Limits of Clipper DBF's and NTX's 
Author Message
 Limits of Clipper DBF's and NTX's

Does someone knows the size limits of .DBF and .NTX ?
I'm working with lots of data on a Novell Server (4.11) with ADS (5.5) on it
and I don't know how far can my files grow ...
I use Blinker 5.10 and Clipper 5.2e.

Thanks,

Luiz - Sao Paulo - Brazil



Mon, 25 Mar 2002 03:00:00 GMT  
 Limits of Clipper DBF's and NTX's


Quote:
> Does someone knows the size limits of .DBF and .NTX ?
> I'm working with lots of data on a Novell Server (4.11) with ADS (5.5) on
it
> and I don't know how far can my files grow ...
> I use Blinker 5.10 and Clipper 5.2e.

At the moment, one of my customers has a three million records table. It is
growing fast, with 12 users permanently updating it.
The operating systems involved are: Novel Netware 3.12, DOS 6.22, Windows
95, Windows 98.
Tables are updated by programs built with Clipper 5.2e and Codebase 6.3/VB
6.
The network runs at 100Mbps.
So far, no performance penalty has been noticed.
Anyway, I had one problem when I did load tests about a year ago. As this
particular table was smaller then, I merged it with several copies of
itself. At about 2 million records, reindexing operations with Clipper 5.2e
often failed. Apparently, as the merging of the table created several copies
of each record (and therefore identical key data), Clipper seemed to go nuts
with huge tables with non-unique keys.

Helder M. Vieira



Mon, 25 Mar 2002 03:00:00 GMT  
 Limits of Clipper DBF's and NTX's


Quote:


> > Does someone knows the size limits of .DBF and .NTX ?
> > I'm working with lots of data on a Novell Server (4.11) with ADS (5.5)
on
> it
> > and I don't know how far can my files grow ...
> > I use Blinker 5.10 and Clipper 5.2e.

> The operating systems involved are: Novel Netware 3.12, DOS 6.22, Windows
> 95, Windows 98.
> Tables are updated by programs built with Clipper 5.2e and Codebase 6.3/VB
> 6.
> itself. At about 2 million records, reindexing operations with Clipper
5.2e
> often failed. Apparently, as the merging of the table created several
copies
> of each record (and therefore identical key data), Clipper seemed to go
nuts
> with huge tables with non-unique keys.

I can agree with you on this one.  I too have quite large DBF tables (I'll
guess at a 500,000 rows) with non-unique indices ({*filter*}, {*filter*}) - and I
often get corruption errors especially when deleting records.  This is on
novell 4.10 with Clipper 5.3b.  I don't use ADS - I am still stuck with
CA-Tools III using the Transaction Tracking features in conjunction with
Novell's TTS.

--

Pietermaritzburg, South Africa



Tue, 26 Mar 2002 03:00:00 GMT  
 Limits of Clipper DBF's and NTX's

Quote:





> > > Does someone knows the size limits of .DBF and .NTX ?
> > > I'm working with lots of data on a Novell Server (4.11) with ADS (5.5)
> on
> > it
> > > and I don't know how far can my files grow ...
> > > I use Blinker 5.10 and Clipper 5.2e.

> > The operating systems involved are: Novel Netware 3.12, DOS 6.22, Windows
> > 95, Windows 98.
> > Tables are updated by programs built with Clipper 5.2e and Codebase 6.3/VB
> > 6.
> > itself. At about 2 million records, reindexing operations with Clipper
> 5.2e
> > often failed. Apparently, as the merging of the table created several
> copies
> > of each record (and therefore identical key data), Clipper seemed to go
> nuts
> > with huge tables with non-unique keys.

> I can agree with you on this one.  I too have quite large DBF tables (I'll
> guess at a 500,000 rows) with non-unique indices ({*filter*}, {*filter*}) - and I
> often get corruption errors especially when deleting records.  This is on
> novell 4.10 with Clipper 5.3b.  I don't use ADS - I am still stuck with
> CA-Tools III using the Transaction Tracking features in conjunction with
> Novell's TTS.

> --

> Pietermaritzburg, South Africa

According to our experience problem with index size is related not to
the number
of rows, but the size of NTX file. When the size of NTX file goes up to
64 MB,
index becomes corrupted.
We use Blinker 5.10 and Netlib 6.5 and application in extended mode.
Program
linked in real mode create index files with size over 64 MB without any
problems.

Arek Majkowski



Tue, 26 Mar 2002 03:00:00 GMT  
 Limits of Clipper DBF's and NTX's


writes:
:>
:>At the moment, one of my customers has a three million
records table. It is
:>growing fast, with 12 users permanently updating it.
:>The operating systems involved are: Novel Netware 3.12,
DOS 6.22, Windows
:>95, Windows 98.
:>Tables are updated by programs built with Clipper 5.2e and
Codebase 6.3/VB
:>6.
:>The network runs at 100Mbps.
:>So far, no performance penalty has been noticed.
:>Anyway, I had one problem when I did load tests about a
year ago. As this
:>particular table was smaller then, I merged it with
several copies of
:>itself. At about 2 million records, reindexing operations
with Clipper 5.2e
:>often failed. Apparently, as the merging of the table
created several copies
:>of each record (and therefore identical key data), Clipper
seemed to go nuts
:>with huge tables with non-unique keys.
:>
:>Helder M. Vieira
:>
:>
:>

Did you find a cure for the problem with the indexing of >2
mil records?  Been looking for that fix (hanging up or
crashing while indexing LARGE files) for some time.

Gary Crossno



Tue, 26 Mar 2002 03:00:00 GMT  
 Limits of Clipper DBF's and NTX's

Quote:
> Did you find a cure for the problem with the indexing of >2
> mil records?  Been looking for that fix (hanging up or
> crashing while indexing LARGE files) for some time.

No. The crashes appeared only when I tested with non-unique keys.
The situation seemed to improve only slightly when more memory was
available.
Anyway, I don't have problems with the 3 million records table, but all the
keys are unique, and the widest has a length of 14 characters.

Helder M. Vieira



Tue, 26 Mar 2002 03:00:00 GMT  
 Limits of Clipper DBF's and NTX's


Quote:
>Did you find a cure for the problem with the indexing of >2
>mil records?  Been looking for that fix (hanging up or
>crashing while indexing LARGE files) for some time.

ADS has no problems with psychotically large indexes.

I've had 500M indexes that worked just fine on my ADS server.

.DBF files have a 2M record limit built into the .DBF format.

ADS can break that barrier as well, but not with Clipper, AFAIK.

--

        Oasis WWW  http://www.the-oasis.net
         FTP Site  ftp://ftp.iag.net/pub/clipper
      Clipper FAQ  http://www.the-oasis.net/clipper.html
  Harbour Project  http://www.Harbour-Project.org

      The game will never end. For the game is
        life itself, and life is Who We Are.



Tue, 26 Mar 2002 03:00:00 GMT  
 Limits of Clipper DBF's and NTX's

Quote:

>.DBF files have a 2M record limit built into the .DBF format.

Phil I am confused. Is 2GB realy the limmiet?

NTXLOCK2.OBJ
This driver will change the locking scheme for your databases so that
you can have more records in a database file.  By default, CA-Clipper
will lock records at 1 billion + the record number.  When databases
get large enough it can bump into this locking area and cause
problems.  With NTXLOCK2.OBJ, the locking offset is moved to 4
billion.  Please note, though, that using NTXLOCK2.OBJ will create
indexes that are not compatible with older versions of CA-Clipper.

Steven



Wed, 27 Mar 2002 03:00:00 GMT  
 Limits of Clipper DBF's and NTX's

Quote:


>>.DBF files have a 2M record limit built into the .DBF format.

>Phil I am confused. Is 2GB realy the limmiet?

Dohh!. Of course. I have LOTS of files running over 500M.

I meant 2G, not 2M.

Quote:
>NTXLOCK2.OBJ
>This driver will change the locking scheme for your databases so that
>you can have more records in a database file.  By default, CA-Clipper
>will lock records at 1 billion + the record number.  When databases
>get large enough it can bump into this locking area and cause
>problems.  With NTXLOCK2.OBJ, the locking offset is moved to 4
>billion.  Please note, though, that using NTXLOCK2.OBJ will create
>indexes that are not compatible with older versions of CA-Clipper.

But, that is to align the locking points with other systems. It
doesn't allow you to put more records in the table than 2G size.

--

        Oasis WWW  http://www.the-oasis.net
         FTP Site  ftp://ftp.iag.net/pub/clipper
      Clipper FAQ  http://www.the-oasis.net/clipper.html
  Harbour Project  http://www.Harbour-Project.org

      The game will never end. For the game is
        life itself, and life is Who We Are.



Wed, 27 Mar 2002 03:00:00 GMT  
 
 [ 9 post ] 

 Relevant Pages 

1. clipper newbie-how to insert into a dbf using several NTX's

2. Discovering corruption dbf's/ntx's

3. dbf limits in sum '87 and 5.2e

4. Clipper NTX's, file size differences....

5. ODBC Driver for Clipper DBF/NTX

6. ODBC for Clipper .dbf/.ntx

7. Clipper DBF or NTX corruption?

8. ODBC DRIVER FOR CLIPPER DBF/DBT THAT SUPPORTS NTX INDEX FILES

9. Delphi and NTX (Clipper DBF) - Apollo or Halcyon?

10. Clipper v5.x DBU utility with S87 DBF'S

11. dbf/ntx to dbf/idx converter

12. Driver to connect to clipper dbf's via Java

 

 
Powered by phpBB® Forum Software