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
* 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
