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Hi,
=20
Can someone please tell me what the size is when I set it to 1000? Is
it one meg?
=20
Thanks.
=20
Peter
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Loo, Peter # PHX wrote:
> Hi,
>=20
> Can someone please tell me what the size is when I set it to 1000? Is
> it one meg?
It's $your_query_row_size * 1000. It's not a byte size, it's a number
of rows.
Regards,
Philip
Loo, Peter # PHX [mailto:Peter.Loo@source.wolterskluwer.com] wrote:
> Sent: Thursday, August 31, 2006 5:17 PM
> To: DBI-Users
> Subject: $dbh->{RowCacheSize} = 1000
>
> Hi,
>
> Can someone please tell me what the size is when I set it to 1000? Is
> it one meg?
>
perldoc DBI:
"RowCacheSize" (integer)
A hint to the driver indicating the size of the local
row cache that the application would like the driver
to use for future "SELECT" statements. If a row cache
is not implemented, then setting "RowCacheSize" is
ignored and getting the value returns "undef".
Some "RowCacheSize" values have special meaning, as
follows:
0 - Automatically determine a reasonable cache size for each SELECT
1 - Disable the local row cache
>1 - Cache this many rows
<0 - Cache as many rows that will fit into this much memory for each
SELECT.
Note that large cache sizes may require a very large
amount of memory (cached rows * maximum size of row).
Also, a large cache will cause a longer delay not only
for the first fetch, but also whenever the cache needs
refilling.
See also the "RowsInCache" statement handle attribute.
Hi All,
What would you recommend I set this option to if I am sending all the
SELECTed rows to a named pipe?
=20
Peter
-----Original Message-----
From: Ronald J Kimball [mailto:rjk-dbi@focalex.com]=20
Sent: Thursday, August 31, 2006 2:23 PM
To: Loo, Peter # PHX; DBI-Users
Subject: RE: $dbh->{RowCacheSize} =3D 1000
Loo, Peter # PHX [mailto:Peter.Loo@source.wolterskluwer.com] wrote:
> Sent: Thursday, August 31, 2006 5:17 PM
> To: DBI-Users
> Subject: $dbh->{RowCacheSize} =3D 1000
>=20
> Hi,
>=20
> Can someone please tell me what the size is when I set it to 1000? Is
> it one meg?
>=20
perldoc DBI:
"RowCacheSize" (integer)
A hint to the driver indicating the size of the local
row cache that the application would like the driver
to use for future "SELECT" statements. If a row cache
is not implemented, then setting "RowCacheSize" is
ignored and getting the value returns "undef".
Some "RowCacheSize" values have special meaning, as
follows:
0 - Automatically determine a reasonable cache size for each
SELECT
1 - Disable the local row cache
>1 - Cache this many rows
<0 - Cache as many rows that will fit into this much memory for
each
SELECT.
Note that large cache sizes may require a very large
amount of memory (cached rows * maximum size of row).
Also, a large cache will cause a longer delay not only
for the first fetch, but also whenever the cache needs
refilling.
See also the "RowsInCache" statement handle attribute.
This E-mail message is for the sole use of the intended recipient(s) and
may contain confidential and privileged information. Any unauthorized
review, use, disclosure or distribution is prohibited. If you are not
the intended recipient, please contact the sender by reply E-mail, and
destroy all copies of the original message.
Loo, Peter # PHX wrote:
>
> "RowCacheSize" (integer)
>=20
> What would you recommend I set this option to if I am sending all the
> SELECTed rows to a named pipe?
I'd recommend you leave it alone, unless your database roundtrips are
really expensive. And if they are, the only thing that can tell you
what the best value would be is to benchmark different settings.
It will only help if the program on the other end of the named pipe can
accept data faster than you can send it.
Philip
The reason I asked the question is that the Pro*C program appears to be
writing the output to a file faster than my Perl program can write to
the named pipe. The other end of the named pipe is a native database
utility similar to the sqlldr (nzload). I don't know where the bottle
neck is so I might have to break up the program into to separate parts.
Have Perl dump the table to a file then feed the file using nzload and
calculate the total time for each step.
=20
Peter
-----Original Message-----
From: Garrett, Philip (MAN-Corporate)
[mailto:Philip.Garrett@manheim.com]=20
Sent: Thursday, August 31, 2006 2:44 PM
To: DBI-Users
Subject: RE: $dbh->{RowCacheSize} =3D 1000
Loo, Peter # PHX wrote:
>
> "RowCacheSize" (integer)
>=20
> What would you recommend I set this option to if I am sending all the=20
> SELECTed rows to a named pipe?
I'd recommend you leave it alone, unless your database roundtrips are
really expensive. And if they are, the only thing that can tell you
what the best value would be is to benchmark different settings.
It will only help if the program on the other end of the named pipe can
accept data faster than you can send it.
Philip
This E-mail message is for the sole use of the intended recipient(s) and
may contain confidential and privileged information. Any unauthorized
review, use, disclosure or distribution is prohibited. If you are not
the intended recipient, please contact the sender by reply E-mail, and
destroy all copies of the original message.
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I would expect a C program to be able to write to a file faster than any =
database loader could load data.
________________________________
From: Loo, Peter # PHX [mailto:Peter.Loo@source.wolterskluwer.com]
Sent: Thu 8/31/2006 5:49 PM
To: Garrett, Philip (MAN-Corporate); DBI-Users
Subject: RE: $dbh->{RowCacheSize} =3D 1000
The reason I asked the question is that the Pro*C program appears to be
writing the output to a file faster than my Perl program can write to
the named pipe. The other end of the named pipe is a native database
utility similar to the sqlldr (nzload). I don't know where the bottle
neck is so I might have to break up the program into to separate parts.
Have Perl dump the table to a file then feed the file using nzload and
calculate the total time for each step.
Peter
-----Original Message-----
From: Garrett, Philip (MAN-Corporate)
[mailto:Philip.Garrett@manheim.com]
Sent: Thursday, August 31, 2006 2:44 PM
To: DBI-Users
Subject: RE: $dbh->{RowCacheSize} =3D 1000
Loo, Peter # PHX wrote:
>
> "RowCacheSize" (integer)
>
> What would you recommend I set this option to if I am sending all the
> SELECTed rows to a named pipe?
I'd recommend you leave it alone, unless your database roundtrips are
really expensive. And if they are, the only thing that can tell you
what the best value would be is to benchmark different settings.
It will only help if the program on the other end of the named pipe can
accept data faster than you can send it.
Philip
This E-mail message is for the sole use of the intended recipient(s) and
may contain confidential and privileged information. Any unauthorized
review, use, disclosure or distribution is prohibited. If you are not
the intended recipient, please contact the sender by reply E-mail, and
destroy all copies of the original message.
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