The "batched" flag creates a complexity which is that the return value of Add
might or might not be meaningful, but it doesn't really buy us very much.
If we are concerned about the ops log size of writing single ops as 21-byte
arrays of 1 op rather than as 13-byte ops, we can make the AddN code smarter
about how it writes ops. And probably should.
Along with this, change Remove to use the batched operation form, which
writes a more meaningful ops log, and return a meaningful value for changes
made. Otherwise, it ends up writing potentially thousands of ops to the
ops log without reporting any OpN, because the number of ops written isn't
the same as the number of changes those ops made. This could result in
files growing by megabytes without OpN changing.
There was a comment here about a test failing with RemoveN. I can't prove
it, but I strongly suspect that this was actually a result of that test
case hitting a particular bug that we eventually fixed, and which we might
have fixed sooner if we'd realized why using RemoveN made that test
fail.
- Previously, on timequantum schemas, we would
create and open a view for the cartesian
product of every possible view and shard.
- This caused us to be very slow on re-open,
and to use lots of memory for views that
held nothing.
- This change makes startup faster, memory
use much lower, and should speed migration.
- 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().
- on startup in blue_green mode, we will migrate
blue to green if blue is empty.
- otherwise, when blue has data, we verify
against green before proceeding with the
blue_green run.
- small optimization in the rbf cursorx.go to
short-circuit processing on a nil bitmap.
This avoids a roaringparanoia tag panic.
- back out holdbkg.go, was too slow.
add a distinct Holder.imu lock instead.
- blue_green for doing migration. Called before Holder.Open finishes.
- holdbkg.go added for index lookup. Less wedging between a deadlock and a race.
- fix fault under read-only map under lmdb at
TestExecutor_Execute_Row_Range/RowIDColumnID by doing cow in roaring.
- roaring -tags gofuzz builds again
- roaringparanoia build tag added to make test targets in Makefile
- add rbf.NewDBWithAllocZero for out-of-bounds memory checks
- .circleci/config.yml test-shardwidth-22 with large run container, kept OOM-ing we suspect.
Fixes#819
- introduce Query Context (Qcx) for managing database-per-shard.
- replaces the MultiTx, so mtx.go is retired and removed.
- introduces the HolderConfig struct and all Holders now have
a path from birth.
- rbf speedups on bitwise writes
- badgerdb is removed due to unresolvable write conflicts.
fixes#703#676
