqlite3_enable_shared_cache(1);
  launch_thread(&err, &threads, vacuum1_thread_writer, 0);
  launch_thread(&err, &threads, vacuum1_thread_writer, 0);
  launch_thread(&err, &threads, vacuum1_thread_writer, 0);
  launch_thread(&err, &threads, vacuum1_thread_vacuumer, 0);
  join_all_threads(&err, &threads);
  sqlite3_enable_shared_cache(0);

  print_and_free_err(&err);
}