Re: monitoring cache hit rate from logs

That's kind of a difficult question to answer, because it is fairly useless to monitor the cache-hit rate in 9i, so the only docs you could be directed to would tell you how to do it wrong. (Although the OEM resource advisors can be useful - see
https://metalink.oracle.com/metalink/plsql/f?p=130:3:4041991811487128610::::p3_database_id,p3_docid,p3_show_header,p3_show_help,p3_black_frame,p3_font:NOT,160127.1,1,1,1,helvetica for the formulae).

There are some interesting scripts here: https://metalink.oracle.com/metalink/plsql/f?p=130:3:4041991811487128610::::p3_database_id,p3_docid,p3_show_header,p3_show_help,p3_black_frame,p3_font:NOT,131704.1,1,1,1,helvetica https://metalink.oracle.com/metalink/plsql/f?p=130:3:4041991811487128610::::p3_database_id,p3_docid,p3_show_header,p3_show_help,p3_black_frame,p3_font:NOT,169935.1,1,1,1,helvetica

Take all scripts with a grain of salt - you need to understand what you are looking at. It took a long time for the cache hit ratio and many other things to be put in proper perspective, so a lot of older scripts floating about incorporate myths.

You should also read the performance tuning guide (after you read the concepts manual, of course). Manuals are available at http://tahiti.oracle.com .

Some other resources here: http://www.dbaoracle.net/readme-cdos.htm

jg

--
@home.com is bogus.  "A low cache hit ratio does not imply that
increasing the size of the cache would be beneficial for performance. A
good cache hit ratio could wrongly indicate that the cache is
adequately sized for the workload."