Include an LCache Stats page in the WordPress admin

[danielbachhuber]

When the plugin is active, we should include an APCu status page in the WordPress admin so the end user easily knows whether the plugin is working or not.

From https://wordpress.org/support/topic/how-install-how-i-know-its-working/

[danielbachhuber]

@joshkoenig @davidstrauss @stevector Suggestions on what APCu stats we might want to include on this page?

[joshkoenig]

I don't know what all stats are at hand, but I think:

• Some kind of high-level "it's working" indicator:
  • Green: all systems go, hitrate is over 50%(?)
  • Yellow: functioning system, hitrate below 50%
  • Red: something is not working (e.g. no APCu, no L2 table, anything else that would make the system inoperative)
• L1 stored data (vs APCu available)
• L1 object count
• L1 hitrate
• L2 stored data
• L2 object count
• L2 hitrate

David also had some notions about instrumenting for "never read objects" and other anti-patterns that could be used to tune the cache and/or suggest upstream improvements in plugins or themes.

[joshkoenig]

Ok, for a first pass (pending a design) here's what I'd like to see:

LCache Status

Message	Condition
All systems go	APCu hitrate > 50%
Cache hitrate low	APCu hitrate < 50%
Installation incomplete	Installation requirements not met

L1 Statistics

Statistic	Explanation
L1 Hitrate	A hitrate of 80% is considered best practice
L1 Objects Stored	Guestimate at what an insane number might look like?
L1 Free Memory	If under 33% free, show a warning

L2 Statistics

Statistic	Explanation
L2 Hitrate	A hitrate of 80% is considered best practice
L2 Objects Stored	Guestimate at what an insane number might look like?

Ignored Objects (only show up if any are ignored)

If LCache detects that objects are being written more than they are read, it will stop caching them to save time. You can probably improve the performance of your site by cleaning up the code around the objects listed below:

Object	Count
Some ACF Fields	A million writes!