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>
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>
Paging code assumes that clustering row range [a, a] contains only one
row which may not be true. Another problem is that it tries to use
range<> interface for dealing with clustering key ranges which doesn't
work because of the lack of correct comparator.
Refs #1446.
Fixes#1684.
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
Message-Id: <1475236805-16223-1-git-send-email-pdziepak@scylladb.com>
CQL server is supposed to throttle requests so that they don't
overflow memory. The problem is that it currently accounts for
request's memory only around reading of its frame from the connection
and not actual request execution. As a result too many requests may be
allowed to execute and we may run out of memory.
Fixes#1708.
Message-Id: <1475149302-11517-1-git-send-email-tgrabiec@scylladb.com>
This patch fixes a bug where queries such as the following are not
handled properly:
"SELECT * FROM ks.cf WHERE token(id) >
9207857967443869328 AND token(id) <= -9223372036854775808"
Here -9223372036854775808 represents the minimum token, which we were
just translating into a token with kind::key, thus returning incorrect
results.
Ref #1139
Ref #693Fixes#1717
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch adds the from_bytes() function to the i_partitioner class,
whose purpose is parse a particular token and explicitly handle the
case when the minimum token is specified.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
* seastar 5b7252d...9e1d5db (5):
> prometheus: prevent illegal prometheus names
> scollectd: raw_to_value should not use network order
> semaphore: Introduce get_units()
> core::scollectd: truncate the identifiers fields on a 63 characters boundary
> Merge "Fix ASAN errors in debug builds" from Tomasz
Before: the range is split only once, so it is split into 2 sub ranges
INFO 2016-09-29 15:52:43,625 [shard 0] repair - target_partitions=100, estimated_partitions=537, ranges.size=2,
range=(8993553141924659802, 8997061146192366917] ->
ranges={
(8993553141924659802, 8995307144058513359], (8995307144058513359, 8997061146192366917]}
After: the range is split mulitple times, resulting 16 sub ranges.
INFO 2016-09-29 15:55:07,934 [shard 0] repair - target_partitions=100, estimated_partitions=67, ranges.size=16,
range=(8993553141924659802, 8997061146192366917] ->
ranges={
(8993553141924659802, 8993772392191391496], (8993772392191391496, 8993991642458123191],
(8993991642458123191, 8994210892724854885], (8994210892724854885, 8994430142991586580],
(8994430142991586580, 8994649393258318274], (8994649393258318274, 8994868643525049969],
(8994868643525049969, 8995087893791781664], (8995087893791781664, 8995307144058513359],
(8995307144058513359, 8995526394325245053], (8995526394325245053, 8995745644591976748],
(8995745644591976748, 8995964894858708443], (8995964894858708443, 8996184145125440138],
(8996184145125440138, 8996403395392171832], (8996403395392171832, 8996622645658903527],
(8996622645658903527, 8996841895925635222], (8996841895925635222, 8997061146192366917]}
Without this patch, repair can do checksum with a range with a lot of
partitions, not the expected less than 100 partitions per checksum. This
can lead to unncessary data transfer since the checksum is too coarse.
For instacne, as above, if the checksum of 1 out of 537 partitions is
different, the whole 527 partitions will be synced.
Fixes#1613
Message-Id: <0775c20c485c105df5f10bd685048227f074c365.1475137029.git.asias@scylladb.com>
The snappy_compress() function expects the "compressed_length" parameter
to contain the actual output buffer length but now we're passing random
garbage from the stack.
Fixes#1711
Message-Id: <1475132127-316-1-git-send-email-penberg@scylladb.com>
* seastar 2b55789...5b7252d (3):
> Merge "rpc: serialize large messages into fragmented memory" from Gleb
> Merge "Print backtrace on SIGSEGV and SIGABRT" from Tomasz
> test_runner: avoid nested optionals
Includes patch from Gleb to adapt to seastar changes.
"This series improves repair by
1) using less streaming sessions
2) reducing unnecessary streaming traffic
3) fixing a hang during shutdown
See commit log for "repair: Reduce stream_plan usage", "repair: Reduce
unnecessary streaming traffic" and "streaming: Fail streaming sessions
during shutdown" for details.
Tested with repair_additional_test.py."
Also add information about for how long has the oldest been sitting in the
queue. This is part of the backpressure work to allow us to throttle incoming
requests if we won't have memory to process them. Shortages can happen in all
sorts of places, and it is useful when designing and testing the solutions to
know where they are, and how bad they are.
This counter is named for consistency after similar counters from transport/.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
Currently, we export the region group where memtables are placed as dirty bytes.
Upcoming patches will optimistically mark some bytes in this region as free, a
scheme we know as "virtual dirty".
We are still interested in knowing the real state of the dirty region, so we
will keep track of the bytes virtually freed and split the counters in two.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
Also make sure to not listen on the same exact address twice in case
listen_address == broadcast_address. Scylla configuration code does not
allow such thing to be configured, but better to be safe.
Message-Id: <20160927102316.GO32178@scylladb.com>
