Ie161e0f was done in a hurry, and so didn't do things in the best ways.
This introduces a new "CachedBagOStuff" that transparently handles all
the logic that had been copy-pasted all over in Ie161e0f.
The differences between CachedBagOStuff and MultiWriteBagOStuff are:
* CachedBagOStuff supports only one "backend".
* There's a flag for writes to only go to the in-memory cache.
* The in-memory cache is always updated.
* Locks go to the backend cache (with MultiWriteBagOStuff, it would wind
up going to the HashBagOStuff used for the in-memory cache).
Change-Id: Iea494729bd2e8c6c5ab8facf4c241232e31e8215
* This can happen due to incr/add races. Use incrWithInit()
instead to handle such cases.
* Also made BagOStuff:incrWithInit() return the new value like incr().
Change-Id: I0e3b02a4cff7c20544a9db2eaabd3f61e5a470b1
If a set() happened around the exact same time as check key was
initialized via get(), the curTTL in future get() calls could
sometimes be 0 instead of a negative value, even though hold-off
should apply.
Change-Id: Ide1fd65112aff425a4798e2ec406d71f2a8e84a7
To allow batch queries for multiple keys that themselves have different check
keys. Previously check keys always applied to all keys being retrieved.
Change-Id: I9e5ba198d79020ce05a802a510762e29fcfb2f1b
* Match behaviour of MapCacheLRU and ProcessCacheLRU.
* Add missing unit tests for TTL and maxCacheKeys eviction behaviour.
Change-Id: I559eae1cd336274b21728e86775cfbad7e2f2c6d
Follows-up 7cddc22.
Also use PHPUnit_Framework_TestCase as parent instead of MediaWikiTestCase
in preparation for library extraction.
Change-Id: I0e68e56ecf8376b52a59c33ba6dd18b671bdcfc9
* Keys that take a long time to generate would run into
the MAX_SNAPSHOT_LAG check and have set() no-op. This
would be fine except that leaves no key there to figure
out the time since expiry and therefore whether to use
the mutex, so it didn't. This now saves the keys but with
a FLG_STALE bit set, making the next caller that sees it
perform a regeneration (unless it can't get the mutex).
* Bumped LOCK_TTL so that keys can stay locked much longer.
* This is easy to test via sleep(5) in tagUsageStatistics()
and two Special:Tags browser tabs.
Bug: T91535
Change-Id: I549e70ace3d2e7da40d3c4346ebacc36024cd522
* In the common ~0 second lag case, transactions up to ~7 seconds
long will have normal set() behavior (instead of just ~5 seconds).
* Like wise with ~0 second transactions tolerating ~7 seconds of
lag (instead of just ~5).
* The lower hold-off time lets caching resume 3 seconds sooner.
Change-Id: I21e2a0a6915492cec422b6a6af5541937745c15b
