Hi Guys,
Every now and then I come across a SQL query and a benchmark such as the
following which purports to be useful in high-level performance problem
spotting. For example:
select activity, cast((end_time) as date) as "Date", (examined/cast
((end_time-start_time) seconds as decimal(18,13))*3600) "Pages backed
up/Hr" from summary where activity='FULL_DBBACKUP' and days(end_time) -
days(start_time)=0
or
select activity, cast((end_time) as date) as "Date", (examined/cast
((end_time-start_time) seconds as decimal(24,2))*3600) "Objects Examined
Up/Hr" from summary where activity='EXPIRATION'
alongside statements that values of less than 5,000,000 pages per hour
and 3,800,000 pages per hour respectively might indicate a performance
issue somewhere in the stack. Has anyone else seen these, or similar
ones, as well?
My concern is that the article I've just come across which contains the
above, quoted from an IBM White Paper, might be a little on the old
side, and particularly with the later expiration query, I'm getting
figures for one system which suggest it should be crawling on its knees
when instead I'd tend to think it's a pretty damn good performer. As I'm
sure TSM Server code improves the expiration algorithm with each
revision, then it's more likely that this later query, and as
importantly the benchmark which goes with it, might get obsoleted.
Does any one have any thoughts on these? Does anyone else have any other
queries or benchmarks which they run from time to time for
'tip-of-the-iceberg' performance troubleshooting.
Rgds,
David McClelland
London, UK
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