Both log level and forced_logs. Allows for log_level to be changed at startup ad runtime. Also allow for a list of forced logs, so if log_level is set > info, individual info logs can be forced to be seen (such as to see stats logs).
This helps with kv_index_tictcatree with the leveled_so backend. Now this cna do folds over ranges of keys with modified filters (as folds over ranges of keys must go over lal keys if the backend is segment_ordered)
Which exposed it wasn't working. If there is no segment list passed - just a modification filter, you don't need to check the position list (as checking the position list returns an empty position so sipping all the matching results!)
Acc in response is now of form {Reason, Acc} not just Acc so that the application can understand the reason for the results ending - and take appropriate action (e.g. restart again from the LastKey to return more results).
To support max_keys and the last modified date range.
This applies the last modified date check on all ledger folds. This is hard to avoid, but ultimately a very low cost.
The limit on the number of heads to fold, is the limit based on passing to the accumulator - not on the limit being added to the accumulator. So if the FoldFun perfoms a filter (e.g. for the preflist), then those filtered results will still count towards the maximum.
There needs to be someway at the end of signalling from the fold if the outcome was or was not 'constrained' by max_keys - as the fold cannot simply tel by lenght checking the outcome.
Note this is used rather than length checking the buffer and throwing a 'stop_fold' message when the limit is reached. The choice is made for simplicity, and ease of testing. The throw mechanism is necessary if there is a need to stop parallel folds across the the cluster - but in this case the node_worker_pool will be used.
Quviq/leveled/issues/13 shows the confusion around the purpose of
start key. Hopefully this commit clarifies that start key is a further
refinement to the range start. It's essentially and AND.
If ther are backups made to the same folder, need to remove any files from that folder that are not included in this backup.
Some initial testing, needs more.
As the fold functions have been added to get_runner in an ad hoc way,
naturally, given the ongoing development of levelEd to support Riak,
it was difficult for a new user (in this case Quviq) to see what folds
are supported, and with what arguments, and expectations.
This PR is for discussion. It is one of many ways to group, spec, and
document the fold functions.
A test is also added for coverage of range queries.
During EQC testing it was found that snapshots are still usable even
if the bookie process crashes. This change has snapshots monitor the
bookie and close when the bookie process dies.
