Continuation reordering could cause us to repeatedly see the
segment-local flag var even though actual write/sync ops are done.
Can cause wild recursion without actual delayed continuation ->
SOE.
Fix by also checking queue status, since this is the wait object.
Message-Id: <1468234873-13581-1-git-send-email-calle@scylladb.com>
sstable_list is now a map<generation, sstable>; change it to a set
in preparation for replacing it with sstable_set. The change simplifies
a lot of code; the only casualty is the code that computes the highest
generation number.
If a CF does not have any sstables at all, we should treat it
as having a replay position of zero. However, since we also
must deal with potential re-sharding, we cannot just set
shard->uuid->zero initially, because we don't know what shards
existed.
Go through all CF:s post map-reduce, and for every shard where
a CF does not have an RP-mapping (no sstables found), set the
global min pos (for shard) to zero.
Fixes#1372
Message-Id: <1465991864-4211-1-git-send-email-calle@scylladb.com>
Using an ordering mechanism better than rw-locks for write/flush
means we can wait for pending write in batch mode, and coalesce
data from more than one mutation into a chunk.
It also means we can wait for a specific read+flush pair (based on
file position).
Downside is that we will not do parallel writes in batch mode (unless
we run out of buffer), which might underutilize the disk bandwidth.
Upside is that running in batch mode (i.e. per-write consistency)
now has way better bandwidth, and also, at least with high mutation
rate, better average latency.
Message-Id: <1465990064-2258-1-git-send-email-calle@scylladb.com>
With big rows I see contention in XFS allocations which cause reactor
thread to sleep. Commitlog is a main offender, so enlarge extent to
commitlog segment size for big files (commitlog and sstable Data files).
Message-Id: <20160404110952.GP20957@scylladb.com>
Cassandra-derived tools (such as sstable2json) may write commitlog segments,
that Scylla cannot recognize. Since we now write them with a distinct name,
we can recognize the name and ignore these segments, as we know the data they
contain is not interesting.
Fixes#1112.
Message-Id: <1459356904-20699-1-git-send-email-avi@scylladb.com>
commitlog's sync period is initialized as the batch period, and not as the
sync period itself as it should be.
I've found this by code inspection, but unless I am missing something
really fundamental, this seems to be completely wrong. It's been working
fine because in our defaults, I have checked that both variables default to
the same value. But it seems to me that as long as anyone would change one
of them, the behavior wouldn't be as expected.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
Message-Id: <2e7c565242fe5d4481a3ee8b0ba425ef14f5e42a.1459252783.git.glauber@scylladb.com>
While is is formally better to take a local lock first and
then first contend for a global, in this case it is arguably
better to ensure we get a gate exception synchronously (early)
instead of potentially in a continuation. Old version might
cause us to do a gate::leave even while never entered.
And since we should really only have one active (contending)
segment per shard anyway, it should not matter.
Message-Id: <1456931988-5876-1-git-send-email-calle@scylladb.com>
The segment->segment_manager pointer has, until now, been a raw pointer,
which in a way is sensible, since making circular shared pointer
relations is in general bad. However, since the code and life cycle
of segments has evolved quite a bit since that initial relation
was defined, becoming both more and then suddenly, in a sense,
less, asynchronous over time, the usage of the relation is in fact
more consistent with a shared pointer, in that a segment needs to
access its manager to properly do things like write and flush.
These two ops in particular depend on accessing the segment manager
in a way that might be fine even using raw pointers, if it was not
again for that little annoying thing of continuation reordering.
So, lets just make the relation a shared pointer, solving the issue
of whether the manager is alive when a segment accesses it. If it
has been "released" (shut down), the existing mechanisms (gate)
will then trigger and prevent any actual _actions_ from taking
place. And we don't have to complicate anything else even more.
Only "big" change is that we need to explicitly orphan all
segments in commitlog destructor (segment_manager is essentially
a p-impl).
This fixes some spurious crashes in nightly unit tests.
Fixes#966.
Message-Id: <1456838735-17108-1-git-send-email-calle@scylladb.com>
Fixes#482
See code comment. Reserve segment allocation count sum can temporarily
overflow due to continuation delay/reordering, if we manage to reach the
on_timer code before finally clauses from previous reserve allocation
invocation has processed. However, since these are benign overflows
(just indicating even more that we don't need to do anything right now)
simply capping the count should be fine.
Avoids assert in boost irange.
Message-Id: <1456740679-4537-1-git-send-email-calle@scylladb.com>
I saw the following Boost format string related warning during commitlog
replay:
INFO [shard 0] commitlog_replayer - Replaying node3/commitlog/CommitLog-1-72057594289748293.log, node3/commitlog/CommitLog-1-90071992799230277.log, node3/commitlog/CommitLog-1-108086391308712261.log, node3/commitlog/CommitLog-1-251820357.log, node3/commitlog/CommitLog-1-54043195780266309.log, node3/commitlog/CommitLog-1-36028797270784325.log, node3/commitlog/CommitLog-1-126100789818194245.log, node3/commitlog/CommitLog-1-18014398761302341.log, node3/commitlog/CommitLog-1-126100789818194246.log, node3/commitlog/CommitLog-1-251820358.log, node3/commitlog/CommitLog-1-18014398761302342.log, node3/commitlog/CommitLog-1-36028797270784326.log, node3/commitlog/CommitLog-1-54043195780266310.log, node3/commitlog/CommitLog-1-72057594289748294.log, node3/commitlog/CommitLog-1-90071992799230278.log, node3/commitlog/CommitLog-1-108086391308712262.log
WARN [shard 0] commitlog_replayer - error replaying: boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::io::too_many_args> > (boost::too_many_args: format-string referred to less arguments than were passed)
While inspecting the code, I noticed that one of the error loggers is
missing an argument. As I don't know how the original failure triggered,
I wasn't able to verify that that was the only one, though.
Message-Id: <1453893301-23128-1-git-send-email-penberg@scylladb.com>
Last series accidently broke batch mode.
With new, fancy, potentitally blocking ways, we need to treat
batch mode differently, since in this case, sync should always
come _after_ alloc-write.
Previous patch caused infinite loop. Broke jenkins.
Message-Id: <1453821077-2385-1-git-send-email-calle@scylladb.com>
Also check closed status in allocate, since alloc queue waiting could
lead to us re-allocating in a segment that gets closed in between
queue enter and us running the continuation.
Message-Id: <1453811471-1858-1-git-send-email-calle@scylladb.com>
Configured on start (for now - and dummy values at that).
When shard write/flush count reaches limit, and incoming ops will queue
until previous ones finish.
Consequently, if an allocation op forces a write, which blocks, any
other incoming allocations will also queue up to provide back pressure.
After this patch, our I/O operations will be tagged into a specific priority class.
The available classes are 5, and were defined in the previous patch:
1) memtable flush
2) commitlog writes
3) streaming mutation
4) SSTable compaction
5) CQL query
Signed-off-by: Glauber Costa <glauber@scylladb.com>
* Match origin log messages
- Demote per-file printouts to "debug" level.
* Print an all-files stat summary for whole replay (begin/summary)
- At info level, like origin
Prompted by dtest that expects origin log output.
Message-Id: <1453216558-18359-1-git-send-email-calle@scylladb.com>
"This series adds support for multiple schema versions to the commit log.
All segments contain column mappings of all schema versions used by the
mutations contained in the segment, which are necessary in order to be
able to read frozen mutations and upgrade them to the current schema
version."
Each segment chunk should contain column mappings for all schema
versions used by the mutations it contains. In order to avoid
duplication db::commitlog::segment remembers all schema versions already
written in current chunk.
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
Current commitlog interface requires writers to specify the size of a
new entry which cannot depend on the segment to which the entry is
written.
If column mappings are going to be stored in the commitlog that's not
enough since we don't know whether column mapping needs to be written
until we known in which segment the entry is going to be stored.
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
read_entry did not verify that current chunk has enough data left
for a minimal entry. Thus we could try to read an entry from the slack
left in a chunk, and get lost in the file (pos > next, skip very much
-> eof). And also give false errors about corruption.
Message-Id: <1452517700-599-1-git-send-email-calle@scylladb.com>
Schema is tracked in memtable and cache per-entry. Entries are
upgraded lazily on access. Incoming mutations are upgraded to table's
current schema on given shard.
Mutating nodes need to keep schema_ptr alive in case schema version is
requested by target node.
We have an API that wraps open_file_dma which we use in some places, but in
many other places we call the reactor version directly.
This patch changes the latter to match the former. It will have the added benefit
of allowing us to make easier changes to these interfaces if needed.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
Message-Id: <29296e4ec6f5e84361992028fe3f27adc569f139.1451950408.git.glauber@scylladb.com>
The config file expresses this number in MB, while total_memory() gives us
a quantity in bytes. This causes the commitlog not to flush until we reach
really skyhigh numbers.
While we need this fix for the short term before we cook another release,
I will note that for the mid/long term, it would be really helpful to stop
representing memory amounts as integers, and use an explicit C++ type for
those. That would have prevented this bug.
Signed-off-by: Glauber Costa <glommer@scylladb.com>
Discern fatal and non-fatal excceptions, and handle data corruption
by adding to stats, resporting it, but continue processing.
Note that "invalid_arguement", i.e. attempting to replay origin/old
segments are still considered fatal, as it is probably better to
signal this strongly to user/admin
