"This patchset contains fixes for the changes introduced in "Query result
size limiting". It also improves handling of short data reads.
I order to minimise chances of digest mismatch during data queries replicas
that were asked just to return a digest also keep track of the size of the
data (in the IDL representation) so that they would stop at the same point
nodes doing full data queries would. Moreover, data queries are not
affected by per-shard memory limit and the coordinator sends individual
result size limits to replicas in order not to depend on hardcoded values.
It is still possible to get digest mismatches if the IDL changes (e.g. a
new field is added), but, hopefully, that won't be a serious problem."
* 'pdziepak/short-read-fixes/v4' of github.com:cloudius-systems/seastar-dev:
query: introduce result_memory_accounter::foreign_state
storage_proxy: fix short reads in parallel range queries
storage_proxy: pass maximum result size to replicas
mutation_partition: use result limiter for digest reads
query: make result_memory_limiter constants available for linker
result_memory_limiter: add accounter for digest reads
idl: allow writers to use any output stream
result_memory_limiter: split new_read() to new_{data, mutation}_read()
idl: is_short_read() was added in 1.6
mutation_partition: honour allowed_short_read for static rows
storage_proxy: fix _is_short_read computation
storage_proxy: disallow short reads if got no live rows
storage_proxy: don't stop after result with no live rows
This reverts commit aa392810ff, reversing
changes made to a24ff47c637e6a5fd158099b8a65f1191fc2d023; it uses
boost::intrusive::detail directly, which it must not, and doesn't compile on
all boost versions as a consequence.
"Reduce the size of mutation_partition by implementing intrusive set using
bi::rbtree_algorithms directly and using tree nodes optimized for size.
This will reduce the size of mutation_partition by:
24 bytes + <number of cql rows> * 8 bytes
This should have a positive impact on performance because mutation_partitions
are stored both in memtable and cache.
Fixes #742."
* 'haaawk/742' of github.com:cloudius-systems/seastar-dev:
intrusive_set: rename size() to calculate_size()
Make intrusive_set_external_comparator::_value_traits static
Implement intrusive set using rbtree_algorithms
mutation_partition: make apply_reversibly_intrusive_set nongeneric
mutation_partition: take schema in find_row and clustered_row
mutation_partition: Extract intrusive set logic to a class.
mutation_partition: Replace value_comp with key_comp calls
This hopefully will make it more apparent that
the time complexity of this method is O(N) not O(1).
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
We may want to change the default individual result size limit in the
future. If it is provided by the coordinator and not hardcoded in the
replicas this can be done without causing data query digest mismatches
or wasteful mutation query results.
Original IDL generated code was hardcoded to always use bytes_ostream.
This patch makes the output stream a template parameter so that any
valid output stream can be used.
Unfortunately, making IDL writers generic requires updates in the code
that uses them, this is fixed in C++17 which would be able to deduce the
parameter in most cases.
- moved to seastar thread
- extracted sstable creation and validation logic
- reduced code duplication
- switched to mutation_reader assertions
- used result of compact_sstable() to locate the new sstable
- rather than setting gc timestamp in the past, bump the clock
before compacting
Refs #1943.
* 'tgrabiec/optimize-bloom-filter' of github.com:cloudius-systems/seastar-dev:
db: Compute key hash once in partition_presence_checker
bloom_filter: Allow checking presence using pre-hashed key
db: Use incremental selector in partition_presence_checker
This patch adds a set of tests for materialized view schema
handling, complementing the dtests for the same feature.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch introduces the do_with_cql_env_thread() function, which
behaves like do_with_cql_env() except that it executes the
user-specified function in the context of a Seastar thread.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This reduces the number of sstables we need to check to only those
whose token range overlaps with the key. Reduces cache update
time. Especially effective with leveled compaction strategy.
Refs #1943.
Incremental selector works with an immutable sstable set, so cache
updates need to be serialized. Otherwise we could mispopulate due to
stale presence information.
Presence checker interface was changed to accept decorated key in
order to gain easy access to the token, which is required by
the incremental selector.
The test assumed that mutations added to the commitlog are visible to
reads as soon as a new segment is opened. That's not true because
buffers are written back in the background, and new segment may be
active while the previous one is still being written or not yet
synced.
Fix the test so that it expectes that the number of mutations read
this way is <= the number of mutations read, and that after all
segments are synced, the number of mutations read is equal.
Message-Id: <1481630481-19395-1-git-send-email-tgrabiec@scylladb.com>
Issue #1918 describes a problem, in which we are generating smaller
memtables than we could, and therefore not respecting the flush
criteria.
That happens because group sizes (and limits) for pressure purposes, and
the the soft threshold is currently at 40 %. This causes system group's
soft threshold to be way below regular's virtual dirty limit and close
to regular group's soft threshold. The system group was very likely to
become under soft pressure when regular was because writes to regular
group are not yet throttled when they cross both soft thresholds.
This is a direct consequence of the linear hierarchy between the regions
and to guarantee that it won't happen we would have acqire the semaphore
of all ancestor regions when flushing from a child region. While that
works, it can lead to problems on its own, like priority inversion if
the regions have different priorities - like streaming and regular, and
groups lower in the hierarchy, like user, blocking explicit flushes
from their ancestors
To fix that, this patch reorganizes the dirty memory region groups so
that groups are now completely independent. As a disadvantage, when
streaming happen we will draw some memory from the cache, but we will
live with it for the time being.
Fixes#1918
Signed-off-by: Glauber Costa <glauber@scylladb.com>
When row cache is disabled, update_cache() will do nothing to the
memtable. Active readers may keep the memtable alive for unbounded
amount of time, preventing it from going away. This doesn't play well
with virtual dirty accounting. Soon before calling update_cache(), the
memory which was subtracted during flush is added back to the amount
of virtual dirty memory. If there was write pressure all along, we
will be at the dirty memory limit. When we give back subtracted memory
this will put virtual dirty way above the limit. This will stall all
writes until another memtable flush drags virtual dirty down or
readers finally release the memtable. We want to prevent upward
jumps of virtual dirty.
First part of the fix is to ensure that as long as the memtable's
region is in the dirty group, we will not revert flushed memory. This
must happen synchronously from region's memory being removed from the
group in order to prevent upward virtual dirty jumps. To make this
easier, tracking of flushed memory was moved to the memtable object.
Another part of the fix is to gradually clear the memtable when cache
is disabled in a similar fashion as when it's moved to cache. This
ensures that the actual memory held by memtable's region is released
sooner than it dies.
Refs #1879
The implementation assumes that memtable's region group is owned by
dirty_memory_manager, and tries to obtain a reference to it like this:
boost::intrusive::get_parent_from_member(_region.group(), &dirty_memory_manager::_region_group));
This is undefined behavior when the region's group does not come from
dirty manager. It's safer to be explicit about this dependency by
taking a reference to dirty_memory_manager in the constructor.
If exception is triggered early in boot when doing an I/O operation,
scylla will fail because io checker calls storage service to stop
transport services, and not all of them were initialized yet.
Scylla was failing as follow:
scylla: ./seastar/core/sharded.hh:439: Service& seastar::sharded<Service>::local()
[with Service = gms::gossiper]: Assertion `local_is_initialized()' failed.
Aborting on shard 0.
Backtrace:
0x000000000048a2ca
0x000000000048a3d3
0x00007fc279e739ff
0x00007fc279ad6a27
0x00007fc279ad8629
0x00007fc279acf226
0x00007fc279acf2d1
0x0000000000c145f8
0x000000000110d1bc
0x000000000041bacd
0x00000000005520f1
0x00007fc279aeaf1f
Aborted (core dumped)
Refs #883.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Signed-off-by: Asias He <asias@scylladb.com>
Message-Id: <963f7b0f5a7a8a1405728b414a7d7a6dccd70581.1479172124.git.asias@scylladb.com>
Problem will cause size tiered to return small jobs when there are
more than max_threshold sstables of similar size. For example, if
max_threshold is 32, and there are 36 sstables of similar size,
strategy will only return 4 sstables to be compacted. That's because
we incorrectly create a new bucket when it meets the max threshold.
What we should do is to allow buckets to grow beyond max threshold
and trim them when selecting the most suitable one for compaction.
Important to mention that estimation for size tiered will now
work better when there are more than max_threshold sstables of
similar size.
Fixes#1901.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <080bad70d6cb86eaf52ac1bdd6765ac47aab5b03.1478316140.git.raphaelsc@scylladb.com>
"We currently write the size_estimates system table for every schema
on a periodic basis, currently set to 5 minutes, which can interfere
with an ongoing workload.
This patchset virtualizes it such that queries are intercepted and we
calculate the results on the fly, only for the ranges the caller is interested in.
Fixes#1616"
* 'virtual-estimates/v4' of github.com:duarten/scylla:
size_estimates_virtual_reader: Add unit test
db: Delete size_estimates_recorder
size_estimates: Add virtual reader
column_family: Add support for virtual readers
storage_service: get_local_tokens() returns a future
nonwrapping_range: Add slice() function
range: Find a sequence's lower and upper bounds
system_keyspace: Build mutations for size estimates
size_estimates: Store the token range as bytes
range_estimates: Add schema
murmur3_partitioner: Convert maximum_token to sstring
"Clusters with a large number of nodes, or a low number of vnodes, and a
high number of shards, or a combination, suffer from an aliasing problem:
both vnodes and intra-node sharding consider the most significant bits
to select the owning node and owning shard respectively. Since the same
bits are used for both, a low number of vnodes leads to some shards
being overcommitted relative to others.
This series fixes the problem by sharding on bits 0:47 of the token
(murmur3 partitioner only), leaving the most significant 12 bits for
vnodes. Simulation shows that this value provides reasonable sharding
for 100-node, 30-shard clusters.
In order to prevent re-sharding sstables on each boot, token ranges for
the range are stored in a new sub-component of the sstable Statistics
component. With the default 12 ignored bits we have 4096 token ranges
for non-Level-compacted SSTables, which takes some space but is still
reasonable.
Fixes #1277."
Sharding on the most significant token bits aliases with the vnode mechanism,
which also uses the most significant bits; this requires a huge number of
vnodes to achieve good sharding.
This patch teaches the murmur3 partitioner to ignore the most significant
N bits when calculating a token's hard, so we use token bits which still have
some entropy. In effect, with changes the token range layout from
shard 0
shard 1
...
shard S-1
to
shard 0
shard 1
...
shard S-1
shard 0
shard 1
...
shard S-1
...
shard 0
shard 1
...
shard S-1
Where the number of repetitions of the block is 2^(ignored msb bits).
For compatibility, the default is zero ignored bits, matching the pre-patch
state, until we wire things up.
After 7c28ed, the schemas defined in the test became compressed by
default. This patch changes the test so that it is explicit about
which schemas shouldn't define a compressor.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Message-Id: <1478646530-5558-1-git-send-email-duarte@scylladb.com>
partition_range passed to row_cache::make_reader
has to be kept alive as long as the resulting reader
is used.
Otherwise weird things start to happen.
This used to work just because of a pure luck.
When I started changing the row_cache implementation
I run into very weird behaviors for this tests.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
Message-Id: <2c9e337dbbcf35f4e1394cad043eda10b8c2bd4a.1478602876.git.piotr@scylladb.com>
Fixes#1775
stream lacks a check "is_open", which is a bummer. We have to both
prevent exception propagation and add a flag of our own to make sure
exceptions in producer code reaches consumer, and does not simply
get lost in the reactor.
Message-Id: <1478508817-18854-1-git-send-email-calle@scylladb.com>
"The atomic sstable deletion provides exception safety at the cost of
quadratic behavior in the number of sstables awaiting deletion. This
causes high cpu utilization during startup.
Change the code to avoid quadratic complexity, and add some unit tests.
See #1812."
Wrapping ranges are a pain, so we are moving wrap handling to the edges.
Since cql can't generate wrapping ranges, this means thrift and the ring
maintenance code; also range->ring transformations need to merge the first
and last ranges.
Message-Id: <1478105905-31613-1-git-send-email-avi@scylladb.com>
Commit 7dcd70124a "tests/sstables: add
test for fast forwarding reader" added a test for skipping parts of
sstable. Unfortunately, it did not include the sstables it was trying to
read.
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
