This is logically two separate things, but the individual changes
are thoroughly intertwined in the code.
The first change is a logical change to the design of the snapshot
queue, which is that it now adjusts the maxOpN the background scan
targets, allowing it to lower that value over time when things are
quiet. We do this because it turns out that on large data sets,
this can make a factor-of-four difference in memory usage!
So, in general, on a quiet system, each pass through the holder
aims for about 1/4 of the existing fragments to get snapshotted.
When there's more load, we adjust those values up.
We also make the snapshot queue a bit less chatty, to make testing
less annoying -- we only print stats if the queue enqueues at least
two snapshots, or skips any.
The second change is threading the holder through things. We've
always threaded the logger through, and then added the snapshot
queue, and some of the Inspect-related work led to wanting to
have a way to thread options through, so what if we just threaded
the holder itself through, and removed the direct copying around
of the logger, snapshot queue, and so on. Similarly, everything
can now use holder.PartitionN instead of having to get its own
copy of PartitionN handed out to each index.
This does imply ensuring that test cases always get a reasonable
default holder.
This is a precursor to adding additional information to the holder,
such as whether it's in a special read-only mode, which would imply
not modifying on-disk files. This is already semi-supported for
the specific case of the background snapshot queue and cache flushing,
which are attached to the (created in a previous commit) new
holder Activate method, instead of being automatic on holder Open.
The change to a snapshot queue can also cause races in tests, because
the fragment.Clean method's "sanity check" accesses a fragment without
a lock. Fix that. Since there's a couple of t.Fatalf(), but we need
to release the lock before closing, we use an anonymous function
with a defer to handle that. Whee!
If the high end of a range is below the low end of the range, there's
no values in it, so we can short-circuit that. If we don't, if the
low end is zero or higher, and the high end is below zero, we can
get very surprising behaviors, such as accepting values up to the
inverse of the high end. Add a test case for this and treat it the
same as a low range end above the field's maximum or a high end
below the field's minimum, returning an empty row immediately.
The computation of available shards is cheap, because realistically, virtually
no one has enough shards that the resulting bitmap is more than one container.
We don't try to fix this at the field/index levels because it's significantly
harder to do there, but I think the creation of these bitmaps is probably
the most expensive part, and switching the unions to union-in-place probably
reduces cost significantly.
Note that the bitmaps being unioned almost certainly have exactly one small
container in them.
If the min/max provided are already on the boundary of int64,
then we don't want to operate on them and cause overflow.
there are still overflow scenarios where a user provides a
min/max which is not on the boundary, but overflow once the
scale is applied. This does not address those cases, but at
least it addresses the default case (where a min/max is not
provided)
This PR adds support for anti-entropy syncing for integer
and decimal fields. It differs from the logic for other
field types in that it does not rely on a consensus to determine
what the value should be; instead, it considers the correct
values to be those of the primary replica. From there, data
is pushed to all non-primary replicas.
this involved adding an optional float value to the ValCount struct
which complicated result types, necessitated grpc changes, and needed
quite a few tests at different layers.
For Fields with ForeignIndex (which have keys), the API was missing
the logic to do that translation against the translateStore of
the foreign index. This commit adds that logic, as well as some
missing translateStore-related logic in the gRPC code.
In the case where a field with a foreign index opens before the
foreign index has opened (and is available as a reference in the
holder), push the field into a queue to have its foreign index
applied once all indexes have opened.
In the `Inspect` function in `server/grpc.go`, getting
the value of an `int` field with a foreign index to
an index with `Keys()`, we need to return the string
key value instead of the BSI int value for the field.
This commit also changes the method `Field.keys()` to be
exported as `Field.Keys()` so that it's accessible in
the server package.
This commit changes the order of FieldOption application so that
it's always set before field.Open() is called.
This was required because field.Open() now uses some of the values
from FieldOptions to determine if/when to use a particular
translateStore. For example, when FieldOptions.ForeignIndex is set,
the translateStore from the foreign index is retrieved during
field.Open().
This allows a BSI field to have an option indicating
that it is a foreign key to another index. If the foreign
index has column keys, then this field handles string values
by using the foreign index's translate store.
