SQLite

    if( 0==(dc&(SQLITE_IOCAP_ATOMIC|(szPage>>8)) || nSector>szPage) ){
      return 0;
    }
  }

  return JOURNAL_HDR_SZ(pPager) + JOURNAL_PG_SZ(pPager);
}
#else
# define jrnlBufferSize(x) 0
#endif

/*
** If SQLITE_CHECK_PAGES is defined then we do some sanity checking
** on the cache using a hash function.  This is used for testing
** and debugging only.
*/

    }
  
    /* Open the journal file if it is not already open. */
    if( !isOpen(pPager->jfd) ){
      if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY ){
        sqlite3MemJournalOpen(pPager->jfd);
      }else{

        int flags = SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE;
        int nSpill;

        if( pPager->tempFile ){
          flags |= (SQLITE_OPEN_DELETEONCLOSE|SQLITE_OPEN_TEMP_JOURNAL);
          nSpill = sqlite3Config.nStmtSpill;
        }else{
          flags |= SQLITE_OPEN_MAIN_JOURNAL;
          nSpill = jrnlBufferSize(pPager);
        }
          
        /* Verify that the database still has the same name as it did when
        ** it was originally opened. */
        rc = databaseIsUnmoved(pPager);
        if( rc==SQLITE_OK ){

          rc = sqlite3JournalOpen (
              pVfs, pPager->zJournal, pPager->jfd, flags, nSpill
          );



        }
      }
      assert( rc!=SQLITE_OK || isOpen(pPager->jfd) );
    }
  
  
    /* Write the first journal header to the journal file and open 

  *pnVal += pPager->aStat[eStat - SQLITE_DBSTATUS_CACHE_HIT];
  if( reset ){
    pPager->aStat[eStat - SQLITE_DBSTATUS_CACHE_HIT] = 0;
  }
}

/*
** Return true if this is an in-memory or temp-file backed pager.
*/
int sqlite3PagerIsMemdb(Pager *pPager){
  return pPager->tempFile;
}

/*
** Check that there are at least nSavepoint savepoints open. If there are
** currently less than nSavepoints open, then open one or more savepoints
** to make up the difference. If the number of savepoints is already
** equal to nSavepoint, then this function is a no-op.

  Tcl_SetResult(interp, zBuf, TCL_VOLATILE);
  return TCL_OK;
}

/*
** Usage:   btree_ismemdb ID
**
** Return true if the B-Tree is currently stored entirely in memory.
*/
static int btree_ismemdb(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  const char **argv      /* Text of each argument */
){
  Btree *pBt;
  int res;
  sqlite3_file *pFile;

  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  pBt = sqlite3TestTextToPtr(argv[1]);
  sqlite3_mutex_enter(pBt->db->mutex);
  sqlite3BtreeEnter(pBt);
  pFile = sqlite3PagerFile(sqlite3BtreePager(pBt));
  res = (pFile->pMethods==0);
  sqlite3BtreeLeave(pBt);
  sqlite3_mutex_leave(pBt->db->mutex);
  Tcl_SetObjResult(interp, Tcl_NewBooleanObj(res));
  return SQLITE_OK;
}

/*

} {-450}
} ; # ifcapable schema_version

# Check to see if TEMP_STORE is memory or disk.  Return strings
# "memory" or "disk" as appropriate.
#
proc check_temp_store {} {
  db eval {
    PRAGMA temp.cache_size = 1;
    CREATE TEMP TABLE IF NOT EXISTS a(b);
    DELETE FROM a;
    INSERT INTO a VALUES(randomblob(1000));
    INSERT INTO a SELECT * FROM a;
    INSERT INTO a SELECT * FROM a;
    INSERT INTO a SELECT * FROM a;
    INSERT INTO a SELECT * FROM a;
    INSERT INTO a SELECT * FROM a;
    INSERT INTO a SELECT * FROM a;
    INSERT INTO a SELECT * FROM a;
    INSERT INTO a SELECT * FROM a;
  }
  db eval {PRAGMA database_list} {
    if {$name=="temp"} {
      set bt [btree_from_db db 1]
      if {[btree_ismemdb $bt]} {
        return "memory"
      }
      return "disk"

  CREATE TEMP TABLE t2(a, b);
  CREATE INDEX i2 ON t2(a, b);
  WITH x(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<500 )
  INSERT INTO t2 SELECT randomblob(100), randomblob(100) FROM x;

  SELECT count(*) FROM t2;
  SELECT count(*) FROM t1;
} {500 10}

do_test 4.1.4 {
  set n [db one { PRAGMA temp.page_count }]
  expr ($n >280 && $n < 300) 
} 1

do_execsql_test 4.1.4 { PRAGMA temp.integrity_check } {ok}

#-------------------------------------------------------------------------
#
reset_db
do_execsql_test 5.1.1 {
  PRAGMA main.cache_size = 10;
  PRAGMA temp.cache_size = 10;

  CREATE TEMP TABLE t2(a, b);
  CREATE INDEX i2 ON t2(a, b);
  WITH x(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<500 )
  INSERT INTO t2 SELECT randomblob(100), randomblob(100) FROM x;

  CREATE TEMP TABLE t1(a, b);
  CREATE INDEX i1 ON t1(a, b);
  INSERT INTO t1 VALUES(1, 2);
}

do_test 5.1.2 {
  set n [db one { PRAGMA temp.page_count }]
  expr ($n > 280 && $n < 290)
} {1}

do_execsql_test 5.1.3 {
  BEGIN;
    UPDATE t1 SET a=2;
    UPDATE t2 SET a=randomblob(100);
    SELECT count(*) FROM t1;
  ROLLBACK;
} {1}

do_execsql_test 5.1.4 {
  UPDATE t2 SET a=randomblob(100);

  SELECT * FROM t1;
} {1 2}

do_execsql_test 5.1.5 { PRAGMA temp.integrity_check } {ok}

#-------------------------------------------------------------------------
# Test this:
#
#   1. Page is DIRTY at the start of a transaction.
#   2. Page is written out as part of the transaction.
#   3. Page is then read back in.

  ROLLBACK;                          -- step 4

  SELECT count(*) FROM t2;
  SELECT * FROM t1;
} {two 500 two}

#-------------------------------------------------------------------------
#
reset_db
sqlite3 db ""
do_execsql_test 7.1 {
  PRAGMA auto_vacuum=INCREMENTAL;
  CREATE TABLE t1(x);
  INSERT INTO t1 VALUES(zeroblob(900));
  INSERT INTO t1 VALUES(zeroblob(900));
  INSERT INTO t1 SELECT x FROM t1;
  INSERT INTO t1 SELECT x FROM t1;
  INSERT INTO t1 SELECT x FROM t1;
  INSERT INTO t1 SELECT x FROM t1;
  BEGIN;
  DELETE FROM t1 WHERE rowid%2;
  PRAGMA incremental_vacuum(4);
  ROLLBACK;
  PRAGMA integrity_check;
} {ok}

#-------------------------------------------------------------------------
# Try changing the page size using a backup operation when pages are
# stored in main-memory only.
#
reset_db
do_execsql_test 8.1 {
  CREATE TABLE t2(a, b);
  CREATE INDEX i2 ON t2(a, b);
  WITH x(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<20 )
  INSERT INTO t2 SELECT randomblob(100), randomblob(100) FROM x;
  PRAGMA page_count;
} {13}

do_test 8.2 {
  sqlite3 tmp ""
  execsql {
    PRAGMA page_size = 8192;
    CREATE TABLE t1(a, b);
    CREATE INDEX i1 ON t1(a, b);
    WITH x(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<100 )
    INSERT INTO t1 SELECT randomblob(100), randomblob(100) FROM x;
    PRAGMA page_count;
  } tmp
} {10}

do_test 8.3 {
  sqlite3_backup B tmp main db main
  B step 5
  B finish
} {SQLITE_READONLY}

do_test 8.4 {
  execsql {
    SELECT count(*) FROM t1;
    PRAGMA integrity_check;
    PRAGMA page_size;
  } tmp
} {100 ok 8192}

do_test 8.5 { 
  tmp eval { UPDATE t1 SET a=randomblob(100) }
} {}

do_test 8.6 {
  sqlite3_backup B tmp main db main
  B step 1000
  B finish
} {SQLITE_READONLY}

tmp close

finish_test