I'am having huge performance problems using a application on win32 which uses alot of .DBF files.
The app uses *alot* of small file reads, varying between 20-512 bytes per read. On Windows there is something, only just learned this, called fastio. This fastio acts like a cache because it reads-ahead 4096-bytes even if you want to have 1 single byte. Ok, that's all nice _but_ after searching and digging a couple of hours though the file-IO calls on the win32 side with filemon, I found out some differences.
Please let me show the difference:
[Server one: Linux - superb fast, no problems]
FASTIO_QUERY_STANDARD_INFO Z:\pv8\8.1f\ADRESSEN.PV FAILURE
IRP_MJ_QUERY_INFORMATION Z:\pv8\8.1f\ADRESSEN.PV SUCCESS FileStandardInformation
IRP_MJ_READ Z:\pv8\8.1f\ADRESSEN.PV SUCCESS Offset: 0 Length: 16384
IRP_MJ_READ* Z:\pv8\8.1f\ADRESSEN.PV SUCCESS Offset: 0 Length: 16384
FASTIO_CHECK_IF_POSSIBLE Z:\pv8\8.1f\ADRESSEN.PV SUCCESS Read: Offset: 16384 Length: 16384
IRP_MJ_READ* Z:\pv8\8.1f\ADRESSEN.PV SUCCESS Offset: 16384 Length: 16384
FASTIO_READ Z:\pv8\8.1f\ADRESSEN.PV SUCCESS Offset: 16384 Length: 16384
FASTIO_CHECK_IF_POSSIBLE Z:\pv8\8.1f\ADRESSEN.PV SUCCESS Read: Offset: 32768 Length: 16384
IRP_MJ_READ* Z:\pv8\8.1f\ADRESSEN.PV SUCCESS Offset: 32768 Length: 16384
FASTIO_READ Z:\pv8\8.1f\ADRESSEN.PV SUCCESS Offset: 32768 Length: 16384
and so on....
[Server two: SunOS - very slow]
FASTIO_QUERY_STANDARD_INFO V:\PerfectView\8.1f\Relbeh\ADRESSEN.PV FAILURE
IRP_MJ_QUERY_INFORMATION V:\PerfectView\8.1f\Relbeh\ADRESSEN.PV SUCCESS FileStandardInformation
IRP_MJ_READ V:\PerfectView\8.1f\Relbeh\ADRESSEN.PV SUCCESS Offset: 0 Length: 16384
IRP_MJ_READ V:\PerfectView\8.1f\Relbeh\ADRESSEN.PV SUCCESS Offset: 16384 Length: 16384
and so on...
Notice the difference here, the reading on the sun doesnt even try to use the other systemcall FASTIO_READ.
Note: Nothing changed in the app, only the location of the database files.
My question about these matters, what can I do about it? Thanks for any help on this.
Best regards, Leroy
Note: It's a relation management program called PerfectView 8.
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