473,326 Members | 2,255 Online
Bytes | Software Development & Data Engineering Community
Post Job

Home Posts Topics Members FAQ

Join Bytes to post your question to a community of 473,326 software developers and data experts.

Is it bad to see "High water mark for database heap = 4291373408" when the server has 4G memory?

When I did db2batch to benchmark a query, it performance details came
back with this reading ...

"High water mark for database heap = 4291373408"

Does this mean it would have caused memory thrashing at the server?
Did I over-allocate resources.

We just increased BuffPage to 16384 from its default of 1000. Pagesize
of the bufferpool was of course set to -1 so it would use the DBM cfg
parameter. But that is just 16MB of memory. Not even 10% of all the
total 4G memory.

Thanks in advance.

Bill
Nov 12 '05 #1
3 3398
After running your db2batch; execute the following command:
get snapshot for db on database_name

Check the database heap high water mark and see if it matches what you
see from db2batch. Ypu'll also see additional information about the heap
- ie. maximum size.

Philip Sherman

sql-db2-dba wrote:
When I did db2batch to benchmark a query, it performance details came
back with this reading ...

"High water mark for database heap = 4291373408"

Does this mean it would have caused memory thrashing at the server?
Did I over-allocate resources.

We just increased BuffPage to 16384 from its default of 1000. Pagesize
of the bufferpool was of course set to -1 so it would use the DBM cfg
parameter. But that is just 16MB of memory. Not even 10% of all the
total 4G memory.

Thanks in advance.

Bill


Nov 12 '05 #2
le****@aptea.com (sql-db2-dba) wrote in message news:<c8**************************@posting.google. com>...
When I did db2batch to benchmark a query, it performance details came
back with this reading ...

"High water mark for database heap = 4291373408"

Does this mean it would have caused memory thrashing at the server?
Did I over-allocate resources.

We just increased BuffPage to 16384 from its default of 1000. Pagesize
of the bufferpool was of course set to -1 so it would use the DBM cfg
parameter. But that is just 16MB of memory. Not even 10% of all the
total 4G memory.

Thanks in advance.

Bill


Since the buffpage is in pages, then 16384 x 4096 (assuming 4K page
size) is about 65 MB. If you page size is larger than 4K, then adjust
accordingly.

IBM seems to be discouraging the use of buffpage in version 8 (it is
hardly mentioned in the manuals anymore), and it is probably better to
alter the bufferpools sizes explicitly (use the immediate keyword to
take effect immediately).
Nov 12 '05 #3

"Mark" <m0****@yahoo.com> wrote in message
news:a5**************************@posting.google.c om...
le****@aptea.com (sql-db2-dba) wrote in message

news:<c8**************************@posting.google. com>...
When I did db2batch to benchmark a query, it performance details came
back with this reading ...

"High water mark for database heap = 4291373408"

Does this mean it would have caused memory thrashing at the server?
Did I over-allocate resources.

We just increased BuffPage to 16384 from its default of 1000. Pagesize
of the bufferpool was of course set to -1 so it would use the DBM cfg
parameter. But that is just 16MB of memory. Not even 10% of all the
total 4G memory.

Thanks in advance.

Bill


Since the buffpage is in pages, then 16384 x 4096 (assuming 4K page
size) is about 65 MB. If you page size is larger than 4K, then adjust
accordingly.

IBM seems to be discouraging the use of buffpage in version 8 (it is
hardly mentioned in the manuals anymore), and it is probably better to
alter the bufferpools sizes explicitly (use the immediate keyword to
take effect immediately).


Another reason why IBM is discouraging the use of BUFFPAGE is that it's
nearly useless (and very confusing) on systems that have more than one
bufferpool, as you then have two places to check/change bufferpool sizes --
the system catalogs for bufferpools with explicit sizes, and then BUFFPAGE
for those with implicit sizes (catalogs have npages set to -1).

--
Matt Emmerton
Nov 12 '05 #4

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

8
by: Maxi | last post by:
Hello, i'm sorry my bad english :( I have CR9 Webservice, how to change databadse name and User_name into Webservice method? (not Viewer Control) Tks!! -- --------------------------
15
by: Joe Van Dyk | last post by:
Can someone explain what a heap and what a stack is? And why I should care? I used to know, but then I forgot. And I can't seem to find it in the C++ FAQ. I keep reading how allocating from...
1
by: Maricel Espejo | last post by:
Hi, Is there anyone encountered this error before & how it is being resolved? Missing end comment mark '*/' The error pops-up when I was running a DTS Import/Export from a SQL server...
11
by: taoberly | last post by:
A few months ago I posted a question about using a file on my hard drive to perform cross-frame scripting and pull data from a server on my company's intranet. I eventually got this working using...
53
by: fdmfdmfdm | last post by:
This is an interview question and I gave out my answer here, could you please check for me? Q. What are the memory allocation for static variable in a function, an automatic variable and global...
0
by: serge | last post by:
I have 2 SQL Enterprise Editions running SP2 and same collation. When i try to start database mirroring I get the following error message: "The remote copy of database "ABC" has not been...
33
by: bill | last post by:
In an application I am writing the user can define a series of steps to be followed. I save them in a sql database using the field "order" (a smallint) as the primary key. (there are in the range...
0
by: not_a_commie | last post by:
Here is some code for the Soft Heap, taken directly from the original paper on the subject with a little help from manish_gupta. Unfortunately, it's about half as fast as a basic binary heap simply...
6
by: haneeshkb | last post by:
I am getting this problem when I tried to build my borland c++ project. (compling and make doesn't giving any problem ) Fatal: Fatal: Assertion failed: !"How can you expand a vapor heap?" at...
0
by: ryjfgjl | last post by:
ExcelToDatabase: batch import excel into database automatically...
0
by: Vimpel783 | last post by:
Hello! Guys, I found this code on the Internet, but I need to modify it a little. It works well, the problem is this: Data is sent from only one cell, in this case B5, but it is necessary that data...
0
by: jfyes | last post by:
As a hardware engineer, after seeing that CEIWEI recently released a new tool for Modbus RTU Over TCP/UDP filtering and monitoring, I actively went to its official website to take a look. It turned...
0
by: ArrayDB | last post by:
The error message I've encountered is; ERROR:root:Error generating model response: exception: access violation writing 0x0000000000005140, which seems to be indicative of an access violation...
1
by: PapaRatzi | last post by:
Hello, I am teaching myself MS Access forms design and Visual Basic. I've created a table to capture a list of Top 30 singles and forms to capture new entries. The final step is a form (unbound)...
1
by: CloudSolutions | last post by:
Introduction: For many beginners and individual users, requiring a credit card and email registration may pose a barrier when starting to use cloud servers. However, some cloud server providers now...
1
by: Defcon1945 | last post by:
I'm trying to learn Python using Pycharm but import shutil doesn't work
1
by: Shællîpôpï 09 | last post by:
If u are using a keypad phone, how do u turn on JavaScript, to access features like WhatsApp, Facebook, Instagram....
0
by: af34tf | last post by:
Hi Guys, I have a domain whose name is BytesLimited.com, and I want to sell it. Does anyone know about platforms that allow me to list my domain in auction for free. Thank you

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.