The anti-entropy feature has never actually worked. We've been
talking about removing it or replacing it for ages, but haven't
had a concrete motivation.
But the anti-entropy interface is the sole user of several components
of the Tx interface, and now that we're trying to replace that
interface, being able to drop those components has some appeal, so
let's remove the one thing that used them, in the hopes that this
will simplify life.
This also lets us drop ForEach and ForEachRange, which were
barely used at all. The one surviving usage (CSV export) can be
handled by using the container iterator we already have, and
making ContainerCallback exported so we can use it to just call
things for every bit.
enriched metadata for tables
added support for the concept of a table and field owners in metadata; mechanism to derive owner from http request metadata; metadata for table description
We centralize the creation paths for test indexes, fields,
etcetera so they all have a common path, all using standard
test holders. There's still two versions, one for test.* functions
and one for internal. They do share a TestHolderConfig though.
Large hunks of the related APIs are simplified/streamlined.
* Fragments are always created with a Field and don't need
a workaround in case they don't have it.
* Creation of test fragments, etc., use optional FieldOptions
but don't specify names because they're all using new holders
for each thing created anyway. This dramatically reduces
the complexity of the calls.
* test fragments are created inside test views which are created
inside test fields, etcetera, so everything is using the same
logic; test views aren't bypassing the other layers, they're
creating themselves normally within a field.
* Quite a few things now use the standard runtime/production
logic instead of being custom workarounds; for instance, instead
of `mustOpenMutexFragment` creating a fragment and then creating
a mutex vector for it, we just create a mutex-typed field and
have the normal runtime code do this.
* Similarly, we now use the same field creation logic that production
does, instead of having our own test-only thing that validates
field names directly, so our test that we're validating field names
is actually testing the runtime code. Yay.
* fragSpec goes away. it was a replacement for fragProxy which existed
to solve memory allocation problems but replaced them with interface
overhead problems. Now we just have pointers to things and maintain
valid data structures.
* Many panics are now Fatal or Fatalf calls.
* Some specific bugs fixed, like a cluster which was requested and
then had its first node directly overwritten, which isn't valid with
shared clusters.
* Drop the temp-dir test flag and TempDir variable, we can just use
$TMPDIR.
* Drop a benchmark of "write file to disk" that was purely a benchmark
of file write speed, not a benchmark of rendering the data that needs
to be written.
* Drop the unused "flags" parameter to fragment creation, which was
only used back when we changed the BSI format.
* Use holder.Txf() rather than index.Txf(). The TxFactory has to be
holder-level anyway, referring to it via the index is misleading.
* Test holders automatically close themselves and delete themselves,
we remove various other things that thought they were responsible
for deleting themselves.
We reuse a fragment. It might seem surprising that this works, but
the fragment code actually doesn't have a persistent bit depth at
all, it just accepts whatever bit depth you tell it to use. Cutting
out the recreation of the fragments saves some time.
We also cap bit depth at 8, instead of 62, because there's a ton
of runtime cost to testing more bit depths, but it doesn't actually
change the logic.
So, nShards used to be 10. If you run a complete test, with go
test -race, and you have the sample input for the unrelated
TestImportMutexSampleData configured to use 64K bit density and 2K
rows, everything is fine. If you run a partial test, everything is
fine. If you run a complete test with -race, but you skip
TestImportMutexSampleData, or reduce either the bit density or the
row count, you get a very strange panic where the go panic handler
panics trying to report what happened so we don't get a valid stack
dump. On Macs. This is as much as I could debug it after about 6
hours. Since there's no special reason to think we need all 10
shards, and 9 still tests the behavior, we're leaving this one a
mystery.
This is a lot more complex than it sounds like it will be.
We shut down the cache flush when a holder is closed, but if you're
deleting an index, we don't check for that, and can have a cache flush
still creating cache files in an index which could conceivably result
in os.RemoteAll() failing. This shouldn't happen often, but it's happened
at least once.
To address this, first, we make sure that every tier of this operation
bails as quickly as it can after the thing it's working on closes. Second,
we retry RemoveAll.
Unfortunately, some things get reopened, so we have to handle that,
have mutexes covering the access to the channel, and so on. Also, some
things were getting double-closed, which was previously harmless but
could now fail. So, first, catch all the existing double-closes and
remove them, second, make the double-close fail with an error. Note
that virtually none of the tests check for errors on close.
This passes tests and should be unable to hit the original problem.
Unfortunately, it's unreasonably hard to check that, because it
requires an incredible coincidence of timing on the delete aligning
with a cache flush.
When closing, we need to wait for existing Tx to exit before truncating
files and unmapping things. This shouldn't matter, because we don't actually
close the DB until all transactions are done, normally... except for the
background usage-gathering task. But really, it's probably just better to
be conservative.
The actual logic is fancier than it looks. We can't hold db.mu.Lock during
this, or the existing Tx can't exit. So we first grab the lock, set the closed
flag, set up a waiter for all current Tx to exit, and then release the lock.
Now we wait on the current Tx exiting. Once that's done, we grab the locks.
Anything coming in that tries to start a Tx will fail out fairly quickly
because the opened flag is now false, so even if other things get those
locks before we do, they won't keep them or create new Tx.
This makes one test deadlock because it opens a Tx and never closes it,
so we change that test to close its Tx.
it was somewhat difficult to avoid ripping this out without also
touching some of the stuff that supports roaring backend. That's going
soon too, so no worries :)
i used this script, a little clunky but it got the job done
```bash
for file in `find . -type f -print | grep '\.go'`; do
sed '1,/^\/\/ limitations under the License.$/d' $file > $file.tmp;
result=`cat $file.tmp`
if [[ result != "" ]]; then
gofmt $file.tmp &> /dev/null;
if [[ $? == 0 ]]; then
mv $file.tmp $file && gofmt -w $file;
else
rm $file.tmp;
fi
else
rm $file.tmp;
fi
done
```
These commits are hard to disentagle, and doing them separately means
re-modifying the same chunks of code several times before removing it,
and similar things.
Basically:
(1) Drop the bolt backend storage.
(2) Drop the blue-green wrapper that compares two backends.
(3) Drop unused or barely-used Tx API components from all the
remaining backends.
(4) Minor related cleanup to simplify things related to these.
The boltdb backend existed only to verify RBF. The blue-green wrapper
was mostly used to verify RBF, but in practice we had to do a lot
of working around that, and it introduced a lot of special cases.
Types removed:
IteratorFinder: Used only to implement the roaring iterator
on top of boltdb, and to complicate the way it worked in roaring.
Reverted the complications. Also unexport NewSliceContainers
which is used only for that outside of roaring's internals.
PortMapper from cluster_internal_test.go: Used only for a test
we removed early this year. Never used for anything else.
RawRoaringData: Totally unused.
TxStore: Totally unused.
Functions removed from Tx API, and sometimes corresponding
members were removed from structs:
* Dump: debugging code, I don't think I found any actually reachable
paths to it.
* Group: only used for debugging TxGroup stuff
* IncrementOpN: only used by fragment, fragment can increment its
own opN.
* Options: unused?
* Pointer: debugging only
* Readonly: used only to decide how to handle Tx in a TxGrp,
but we never add a non-readonly Tx to a TxGrp. Removed also all
the corresponding write-aware stuff.
* RoaringBitmapReader: Used exactly once, can just be a bm.WriteTo.
* Sn (and OpenSnList): Unused
* UnionInPlace: unused and conceptually-invalid; it didn't write
to storage and shouldn't have, and was just "create a bitmap
then call union-in-place", which we can do directly.
* UseRowCache: just checked storage.UseRowCache.
Other things removed:
The SetRequiredForAtomicWriteTx and ClearRequiredForAtomicWriteTx
functions go away, since nothing now seems to be using them? Same
for holder_internal_test's `testHasBit` and `testMustNotHaveBit`,
which were unused.
The DBPerShard "DeleteDBPath" and "HasData" functions and related
parts were mostly unused; took out the parts that were never
actually being reached.
Changed the API of one function to simplify special cases and
remove things:
* ImportRoaringBits had a special "data" argument which gave it
subtly different semantics for RBF and roaring (for roaring, it
could produce a roaring bitmap *with ops log*), didn't seem to
be adding much. Removed corresponding "readStorageFromArchive"
which is not otherwise used.
Also took out various debugging/dumping functions that were unused
and may have bitrotted.
Dropped a test from txfactory_internal_test, and the "pjobs"
code, because those two were the only things that needed Barrier
and thus idem, which lets us drop two more dependencies. We already
have errgroup for grouping things which want to terminate as
soon as one of them errors, approximately. To do better we'd have
to have context-threading, really.
Unbroke the WriteFragment test for non-roaring tests and made it
not roaring-only.
Performance of tests on MacOS has been atrocious for a while, and
a lot of that is fsync, so we're trying to make that optional.
To test all of this, I modified RBF to panic if anything tried to
open an RBF database without disabling fsync, and ran the tests that
way, and tracked down the various places this could still happen.
There's a lot of places in our tree where we were creating
test holders which were not getting created with fsync disabled, which
results in a surprisingly large number of points at which we end
up calling fsync in tests, which makes tests much slower than they
need to be. There's also a bunch of places where the flags don't get
propagated correctly; for instance, storage.fsync didn't propagate
to the RBFConfig.
We add an "fsync enabled" flag to OpenTranslateStoreFunc, so we can
tell translation stores that we don't need syncing, so the server's
config can be passed on appropriately.
More of the test code that sets things up is correctly configuring
that flag by default.
We also change the barely-used bolt storage backend to support this as
well.
With this done, the only calls to fsync left in a run of `go test -short`
in the top-level directory are from the zap logger in etcd, and consumed
around 0.03 seconds. The overall impact is that `go test -short`
went from "takes enough more than 10 minutes that i don't know how long
it takes" to about 2.5 minutes.
When doing the import tests, import all the data sets if there's
multiple data sets, and check that we're producing the correct number of
results including overwriting previous values, not just that we produce
the same number of values that we set, which shouldn't happen if there's
any overlap.
Also add a specific test that triggers the case I first ran into this for.
In fact, we have a number of things assuming that values passed to Import
always fit within a single known shard, so, drop all the extra complexity
around this, drop the computation of fancy view/shard keys, and so on.
There's a lot of room left to improve this probably but it's at least
better, I think.
Unfortunately, there's a handful of things, basically all of which are
test cases, which were relying on this, so, we also add functionality
for splitting import requests by shards. But this allows us to stop
duplicating each shard's inputs one at a time... which turns out to
mean that we now care that the import operation can write back to the
import request. This only affects test cases, so we adopt a crufty
hack involving cloning import requests in those rare cases, and also
when reusing the same column IDs to write to the existence field that
we'd be using later to write to another field.
Note that even if we weren't overwriting the column IDs with positions,
we'd be sorting the column/row ID lists by row-then-column, which means
we'd still be corrupting the column ID lists. This may want to change
at some point.
We also reuse a single Tx for all the views, because DB-per-shard
means that should work fine, and reduces the cost of doing these
updates, probably.
TxBitmap was a workaround for performance problems with doing
individual-bit operations directly on RBF, used only in the
large-writes path of importValue. With importValue no longer
using that path, ever, there are zero remaining users of TxBitmap,
and the test for it no longer exercises it.
Solution: Remove it.
With timestamps, we probably want to at least check larger BSI fields,
so we add that. Also, tweak the interpretation of b.N (making each
N count for 10,000 bits) so we can see allocation load at all. But we
also reduce the sparse set to be about one bit per 19 bits, because
if we do one per 70,000, and are doing field-at-a-time imports, we're
getting hundreds of imports to try to match a target of, say, around
a million values.
We also sort the inputs, because ImportValue is about to start requiring
that, since the API does it anyway.
Also, extend this to be available on Fields, because field.ImportValue
is ALSO doing things which could be inefficient or expensive.
Attributes are unmaintained and unused.
They have become more of a liability than a benefit.
This change eliminates them from the codebase.
The only user-visible change (assuming that attrs are not used) is that the attrs field will no longer appear in row JSON.
The mutex tests had weird and un-idiomatic definitions for b.N, and
in particular would report ludicrously low times for high values of
b.N because they'd still only do a small amount of importing, then
get counted as having done a much larger number of iterations. Also,
the computation of the number of values to create was pretty noticably
wrong so the secondary data set was unduly tiny.
Do tests with ranked cache and larger row counts because we have
reason to suspect that the cache behavior is mattering. We adjust the
range of tests performed to reflect real world data a bit. We also
drop the "don't do large mutex tests" thing because the insanely
bad performance on larger mutex data should be fixed now, we hope.
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.
In nearly all cases, we can just switch ioutil.TempDir->testhook.TempDir
and similarly for TempFile. There's one case where we can't because we
need files to be removed before tests are over.
Also in the process give identifiable names to a lot of temporary files
and make sure they're being cleaned up, and don't use "/tmp/foo" as a
file name in a test that could be running in more than one test process
at once. :)
- 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.
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.
Added additional mutex sample data and batches of it so we can
confirm that overwrite works. It didn't work, so that needed to be fixed.
Couple of things:
(1) Wasn't updating "last value seen" so the check for an unsorted list
didn't work.
(2) Also didn't handle the case where there were to-clear values higher
than any to-set value.
This could result in bits not getting cleared, which could result in
there being more than N bits to clear for N new bits. And that could cause
really strange problems when the input slices were parts of a single
larger slice, because bit positions to clear could get shoved in as
possible columns in a future batch.
For the Rows benchmark, we were continuing to use the original writable
transaction, meaning RBF was spending all its time looking up dirty
pages in the transaction's dirty page cache rather than working with
the disk in any way. It wasn't clear whether this was hurting or
helping performance, but it was clear that it wasn't testing the
"real" workload use case, where queries are done against the RBF
file rather than the dirty page cache.
Modify the benchmark to test it both ways for comparison. Answer:
The RBF file is faster than the in-memory map (!).
This is a partial solution to a nasty performance problem, which is that
a ContainerIterator has to *generate* all the containers. With roaring, this
was cheap because they already exist in memory; with transactional backends,
it's an allocation per container, *even for the containers we don't use*.
This design admits filters which can distinguish between answers they
can give just based on keys and times when they actually need containers
instantiated, and can also give hints as to future answers -- saying "yes"
or "no" to entire rows at a time, or indicating when they're done.
This is only part of the solution; we also need a Tx API hook for
doing scans like this which doesn't rely on ContainerIterator.
- 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
- allows blue-green testing with concurrent readers/writers.
- otherwise we don't start/end the blue and green Tx
together, and they get split by a read/write concurrently.
