RTrim only worked in special case of key matching, that would never
occur in real world range query. RTrim should really check for key
passing.
Returning empty list should not be possible - unless the query is
outside of the range entirely (and such a query should never go to this
SST).
No evidence from valume test that the scan width has made a posiitve
difference - so reverting, but not fully as slots may now be twice as
big, so sticking to half previous value
When testing with large numbers of 2i terms (and hence more Riak
Metadata), there is a surge in slow response times when there are
multiple concurrent merge events.
This could be veyr short term CPU starvation because of the merge
process. Perhaps it is delays waiting for the scan to complete -
smaller scanwidth may mena more interleaving and less latency?
A mistake meant resetting to lookup on a skipped key would cause issues
if the skipped key ocurred under a no_lookup slot after the ?SLOT_SIZE
had been reached. This caused the slot to switch to lookup, but beyond
the maximum size
The manifest and the logs are bloated by having the full file path for
every filename in there - given the root path is constant.
Could also cause issues if the mount point is ever changed.
When running a load of mainly 2i queries, there is a huge cost in the
previous snapshot code. The time taken to create a clone of the
Penciller (duplicating all the LoopState) varied between 1 and 200ms
depedning on the size of the LoopState.
For 2i queries, most of that LoopState was then being thrown away after
running the query against the levelzero_cache. This was taking < 1ms on
average. It would be better to avoid the o(100)ms of CPU burning and
block for o(1)ms - so th eorder of events have been changed ot filter
first so only the small part of the LoopState actually required is
copied to the clone.
well random had me foxed. As the clone was short-lived process it only
called random once - and so always got the same answer.
random has to be seeded to give different answers when called once from
a process - so this is now seeded in leveed_log
