RE: Multiple block sizes

[John Kanagaraj]

Title: Message

Mladen/Avinish,

 

I would just be a little careful about keeping 'hot' indexes in 32K blocks. The chances of encountering buffer busy waits during multiple, simultaneous INSERTs and DELETEs would be higher as root blocks and branch blocks that need to be updated would now hold a larger number of entries and thus be more likely candidates for block contention.... Same is the case with more chances of running out of ITL space/entries in hot data blocks. IMHO, DSS type applications benefit most from larger block sizes and support for multiple block sizes in 9i was provided so that 'large-blocksize' tablespaces that contain transaction history can be transported from a 'otherwise-small blocksize' based OLTP database into DSS databases that traditionally have large block sizes. For e.g. in a 9i Db, you might have the OLTP tables based on 8K blocksized tablespaces, create monthly history from these transaction tables into a 32K blocksize based tablespace in the same 9i database so that you can Tablespace-Transport it to a 9i, 32k blocksized DSS database.

 

Back to imbibing a thick, black brew after writing this complicated note :)

John Kanagaraj
DB Soft Inc
Phone: 408-970-7002 (W)

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** The opinions and facts contained in this message are entirely mine and do not reflect those of my employer or customers **

-----Original Message-----
From: Mladen Gogala [mailto:[EMAIL PROTECTED]
Sent: Wednesday, September 24, 2003 12:20 PM
To: Multiple recipients of list ORACLE-L
Subject: RE: Multiple block sizes

Great! You're exactly the guy that I was looking for. Any problems encountered/advice to give?

 

 

--
Mladen Gogala
Oracle DBA

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Wednesday, September 24, 2003 1:55 PM
To: Multiple recipients of list ORACLE-L
Subject: RE: Multiple block sizes

I have little bit experience on that. I am keeping indexes in 32K block  'cause Oracle access indexes sequentially and placing indexes in large block would help in reducing IO.  All the tables are in 8K block size but you can think about putting small tables in 2K or 4KB block size to better utilize your RAM. We are on AIX 5.1 , Oracle 9202.

-----Original Message-----
From: Mladen Gogala [mailto:[EMAIL PROTECTED]
Sent: Wednesday, September 24, 2003 9:05 AM
To: Multiple recipients of list ORACLE-L
Subject: Multiple block sizes

Does anybody have any experience with the multiple block sizes in the database? I'm about to reconfigure

my database to have a tablespace with blocksize 16k in addition to the existing 8k tablespaces. Tables

in this tablespace will be loaded weekly and read daily, frequently using full table scan (DW style reporting.

I'm planning to have bitmap indexes and the rest of the DW arsenal). Does anybody have any negative experiences

with that kind of stuff? It's 9.2.0.4 on RH 7.3. Am I running into ora-7445 and ora-0600 type errors?

 

--
Mladen Gogala
Oracle DBA

 

 

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