db_block_size = 16K inflates tables

From: ivan vasquez <ivan_at_itos.uga.edu>
Date: Tue, 12 Nov 2002 18:12:16 -0500
Message-ID: <aqs1sg$4q3$1@cronkite.cc.uga.edu>

Hi,

I just installed a 9.2.0 instance for GIS applications (ESRI ArcSDE). The manufacturer suggests using db_block_size = 16K. After a first installation using block size 8K, I reinstalled the database using 16K to see if the performance improved. However, a more important problem appeared: Tables are growing way too fast.

(All tablespaces have been created locally managed, auto segment space mgmt.)
In a 8K blocksize tablespace, a table with only 160 rows, 46 bytes per row, uses 5 data blocks.
In a 16K blocksize tablespace, the exact same table uses 61 data blocks!

The tables were created with no storage statements, so defaults should apply. The data was retrieved from user_tables after analyzing them.

What could be "wrong"?
Thank you,
Ivan.

Table description:

SQL> desc ga_cnt00
Name Null? Type

-------- ------------------------

OBJECTID NOT NULL NUMBER(10) AREA NUMBER(24,5) COUNTY VARCHAR2(5) NAME VARCHAR2(13) LR_ID NUMBER(16) POP00 NUMBER(16) ID VARCHAR2(5) SHAPE NUMBER(10) Received on Tue Nov 12 2002 - 17:12:16 CST