C++20 introduced `contains` member functions for maps and sets for
checking whether an element is present in the collection. Previously
`count` function was often used in various ways.
`contains` does not only express the intend of the code better but also
does it in more unified way.
This commit replaces all the occurences of the `count` with the
`contains`.
Tests: unit(dev)
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
Message-Id: <b4ef3b4bc24f49abe04a2aba0ddd946009c9fcb2.1597314640.git.piotr@scylladb.com>
Merged pull request https://github.com/scylladb/scylla/pull/7018
by Piotr Sarna:
This series addresses various issues with metrics and semaphores - it mainly adds missing metrics, which makes it possible to see the length of the queues attached to the semaphores. In case of view building and view update generation, metrics was not present in these services at all, so a first, basic implementation is added.
More precise semaphore metrics would ease the testing and development of load shedding and admission control.
view_builder: add metrics
db, view: add view update generator metrics
hints: track resource_manager sending queue length
hints: add drain queue length to metrics
table: add metrics for sstable deletion semaphore
database: remove unused semaphore
Now that it is safe to filter md format sstable by min/max column names
we can remove the `filtering_broken` variable that disabled filtering
in 19b76bf75b to fix#4442.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
To prevent https://github.com/scylladb/scylla/issues/3552
we want to ensure that in any case that the partition exists in any
sstable, we emit partition_start/end, even when returning no rows.
In the first filtering pass, filter_sstable_for_reader_by_pk filters
the input sstables based on the partition key, and num_sstables is set the size
of the sstables list after the first filtering pass.
An empty sstables list at this stage means there are indeed no sstables
with the required partition so returning an empty result will leave the
cache in the desired state.
Otherwise, we filter again, using filter_sstable_for_reader_by_ck,
and examine the list of the remaining readers.
If num_readers != num_sstables, we know that
some sstables were filterd by clustering key, so
we append a flat_mutation_reader_from_mutations to
the list of readers and return a combined reader as before.
This will ensure that we will always have a partition_start/end
mutations for the queried partition, even if the filtered
readers emit no rows.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
With the md sstable format, min/max column names in the metadata now
track clustering rows (with or without row tombstones),
range tombstones, and partition tombstones (that are
reflected with empty min/max column names - indicating
the full range).
As such, min and max column names may be of different lengths
due to range tombstones and potentially short clustering key
prefixes with compact storage, so the current matching algorithm
must be changed to take this into account.
To determine if a slice range overlaps the min/max range
we are using position_range::overlaps.
sstable::clustering_components_ranges was renamed to position_range
as it now holds a single position_range rather than a vector of bytes_view ranges.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Move contains_rows from table code to sstable::may_contain_rows
since its implementation now has too specific knowledge of sstable
internals.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Static rows aren't reflected in the sstable min/max clustering keys metadata.
Since we don't have any indication in the metadata that the sstable stores
static rows, we must read all sstables if a static column is requested.
Refs #3553
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
We're about to drop `filtering_broken` in a future patche
when clustering filtering can be supported for md-format sstables.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Move the logic from table to sstable as it will contain
intimate knowledge of the sstable min/max column names validity
for md format.
Also, get rid of the sstable::clustering_components_ranges() method
as the member is used only internally by the sstable code now.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Merged pull request https://github.com/scylladb/scylla/pull/6910
by Wojciech Mitros:
This patch enables selecting more than 2^32 rows from a table. The change
becomes active after upgrading whole cluster - until then old limits are
used.
Tested reading 4.5*10^9 rows from a virtual table, manually upgrading a
cluster with ccm and performing cql SELECT queries during the upgrade,
ran unit tests in dev mode and cql and paging dtests.
tests: add large paging state tests
increase the maximum size of query results to 2^64
"
With this patches a monitor is destroyed before the writer, which
simplifies the writer destructor.
"
* 'espindola/simplify-write-monitor-v2' of https://github.com/espindola/scylla:
sstables: Delete write_failed
sstables: Move monitor after writer in compaction_writer
Currently, we cannot select more than 2^32 rows from a table because we are limited by types of
variables containing the numbers of rows. This patch changes these types and sets new limits.
The new limits take effect while selecting all rows from a table - custom limits of rows in a result
stay the same (2^32-1).
In classes which are being serialized and used in messaging, in order to be able to process queries
originating from older nodes, the top 32 bits of new integers are optional and stay at the end
of the class - if they're absent we assume they equal 0.
The backward compatibility was tested by querying an older node for a paged selection, using the
received paging_state with the same select statement on an upgraded node, and comparing the returned
rows with the result generated for the same query by the older node, additionally checking if the
paging_state returned by the upgraded node contained new fields with correct values. Also verified
if the older node simply ignores the top 32 bits of the remaining rows number when handling a query
with a paging_state originating from an upgraded node by generating and sending such a query to
an older node and checking the paging_state in the reply(using python driver).
Fixes#5101.
We need only one of the shards owning each ssatble to call create_links.
This will allow us to simplify it and only handle crash/replay scenarios rather than rename/link/remove races.
Fixes#1622
Test: unit(dev), database_test(debug)
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Message-Id: <20200803065505.42100-3-bhalevy@scylladb.com>
"
While working on another patch I was getting odd compiler errors
saying that a call to ::make_shared was ambiguous. The reason was that
seastar has both:
template <typename T, typename... A>
shared_ptr<T> make_shared(A&&... a);
template <typename T>
shared_ptr<T> make_shared(T&& a);
The second variant doesn't exist in std::make_shared.
This series drops the dependency in scylla, so that a future change
can make seastar::make_shared a bit more like std::make_shared.
"
* 'espindola/make_shared' of https://github.com/espindola/scylla:
Everywhere: Explicitly instantiate make_lw_shared
Everywhere: Add a make_shared_schema helper
Everywhere: Explicitly instantiate make_shared
cql3: Add a create_multi_column_relation helper
main: Return a shared_ptr from defer_verbose_shutdown
If the read is not paged (short read is not allowed) abort the query if
the hard memory limit is reached. On reaching the soft memory limit a
warning is logged. This should allow users to adjust their application
code while at the same time protecting the database from the really bad
queries.
The enforcement happens inside the memory accounter and doesn't require
cooperation from the result builders. This ensures memory limit set for
the query is respected for all kind of reads. Previously non-paged reads
simply ignored the memory accounter requesting the read to stop and
consumed all the memory they wanted.
If somebody wants to bypass proper memory accounting they should at
the very least be forced to consider if that is indeed wise and think a
second about the limit they want to apply.
Use the recently added `max_result_size` field of `query::read_command`
to pass the max result size around, including passing it to remote
nodes. This means that the max result size will be sent along each read,
instead of once per connection.
As we want to select the appropriate `max_result_size` based on the type
of the query as well as based on the query class (user or internal) the
previous method won't do anymore. If the remote doesn't fill this
field, the old per-connection value is used.
seastar::make_lw_shared has a constructor taking a T&&. There is no
such constructor in std::make_shared:
https://en.cppreference.com/w/cpp/memory/shared_ptr/make_shared
This means that we have to move from
make_lw_shared(T(...)
to
make_lw_shared<T>(...)
If we don't want to depend on the idiosyncrasies of
seastar::make_lw_shared.
Signed-off-by: Rafael Ávila de Espíndola <espindola@scylladb.com>
A variant of `make_range_sstable_reader()` that wraps the reader in a
restricting reader, hence making it wait for admission on the read
concurrency semaphore, before starting to actually read.
We'd like to use the same uuid both for printing compaction log
messages and to update compaction_history.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
This patch changes the per table latencies histograms: read, write,
cas_prepare, cas_accept, and cas_learn.
Beside changing the definition type and the insertion method, the API
was changed to support the new metrics.
Signed-off-by: Amnon Heiman <amnon@scylladb.com>
This patch changes the row locking latencies to use
time_estimated_histogram.
The change consist of changing the histogram definition and changing how
values are inserted to the histogram.
Signed-off-by: Amnon Heiman <amnon@scylladb.com>
get_shards_for_this_sstable() can be called inside table::add_sstable()
because the shards for a sstable is precomputed and so completely
exception safe. We want a central point for checking that table will
no longer added shared SSTables to its sstable set.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
no longer need to conditionally track the SSTable metadata,
as table will no longer accept shared SSTables.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Now that table will no longer accept shared SSTables, it no longer
needs to keep track of them.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Now that table no longer accept shared SSTables, those two functions can
be simplified by removing the shared condition.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
With off-strategy work on reshard on boot and refresh, table no
longer needs to work with Shared SSTables. That will unlock
a host of cleanups.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Now when the snapshot stopping is correctly handled, we may pull the database
reference all the way down to the schema::describe().
One tricky place is in table::napshot() -- the local db reference is pulled
through an smp::submit_to call, but thanks to the shard checks in the place
where it is needed the db is still "local"
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Before Scylla 3.0, we used to send streaming mutations using
individual RPC requests and flush them together using dedicated
streaming memtables. This mechanism is no longer in use and all
versions that use it have long reached end-of-life.
Remove this code.
Streaming is handled by just once group for CPU scheduling, so
separating it into read and write classes for I/O is artificial, and
inflates the resources we allow for streaming if both reads and writes
happen at the same time.
Merge both classes into one class ("streaming") and adjust callers. The
merged class has 200 shares, so it reduces streaming bandwidth if both
directions are active at the same time (which is rare; I think it only
happens in view building).
Uploading of SSTables is problematic: for historical reasons it takes a
lock that may have to wait for ongoing compactions to finish, then it
disables writes in the table, and then it goes loading SSTables as if it
knew nothing about them.
With the sstable_directory infrastructure we can do much better:
* we can reshard and reshape the SSTables in place, keeping the number
of SSTables in check. Because this is an background process we can be
fairly aggressive and set the reshape mode to strict.
* we can then move the SSTables directly into the main directory.
Because we know they are few in number we can call the more elegant
add_sstable_and_invalidate_cache instead of the open coding currently
done by load_new_sstables
* we know they are not shared (if they were, we resharded them),
simplifying the load process even further.
The major changes after this patch is applied is that all compactions
(resharding and reshape) needed to make the SSTables in-strategy are
done in the streaming class, which reduces the impact of this operation
on the node. When the SSTables are loaded, subsequent reads will not
suffer as we will not be adding shared SSTables in potential high
numbers, nor will we reshard in the compaction class.
There is also no more need for a lock in the upload process so in the
fast path where users are uploading a set of SSTables from a backup this
should essentially be instantaneous. The lock, as well as the code to
disable and enable table writes is removed.
A future improvement is to bypass the staging directory too, in which
case the reshaping compaction would already generate the view updates.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
When we are scanning an sstable directory, we want to filter out the
manifest file in most situations. The table class has a filter for that,
but it is a static filter that doesn't depend on table for anything. We
are better off removing it and putting in another independent location.
While it seems wasteful to use a new header just for that, this header
will soon be populated with the sstable_directory class.
Tests: unit (dev)
Signed-off-by: Glauber Costa <glauber@scylladb.com>
"
The new seastar api changes make_file_output_stream and
make_file_data_sink to return futures. This series includes a few
refactoring patches and the actual transition.
"
* 'espindola/api-v3-v3' of https://github.com/espindola/scylla:
table: Fix indentation
everywhere: Move to seastar api level 3
sstables: Pass an output_stream to make_compressed_file_.*_format_output_stream
sstables: Pass a data_sink to checksummed_file_writer's constructor
sstables: Convert a file_writer constructor to a static make
sstables: Move file_writer constructor out of line
After 7f1a215, a sstable is only added to backlog tracker if
sstable::shared() returns true.
sstable::shared() can return true for a sstable that is actually owned
by more than one shard, but it can also incorrectly return true for
a sstable which wasn't made explicitly unshared through set_unshared().
A recent work of mine is getting rid of set_unshared() because a
sstable has the knowledge to determine whether or not it's shared.
The problem starts with streaming sstable which hasn't set_unshared()
called for it, so it won't be added to backlog tracker, but it can
be eventually removed from the tracker when that sstable is compacted.
Also, it could happen that a shared sstable, which was resharded, will
be removed from the tracker even though it wasn't previously added.
When those problems happen, backlog tracker will have an incorrect
account of total bytes, which leads it to producing incorrect
backlogs that can potentially go negative.
These problems are fixed by making every add / removal go through
functions which take into account sstable::shared().
Fixes#6227.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20200512220226.134481-2-raphaelsc@scylladb.com>
New SStables are only added to backlog tracker if set_unshared() was
called on their behalf. SStables created for streaming are not being
added to the tracker because make_streaming_sstable_for_write()
doesn't call set_unshared() nor does it caller. Which results in backlog
not accounting for their existence, which means backlog will be much
lower than expected.
This problem could be fixed by adding a set_unshared() call but it
turns out we don't even need set_unshared() anymore. It was introduced
when Scylla metadata didn't exist, now a SSTable has built-in knowledge
of whether or not it's shared. Relying on every SSTable creator calling
set_unshared() is bug prone. Let's get rid of it and let the SStable
itself say whether or not it's shared. If an imported SSTable has not
Scylla metadata, Scylla will still be able to compute shards using
token range metadata.
Refs #6021.
Refs #6227.
Fixes#6441.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20200512220226.134481-1-raphaelsc@scylladb.com>
