Re: how to avoid table chain?

From: Barth Siemens <nospam_at_portal.ca>
Date: Sat, 27 Jun 1998 05:03:10 GMT
Message-ID: <35957911.914348433@news.portal.ca>

On 25 Jun 1998 22:58:02 GMT, dshi_at_magpage.com (David Shi) wrote:

>I am trying to simulate a 700 column table, each column is varchar2(1). I
>created the data in a flat file and loaded into Oracle, looks like all the rows
>are chained and one block only hold 1 row.

Have you tried to define each column as char(1) instead. I'm not sure, but I seem to recall hearing that the datatype char takes less overhead space than varchar2. If that's not the case, then you'll need to increase your block size.

>The block size is 16k, and average
>row length is 1409 from the "estimate statistics", I can't figure out why Oracle
>has to chain (I used the "pctfree 0").

You haven't taken the header (in each block) into account. Finally, pctfree fixes row migration not row chaining. --
Barth Siemens
Change the email address from nospam to barth. Received on Sat Jun 27 1998 - 00:03:10 CDT