Diagnose report: fix disk total query

[YKG]

Signed-off-by: Kaige Ye [email protected]

This PR is intended to close this issue: tidb-challenge-program/bug-hunting-issue#101

Explanation:

What I changed in this PR is to delete this condition:

AND `DEVICE_NAME` NOT LIKE '/dev/loop%' AND (`DEVICE_NAME` LIKE '/dev%' or `DEVICE_NAME` LIKE 'sda%' or`DEVICE_NAME` LIKE 'nvme%') group by instance,device_name,value

after beautify:

AND `DEVICE_NAME` NOT LIKE '/dev/loop%' 
AND (`DEVICE_NAME` LIKE '/dev%' 
  or `DEVICE_NAME` LIKE 'sda%' 
  or `DEVICE_NAME` LIKE 'nvme%') 
group by instance,device_name,value

• first of all, the last group by is useless, since each row the result will just be saved into a map
• DEVICE_NAME LIKE '/dev%' is useless, because the system info retrived from RPC doesn't not include this prefix
• DEVICE_NAME LIKE 'sda%' or DEVICE_NAME LIKE 'nvme%' is not enough, because sdb%/sdc%/vda% are also valid, more than that, we should not have any assumption on the name
• For the DEVICE_NAME NOT LIKE '/dev/loop%' part, if it should be hidden in dashboard, the right place to do that is to filter it in the datasouce(i.e. these info should be filtered in TiDB/PD/TiKV/TiFlash server info collector)

Another thing is, from a designer's perspective, dashboard SHOULD NOT filter any thing the underline services' report. If anything should be filtered, they should be filtered in the underline services, or these infomation will become junk info, no one use it. The only situation I can imagine to do the filter in dashboard is to do some temporary hack.

[baurine]

@crazycs520 PTAL

[breezewish]

cool. How will be the report looks like after this change?

[YKG]

@breeswish Here is the report after this change:

[YKG]

And now I confirmed that TiKV does't have a correct disk info collector in v4.0.0-rc.2 which I have mentioned in this bug report. The root cause is the sysinfo doesn't have correct implementation, it's sysinfo again. I also confirmed that it has been fixed in the latest sysinfo.

[breezewish]

@crazycs520 How is this PR differs from yours?

[breezewish]

Thanks for the contribution! I'm going to close this PR since @crazycs520 proposed a similar one and changed less.

[YKG]

@breeswish I reviewed #624, but I'd like to copy my old comments above to here:

• first of all, the last group by is useless, since each row the result will just been saved into a map
  ...
• For the DEVICE_NAME NOT LIKE '/dev/loop%' part, if it should be hidden in dashboard, the right place to do that is to filter it in the datasouce(i.e. these info should be filtered in TiDB/PD/TiKV/TiFlash server info collector)

[breezewish]

@YKG Thanks for the comment! For the /dev/loop I think this is the right place to filter, since the hardware table only displays hardwares and does not care about what kind of data is actually useful. It's up to user to decide what they need. While in the diagnostics report we specifically want to minimize the data we provide to users.