This patch adds the estimated_keys_for_range() function, which
estimates the number of keys present between the specified range.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
"The version is taken from the installation rather than the API, a mode command
line indicated that this is part of the setup and uuid is used for the
interaction with the checkversion server."
* 'amnon/check_version_on_startup_v3' of github.com:cloudius-systems/seastar-dev:
scylla_setup: Check and report the scylla version
scylla-housekeeping: check version during setup
There is already queue_length-requests_blocked_memory, but it's a
gauge so does not reflect what happened between the sampling points.
total_operations-requests_blocked_memory will allow to see if there
were any (and how many) requests which were blocked by dirty memory.
Message-Id: <1476098616-12682-1-git-send-email-tgrabiec@scylladb.com>
Presents current heap profile recording.
Works in text mode or dumps to collapsed stacks format from which
flame graph can be generated.
To generate a flamegraph:
(gdb) scylla heapprof --flame
Wrote heapprof.stacks
$ flamegraph.pl --colors mem < heapprof.stacks > heapprof.svg
flamegraph.pl comes from:
https://github.com/brendangregg/FlameGraph.git
Text mode example:
(gdb) scylla heapprof --min 100000000
All (274699676, #10213)
\-- void* memory::cpu_pages::allocate_large_and_trim<memory::cpu_pages::allocate_large_aligned(unsigned int, unsigned int)::{lambda(unsigned int, unsigned int)#1}>(unsigned int, memory::cpu_pages::allocate_large_aligned(unsigned int, unsigned int)::{lambda(unsigned int, unsigned int)#1}) + 169 (268435456, #1)
memory::allocate_large_aligned(unsigned long, unsigned long) + 87
memory::allocate_aligned(unsigned long, unsigned long) + 48
aligned_alloc + 9
logalloc::segment_zone::segment_zone() + 304
logalloc::segment_pool::allocate_segment() + 477
logalloc::segment_pool::segment_pool() + 304
__tls_init.part.801 + 72
logalloc::region_group::release_requests() + 1333
logalloc::region_group::add(logalloc::region_group*) + 514
The branches are formatted like this:
-- <symbol> (<size>, #<count>)
Where <size> is total size of live objects and <count> is total
number of live objects, for all objects allocated from paths going
through this node.
Nodes which share the same <size> and <count> are stacked like this:
-- <symbol_1> (<size>, #<count>)
<symbol_2>
<symbol_3>
Message-Id: <1475583334-19524-1-git-send-email-tgrabiec@scylladb.com>
Limiting the concurrency of memtable flushes to 4 was a temporary
workaround for the fact that we lacked good write behind support. Now
that write behind is properly merged we can reduce the concurrency to
what it should be, one.
This means that memtable flushes will now be serialized, and only when
one of them ends will the next one begin. Disk parallelism is obtained
through the write-behind mechanism.
Fixes#1373
Signed-off-by: Glauber Costa <glauber@scylladb.com>
Message-Id: <528f9ef928b5101bed952df600eb8555c275497a.1475881100.git.glauber@scylladb.com>
There is a limit to concurrency of sstable readers on each shard. When
this limit is exhausted (currently 100 readers) readers queue. There
is a timeout after which queued readers are failed, equal to
read_request_timeout_in_ms (5s by default). The reason we have the
timeout here is primarily because the readers created for the purpose
of serving a CQL request no longer need to execute after waiting
longer than read_request_timeout_in_ms. The coordinator no longer
waits for the result so there is no point in proceeding with the read.
This timeout should not apply for readers created for streaming. The
streaming client currently times out after 10 minutes, so we could
wait at least that long. Timing out sooner makes streaming unreliable,
which under high load may prevent streaming from completing.
The change sets no timeout for streaming readers at replica level,
similarly as we do for system tables readers.
Fixes#1741.
Message-Id: <1475840678-25606-1-git-send-email-tgrabiec@scylladb.com>
Make split_after() more generic by allowing split_point to be anywhere,
not just within the input range. If the split_point is before, the entire
range is returned; and if it is after, stdx::nullopt is returned.
"before" and "after" are not well defined for wrap-around ranges, so
but we are phasing them out and soon there will not be
wrapping_range::split_after() users.
This is a prerequisite for converting partition_range and friends to
nonwrapping_range.
Message-Id: <1475765099-10657-1-git-send-email-avi@scylladb.com>
Commit log replay is a synchronous operation in bootstrap, so services
will only be started after it's completed. By starting compaction before,
less bandwidth will be available to both and consequently boot will be
slowed down. Fix is simply about moving compaction, which is an
asynchronous operation after commitlog replay is over.
Fixes#1620.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <d2a173a4ee4d474317b970c6b39530e61067fea9.1475527955.git.raphaelsc@scylladb.com>
This patch adds the parsing for the "CREATE MATERIALIZED VIEW" statement,
following Cassandra 3 syntax. For example:
CREATE MATERIALIZED VIEW building_by_city
AS SELECT * FROM buildings
WHERE city IS NOT NULL
PRIMARY KEY(city, name);
It also adds the "IS NOT NULL" operator needed for this purpose.
As in Cassandra, "IS NOT NULL" can only be used for materialized
view creation, and not in a normal SELECT. It can only be used with
the NULL operand (i.e., "IS NOT 3" will be a syntax error).
The current implementation of this statement just does some sanity
checking (such as to verify that "city" is a valid column name and that
the "building" base table exists), complains that materialized views are
not yet supported:
SyntaxException: <ErrorMessage code=2000 [Syntax error in CQL query] message="Failed parsing statement: [CREATE MATERIALIZED VIEW building_by_city AS
SELECT * FROM buildings
WHERE city IS NOT NULL
PRIMARY KEY(city, name);] reason: unsupported operation: Materialized views not yet supported">
As mentioned above, the "IS NOT NULL" restriction is not allowed in
ordinary selects not creating a materialized views:
SELECT * FROM buildings WHERE city IS NOT NULL;
InvalidRequest: code=2200 [Invalid query] message="restriction 'city IS NOT null' is only supported in materialized view creation"
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <1475742927-30695-1-git-send-email-nyh@scylladb.com>
The latest virtual dirty patches broke the SSTable tests. The reason for
this is that those tests will flush synthetic memtables that do not have
a region_group attached to it.
Normally in cases like this we would just give the flush_reader an empty
region group. However, the memtable class constructor takes a
region_group pointer and that can be null according to the interface.
So we must conditionally test it.
If there isn't a region_group involved, the virtual dirty accounting
should be disabled: after all, we won't even have the baseline memory
to begin with.
One of the approaches to fix this could be to just provide null
accounter classes to be used as a surrogate for the accounting classes
in this case. However, since this is mostly used for tests, a much
simpler way is to just revert back to the scanning reader in that case.
The scanning reader is similar enough to the flush_reader, except that
it can handle partial ranges, slices, and delegate accesses to an
sstable post-flush. We don't need any of that, but as argued above,
there is no need to remove it either.
Signed-off-by: Glauber Costa <glommer@scylladb.com>
Message-Id: <1475667271-60806-1-git-send-email-glommer@scylladb.com>
Remove inclusions from header files (primary offender is fb_utilities.hh)
and introduce new messaging_service_fwd.hh to reduce rebuilds when the
messaging service changes.
Message-Id: <1475584615-22836-1-git-send-email-avi@scylladb.com>
"Description:
============
Scylla currently suffers from a brick wall behavior of the request throttler.
Requests pile up until we reach the dirty memory limit, at which point we stop
serving them until we have freed enough memory to allow for more requests.
The problem is that freeing dirty memory means writing an SSTable to completion.
That can take a long time, even if we are blessed with great disks. Those long
waiting times can and will translate into timeouts. That is bad behavior.
What this patch does is introduce one form of virtual dirty memory accounting.
Instead of allowing 100 % of the dirty memory to be filled up until we stop
accepting requests, we will do that when we reach 50 % of memory. However,
instead of releasing requests only when an SSTable is fully written, we start
releasing them when some memory was written.
The practical effect of that, is that once we reach 50 % occupancy in our dirty
memory region, we will bring the system from CPU speed to disk speed, and will
start accepting requests only at the rate we are able to write memory back.
Results
=======
With this patchset running a load big enough to easily saturate the disk,
(commitlog disabled to highlight the effects of the memtable writer), I am able
to run scylla for many minutes, with timeouts occurring only when I run out of
disk space, whereas without this patch a swarm of timeouts would start merely 2
seconds after the load started - and would never get stable.
In V2, I have sent a set of graphs illustrating the performance of this solution.
This version does not have any significant differences in that front.
For details, please refer to
https://groups.google.com/d/msg/scylladb-dev/iCvD-3Z-QqY/EM8KUh_MAQAJ
Accuracy of the accounting:
---------------------------
It is important for us to be as accurate as possible when accounting freed
memory, since every byte we mark as freed may allow one or more requests to be
executed. I have measured the accuracy of this approach (ignoring padding,
object size for the mutation fragments) to be 99.83 % of used memory in the
test workload I have ran (large, 65k mutations). Memtables under this circumnstance
tend to have a very high occupancy ratio because throttle breeds idle, and idle
breeds compact-on-idle.
Known Issues:
-------------
A lot of time can be elapsed between destroying the flush_reader and actually
releasing memory. The release of memory only happens when the SSTable is fully
sealed, and we have to flush the files, as well as finish writing all SSTable
components at this point. This happened in practice with a buggy kernel that
would result in flushes taking a long time.
After that is fixed, this is just a theoretical problem and in practice it
shouldn't matter given the time we expect those operations to take."
* 'virtual-dirty-v6' of github.com:glommer/scylla:
database: allow virtual dirty memory management
streamed_mutation: make _buffer private
add accounting of memory read to partition_snapshot_reader
move partition_snapshot_reader code to header file
LSA: allow a group to query its own region group
memtables: split scanning reader in two
sstables: use special reader for writing a memtable
LSA: export information about object memory footprint
LSA: export information about size of the throttle queue
database: export virtual dirty bytes region group
* seastar 18f7bb8...f937fb0 (5):
> Merge "Fix signal mask corruption" from Tomasz
> core/memory: Avoid violating strict aliasing when accessing allocation sites
> core/memory: Avoid indirection when storing allocation sites
> core/memory: Add a way to disable abort on allocation failure in some scope
> core/sharded: Allow mapper to take the service by non-const reference
Scylla currently suffers from a brick wall behavior of the request throttler.
Requests pile up until we reach the dirty memory limit, at which point we stop
serving them until we have freed enough memory to allow for more requests.
The problem is that freeing dirty memory means writing an SSTable to completion.
That can take a long time, even if we are blessed with great disks. Those long
waiting times can and will translate into timeouts. That is bad behavior.
What this patch does is introduce one form of virtual dirty memory accounting.
Instead of allowing 100 % of the dirty memory to be filled up until we stop
accepting requests, we will do that when we reach 50 % of memory. However,
instead of releasing requests only when an SSTable is fully written, we start
releasing them when some memory was written.
The practical effect of that is that once we reach 50 % occupancy in our dirty
memory region, we will bring the system from CPU speed to disk speed, and will
start accepting requests only at the rate we are able to write memory back.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
It is currently protected, but now all users go through
push_mutation_fragment(). So we can safely move its visibility to guarantee
that it stays that way.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
By default, we don't do any accounting. By specializing this class and providing
an accounter class, we can account how much memory are we reading as we read
through the elements.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
This is so we can template it without worrying about declaring the
specializations in the .cc file.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
The code that is common will live in its own reader, the iterator_reader. All
friendly private access to memtable attributes and methods happen through the
iterator reader.
After this patch, we are now left with the scanning_reader - same as always,
but now implemented on top of the iterator_reader, and a flush_reader, which
will be used by SSTable flushes only.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
Right now the special reader doesn't do much, but the idea is that we will
soon replace it will a reader that specializes in flush, and is in turn able
to provide read-side on-flush functionality like virtual dirty.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
We allocate objects of a certain size, but we use a bit more memory to hold
them. To get a clerer picture about how much memory will an object cost us, we
need help from the allocator. This patch exports an interface that allow users
to query into a specific allocator to get that information.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
In order to allow Scylla’s docker container to handle multiple network
interfaces, the start-scylla script was refactored:
- `$IP` is now called `$SCYLLA_LISTEN_ADDRESS`, so it is less likely to
be confused or interfere with other environment variables.
- `$SCYLLA_LISTEN_ADDRESS` now checks its value and also tries to
resolve a hostname, if no IP was set to it.
- `$SCYLLA_LISTEN_DEVICE` can now be set as environment variable and
contain any available NIC device name (e.g. `eth0`). The script
automatically retrieves the IP address from the device.
Usage:
1. With `$SCYLLA_LISTEN_ADDRESS` as IP:
`docker run -t -i --rm --name scylla -e SCYLLA_LISTEN_ADDRESS=192.168.1.100 scylladb/scylla`
2. With `$SCYLLA_LISTEN_ADDRESS` as hostname:
`docker run -t -i --rm --name scylla -e SCYLLA_LISTEN_ADDRESS=containername.network.lan scylladb/scylla`
3. With `$SCYLLA_LISTEN_DEVICE`:
`docker run -t -i --rm --name scylla -e SCYLLA_LISTEN_DEVICE=eth0 scylladb/scylla`
Message-Id: <20161003151230.67672-1-marius@twostairs.com>
Currently, the code responsible for calculating ranges for the next
request could produce a wrap-around partition range. For example, if the
original range was (unimportant, A] and the last partition key A then
the output range would be (A, A].
This patch adds checks to make sure that in such cases the range is
removed.
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
Message-Id: <1475497244-2790-1-git-send-email-pdziepak@scylladb.com>
cassandra_exception::prepare_message() is called from derived classes'
constructors before the base cassnadra_exception object is constructed.
This is technically illegal but harmless. Fix by marking the function
static.
Found by clang.
"This patch set ensures we can correctly handle queries
where the minimum token is specified."
* 'min-token/v3' of github.com:duarten/scylla:
cql_query_test: Add test case for min/max token bounds
token_restriction: Deal with minimum tokens
partitioner: Parse token from bytes
This object, similarly to a global_schema_ptr, allows to dynamically
create the trace_state_ptr objects on different shards in a context
of the original tracing session.
This object would create a secondary tracing session object from the
original trace_state_ptr object when a trace_state_ptr object is needed
on a "remote" shard, similarly to what we do when we need it on a remote
Node.
Fixes#1678Fixes#1647
Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
Message-Id: <1474387767-21910-1-git-send-email-vladz@cloudius-systems.com>
This patch adds a call to the scylla-housekeeping check version during
setup, so a warning will be printed if a newer version is available.
Signed-off-by: Amnon Heiman <amnon@scylladb.com>
This changes are for running scylla during setup.
It contains the following changes:
1. get the current version from the command line (as the syclla does not
run at this stage).
2. It support a mode parameter in the command line to indicate that we
running during the installation.
3. It accept an external uuid that will be used with all interaction
with the check_version server.
Signed-off-by: Amnon Heiman <amnon@scylladb.com>
When max sstable size is increased, higher levels are suffering from
starvation because we decide to compact a given level if the following
calculation results in a number greater than 1.001:
level_size(L) / max_size_for_level_l(L)
Fixes#1720.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Uniform token range distribution across sstables in a level > 1 was broken,
because we were only choosing sstable with lowest first key, when compacting
a level > 0. This resulted in performance problem because L1->L2 may have a
huge overlap over time, for example.
Last compacted key will now be stored for each level to ensure sort of
"round robin" selection of sstables for compactions at level >= 1.
That's also done by C*, and they were once affected by it as described in
https://issues.apache.org/jira/browse/CASSANDRA-6284.
Fixes#1719.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
