I am evaluating Jet Profiler before I purchase and I have a few questions.
1) The Scans preset shows that at times a large percentage of table scans are running , upwards of 70%. But how do I find WHAT selects are scanning? I highlight a peak area of the graph and the lower Top Queries area is empty. How do I find the scanning queries?
Same thing happens when I select on other presets, for instance: 'Questions'. After capturing for 20 minutes I see two spikes each about 2 minutes long. The rest of the graph is below 50 queries, but these two areas are above 175 - a significant peak. But when I highlight the lower of the two (with a buffer of a minute on each side) the Top Queries section is empty. The higher peak shows only 1 item and it isn't a select, its an insert.
So two problems here ...
2) Obviously with a peak over 175 and only one query showing something is missing, so how do I see the queries?
3) Can the queries be filtered for recording? I know they can be filtered in the lower section, that isn't what I mean. I'd like the graph to indicate specific query-type levels.
Without being able to see the actual queries causing a load it is hard to justify a purchase.
1 and 2) I can think of two possible causes here. First, JP uses polling so there's always a chance that it does not see the queries causing the load. In particular, if the load on your system is too low cpu-wise, you might not see the queries. The Table Scans and Questions statistics are fetched from counters inside the database, which sees all queries. So those numbers might go up, but no queries show up in the Top Queries. In the long run, provided you have some load (>5%) you should start seeing results. Try polling more often (Recording Settings => Poll interval). Also "Questions" include inserts as well as selects.
The second possible cause is that you do not have enough privileges to see all queries. Make sure you are able to see queries issued by other users than the JP user. You can try this by logging in to MySQL from command line as a different user and issuing a long query, e.g.
SELECT SLEEP(30);
3) Not currently, but we're working on adding some filtering / rewriting mechanism in a coming release.
Thanks for the reply. I don't think privileges is the problem. I see multiple users in the lower section. I have increased the poll interval. It was 1 sec and I bumped it to .1 sec and I am seeing many more queries now.
I thought of a feature that would be useful... When a query is highlighted below, have the graph show a vertical indicator of the times when that query ran.