Currently we select 20 rows, and return the accurate count if it's less
than that, so up to 19 rows. Since we want to return an accurate count
if it's 20 rows or less, select one more row, 21, so we can differentiate
between only having 20 result rows or hitting the limit. This is the same
technique used in MediaWiki's Pager system.
Change-Id: I50fa96238eb4c7178414ee92c53799fd69520926
* The code now produces an accurate count if the number of
errors for a category is below the threshold set by a
public constant MAX_ACCURATE_COUNT (currently 20).
The database record count limit was originally set to 1,
to determine accurately, if there were actually 0 errors
in a category as the estimate code would never report 0.
If not 0, it would use the estimated count which does not
produce an accurate count for any other number of errors.
For low error counts this is annoying to editors and
unnecessary. The additional CPU/disk activity to accurately
check for low error counts is not significantly more than
checking for 0 or 1, as checking for 0 likely requires
a complete table scan which is probably expensive compared
to a low count that early outs when it hits to record limit.
* An improvement to consider is recording the accurate count in
a separate tiny table, and maintaining an accurate count there
which is used in preference to doing the select with row limit
based on say a 30 second TTL, to prevent a stampede of requests
from doing extraneous database operations.
* Added unit test coverage for accurately counting low error
conditions that are lower than the threshold and also verify
that the estimate is inaccurate beyond the error count
threshold.
Bug: T194872
Change-Id: I4f74cfe3bf9601baa0dc8fa6464a68030ac2bc4b
The following sniffs are failing and were disabled:
* MediaWiki.FunctionComment.Missing.Protected
* MediaWiki.FunctionComment.Missing.Public
Change-Id: I96e32df48d13040893bfd1be6d90d0db4f7c7d0a
The query itself is too expensive to be run on large Wikimedia wikis. So
put it behind WAN cache and touch the check keys for each category
whenever those have errors added or deleted from them.
If this happens to get out of sync, it will get fully refreshed
regularly when the totals are sent to statsd.
WANObjectCache's 'lockTSE' feature will help avoid cache stampedes that
made this query expensive in the past.
Change-Id: I3774103a29fa0f29d36283950f136259fa71bffe
These tests insert variations of fake lint errors into the database, and
then read out of the database to check they round-trip properly.
And while we're at it, improve the setForPage() return value.
These tests can be run with something like:
php tests/phpunit/phpunit.php extensions/Linter/tests/phpunit/
Change-Id: Ifdba8a8a104d218a822f909bc5d7b3512aca499d
