Best block size

#1

Is there a way to find out how "full" a table is?

Jostein Bakke

#2

Compare its size and the size of its largest indices to the theoretical
size for the block size you are using. There are several threads on
block size at the pnews groups you might want to search for and a couple
of references you may want to check on Bertil's bug list.

Denn Santoro
President
Resource Development Associates
http://www.RDAWorldWide.Com
Offices in the United States and Germany
Providing solutions to health care, business, governments and
non-profits since 1982

#3

That was quick, Dennis!
"Compare its size" = the FILE size?
Jostein

"Dennis Santoro" <RDAPres (AT) NoRDASpamWorldWide (DOT) com> skrev i melding
news:44F08691.ED71A13B (AT) NoRDASpamWorldWide (DOT) com...

Quote:

Compare its size and the size of its largest indices to the theoretical
size for the block size you are using. There are several threads on
block size at the pnews groups you might want to search for and a couple
of references you may want to check on Bertil's bug list.

Denn Santoro
President
Resource Development Associates
http://www.RDAWorldWide.Com
Offices in the United States and Germany
Providing solutions to health care, business, governments and
non-profits since 1982

#4

yup, file size.

Denn Santoro
President
Resource Development Associates
http://www.RDAWorldWide.Com
Offices in the United States and Germany
Providing solutions to health care, business, governments and non-profits
since 1982

#5

So - if my 16-block-size table (of some 800000 records) is about 500 mb, it
is ca 50% filled up?
BTW:
1) Is there any disadvantages with using a larger block size?
2) Can you tell what block size a table has (if you have forgotten)?
Jostein

"Dennis Santoro" <RDAPres (AT) NoRDASpamWorldWide (DOT) com> skrev i melding
news:44F131A9.78C7C4D7 (AT) NoRDASpamWorldWide (DOT) com...

Quote:

yup, file size.

Denn Santoro
President
Resource Development Associates
http://www.RDAWorldWide.Com
Offices in the United States and Germany
Providing solutions to health care, business, governments and non-profits
since 1982

#6

Quote:

So - if my 16-block-size table is about 500 mb, it is ca 50% filled up?

correct

Quote:

1) Is there any disadvantages with using a larger block size?

no

Quote:

2) Can you tell what block size a table has (if you have forgotten)?

the repair tool screen includes block size

--
Steven Green - Waldorf Maryland USA

Diamond Software Group
http://www.diamondsg.com/main.htm
Paradox Support & Sales - Corel CTech Paradox

Diamond Sports Gems
http://www.diamondsg.com/gemsmain.htm
Sports Memorabilia and Trading Cards

#7

Thanks Dennis and Steven.
Have a nice sunday!
Jostein

"Steven Green" <greens (AT) diamondsg (DOT) com> skrev i melding
news:44f17c3c$1 (AT) pnews (DOT) thedbcommunity.com...

Quote:

So - if my 16-block-size table is about 500 mb, it is ca 50% filled up?

correct

1) Is there any disadvantages with using a larger block size?

no

2) Can you tell what block size a table has (if you have forgotten)?

the repair tool screen includes block size

--
Steven Green - Waldorf Maryland USA

Diamond Software Group
http://www.diamondsg.com/main.htm
Paradox Support & Sales - Corel CTech Paradox

Diamond Sports Gems
http://www.diamondsg.com/gemsmain.htm
Sports Memorabilia and Trading Cards

#8

But you also have to look at the size of the indices too since if they are
around half the max size you may get into trouble. Also there are some
issues, as I mentioned, with some block sizes. Some are known such as the
compound index issues you can find in Bertil's bug list and others are not
understood such as the one discussed in a thread I started on the Pnews
server back in may in the Paradox-development group.

Denn Santoro
President
Resource Development Associates
http://www.RDAWorldWide.Com
Offices in the United States and Germany
Providing solutions to health care, business, governments and non-profits
since 1982

#9

"Steven Green" <greens (AT) diamondsg (DOT) com> wrote:

Quote:

1) Is there any disadvantages with using a larger block size?

no

Steven,

I'd have to disagree with you. On a network, whenever you open a table,
you will get 8 blocks of data. This seems to be for speeding up sequential
processing. But, if you are doing random reads via qLocate() then you are
forcing a lot of wasted network traffic.

I thought the same as you until my network users started screaming. After
using the Ethereal Network Monitor (a great product, btw), I found all the
wasted network traffic. My tables had 4kb blocks and I switched them to
16kb blocks, and the system couldn't keep up with the network traffic.

Thanks,
Jim Moseley

#10

interesting observation.. thanks for sharing it..

--
Steven Green - Waldorf Maryland USA

Diamond Software Group
http://www.diamondsg.com/main.htm
Paradox Support & Sales - Corel CTech Paradox

Diamond Sports Gems
http://www.diamondsg.com/gemsmain.htm
Sports Memorabilia and Trading Cards

"Jim Moseley" <jmose (AT) mapson (DOT) attglobal.net> wrote

Quote:

"Steven Green" <greens (AT) diamondsg (DOT) com> wrote:
1) Is there any disadvantages with using a larger block size?

no

Steven,

I'd have to disagree with you. On a network, whenever you open a table,
you will get 8 blocks of data. This seems to be for speeding up
sequential
processing. But, if you are doing random reads via qLocate() then you are
forcing a lot of wasted network traffic.

I thought the same as you until my network users started screaming. After
using the Ethereal Network Monitor (a great product, btw), I found all the
wasted network traffic. My tables had 4kb blocks and I switched them to
16kb blocks, and the system couldn't keep up with the network traffic.

Thanks,
Jim Moseley