Re: how to avoid table chain?

On Sat, 27 Jun 1998 05:03:10 GMT, nospam_at_portal.ca (Barth Siemens) wrote:

>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.

The block size is 16k, with pctfree being 0, even counting header, one block should store more than one row (less than 2k). Received on Sun Jun 28 1998 - 12:41:35 CDT