proutil database_name -C idxbuild all -TB ?? -TM ??

T

triqt

New Member
Hi,

Please explain the -TB and -TM from the proutil command. I looked in the admin guide, but it does not talk much about the parameters. Thanks


proutil database_name -C idxbuild all -TB ?? -TM ??

Use the Speed Sort (-​
TB), Merge Number (-TM), and Blocks in Database Buffers (-B)
startup parameters to improve index rebuild performance. For more information on these​

parameters, see the Progress Startup Command and Parameter Reference.
 
And a small -B , say 256 or 512 is said to be a good value to use with idxbuild. (I have never done serious test with his though, I just use the small values).

Casper.
 
I find that the ideal -B for an index rebuild is indeed "small" but when it comes to -B my definition of "small" is more like 20000, I don't have a word to describe 256 ;) (If you go too high performance will start to degrade).

The point where things get funky seems to vary from release to release, by db block size and is also probably related to the data itself. So if I haven't got time to test it I'll usually use something like 10000 or 20000.
 
I don't have a word to describe 256 ;)
Click to expand...
well, we agree on small :-)
I just used this value from a post from George@PEG some 2 years ago.

BTW apart from big databases (which probably are small to you ;-)) we also administer databases where a -B (in the startup parameters) of 20000 is way to big :-)

Casper.
 
to calculate the normal -B parameter pass a
proutil [dbname] -C dbanalys > analys.txt and
go to the last line ...

read
1722 total blocks found in the database.

the block is the block size of file system:
stat -f /
or windows chkdsk c:

4k = 4096 ->

The magic formule is:

-B = 5-10% of total blocks

-B = 1722 / 20

-B = 86
 
idxbuild is a off-line operation ... use all the RAM you have.
Click to expand...

That is not correct, high values of -B tend to slow down the idxbuild proces.

The magic formule is:

-B = 5-10% of total blocks
Click to expand...

This can be used as a starting point, only with good measurment you can find the optimum value for -B which can be lower then 5% and higher then 10% depending on te nature of the data in the database and the way it is accessed.

Casper.
 
rstanciu said:
to calculate the normal -B parameter
Click to expand...

There is no simple rule for calculating -B. If there were then there would be no need for a parameter.

There are some starting points for guessing (this is one) but it is only a guess and not a very good one at that.
 
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