We execute the aggregate Distinct calls after the GroupBy is complete,
and we need these to act like non-remote calls in that they forward to
all nodes, but like remote calls in that they bypass key
translation. Added a "PreTranslated" flag to the QueryRequest to
achieve this.
Discovered an issue where a nil *Row in EmbeddedData would cause a
panic in the protobuf serialization. Changed the encoding code we
control to never pass a nil *Row.
Got fed up with lack of context on errors and added wrapping to all
calls under executor.executeCall as well as a few other places.
Handled a situation where not having data on a shard for a particular
field could cause a query to error instead of just treating that
fragment as being empty. (see the switch in executeDistinctShardSet)
Stopped GroupBy from executing the Count(Distinct) aggregate on Remote
calls.
Fixed a longstanding issue where errors retrieved from remote query
calls had a garbage character at the front due to treating a protobuf
payload as an error message instead of decoding it. (see
http/client.go)
If you're running a Pilosa with mostly default configuration on your
system, some of these tests would fail due to things like port
conflicts. These changes address the most common failures.
From Nia:
While debugging the Q2 bugs this was somewhat useful in analyzing cluster events. As for the spammy part. . . that seems to be more of an issue with spamming our resets than an issue with the log itself.
This used to be possible to hit, but I think now that Distinct on a
set field returns a *Row rather than a SignedRow it isn't an issue. (I
wasn't able to trigger it in the tests). Adding the fix anyway as it
seems safer than not.
The rest of the changes are test infrastructure to make it easy to
call GRPC queries and verify the results as CSV.
I used a "paranoia" check to find these, but then realized the check
had a ton of false positives and doing it properly wasn't going to be
straightforward. I'm leaving the paranoia stuff in unless there are
objections, because I've wanted it before and not had it.
I also removed a log line that is very verbose and I don't think helps
anyone.
This commit changes executeDistinct to return either a *Row or a
SignedRow (instead of only being able to return a SignedRow). Distinct
on a set field will return a *Row while an int field will still return
a signed row.
We then add Field and Index fields to the Row object so that we can
determine how to translate the rows IDs to keys (if needed). This adds
a lot of logic around the translation which fixes bugs where Distinct
calls would fail to get translated.
There are, I think, still issues if you were to try to join a keyed
field to a keyed index which wasn't explicitly specified as the
field's foreign index. The IDs in the field wouldn't be using the same
translation as the IDs in the index, so the query might appear to work
but give incorrect results.
add Distinct test with integer data, and because one of the records
had a null value (and was in a shard by itself), it uncovered this
issue. I added a special error type if a view or fragment is not found
when so that we can match against it and ignore it when calculating
the results for a query.
I also added an implementation within executeCount to handle the
SignedRow case, but discovered that handlePrecalls always dumps the
negative data and that will be a bigger thing to fix
the Distinct call would get precomputed correctly, but then the
executeCount would happen in the available shards context of the
index. So if the index only had records in (e.g.) shards 10,12,18,22,
and all the values of the Distinct call were in shard 0, you'd see 0
results.
The fix skips the whole map/reduce step of executeCount (which was
basically fake anyway when the argument is precomputed), and just adds
up all counts of all the precomputed segments.
This currently won't properly count Distinct values from an int field
which contains negative numbers... going to add a test and fix for
that next.
There is also still a key translation bug which is why the one test
case is commented out... fix coming for that soon as well.
- 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.
this should avoid a race condition with CreateField where createdAt
can get out of sync if there are multiple concurrent requests.
The client methods didn't allow specification of the URI, so I
modified the implementation to find the coordinator and send to it
explicitly.
unclearSets was completely broken and I have no idea why the test I thought
was testing it didn't actually catch that problem. Added unit tests and fixed
the logic. Improved/clarified prune and fullPrune, and unexported their
names because why export methods on an unexported type.
Also improve some comments and rename a variable or two to improve clarity.
On roaring, CountRange needs to have exclusive access to a fragment, but
doesn't currently require a lock, because it's usually used from inside
other already-locked things.
CountRange for RBF had a subtle bug which wasn't noticed, so, let's
have some CountRange testing and also a benchmark.
We also fix a couple of subtle bugs caught in the process of developing
and testing this.
SliceContainers will allow nil containers, but doesn't return them when
iterating because there's various things that can panic if called on a nil
container. Since countEmptyContainers() has to traverse the whole bitmap
anyway, it doesn't matter which it counts, so we replace it with
countNonEmptyContainers(), and adjust test cases accordingly. This fixes
an issue where if roaring is smart enough to insert a nil container
into a SliceContainers, trying to write it to a file produces an invalid
bitmap with offsets off by 16 and one container fewer than its header predicts.
RBF: don't try to count 0 bits in a container
If we're to the "last container", and we'd be counting all the bits less than
zero, we can skip that. This avoids hitting a bug, which is that c.countRange
doesn't handle BitmapPtr.
Several issues:
1. tx.frag could be non-nil but not the fragment requested.
2. start and end need not be exact row boundaries.
3. therefore this could be returning the count of the row containing
"start", for a fragment other than the one requested.
4. also in fact the rowcache wasn't populated before this so in one
memory profile, this function alone was responsible for nearly
100GB of cached values...
