The flat_mutation_reader files were conflated and contained multiple
readers, which were not strictly necessary. Splitting optimizes both
iterative compilation times, as touching rarely used readers doesn't
recompile large chunks of codebase. Total compilation times are also
improved, as the size of flat_mutation_reader.hh and
flat_mutation_reader_v2.hh have been reduced and those files are
included by many file in the codebase.
With changes
real 29m14.051s
user 168m39.071s
sys 5m13.443s
Without changes
real 30m36.203s
user 175m43.354s
sys 5m26.376s
Closes#10194
Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.
Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.
The changes we applied mechanically with a script, except to
licenses/README.md.
Closes#9937
As requested from field engineering, add a way to disable
the optimized TWCS query algorithm (use regular query path)
just in case a bug or a performance regression shows up in
production.
To disable the optimized query path, add
'enable_optimized_twcs_queries': 'false' to compaction strategy options,
e.g.
```
alter table ks.t with compaction =
{'class': 'TimeWindowCompactionStrategy',
'enable_optimized_twcs_queries': 'false'};
```
Setting the `enable_optimized_twcs_queries` key to anything other than
`'false'` (note: a boolean `false` expands to a string `'false'`) or
skipping it (re)enables the optimized query path.
Note: the flag can be set in a cluster in the middle of upgrade. Nodes
which do not understand it simply ignore it, but they do store it in
their schema tables (they store the entire `compaction` map). After
these nodes are upgraded, they will understand the flag and act
accordingly.
Note: in the situation above, some nodes may use the optimized path and
some may use the regular path. This may happen also in a fully upgraded
cluster when compaction options are changed concurrently to reads;
there is a short period of time where the schema change propagates and
some nodes got the flag but some didn't.
These should not be a problem since the optimization does not change the
returned read results (unless there is a bug).
Generally, the flag is not intended for normal use, but for field
engineers to disable it in case of a serious problem.
Ref #6418.
Closes#9900
Move replica-oriented classes to the replica namespace. The main
classes moved are ::database, ::keyspace, and ::table, but a few
ancillary classes are also moved. There are certainly classes that
should be moved but aren't (like distributed_loader) but we have
to start somewhere.
References are adjusted treewide. In many cases, it is obvious that
a call site should not access the replica (but the data_dictionary
instead), but that is left for separate work.
scylla-gdb.py is adjusted to look for both the new and old names.
The database, keyspace, and table classes represent the replica-only
part of the objects after which they are named. Reading from a table
doesn't give you the full data, just the replica's view, and it is not
consistent since reconciliation is applied on the coordinator.
As a first step in acknowledging this, move the related files to
a replica/ subdirectory.
Cannot be fully converted to flat_mutation_reader_v2 yet, as the
selector is built on combined_reader interface which is still not
converted. So only updated wherever possible.
Subsequent work will update sstable_set readers, which uses the
selector, to flat_mutation_reader_v2.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
sstable_set_impl::all() may have to copy all sstables from multiple
sets, if compound. let's avoid this overhead by using
sstable_set_impl::for_each_sstable().
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20211127181037.56542-1-raphaelsc@scylladb.com>
Add schema parameter so that:
* Caller has better control over schema -- especially relevant for
reverse reads where it is not possible to follow the convention of
passing the query schema which is reversed compared to that of the
mutations.
* Now that we don't depend on the mutations for the schema, we can lift
the restriction on mutations not being empty: this leads to safer
code. When the mutations parameter is empty, an empty reader is
created.
Add "make_" prefix to follow convention of similar reader factory
functions.
Tests: unit(dev)
Signed-off-by: Botond Dénes <bdenes@scylladb.com>
Message-Id: <20211115155614.363663-1-bdenes@scylladb.com>
Push down reversing to the mutation-sources proper, instead of doing it
on the querier level. This will allow us to test reverse reads on the
mutation source level.
The `max_size` parameter of `consume_page()` is now unused but is not
removed in this patch, it will be removed in a follow-up to reduce
churn.
`time_series_sstable_set` uses `clustering_combined_reader` to implement
efficient single-partition reads. It provides a `position_reader_queue`
to the reader. This queue returns readers to the sstables from the set
in order of the sstables' lower bounds, and with each reader it provides
an upper bound for the positions-in-partition returned by the reader.
Until now we would assume non-reversed queries only. Reversed queries
were implemented by performing forward query in the lower layers
and reversing the results at the upper-most layer of the reader stack.
Before pushing the reversing down to the sources (in particular,
to sstable readers), we need to support the reverse mode in
`time_series_sstable_set` and the queue it provides to
`clustering_combined_reader`.
This requires using different lower and upper bounds in the queue.
For non-reversed reads we used `sstable::min_position()` as the lower
bound and `sstable::max_position()` as the upper bound. For reversed
reads all comparisons performed by `clustering_combined_reader` will be
reversed, as it will use a reversed schema. We can then use
`sstable::max_position().reversed()` for the lower bound and
`sstable::min_position().reversed()` for the upper bound.
Get rid of unused includes of seastar/util/{defer,closeable}.hh
and add a few that are missing from source files.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Rename the old version to `sstables::make_reader_v1()`, to have a
nicely searcheable eradication target.
Signed-off-by: Michael Livshin <michael.livshin@scylladb.com>
When perfing cleanup, merging reader showed up as significant.
Given that cleanup is performed on a single sstable at a time,
merging reader becomes an extra layer doing useless work.
1.71% 1.71% scylla scylla [.] merging_reader<mutation_reader_merger>::fill_buffer(std::chrono::time_point<seastar::lowres_clock, std::chrono::duration<long, std::ratio<1l, 1000l> > >)::{lambda()#1}::operator()
mutation compactor, to get rid of purgeable expired data
and so on, still consumes the data retrieved by sstable
reader, so no semantic change is done.
With the overhead removed, cleanup becomes ~9% faster, see:
BEFORE
real 1m15.240s
user 0m2.648s
sys 0m0.128s
240MB to 237MB (~98% of original) in 3301ms = 71MB/s.
719MB to 719MB (~99% of original) in 9761ms = 73MB/s.
1GB to 1GB (~100% of original) in 15372ms = 73MB/s.
1GB to 1GB (~100% of original) in 15343ms = 74MB/s.
1GB to 1GB (~100% of original) in 15329ms = 74MB/s.
1GB to 1GB (~100% of original) in 15360ms = 73MB/s.
AFTER
real 1m9.154s
user 0m2.428s
sys 0m0.123s
240MB to 237MB (~98% of original) in 3010ms = 78MB/s.
719MB to 719MB (~99% of original) in 8997ms = 79MB/s.
1GB to 1GB (~100% of original) in 14114ms = 80MB/s.
1GB to 1GB (~100% of original) in 14145ms = 80MB/s.
1GB to 1GB (~100% of original) in 14106ms = 80MB/s.
1GB to 1GB (~100% of original) in 14053ms = 80MB/s.
With 1TB set, ~20m would had been reduced instead.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20210730190713.462135-1-raphaelsc@scylladb.com>
Since compaction is layered on top of sstables, let's move all compaction code
into a new top-level directory.
This change will give me extra motivation to remove all layer violations, like
sstable calling compaction-specific code, and compaction entanglement with
other components like table and storage service.
Next steps:
- remove all layer violations
- move compaction code in sstables namespace into a new one for compaction.
- move compaction unit tests into its own file
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20210707194058.87060-1-raphaelsc@scylladb.com>
Incremental selection may not work properly for LCS and ICS due to an
use-after-free bug in partitioned set which came into existence after
compound set was introduced.
The use-after-free happens because partitioned set wasn't taking into
account that the next position can become the current position in the
next iteration, which will be used by all selectors managed by
compound set. So if next position is freed, when it were being used
as current position, subsequent selectors would find the current
position freed, making them produce incorrect results.
Fix this by moving ownership of next pos from incremental_selector_impl
to incremental_selector, which makes it more robust as the latter knows
better when the selection is done with the next pos. incremental_selector
will still return ring_position_view to avoid copies.
Fixes#8802.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20210611130957.156712-1-raphaelsc@scylladb.com>
Compound set's incremental selector isn't needed when only one set
contains sstables, which is the common case because secondary set
will only contain data during maintenance operations.
From now on, if only primary set contains data, its selector will
be built directly without compound set's selector acting as an
interposer.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20210607193651.126937-1-raphaelsc@scylladb.com>
Clang warns when "return std::move(x)" is needed to elide a copy,
but the call to std::move() is missing. We disabled the warning during
the migration to clang. This patch re-enables the warning and fixes
the places it points out, usually by adding std::move() and in one
place by converting the returned variable from a reference to a local,
so normal copy elision can take place.
Closes#8739
This function will be reused by TWCS reshape when checking if all
sstables in a window are disjoint and can be all compacted together.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
When a particular partition exists in at least one sstable, the cache
expects any single-partition query to this partition to return a `partition_start`
fragment, even if the result is empty.
In `time_series_sstable_set::create_single_key_sstable_reader` it could
happen that all sstables containing data for the given query get
filtered out and only sstables without the relevant partition are left,
resulting in a reader which immediately returns end-of-stream (while it
should return a `partition_start` and if not in forwarding mode, a
`partition_end`). This commit fixes that.
We do it by extending the reader queue (used by the clustering reader
merger) with a `dummy_reader` which will be returned by the queue as
the very first reader. This reader only emits a `partition_start` and,
if not in forwarding mode, a `partition_end` fragment.
Fixes#8447.
Closes#8448
Procedure is rewritten using std::partition, making it easier to
maintain and it also fixes a theoretical quadratic behavior because
list is entirely copied when extending it, which isn't harmful
because maintenance set will be rarely populated and there are only
2 sets at most.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20210409171412.57729-1-raphaelsc@scylladb.com>
The filter passed to `min_position_reader_queue`, which was used by
`clustering_order_reader_merger`, would incorrectly include sstables as
soon as they passed through the PK (bloom) filter, and would include
sstables which didn't pass the PK filter (if they passed the CK
filter). Fortunately this wouldn't cause incorrect data to be returned,
but it would cause sstables to be opened unnecessarily (these sstables
would immediately return eof), resulting in a performance drop. This commit
fixes the filter and adds a regression test which uses statistics to
check how many times the CK filter was invoked.
Fixes#8432.
Closes#8433
compound set isn't overriding create_single_key_sstable_reader(), so
default implementation is always called. Although default impl will
provide correct behavior, specialized ones which provides better perf,
which currently is only available for TWCS, were being ignored.
compound set impl of single key reader will basically combine single key
readers of all sets managed by it.
Fixes#8415.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20210406205009.75020-1-raphaelsc@scylladb.com>
This new sstable set implementation is useful for combining operation of
multiple sstable sets, which can still be referenced individually via
its shared ptr reference.
It will be used when maintenance set is introduced in table, so a
compound set is required to allow both sets to have their operations
efficiently combined.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
The existing implementation wrongfully shares _all sstables
rather than cloning it. This caused a use-after-free
in `repair_meta::do_estimate_partitions_on_local_shard`
when traversing a shared sstable_set, during which
`table::make_reader_excluding_sstables` erased an entry.
The erase should have happened on a cloned copy
of the sstable_list, not on a shared copy.
The regression was introduced in
c3b8757fa1.
Added a unit test that reproduces the share-on-copy issue
for partitioned_stable_set (sstables::sstable_set).
Fixes#8274
Test: unit(release, debug)
DTest: materialized_views_test.py:TestMaterializedViews.simple_repair_test(debug)
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Reviewed-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20210317145552.701559-1-bhalevy@scylladb.com>
compound set will select runs from all of its managed sets, so let's
adjust select_sstable_runs() to only return runs which belong to it.
without this adjustment, selection of runs would fail because
function would try to unconditionally retrieve the run which may
live somewhere else.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20210312042255.111060-3-raphaelsc@scylladb.com>
after compound set is introduced, select_sstable_runs() will no longer
work because the sstable runs live in sstable_set, but they should
actually live in the sstable_set being written to.
Given that runs is a concept that belongs only to strategies which
use partitioned_sstable_set, let's move the implementation of
select_sstable_runs() to it.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20210312042255.111060-2-raphaelsc@scylladb.com>
