Bug #71570 QUAN seems to show high frequency queries from MEM agent in wrong db
Submitted: 3 Feb 2014 21:15 Modified: 9 Jan 2015 16:04
Reporter: Simon Mudd (OCA) Email Updates:
Status: Can't repeat Impact on me:
Category:MySQL Enterprise Monitor: Server Severity:S2 (Serious)
Version:3.0.5. OS:Any
Assigned to: Mark Leith CPU Architecture:Any
Tags: windmill

[3 Feb 2014 21:15] Simon Mudd
This may be an agent thing, it may be a display thing. Right now it's not clear.
See attached screenshot.

How to repeat:
I was reviewing an issue on the server concerned in a very small time window.

- The data I see seems wrong as it looks like MEM agent queries, but the database that's shown as the current database is one starting with conf* (full db not relevant here), rather than mysql which is what is expected. I don't believe the other applications on the server were doing these sort of MEM agent queries.
- In the 4 minute period it seems that 22,080 SELECT COUNT(*) FROM .... ( The full normalised SQL is SELECT COUNT ( * ) FROM `INFORMATION_SCHEMA` . `TABLES` WHERE `TABLE_SCHEMA` = ? AND TABLE_NAME = ? ). That value is a large number and if true seems very excessive.  This server does not have a large number of tables but running the same query on other servers would be very intrusive.
- If the data is correct it looks wrong, but I'm more inclined to think that the data is not correct and it's the presentation that's wrong in which case collecting and showing the data correctly is very important.

Note: prior to this the QUAN data collection had been turned off due to some performance issues I'm seeing. I turned it on about the same time but am not sure if this was prior to or just after the time shown.

(that is changes in Configuration -> Advisors -> Query Analysis -> Query Analysis Reporting (disabled and then set back to enabled every 5 minutes)

Suggested fix:
1. Check that the data is correct, fixing the collection if that's wrong to be less aggressive (if that's the case) or fixing the presentation to show the correct values (if applicable).
2. The times shown are according to the values configured for each user but given that different users may be in different timezones, screenshots such as this may be misleading if some representation of the timezone is not shown. So please consider making it clear the timezone of the data being shown.
[3 Feb 2014 21:16] Simon Mudd
Screenshot showing the "unusual queries"

Attachment: screen_shot_2014-02-03_19.10.19.png (image/png, text), 166.56 KiB.

[3 Feb 2014 21:17] Simon Mudd
3. Make sure that the agent "stays" or "reports" data from the "mysql" database (if applicable).