Per slack discussion with Seebs and Nia,
we'll try not automatically resetting the Qcx.
The worry was that our goroutine shutdown
management is so poor that we are asking for
GetTx on a goroutine that still has a Qcx
from a query that was cancelled.
If this is the case, we will now panic instead of
issuing a new Tx. Then we can fix the poor
goroutine management.
- also require Qcx.Finish or Abort before Reset
- only allocate the rowcache if it is in use (avoid allocation per fragment)
- when the rowcache is use, fragment.go intRowIterator must write lock the
fragment because the f.rowCache will be updated.
- eliminate unused bitmapCache interface to keep the linter happy.
- fixes#1035
- we return to checkpointing after every commit, by default.
- the internal rbf logic is not ready to have
checkpoints deferred. Doing so results in
references to WAL segments that are not
in the current slice of live segments.
- view.openFragmentInTx was forcing a directory scan
for shards on every open fragment during Holder.Open().
Seen by pprof profile having excessive allocations
from dbshard.go listDirUnderDir().
The "seenThisRow" value was never getting cleared, which meant that
if the first container on a row didn't happen to contain any post-filter
bits, the rest of the row wouldn't get evaluated.
Add an exported IntersectionAny() from roaring to let us quickly
check whether two containers have overlap, so we can avoid performing
intersections we don't need to when evaluating containers within
the same row as a previous match. (IntersectionCount on the whole
bitmap would imply doing up to 16 intersections even if we find a bit
right away.)
We also allow ForeignIndex to be set on set, mutex, and time fields,
since all of those could now be reasonable operands for Distinct
ops.
Not yet present: Handling time quantums, but that seems really
desireable.
