"Igor Tandetnik" <[EMAIL PROTECTED]> wrote:
> [EMAIL PROTECTED] wrote:
> > Are there some
> > special flags that SQLite could pass to CreateFileW() to
> > trick windows into doing a better job of caching temp
> > files?
>
> FILE_ATTRIBUTE_TEMPORARY
> A file is being used for temporary storage. File systems avoid writing
> data back to mass storage if sufficient cache memory is available,
> because an application deletes a temporary file after a handle is
> closed. In that case, the system can entirely avoid writing the data.
> Otherwise, the data is written after the handle is closed.
>
I went to implement this suggestion and quickly discovered
that SQLite already uses the FILE_ATTRIBUTE_TEMPORARY flag
on TEMP tables. Or at least I think it does. Can somebody
with a symbolic debugger that runs on windows please confirm
that the marked line of code in below (found in os_win.c) gets
executed when using TEMP tables:
int sqlite3WinOpenExclusive(const char *zFilename, OsFile **pId, int delFlag){
winFile f;
HANDLE h;
DWORD fileflags;
void *zConverted = convertUtf8Filename(zFilename);
if( zConverted==0 ){
return SQLITE_NOMEM;
}
assert( *pId == 0 );
fileflags = FILE_FLAG_RANDOM_ACCESS;
#if !OS_WINCE
if( delFlag ){
/****** The following line should run when opening a TEMP table ******/
fileflags |= FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_DELETE_ON_CLOSE;
}
#endif
--
D. Richard Hipp <[EMAIL PROTECTED]>
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