There are times in which we read the Summary file twice. That actually happens
every time during normal boot (it doesn't during refresh). First during
get_sstable_key_range and then again during load().
Every summary will have at least one entry, so we can easily test for whether
or not this is properly initialized.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
Using leveled compaction strategy, only a few sstables will contain a
given key, so we need to filter out the rest. Using the summary entries
to filter keys works if the key is before the first summary entry,
but does not work if it is after the last summary entry, because the last
summary entry does not represent the last key; so sstables that are
are towards the beginning of the ring are read even if they do not contain
the key, greatly reducing read performance.
Fix by consulting the summary's first_key/last_key entries before consulting
the summary entry array.
(cherry picked from commit 715794cce6)
* seastar aa281bd...0225940 (10):
> memory: avoid exercising the reclaimers for oversized requests
> memory: fix live objects counter underflow due to cross-cpu free
> core/reactor: Don't abort in allocate_aligned_buffer() on allocation failure
> scripts/posix_net_conf.sh: added a support for bonding interfaces
> scripts/posix_net_conf.sh: move the NIC configuration code into a separate function
> scripts/posix_net_conf.sh: implement the logic for selecting default MQ mode
> scripts/posix_net_conf.sh: forward the interface name as a parameter
> http/routes: Remove request failure logging to stderr
> lowres_clock: Initialize _now when the clock is created
> apps/iotune: fix broken URL
Reproduced by dtest paging_test.py:TestPagingData.static_columns_paging_test.
Broken by f15c380a4f, where the
calcualtion of has_ck_selector got broken, in such a way that present
clustering restrictions were treated as if not present, which resulted
in static row being returned when it shouldn't.
While at it, unify the check between query_compacted() and
do_compact() by extracting it to a function.
(cherry picked from commit c2b955d40b)
The first erase_and_dispose(), which removes rows between last
position and beginning of the next range, can invalidate end()
iterator of the range. Fix by looking up end after erasing.
mutation_partition::range() was split into lower_bound() and
upper_bound() to allow for that.
This affects for example queries with descending order where the
selected clustering range is empty and falls before all rows.
Exposed by f15c380a4f, which is now
calling do_compact() during query.
Reproduced by dtest paging_test.py:TestPagingData.static_columns_paging_test
(cherry picked from commit a1539fed95)
Currently data query digest includes cells and tombstones which may have
expired or be covered by higher-level tombstones. This causes digest
mismatch between replicas if some elements are compacted on one of the
nodes and not on others. This mismatch triggers read-repair which doesn't
resolve because mutations received by mutation queries are not differing,
they are compacted already.
The fix adds compacting step before writing and digesting query results by
reusing the algorithm used by mutation query. This is not the most optimal
way to fix this. The compaction step could be folded with the query writing,
there is redundancy in both steps. However such change carries more risk,
and thus was postponed.
perf_simple_query test (cassandra-stress-like partitions) shows regression
from 83k to 77k (7%) ops/s.
Fixes#1165.
(cherry picked from commit f15c380a4f)
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>
(cherry picked from commit 70575699e4)
Until recently, we believed that range tombstones we read from sstables will
always be for entire rows (or more generalized clustering-key prefixes),
not for arbitrary ranges. But as we found out, because Cassandra insists
that range tombstones do not overlap, it may take two overlapping row
tombstones and convert them into three range tombstones which look like
general ranges (see the patch for a more detailed example).
Not only do we need to accept such "split" range tombstones, we also need
to convert them back to our internal representation which, in the above
example, involves two overlapping tombstones. This is what this patch does.
This patch also contains a test for this case: We created in Cassandra
an sstable with two overlapping deletions, and verify that when we read
it to Scylla, we get these two overlapping deletions - despite the
sstable file actually having contained three non-overlapping tombstones.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <b7c07466074bf0db6457323af8622bb5210bb86a.1459399004.git.glauber@scylladb.com>
(cherry picked from commit 99ecda3c96)
This is a rewrite of Glauber's earlier patch to do the same thing, taking
into account Avi's comments (do not use a class, do not throw from the
constructor, etc.). I also verified that the actual use case which was
broken in #1136 was fixed by this patch.
Currently, we have no support for range tombstones because CQL will not
generate them as of version 2.x. Thrift will, but we can safely leave this for
the future.
However, we have seen cases during a real migration in which a pure-CQL
Cassandra would generate range tombstones in its SSTables.
Although we are not sure how and why, those range tombstones were of a special
kind: their end and next's start range were adjacent, which means that in
reality, they could very well have been written as a single range tombstone for
an entire clustering key - which we support just fine.
This code will attempt to fix this problem temporarily by merging such ranges
if possible. Care must be taken so that we don't end up accepting a true
generic range tombstone by accident.
Fixes#1136
Signed-off-by: Glauber Costa <glauber@scylladb.com>
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <1459333972-20345-1-git-send-email-nyh@scylladb.com>
(cherry picked from commit 0fc9a5ee4d)
As Nadav noticed in his bug report, check_marker is creating its error messages
using characters instead of numbers - which is what we intended here in the
first place.
That happens because sprint(), when faced with an 8-byte type, interprets this
as a character. To avoid that we'll use uint16_t types, taking care not to
sign-extend them.
The bug also noted that one of the error messages is missing a parameter, and
that is also fixed.
Fixes#1122
Signed-off-by: Glauber Costa <glauber@scylladb.com>
Message-Id: <74f825bbff8488ffeb1911e626db51eed88629b1.1459266115.git.glauber@scylladb.com>
(cherry picked from commit 23808ba184)
While Seastar in general can accept any parameter for its I/O queues, Scylla
in particular shouldn't run with them disabled. Such will be the status when
the max-io-requests parameter is not enabled.
On top of that, we would like to have enough depth per I/O queue not to allow
for shard-local parallelism. Therefore, we will require a minimum per-queue
capacity of 4. In machines where the disk iodepth is not enough to allow for 4
concurrent requests per shard, one should reduce the number of I/O queues.
For --max-io-requests, we will check the parameter itself. However, the
--num-io-queues parameter is not mandatory, and given enough concurrent
requests, Seastar's default configuration can very well just be doing the right
thing. So for that, we will check the final result of each I/O queue.
As it is the case with other checks of the sorts, this can be overridden by
the --developer-mode switch.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
Message-Id: <63bf7e91ac10c95810351815bb8f5e94d75592a5.1458836000.git.glauber@scylladb.com>
(cherry picked from commit e750a94300)
After 4e52b41a4, remove_by_toc_name() became aware of temporary TOC
files, however, it doesn't consider that some components may be
missing if temporary TOC is present.
When creating a new sstable, the first thing we do is to write all
components into temporary TOC, so content of a temporary TOC isn't
reliable until it is renamed.
Solution is about implementing the following flow (described by Avi):
"Flow should be:
- remove all components in parallel
- forgive ENOENT, since the compoent may not have been written;
otherwise deletion error should be raised
- fsync the directory
- delete the temporary TOC
"
This problem can be reproduced by running compaction without disk
space, so compaction would fail and leave a partial sstable that would
be marked for deletion. Afterwards, remove_by_toc_name() would try to
delete a component that doesn't exist because it looked at the content
of temporary TOC.
Fixes#1095.
Signed-off-by: Raphael Carvalho <raphaelsc@scylladb.com>
Message-Id: <0cfcaacb43cc5bad3a8a7ea6c1fa6f325c5de97d.1459194263.git.raphaelsc@scylladb.com>
(cherry picked from commit d515a7fd85)
We had a problem reading certain existing Cassandra sstables into
Scylla.
Our consume_range_tombstone() function assumes that the start and end
columns have a certain "end of component" markers, and want to verify
that assumption. But because of bugs in older versions of Cassandra,
see https://issues.apache.org/jira/browse/CASSANDRA-7593, sometimes the
"end of component" was missing (set to 0). CASSANDRA-7593 suggested
this problem might exist on the start column, so we allowed for that,
but now we discovered a case where also the end column is set to 0 -
causing the test in consume_range_tombstone() to fail and the sstable
read to fail - causing Scylla to no be able to import that sstable from
Cassandra. Allowing for an 0 also on the end column made it possible
to read that sstable, compact it, and so on.
Fixes#1125.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <1459173964-23242-1-git-send-email-nyh@scylladb.com>
(cherry picked from commit a05577ca41)
Problem found by dtest which loads sstables with generation 1 and 2 into an
empty column family. The root of the problem is that reshuffle procedure
changes new sstables to start from generation 2 at least. So reshuffle could
try to set generation 1 to 2 when generation 2 exists.
This problem can be fixed by starting from generation 1 instead, so reshuffle
would handle this case properly.
Fixes#1099.
Signed-off-by: Raphael Carvalho <raphaelsc@scylladb.com>
Message-Id: <88c51fbda9557a506ad99395aeb0a91cd550ede4.1458917237.git.raphaelsc@scylladb.com>
(cherry picked from commit e6e5999282)
Fixes#797
To make sure an inopportune crash after truncate does not leave
sstables on disk to be considered live, and thus resurrect data,
after a truncate, use delete function that renames the TOC file to
make sure we've marked sstables as dead on disk when we finish
this discard call.
Message-Id: <1458575440-505-2-git-send-email-calle@scylladb.com>
Rebase to 1.0:
Signed-off-by: Glauber Costa <glauber@scylladb.com>
Note: "normal" remove_by_toc_name must now be prepared for and check
if the TOC of the sstable is already moved to temp file when we
get to the juicy delete parts.
Message-Id: <1458575440-505-1-git-send-email-calle@scylladb.com>
For the rebase to 1.0:
Signed-off-by: Glauber Costa <glauber@scylladb.com>
A STREAM_MUTATION_DONE message will signal the receiver that the sender
has completed the sending of streams mutations. When the receiver finds
it has zero task to send and zero task to receive, it will finish the
stream_session, and in turn finish the stream_plan if all the
stream_sessions are finished. We should call receive_task_completed only
after the flush finishes so that when stream_plan is finshed all the
data is on disk.
Fixes repair_disjoint_data_test issue with Glauber's "[PATCH v4 0/9] Make
sure repairs do not cripple incoming load" serries
======================================================================
FAIL: repair_disjoint_data_test
(repair_additional_test.RepairAdditionalTest)
----------------------------------------------------------------------
Traceback (most recent call last):
File "scylla-dtest/repair_additional_test.py",
line 102, in repair_disjoint_data_test
self.check_rows_on_node(node1, 3000)
File "scylla-dtest/repair_additional_test.py",
line 33, in check_rows_on_node
self.assertEqual(len(result), rows, len(result))
AssertionError: 2461
(cherry picked from commit c2eff7e824)
The repair code as it is right now is a bit convoluted: it resorts to detached
continuations + do_for_each when calling sync_ranges, and deals with the
problem of excessive parallelism by employing a semaphore inside that range.
Still, even by doing that, we still generate a great number of
checksum requests because the ranges themselves are processed in parallel.
It would be better to have a single-semaphore to limit the overall parallelism
for all requests.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
(cherry picked from commit f49e965d78)
Theoretically, because we can have a lot of pending streaming memtables, we can
have the database start throttling and incoming connections slowing down during
streaming.
Turns out this is actually a very easy condition to trigger. That is basically
because the other side of the wire in this case is quite efficient in sending
us work. This situation is alleviated a bit by reducing parallelism, but not
only it does't go away completely, once we have the tools to start increasing
parallelism again it will become common place.
The solution for this is to limit the streaming memtables to a fraction of the
total allowed dirty memory. Using the nesting capability built in in the LSA
regions, we will make the streaming region group a child of the main region
group. With that, we can throttle streaming requests separately, while at the
same time being able to control the total amount of dirty memory as well.
Because of the property, it can still be the case that incoming requests will
throttle earlier due to streaming - unless we allow for more dirty memory to be
used during repairs - but at least that effect will be limited.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
(cherry picked from commit 34a9fc106f)
The repair process will potentially send ranges containing few mutations,
definitely not enough to fill a memtable. It wants to know whether or not each
of those ranges individually succeeded or failed, so we need a future for each.
Small memtables being flushed are bad, and we would like to write bigger
memtables so we can better utilize our disks.
One of the ways to fix that, is changing the repair itself to send more
mutations at a single batch. But relying on that is a bad idea for two reasons:
First, the goals of the SSTable writer and the repair sender are at odds. The
SSTable writer wants to write as few SSTables as possible, while the repair
sender wants to break down the range in pieces as small as it can and checksum
them individually, so it doesn't have to send a lot of mutations for no reason.
Second, even if the repair process wants to process larger ranges at once, some
ranges themselves may be small. So while most ranges would be large, we would
still have potentially some fairly small SSTables lying around.
The best course of action in this case is to coalesce the incoming streams
write-side. repair can now choose whatever strategy - small or big ranges - it
wants, resting assure that the incoming memtables will be coalesced together.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
(cherry picked from commit 455d5a57d2)
Keeping the mutations coming from the streaming process as mutations like any
other have a number of advantages - and that's why we do it.
However, this makes it impossible for Seastar's I/O scheduler to differentiate
between incoming requests from clients, and those who are arriving from peers
in the streaming process.
As a result, if the streaming mutations consume a significant fraction of the
total mutations, and we happen to be using the disk at its limits, we are in no
position to provide any guarantees - defeating the whole purpose of the
scheduler.
To implement that, we'll keep a separate set of memtables that will contain
only streaming mutations. We don't have to do it this way, but doing so
makes life a lot easier. In particular, to write an SSTable, our API requires
(because the filter requires), that a good estimate on the number of partitions
is informed in advance. The partitions also need to be sorted.
We could write mutations directly to disk, but the above conditions couldn't be
met without significant effort. In particular, because mutations can be
arriving from multiple peer nodes, we can't really sort them without keeping a
staging area anyway.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
(cherry picked from commit 5fa866223d)
Streaming has currently one class, that can be used to contain the read
operations being generated by the streaming process. Those reads come from two
places:
- checksums (if doing repair)
- reading mutations to be sent over the wire.
Depending on the amount of data we're dealing with, that can generate a
significant chunk of data, with seconds worth of backlog, and if we need to
have the incoming writes intertwined with those reads, those can take a long
time.
Even if one node is only acting as a receiver, it may still read a lot for the
checksums - if we're talking about repairs, those are coming from the
checksums.
However, in more complicated failure scenarios, it is not hard to imagine a
node that will be both sending and receiving a lot of data.
The best way to guarantee progress on both fronts, is to put both kinds of
operations into different classes.
This patch introduces a new write class, and rename the old read class so it
can have a more meaningful name.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
(cherry picked from commit 10c8ca6ace)
The column family still has to teach the memtable list how to allocate a new memtable,
since it uses CF parameters to do so.
After that, the memtable_list's constructor takes a seal and a create function and is complete.
The copy constructor can now go, since there are no users left.
The behavior of keeping a reference to the underlying memtables can also go, since we can now
guarantee that nobody is keeping references to it (it is not even a shared pointer anymore).
Individual memtables are, and users may be keeping references to them individually.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
(cherry picked from commit 635bb942b2)
Each list can have a different active memtable. The column family method keeps
existing, since the two separate sets of memtable are just an implementation
detail to deal with the problem of streaming QoS: *the* active memtable keeps
being the one from the main list.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
(cherry picked from commit 6ba95d450f)
memtable_list is currently just an alias for a vector of memtables. Let's move
them to a class on its own, exporting the relevant methods to keep user code
unchanged as much as possible.
This will help us keeping separate lists of memtables.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
(cherry picked from commit af6c7a5192)
