We add a test that validates that indexed queries
do not throw a warning related to vector search paging
Fixes: SCYLLADB-248
Closesscylladb/scylladb#28077
The PRUNE MATERALIZED VIEW statement is performed as follows:
1. Perform a range scan of the view table from the view replicas based
on the ranges specified in the statement.
2. While reading the paged scan above, for each view row perform a read
from all base replicas at the corresponding primary key. If a discrepancy
is detected, delete the row in the view table.
When reading multiple rows, this is very slow because for each view row
we need to performe a single row query on multiple replicas.
In this patch we add an option to speed this up by performing many of the
single base row reads concurrently, at the concurrency specified in the
USING CONCURRENCY clause.
Aside from the unit test, I checked manually on a 3-node cluster with 10M rows, using vnodes. There were actually no ghost rows in the test, but we still had to iterate over all view rows and read the corresponding base rows. And actual ghost rows, if there are any, should be a tiny fraction of all rows. I compared concurrencies 1,2,10,100 and the results were:
* Pruning with concurrency 1 took total 1416 seconds
* Pruning with concurrency 2 took total 731 seconds
* Pruning with concurrency 10 took total 234 seconds
* Pruning with concurrency 100 took total 171 seconds
So after a concurrency of 10 or so we're hitting diminishing returns (at least in this setup). At that point we may be no longer bottlenecked by the reads, but by CPU on the shard that's handling the PRUNE
Fixes https://github.com/scylladb/scylladb/issues/27070Closesscylladb/scylladb#27097
* github.com:scylladb/scylladb:
mv: allow setting concurrency in PRUNE MATERIALIZED VIEW
cql: add CONCURRENCY to the USING clause
And switch to std::source_location.
Upcoming seastar update will deprecate its compatibility layer.
The patch is
for f in $(git grep -l 'seastar::compat::source_location'); do
sed -e 's/seastar::compat::source_location/std::source_location/g' -i $f;
done
and removal of few header includes.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Closesscylladb/scylladb#27309
The PRUNE MATERALIZED VIEW statement is performed as follows:
1. Perform a range scan of the view table from the view replicas based
on the ranges specified in the statement.
2. While reading the paged scan above, for each view row perform a read
from all base replicas at the corresponding primary key. If a discrepancy
is detected, delete the row in the view table.
When reading multiple rows, this is very slow because for each view row
we need to performe a single row query on multiple replicas.
In this patch we add an option to speed this up by performing many of the
single base row reads concurrently, at the concurrency specified in the
USING CONCURRENCY clause.
Fixes https://github.com/scylladb/scylladb/issues/27070
In some uses of SELECT, such as aggregation (sum() et al.), GROUP BY or
secondary index, it needs to perform internal scans. It uses an "internal
page size" which before this patch was always DEFAULT_COUNT_PAGE_SIZE = 10000.
There was an ad-hoc and undocumented way to override this default in C++
tests, using functions in test/lib/select_statement_utils.hh, but it
was so non-obvious that the test that most needed to override this
default - the very slow test test_indexing_paging_and_aggregation which
would have been must faster with a lower setting - never used it.
So in this patch we replace the ad-hoc configuration functions by a
bona-fide Scylla configuration option named "select_internal_page_size".
The few C++ tests that used the old configuration functions were
modified to use the new configuration parameters. The slow test
test_indexing_paging_and_aggregation still doesn't use the new
configuration to become faster - we'll do this in the next patch.
Another benefit of having this "internal page size" as a configuration
option is that one day a user might realize that the default choice
10,000 is bad for some reason (which I can't envision right now), so
having it configurable might come it handy.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
The Boost test test_indexing_paging_and_aggregation is one of the slowest
boost tests. But it's hard to understand why it needs to be so slow - the
C++ test code is opaque, and uncommented. The test didn't need to be in
C++ - it only uses CQL, not any internal interfaces - but it was written
in 2019, a year before test/cqlpy was created.
So before we can make this test faster, this patch translates it to
Python and adds significant amount of comments. The new Python test is
functionally identical to the old C++ test - it is not (yet) made
smaller or faster. The new test takes a whopping 9 seconds to run on
my laptop (in dev build mode). We'll reduce that in the next patch.
As usual, the cqlpy test can also be tested on Cassandra, and
unsurprisingly, it passes.
Refs #16134 (which asks to translate more MV and SI tests to Python).
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
The PRUNE MATERIALIZED VIEW statement is supposed to remove ghost rows from the
view. Ghost rows are rows in the view with no corresponding row in the base table.
Before this patch, only rows whose primary key columns of the base table had
different values than any of the base rows were treated as ghost rows by the PRUNE
statement. However, view rows which have a column in their primary key that's not
in the base primary can also be ghost rows if this column has a different value
than the base row with the same values of remaining primary key columns. That's
because these rows won't be deleted unless we change value of this column in the
base table to this specific value.
In this patch we add a check for this column in the PRUNE MATERIALIZED VIEW logic.
If this column isn't the same in the base table and the view, these rows are also
deleted.
Fixes https://github.com/scylladb/scylladb/issues/25655Closesscylladb/scylladb#25720
Added function returning custom index class name.
Added printing custom index class name when using DESCRIBE.
Changed validation to reflect current support of indices.
The partition range vector is an std::vector, which means it performs
contiguous allocations. Large allocations are known to cause problems
(e.g., reactor stalls).
For paged queries, limit the vector size to 1000. If more partition keys
are available in the query result, discard them. Ideally, we should not
be fetching them at all, but this is not possible without knowing the
size of each partition.
Currently, each vector element is 120 bytes and the standard allocator's
max preferred contiguous allocation is 128KiB. Therefore, the chosen
value of 1000 satisfies the constraint (128 KiB / 120 = 1092 > 1000).
This should be good enough for most cases. Since secondary index queries
involve one base table query per partition key, these queries are slow.
A higher limit would only make them slower and increase the probability
of a timeout. For the same reason, saving a follow-up paged request from
the client would not increase the efficiency much.
For unpaged queries, do not apply any limit. This means they remain
susceptible to stalls, but unpaged queries are considered unoptimized
anyway.
Finally, update the unit test reproducer since the bug is now fixed.
Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>
Secondary index queries which fetch partitions from the base table can
cause large allocations that can lead to reactor stalls.
Reproduce this with a unit test that runs an indexed query on a table
with thousands of single-row partitions, and checks the memory stats for
any large contiguous allocations.
Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>
To reduce test executable size and speed up compilation time, compile unit
tests into a single executable.
Here is a file size comparison of the unit test executable:
- Before applying the patch
$ du -h --exclude='*.o' --exclude='*.o.d' build/release/test/boost/ build/debug/test/boost/
11G build/release/test/boost/
29G build/debug/test/boost/
- After applying the patch
du -h --exclude='*.o' --exclude='*.o.d' build/release/test/boost/ build/debug/test/boost/
5.5G build/release/test/boost/
19G build/debug/test/boost/
It reduces executable sizes 5.5GB on release, and 10GB on debug.
Closes#9155Closesscylladb/scylladb#21443
Modernize the codebase by replacing Boost range adaptors with C++23 standard library views,
reducing external dependencies and leveraging modern C++ language features.
Key Changes:
- Replace `boost::adaptors::filtered` with `std::views::filter`
- Remove `#include <boost/range/adaptor/filtered.hpp>`
- Utilize standard library range views
Motivation:
- Reduce project's external dependency footprint
- Leverage standard library's range and view capabilities
- Improve long-term code maintainability
- Align with modern C++ best practices
Implementation Challenges and Considerations:
1. Range Conversion and Move Semantics
- `std::ranges::to` adaptor requires rvalue references
- Necessitated updates to variable and parameter constness
- Example: `cql3/restrictions/statement_restrictions.cc` modified to remove `const`
from `common` to enable efficient range conversion
2. Range Iteration and Mutation
- Range views may mutate internal state during iteration
- Cannot pass ranges by const reference in some scenarios
- Solution: Pass ranges by rvalue reference to explicitly indicate
state invalidation
Limitations:
- One instance of `boost::adaptors::filtered` temporarily preserved
due to lack of a C++23 alternative for `boost::join()`
- A comprehensive replacement will be addressed in a follow-up change
This change is part of our ongoing effort to modernize the codebase,
reducing external dependencies and adopting modern C++ practices.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#21648
Reproduces scylladb/scylladb#20772.
Add error injection to `raft_server_with_timeouts::read_barrier`,
which does 1s sleep before doing the read barrier.
assert() is traditionally disabled in release builds, but not in
scylladb. This hasn't caused problems so far, but the latest abseil
release includes a commit [1] that causes a 1000 insn/op regression when
NDEBUG is not defined.
Clearly, we must move towards a build system where NDEBUG is defined in
release builds. But we can't just define it blindly without vetting
all the assert() calls, as some were written with the expectation that
they are enabled in release mode.
To solve the conundrum, change all assert() calls to a new SCYLLA_ASSERT()
macro in utils/assert.hh. This macro is always defined and is not conditional
on NDEBUG, so we can later (after vetting Seastar) enable NDEBUG in release
mode.
[1] 66ef711d68Closesscylladb/scylladb#20006
get0() dates back from the days where Seastar futures carried tuples, and
get0() was a way to get the first (and usually only) element. Now
it's a distraction, and Seastar is likely to deprecate and remove it.
Replace with seastar::future::get(), which does the same thing.
Fixes some typos as found by codespell run on the code.
In this commit, I was hoping to fix only comments, not user-visible alerts, output, etc.
Follow-up commits will take care of them.
Refs: https://github.com/scylladb/scylladb/issues/16255
Signed-off-by: Yaniv Kaul <yaniv.kaul@scylladb.com>
dht::shard_of() does not use the correct sharder for tablet-based tables.
Code which is supposed to work with all kinds of tables should use erm::get_sharder().
Secondary index creation is asynchronous, meaning it
takes time for existing data to be reflected within
the index. However, new data added after the
index is created should appear in it immediately.
The test consisted of two parts. The first created
a series of indexes for one table, added
test data to the table, and then ran a series of checks.
In the second part, several new indexes were added to
the same table, and checks were made to make sure that
already existing data would appear in them. This
last part was flaky.
The patch just moves the index creation statements
from the second part to the first.
Fixes: #14076Closes#14090
CWG 2631 (https://cplusplus.github.io/CWG/issues/2631.html) reports
an issue on how the default argument is evaluated. this problem is
more obvious when it comes to how `std::source_location::current()`
is evaluated as a default argument. but not all compilers have the
same behavior, see https://godbolt.org/z/PK865KdG4.
notebaly, clang-15 evaluates the default argument at the callee
site. so we need to check the capability of compiler and fall back
to the one defined by util/source_location-compat.hh if the compiler
suffers from CWG 2631. and clang-16 implemented CWG2631 in
https://reviews.llvm.org/D136554. But unfortunately, this change
was not backported to clang-15.
before switching over to clang-16, for using std::source_location::current()
as the default parameter and expect the behavior defined by CWG2631,
we have to use the compatible layer provided by Seastar. otherwise
we always end up having the source_location at the callee side, which
is not interesting under most circumstances.
so in this change, all places using the idiom of passing
std::source_location::current() as the default parameter are changed
to use seastar::compat::source_location::current(). despite that
we have `#include "seastarx.h"` for opening the seastar namespace,
to disambiguate the "namespace compat" defined somewhere in scylladb,
the fully qualified name of
`seastar::compat::source_location::current()` is used.
see also 09a3c63345, where we used
std::source_location as an alias of std::experimental::source_location
if it was available. but this does not apply to the settings of our
current toolchain, where we have GCC-12 and Clang-15.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closes#14086
these warnings are found by Clang-17 after removing
`-Wno-unused-lambda-capture` and '-Wno-unused-variable' from
the list of disabled warnings in `configure.py`.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
We have enabled the command line options without changing a
single line of code, we only had to replace old include
with scylla_test_case.hh.
Next step is to add x-log-compaction-groups options, which will
determine the number of compaction groups to be used by all
instantiations of replica::table.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
The former allows for expressing more positions, like a position
before/after a clustering key. This practically enables the coordinator
side paging logic, for a query to be stopped at a tombstone (which can
have said positions).
The tests checks if manually injected ghost rows are properly deleted
by the ghost row delete statement - and, that non-ghost regular rows
are left intact.
In CQL, table names are limited to so-called word characters (letters,
numbers and underscores), but column names don't have such a limitation.
When we create a secondary index, its default name is constructed from
the column name - so can contain problematic characters. It can include
even the "/" character. The problem is that the index name is then used,
like a table name, to create a directory with that name.
The test included in this patch demonstrates that before this patch, this
can be misused to create subdirectories anywhere in the filesystem, or to
crash Scylla when it fails to create a directory (which it considers an
unrecoverable I/O error).
In this patch we do what Cassandra does - remove all non-word
characters from the indexed column name before constructing the default
index name. In the included test - which can run on both Scylla and
Cassandra - we verify that the constructed index name is the same as
in Cassandra, which is useful to know (e.g., because knowing the index
name is needed to DROP the index).
Also, this patch adds a second line of defense against the security problem
described above: It is now an error to create a schema with a slash or
null (the two characters not allowed in Unix filenames) in the keyspace
or table names. So if the first line of defense (CQL checking the validity
of its commands) fails, we'll have that second line of defense. I verified
that if I revert the default-index-name fix, the second line of defense
kicks in, and the index creation is aborted and cannot create files in
the wrong place to crash Scylla.
Fixes#3403
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20220320162543.3091121-1-nyh@scylladb.com>
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
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.
Prepare for the upcoming strict ALLOW FILTERING check by modifying
unit-test queries that need it. Current code allows such queries both
with and without ALLOW FILTERING; future code will reject them without
ALLOW FILTERING.
Signed-off-by: Dejan Mircevski <dejan@scylladb.com>
Add tests of SELECTs with TOKEN clauses on tables with secondary
indexes (both global and local).
test_select_with_token_range_cases checks all possible token range
combinations (inclusive/exclusive/infinity start/end) on tables without
index, with local or with global index.
test_select_with_token_range_filtering checks whether TOKEN restrictions
combined with column restrictions work properly. As different code paths
are taken if index is created on clustering key (first or non-first) or
non-primary-key column, the tests checks scenarios when index is created
on different columns.
Extract test data to a separate variables, allowing it to be easily
reused by other tests. The tokens are hard-coded, because calculating
their value brought too much complexity to this code.
Timeout config is now stored in each connection, so there's no point
in tracking it inside each query as well. This patch removes
timeout_config from query_options and follows by removing now
unnecessary parameters of many functions and constructors.
Previously, single_column_restrictions::value_for() assumed that a
column's restriction specifies exactly one value for the column. But
since 37ebe521e3, multiple equalities on the same column are allowed,
so the restriction could be a conjunction of conflicting
equalities (eg, c=1 AND c=0). That violates an assert and crashes
Scylla.
This patch fixes value_for() by gracefully handling the
impossible-restriction case.
Fixes#7772
Signed-off-by: Dejan Mircevski <dejan@scylladb.com>
Previously, statement_restrictions::find_idx() would happily return an
index for a non-EQ restriction (because it checked only the column
name, not the operator). This is incorrect: when the selected index
is for a non-EQ restriction, it is impossible to query that index
table.
Fixes#7659.
Tests: unit (dev)
Signed-off-by: Dejan Mircevski <dejan@scylladb.com>
Closes#7665
The downstream code expects a single-column restriction when using an
index. We could fix it, but we'd still have to filter the rows
fetched from the index table, unlike the code that queries the base
table directly. For instance, WHERE (c1,c2,c3) = (1,2,3) with an
index on c3 can fetch just the right rows from the base table but all
the c3=3 rows from the index table.
Fixes#7680
Signed-off-by: Dejan Mircevski <dejan@scylladb.com>
I noticed that we require filtering for continuous clustering key, which is not necessary. I dropped the requirement and made sure the correct data is read from the storage proxy.
The corresponding dtest PR: https://github.com/scylladb/scylla-dtest/pull/1727
Tests: unit (dev,debug), dtest (next-gating, cql*py)
Closes#7460
* github.com:scylladb/scylla:
cql3: Delete some newlines
cql3: Drop superfluous ALLOW FILTERING
cql3: Drop unneeded filtering for continuous CK
Add new test validating that rows returned from both non-indexed selects
and indexed selects return rows sorted in token order (making sure
that both positive and negative tokens are present to test if signed
comparison order is maintained).
Raname token_column_computation to legacy_token_column_computation, as
it will be replaced with new column_computation. The reason is that this
computation returns bytes, but all tokens in Scylla can now be
represented by int64_t. Moreover, returning bytes causes invalid token
ordering as bytes comparison is done in unsigned way (not signed as
int64_t). See issue:
https://github.com/scylladb/scylla/issues/7443
Add additional comments to select_statement_utils, fix formatting, add
missing #pragma once and introduce set_internal_paging_size_guard to
set internal_paging in RAII fashion.
Closes#7507
