How mush blocksize it's better?

Posted by Admin on 25-Oct-2006 04:12

my platform: HP-UX 64 11i (2 process 800M, 1 G memory,mirror disk 73G) , OS block size is 8192.

My progress Rev: V8.3e (SP05)

My applications: 20 concurrent MFG/pro 9.0 users , character !

Now DB size: 4.2G , 1024 (default blocksize)

I want to now how to improve the DB performance ? I read some documents about the blocksize, they suggest: blocksize = 1 or 2 times of OS blocksize, Can I use the 8192 as my DB blocksize?

I found 1 tools in PEG, but after the tabanalys cacluate : It's best to use 2048 as my DB blocksize ?

Anyone can tell me whick suggestion is right? thanks

All Replies

Posted by jtownsen on 25-Oct-2006 10:02

Given that your OS block size is 8K, you probably want to use an 8K database blocksize too.

I don't know which tool you were using, but I'm wondering how old it might be. Quite a few years ago, you could not specify the number of records per block. This is what you're usually trying to optimise if you're looking at information from the tabanalys.

There's is heaps of information here in PSDN if you search for "records per block" or "performance tuning".

Posted by gus on 25-Oct-2006 16:25

Take a look at "OpenEdge RDBMS Performance Tuning Made Simple" available here on PSDN at this link:

If that leaves you with unaswered questions, post again.


Posted by ChUIMonster on 25-Oct-2006 19:03

If that's the tool that I think it is then it is giving you the optimum block size in terms of "least storage" rather than "best performance".

There is (usually) a trade-off in version 8 -- 8k blocks (usually) perform (much) better. But your average record size is probably smaller than the optimum for an 8k block and 64 rows per block (you cannot adjust rows per block in v8). This means that the disk storage footprint of your database will probably grow when you dump & load it to get to 8k. It may double in size. It might even get bigger than that.

IMHO it is almost always worth it anyway. If you need performance and you're stuck on v8 then 8k blocks are almost always a big winner. (Yes, there are rare cases where they are not -- so test this before you do this to an important production system. Then again, if it's still running v8 maybe it isn't very important.)

On the other hand you can do much, much better by upgrading to v9 or, better yet, OE10 and taking advantage of the improvements that the last 10 years of development have brought to the database engine.

Posted by Admin on 25-Oct-2006 21:31

Thanks Tom, (even to Gus & Jamine!)

For the pdf file I have already downlaoded before, but you know V8 is very old, most users use V9 or OE...So dificulty to find some tips about V8 progress!

We'are planning to upgrade the progress&MFG/pro in Y2008 (2007 in EU, 2008 in Aisa & US).

I'm a newer in progress DBA, I will try to test the DB performance with 8K blocksize! Finally thanks again for your reply!

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